INTRODUCTION — Due to advances in technology in electrophysiology (EP), interventional cardiology, and transesophageal echocardiography (TEE) technology, complex interventional procedures that may require anesthesia care are usually performed in these specialized settings remote from the main operating rooms. Many patients requiring such procedures have severe cardiovascular disease or pulmonary comorbidity; thus, they are at high risk for oversedation and hemodynamic instability. Even relatively healthy patients may not tolerate remaining motionless during prolonged or painful interventional procedures. For these reasons, the number of cases that require monitored anesthesia care (MAC) or general anesthesia in these off-site settings has increased (eg, >50 percent of EP cases [1]). Given the special considerations and growing need, some institutions have a subspecialized anesthesia team dedicated to these settings.

This topic will review anesthetic management of adult patients undergoing procedures in EP, interventional cardiology, and TEE suites. Anesthetic considerations in other off-site settings (eg, magnetic resonance imaging [MRI], computed tomography [CT], gastrointestinal endoscopy) are reviewed in other topics. (See "Anesthesia for magnetic resonance imaging and computed tomography procedures" and "Anesthesia for gastrointestinal endoscopy in adults".)

PREANESTHESIA PLANNING — Multiple factors affect the selection of anesthetic technique, dosing of anesthetic and adjuvant agents, and whether invasive monitoring will be employed for electrophysiology (EP), interventional cardiology, or transesophageal echocardiography (TEE) procedures. Unique patient- or procedure-related considerations are discussed in advance with members of the interventional team [2]. (See "Safety in the operating room", section on 'Briefings'.)

Anesthetic challenges in off-site locations — Typically, EP, interventional cardiology, and TEE suites are remote from the main operating room (OR) area. Challenges for anesthesiologists in such off-site locations often include lack of standard anesthesia machines, monitors, supplies, or scavenging equipment for anesthetic gases. Additional time is required for transport of necessary items from a distant OR location, and subsequent setup and positioning of all equipment in the off-site location. Ensuring availability of well-located portable shields, lead aprons, thyroid collars, and eye protection for all anesthesia personnel is necessary for procedures with radiation risks. Another challenge is interdisciplinary communication, which may be hindered by lack of familiarity with the procedures and techniques planned by each specialist. Further discussion of challenges in remote locations is available elsewhere. (See "Anesthesia for magnetic resonance imaging and computed tomography procedures", section on 'Anesthetic challenges in remote locations' and "Anesthesia for magnetic resonance imaging and computed tomography procedures", section on 'Radiation risks'.)

Patient and procedure-related considerations — The following factors should be considered:

●Cardiovascular pathology for which the procedure is being performed influences anesthetic management. In particular, arrhythmias, acute coronary syndrome, cardiomyopathy, valvular heart disease, or presence of a cardiac implantable electronic device may affect anesthetic care and risk of complications. Details are explained in separate topics:

•(See "Anesthesia for noncardiac surgery in patients with ischemic heart disease".)

•(See "Intraoperative management for noncardiac surgery in patients with heart failure".)

•(See "Anesthesia for noncardiac surgery in patients with aortic or mitral valve disease".)

•(See "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator".)

●Comorbid conditions (eg, obstructive sleep apnea [OSA], morbid obesity, chronic obstructive pulmonary disease [COPD], pulmonary hypertension with right heart dysfunction) may cause respiratory or hemodynamic compromise during sedation or general anesthesia. Anesthetic considerations for patients with these comorbidities are discussed in separate topics:

•(See "Intraoperative management of adults with obstructive sleep apnea".)

•(See "Anesthesia for the patient with obesity".)

•(See "Anesthesia for patients with chronic obstructive pulmonary disease".)

•(See "Anesthesia for adults with congenital heart disease undergoing noncardiac surgery", section on 'Pulmonary arterial hypertension'.)

●Older patients and those with renal or hepatic insufficiency typically require dosing adjustments of anesthetic agents, as discussed in other topics:

•(See "Anesthesia for the older adult", section on 'Selection and dosing of anesthetic agents'.)

•(See "Anesthesia for dialysis patients", section on 'Intraoperative anesthetic management'.)

•(See "Anesthesia for the patient with liver disease", section on 'Effects of liver disease on anesthetic drug administration'.)

●Patients with preexisting renal insufficiency are at increased risk for developing acute kidney injury, particularly if intravenous (IV) contrast media is used during the procedure. Prevention is reviewed separately. (See "Prevention of contrast-associated acute kidney injury related to angiography".)

●Risks for an allergic reaction are assessed, including history of prior allergic reaction to iodinated contrast agents or to protamine [3,4]. Preoperative steps to reduce or mitigate severity of allergic reactions include premedication with corticosteroids and H1 antihistamines (table 1), as well as use of a nonionic contrast agent if feasible. (See "Complications of diagnostic cardiac catheterization", section on 'Allergic reactions'.)

●Expected duration of the procedure may affect choice of anesthetic technique. (See 'Selection of anesthetic technique' below.)

●If use of radiation is planned, precautions are employed to minimize radiation risks for all patients and anesthesia personnel. A pregnancy test is obtained on the morning of the procedure for any woman of childbearing capacity. (See "Anesthesia for magnetic resonance imaging and computed tomography procedures", section on 'Radiation risks'.)

●If phrenic nerve stimulation is planned (eg, for cryoballoon ablation), complete resolution of neuromuscular blockade must be confirmed by standard peripheral nerve stimulation monitoring. (See 'Ablation of cardiac arrhythmias' below.)

●Specific requirements for the imaging procedure may impose cardiorespiratory challenges. These include:

•Requirement for frequent periods of apnea or jet ventilation. (See 'General anesthesia with conventional ventilation' below and 'General anesthesia with jet ventilation' below.)

•Anticipated periods of hemodynamic instability (eg, induced arrhythmias during an EP procedure, temporary coronary occlusion during an interventional cardiology procedure). (See 'Ventricular arrhythmias' below and 'Procedures for cardiac implantable electronic devices' below.)

●Preoperative type and screen testing may be completed for procedures with risk for retroperitoneal or other bleeding complications (eg, ablation procedures for atrial fibrillation [AF] or ventricular fibrillation). (See "Periprocedural complications of percutaneous coronary intervention", section on 'Retroperitoneal bleeding' and "Atrial fibrillation: Catheter ablation", section on 'Vascular complications'.)

●Preparation for possible emergencies may obviate the need for a standard "code team" response for anesthetic-related respiratory or cardiac arrest. As in the operating room, these events may be managed most appropriately by the anesthesiology and cardiology teams performing the procedures. (See "Anesthesia for magnetic resonance imaging and computed tomography procedures", section on 'Cardiopulmonary resuscitation'.)

●The location for patient recovery from anesthesia is determined in advance (eg, interventional suite recovery area, post-anesthesia care unit, intensive care unit) since this may be affected by factors such as post-procedure care requirements and recovery bed availability.

Management of preoperative medications — For procedures in the interventional cardiology or TEE suites, doses of chronically administered cardiovascular medications (eg, beta blockers, statins, aspirin) are typically administered at their usual times before an interventional procedure. (See "Perioperative medication management".)

Timing of the most recent doses of anticoagulant or antiplatelet medications should be discussed with the interventional cardiology team since these agents increase risk for bleeding during EP and other interventional procedures. However, many patients undergoing EP procedures require ongoing anticoagulation to prevent periprocedural thrombus formation, similar to patients undergoing cardioversion of AF [5]. Outpatients should receive instructions for periprocedural anticoagulant dosing from the interventional team. These instructions vary depending on the planned procedure, patient specific factors, and institutional preferences. If there is uncertainty about the patient's anticoagulation status when he/she arrives for the procedure, coagulation tests are obtained (eg, prothrombin time [PT] and international normalized ratio [INR]) to determine whether the procedure should be rescheduled.

Antiarrhythmic medications that affect atrioventricular (AV) node conduction (eg, calcium channel blockers, digoxin (table 2)) are typically discontinued several days prior to a scheduled invasive EP procedure [5]; however, beta blockers may be gradually tapered. Patients should receive specific instructions from the EP team regarding their antiarrhythmic medications and are queried about the timing of their most recent doses shortly before the procedure. Discussion with the electrophysiologist is necessary when there is uncertainty regarding these instructions and/or the patient's compliance. (See "Invasive diagnostic cardiac electrophysiology studies", section on 'Preprocedural evaluation'.)

Selection of anesthetic technique — For interventional procedures in the EP, interventional cardiology, or TEE suite that are not likely to have a prolonged duration or result in hemodynamic instability, minimal or moderate sedation is often performed by credentialed nursing staff and interventional cardiologists, without the presence of an anesthesiologist (table 3) [6]. (See "Procedural sedation in adults outside the operating room".)

The interventional team should consult anesthesia personnel to determine what type of anesthetic care is necessary in certain patients. For example, moderate sedation may be inadequate in severely anxious patients, and deep sedation may be challenging or hazardous in patients with morbid obesity or difficult airways. Anesthesiologist-provided deep sedation or general endotracheal anesthesia may be safer in such patients. General anesthesia might also be requested by the interventional team if the planned procedure would be compromised by patient movement, is likely to be prolonged, or if endotracheal intubation is necessary due to limited airway access or requirement for TEE monitoring during the procedure.

ELECTROPHYSIOLOGY PROCEDURES — During administration of sedatives, opioids, or other anesthetic agents for monitored anesthesia care (MAC) or general anesthesia, monitoring always includes standard American Society of Anesthesiologists (ASA) monitors, with pulse oximetry and capnography to ensure that hypoxia or apnea is avoided (table 4) [7,8]. (See "Monitored anesthesia care in adults", section on 'Standard physiologic monitors' and "Induction of general anesthesia: Overview", section on 'Preparation for anesthetic induction'.)

Monitored anesthesia care — Anesthesia personnel may be consulted to provide monitored anesthesia care (MAC) in selected patients (table 3). (See 'Selection of anesthetic technique' above.).

Several sedative and/or opioid agents may be employed by anesthesia personnel to provide moderate or deep sedation as needed. Typically, a propofol infusion is titrated at 25 to 75 mcg/kg per minute, with or without an initial propofol bolus. An opioid may be added, typically remifentanil 0.025 to 0.1 mcg/kg per minute. Another common option is dexmedetomidine, which produces sedation with minimal respiratory changes [9,10]. Alternative regimens include combinations of other sedative and analgesic agents (eg, ketamine, midazolam, or other opioids, such as fentanyl) [11,12]. Agents and dosing are discussed in a separate topic. (See "Monitored anesthesia care in adults", section on 'Drugs used for sedation and analgesia for monitored anesthesia care'.)

If the electrophysiologist requests minimal sedation so that catecholamine-mediated arrhythmias may be readily elicited, we use the lowest dose ranges of previously prepared infusions of sedative and analgesic agents, or small bolus doses of midazolam (0.5 to 2 mg) and/or fentanyl (50 to 100 mcg).

Supplemental oxygen may be administered by face mask as needed to keep oxygen saturation within normal limits. Standard precautions are employed to minimize risk of a fire, particularly if the oxygen source and the patient's face are covered under the surgical drapes [13]. (See "Fire safety in the operating room".)

General anesthesia with conventional ventilation

Preparation and induction — If general anesthesia is requested, adequate intravenous (IV) access is critical since the patient's arms are typically tucked at the sides and inaccessible during the procedure. In most cases, a second peripheral IV catheter is inserted before or shortly after induction of general anesthesia so that multiple drugs or infusions can be administered.

An intra-arterial catheter is inserted in selected patients with high cardiovascular risk (eg, very low ejection fraction, arrhythmias with a ventricular response too rapid for accurate monitoring with a blood pressure cuff, hemodynamic instability) or when multiple blood samples are required to monitor anticoagulation or arterial blood gases [5]. As backup in an emergency, the femoral intravascular sheaths inserted by the electrophysiologist can be accessed.

Selection of induction agents and techniques for induction of general anesthesia depends on the patient's comorbidities. Options are discussed elsewhere (see "Induction of general anesthesia: Overview", section on 'Selection of induction technique'). A neuromuscular blocking agent (NMBA) may be administered to facilitate endotracheal intubation, but long-acting agents are avoided if phrenic nerve stimulation is planned (eg, during cryoablation) (table 5). (See 'Ablation of cardiac arrhythmias' below.)

In selected patients, transesophageal echocardiography (TEE) examination may be performed before beginning the EP procedure, with particular attention to the left atrial (LA) appendage, in order to ensure absence of intracardiac thrombus and thereby reduce stroke risk. If intracardiac thrombus is detected, the procedure is cancelled and rescheduled. For this reason, if suspicion for thrombus is high, TEE may be performed the day before the procedure or prior to induction of general anesthesia. If a TEE examination is to be performed immediately after induction, short-acting anesthetics and NMBAs are selected, so that rapid awakening can be achieved if thrombus is detected (table 5). An alternative technique is performance of the TEE examination during general anesthesia with a laryngeal mask airway (LMA) rather than an endotracheal tube (ETT), thereby avoiding the need to place an ETT in selected patients, as well as avoiding the need to administer an NMBA and reducing the doses of anesthetic agents during the ablation procedure [14]. When this technique is chosen, the TEE probe is placed prior to LMA insertion.

After removal of the TEE probe, an esophageal temperature probe is inserted orally. Insertion of the temperature probe via the nasal route is avoided, particularly if the patient received a recent dose of an anticoagulant agent, due to the possibility of significant nasal bleeding. In selected cases, the electrophysiologist will subsequently direct precise positioning of the esophageal probe using fluoroscopy to facilitate optimal monitoring of esophageal temperature (eg, to avoid thermal injury during radiofrequency ablation in the posterior LA near the esophagus). (See 'Ablation of cardiac arrhythmias' below.)

Maintenance — General anesthesia may be maintained with a technique that employs either inhalation or IV anesthetics as the primary agents, or a combination of agents administered by both routes [5]. Although many anesthetics cause mild prolongation of the QT interval (>440 ms) or slight depression of sinoatrial (SA) or atrioventricular (AV) nodal function (eg, volatile anesthetic agents, opioids, dexmedetomidine, midazolam, etomidate, ketamine), these effects are not clinically significant and are not associated with alteration of arrhythmia inducibility [15-30]. In general, there are no anesthetic agents that are specifically avoided. If an opioid is administered, a short-acting agent is preferred (eg, remifentanil), so that its effect can be rapidly reversed if bradycardia or hemodynamic instability occurs [31,32]. (See "Maintenance of general anesthesia: Overview" and "Perioperative uses of intravenous opioids in adults: General considerations".)

If necessary, doses of an NMBA may be administered to maintain immobility. However, if phrenic nerve stimulation (ie, pacing) is to be employed, maintenance dosing of an NMBA is avoided so that responsiveness of the phrenic nerve is maintained. (See 'Ablation of cardiac arrhythmias' below.)

Hypotension requiring treatment with vasopressors may develop during the electrophysiology (EP) procedure (table 6). Causes of hypotension include excessive depth of anesthesia, underlying cardiovascular disease, rapid myocardial pacing, or administration of isoproterenol to elicit arrhythmias. Other potential causes are mechanical, including blood loss and/or pericardial tamponade due to cardiac or vascular perforation during placement of a transvenous lead or during manipulation of an ablation catheter in the LA or right ventricle (RV). It is important to consider all potential causes of hypotension, and close communication with the electrophysiologist is necessary for accurate diagnosis and appropriate treatment.

Standard ventilation — When patients are receiving standard positive pressure mechanical ventilation, frequent temporary pauses in respiration (eg, 10 to 60 seconds) may be necessary during critical periods of certain procedures to facilitate stability of an ablation catheter (see 'Ablation of cardiac arrhythmias' below). Increased minute ventilation may be required following apneic periods and is guided by capnography.

General anesthesia with jet ventilation — The use of high frequency jet ventilation (HFJV) is requested by some electrophysiologists during critical periods of ablation procedures to decrease chest wall excursions and facilitate stability of the ablation catheter [33] (see 'Ablation of cardiac arrhythmias' below). Use of HFJV requires certain modifications in preparation and administration of general anesthesia.

Preparation and induction — The following preparations are particularly important if use of HFJV is planned:

●A second reliable peripheral IV is inserted for administration of agents for a total IV anesthesia (TIVA) technique.

●Neuromonitoring with a processed or unprocessed electroencephalogram (EEG) such as the bispectral index (BIS) or patient state index (PSI) is typically employed to minimize risk of awareness during TIVA (table 7). (See "Accidental awareness after general anesthesia", section on 'Total intravenous anesthesia' and "Accidental awareness after general anesthesia", section on 'Brain monitoring'.)

●An intra-arterial catheter is often inserted before or after anesthetic induction to monitor arterial blood gases (ABGs) before, during, and after the period of jet ventilation, particularly in patients with severe cardiopulmonary disease (eg, heart failure, severe pulmonary disease). In patients without significant comorbidities, venous blood gases may be obtained by the electrophysiologist from the femoral venous access catheter to assure adequacy of ventilation rather than inserting an intra-arterial catheter to obtain ABGs.

Similar to general anesthesia with conventional ventilation, endotracheal intubation is necessary because HFJV is delivered via a connection to the endotracheal tube (ETT).

Maintenance — The electrophysiologist notifies the anesthesiologist several minutes before HFJV will be needed, typically just before puncture of the atrial septum to access the left side of the heart. TIVA is necessary during jet ventilation because the anesthesia machine is temporarily removed from the breathing circuit so that use of an inhalation agent is precluded [5].

Agents employed for the TIVA technique include a propofol infusion at 100 to 150 mcg/kg per minute combined with an opioid. A remifentanil infusion at 0.1 to 0.2 mcg/kg per minute is typically selected since a longer-acting opioid may exacerbate comorbid conditions such as chronic obstructive pulmonary disease (COPD) or sleep apnea, and postoperative pain is minimal. Neuromonitoring of the processed or unprocessed EEG is employed to detect high indices (eg, BIS value >60) that may indicate awareness during TIVA, particularly if an NMBA is also administered. (See "Maintenance of general anesthesia: Overview", section on 'Total intravenous anesthesia' and "Accidental awareness after general anesthesia", section on 'Brain monitoring'.)

Just before HFJV is required, general anesthetic depth is increased because initiation of this ventilatory technique stimulates airway reflexes and may cause coughing or bucking. Administration of a bolus dose of an opioid (eg, remifentanil 50 to 100 mcg) attenuates the sympathetic response to this stimulation. Subsequently, adequate anesthetic depth must be maintained with the TIVA technique throughout the period that HFJV is being used. Some clinicians administer a dose of an NMBA unless phrenic nerve pacing is planned. If mild to moderate hypotension occurs, initial treatment is with a phenylephrine infusion (table 6), rather than decreasing anesthetic depth to a light level.

Jet ventilation — Management of HFJV for an EP procedure differs somewhat from management of HFJV in other settings (eg, the intensive care unit) (see "High-frequency ventilation in adults", section on 'High-frequency jet ventilation'). In a patient with average body habitus and without pulmonary comorbidity, typical initial settings are:

●Driving pressure – 30 pounds/square inch (psi)

●Frequency of respirations – 100 breaths/minute

●Fraction of inspired oxygen (FiO₂) – 80 percent

●Inspiratory fraction – 30 percent

●Humidity – 50 percent

End-tidal carbon dioxide (ETCO₂) monitoring is employed throughout the period of HFJV. A "saw-tooth" appearance of the ETCO₂ waveform is typical (picture 1). Arterial blood gases are monitored before and shortly after initiating HFJV, approximately every 30 minutes during HFJV, and once more shortly after reestablishing conventional ventilation. If hypercarbia develops, setting changes to correct the problem include:

●Decreasing the frequency of respirations (eg, to 80 bpm), thereby allowing more time in the expiratory phase for passive diffusion of CO₂

●Decreasing the inspiratory time (eg, to 25 percent), thereby increasing the expiratory phase

●Increasing the driving pressure (eg, to 32 psi)

The decision to use HFJV is carefully considered in each individual patient and reevaluated as the EP procedure proceeds. Hypercarbia and/or increased plateau pressure with barotrauma risk may occur due to factors such as COPD, asthma, or morbid obesity. If these problems cannot be corrected by changing HFJV settings, its use is abandoned and controlled mechanical ventilation is resumed at appropriate settings.

After completion of critical portions of the EP procedure requiring absence of lung movement (eg, ablation of arrhythmogenic foci), HFJV is discontinued and conventional ventilation is resumed until the procedure is finished.

Coagulation management — Anticoagulation with heparin is common during EP procedures [5]. Protocols for heparin administration depend on the specific procedure and institutional and/or electrophysiologist preferences. Typically, monitoring of activated whole blood clotting time (ACT) is employed to achieve a targeted value indicating adequate heparin effect during the procedure, as well as adequate reversal with protamine at the end of the procedure.

Protamine is typically administered prior to intravascular sheath removal. The trachea may be extubated before or after the femoral sheaths are removed at the end of the procedure. Since coughing after sheath removal may result in significant bleeding and hematoma at the intravascular cannulation site, patients with reactive airways disease or other comorbidity that may cause coughing are extubated with the sheaths in place, similar to the interventional cardiology suite. (See 'General anesthesia' below.)

Postoperative management — Since postoperative pain after EP or interventional cardiology procedures is not common and is rarely severe, administration of analgesic agents at the end of the procedure is not routine. Some patients complain about lower back pain shortly after extubation, particularly if the case duration was prolonged, with the patient lying supine on an imaging table. In such cases, analgesic treatment before exiting the procedure room may include administration of ketorolac 15 to 30 mg IV over 15 seconds or small bolus doses of opioids (eg, fentanyl, hydromorphone, morphine). (See "Management of acute perioperative pain", section on 'Therapeutic options'.)

Patients are typically required to lie flat for a few hours after removal of a large femoral arterial sheath. In selected patients who are unable to maintain adequate ventilation and oxygenation in the supine position, sedation with controlled ventilation may be necessary for a few hours after removal of a femoral sheath.

Anesthetic considerations for specific procedures

Ablation of cardiac arrhythmias — Catheter ablation using radiofrequency or cryothermal energy is employed to treat several types of tachyarrhythmias (table 8) [5,34]. Other topics address technical procedural considerations. (See "Overview of catheter ablation of cardiac arrhythmias" and "Catheter ablation for the treatment of atrial fibrillation: Technical considerations for non-electrophysiologists".)

Atrial arrhythmias

●Atrial fibrillation ablation — Atrial fibrillation (AF) ablation may be performed using circumferential point-by-point radiofrequency ablation (RFA) lesions or using the cryoballoon ablation (CBA) technique to electrically isolate the pulmonary vein ostia from the body of the LA, thereby eliminating the trigger(s) for AF. General anesthesia is typically necessary, and some electrophysiologists use HFJV during critical portions of the procedure. (See 'General anesthesia with jet ventilation' above.)

Certain technical considerations influence anesthetic care [5]:

•Radiofrequency ablation (RFA) – RF energy heats myocardial tissue and can cause thermal injury to adjacent structures such as the esophagus. The electrophysiologist uses radiographic imaging to identify the esophageal temperature probe and assist the anesthesiologist in positioning it in the esophagus directly behind the myocardial foci targeted for ablation. During active ablation, the anesthesiologist and electrophysiologist continuously monitor esophageal temperature to avoid burn injury.

Saline flushing via the ablation catheter is employed by the electrophysiologist to cool the myocardium throughout an RFA procedure. Since several liters of fluid may be administered by such flushing, the anesthesiologist needs to minimize IV fluid administration and calculate total fluid balance at frequent intervals (eg, every 30 minutes). If fluid overload is suspected, an intraoperative dose of furosemide 20 mg IV may be administered to achieve diuresis.

•Cryoballoon ablation (CBA) – Cryothermal energy freezes myocardial tissue by insertion of a balloon-based catheter into each individual pulmonary vein; this catheter can expand and freeze the surrounding tissue. Phrenic nerve stimulation is used if cryoablation sites are near this nerve (picture 2), necessitating avoidance of neuromuscular blockade. Other considerations during CBA include hypothermia due to systemic cooling and changes in pulmonary gas exchange during occlusion of a pulmonary vein for several minutes.

●Atrial flutter and other supraventricular tachycardia ablation — Atrial flutter and other supraventricular tachycardia ablation procedures are often performed with moderate sedation administered by a credentialed nurse and the electrophysiologist because the procedure is of much shorter duration and less painful compared with AF ablation. In selected patients, anesthesia personnel may be consulted to provide deeper levels of sedation with MAC or general anesthesia with conventional ventilation. (See 'Monitored anesthesia care' above and 'General anesthesia with conventional ventilation' above.)

Ventricular arrhythmias — Indications for catheter ablation of ventricular arrhythmias include frequent ventricular ectopy or recurrent sustained monomorphic ventricular tachycardia (VT) due to reentry circuits that have formed around regions of myocardial scar tissue [35]. Patients with ventricular arrhythmias typically have underlying severe cardiac pathology (eg, ischemic heart disease, congenital heart disease, cardiomyopathy). (See "Overview of catheter ablation of cardiac arrhythmias".)

●Noninvasive physiological stimulation – If the patient has an indwelling cardiac implantable electronic device (CIED), noninvasive physiological stimulation (NIPS) of the ventricular arrhythmia may be performed before beginning a VT ablation procedure in order to stimulate and precisely localize the arrhythmia. A brief period of unconsciousness is necessary for NIPS, typically achieved with small bolus doses of propofol (with or without small bolus doses of midazolam). This is similar to the anesthetic technique employed for cardioversion. (See 'Cardioversion' below.)

●Ventricular tachycardia ablation – There are two procedural approaches to VT ablation:

•Endocardial ablation – Most VT ablations are performed via endocardial ablation. This is always the case in patients with previous heart surgery or thoracic radiation because the pericardial space has been obliterated and the epicardium is inaccessible. The left ventricular (LV) endocardium can be accessed in a retrograde manner with a catheter inserted through the femoral artery into the aorta and across the aortic valve, or anterograde through the femoral vein with transseptal placement into the LA, across the mitral valve, and into the LV. (See "Overview of catheter ablation of cardiac arrhythmias", section on 'Epicardial ventricular mapping' and "Overview of catheter ablation of cardiac arrhythmias", section on 'Endocardial mapping techniques'.)

Deep sedation with MAC is typically employed for endocardial ablation of recurrent slow VT or frequent premature ventricular contractions (PVCs) in patients who are hemodynamically stable (see 'Monitored anesthesia care' above). In patients with actual or potential hemodynamic instability, general anesthesia is employed. (See 'General anesthesia with conventional ventilation' above.)

•Epicardial ablation – Epicardial subxiphoid percutaneous puncture for pericardial access may be employed if the patient's arrhythmia arises from the epicardial surface of the heart. Epicardial ventricular mapping can also be performed with recording catheters that are steered in the branches of the coronary sinus. (See "Overview of catheter ablation of cardiac arrhythmias", section on 'Epicardial ventricular mapping'.)

Epicardial ablation is performed under general anesthesia because pericardial access and catheter manipulation can be painful. In some cases, the electrophysiologist may request a period of minimal sedation at the beginning of the procedure for initial mapping to confirm the epicardial nature of arrhythmogenic foci.

Patients with frequent episodes of malignant arrhythmias, acute coronary syndrome, or severe heart failure may develop hemodynamic instability during a VT ablation procedure. In such cases, an intra-arterial catheter is inserted prior to or following induction of general anesthesia for continuous monitoring of systemic blood pressure. If hypotension develops during defibrillation attempts, norepinephrine is typically selected for vasopressor support (table 6). In rare cases, an intraaortic balloon pump (IABP) or percutaneous left ventricular assist device (LVAD) may be necessary to maintain hemodynamic stability during an ablation procedure for ventricular arrhythmias. (See "Intraaortic balloon pump counterpulsation" and "Short-term mechanical circulatory assist devices".)

Complications — Complications of catheter ablation include cardiac perforation with tamponade, damage to a cardiac valve, arterial injury during vascular access, heart block requiring a permanent pacemaker, myocardial infarction, and thromboembolism [5]. Management of these complications is addressed separately. (See "Overview of catheter ablation of cardiac arrhythmias", section on 'Complications' and "Atrial fibrillation: Catheter ablation", section on 'Complications'.)

Procedures for cardiac implantable electronic devices — Patients presenting for implantation or explantation of a CIED and lead system for a permanent pacemaker (PM) or implantable cardioverter-defibrillator often have severe cardiovascular disease (eg, ischemic heart disease, congenital heart disease, cardiomyopathy).

Implantation of CIED and lead systems — Transvenous implantation of CIED lead systems and the accompanying subcutaneous implantation of the pulse generator for the device (eg, implantable cardioverter-defibrillator [ICD] or PM) are procedures typically performed with moderate sedation administered by a credentialed nurse and the electrophysiologist. (See "Cardiac implantable electronic devices: Periprocedural complications", section on 'Periprocedural monitoring'.)

In some cases, the EP team may request deep sedation with MAC [11]. (See 'Monitored anesthesia care' above.)

Occasionally, general anesthesia is necessary. Examples include:

●Need for tunneling of a subcutaneous ICD lead across the chest wall since this is a painful procedure.

●Severe anxiety, patient inability to lie supine and remain still during the procedure, morbid obesity, or a difficult airway.

●Epicardial lead placement (eg, for a patient with complicated vascular access or active bloodstream infection). These cases are typically performed in the operating room (OR), rather than the EP suite, since a lateral mini-thoracotomy or sternotomy are required. (See "Cardiac implantable electronic devices: Periprocedural complications", section on 'Epicardial lead systems'.)

An ETT is typically employed if general anesthesia is selected, particularly if airway access will be limited. A soft bite-block should be inserted to protect the patient's teeth and tongue during defibrillation attempts. Final patient positioning should be carefully checked for appropriate padding to avoid injury during movement caused by defibrillation shocks.

In selected patients (eg, those with limited vascular access and/or high risk for deep sedation or general anesthetic techniques), subcutaneous ICD placement may be accomplished with a regional anesthetic technique such as a serratus anterior plane block (SAPB) combined with a thoracic paravertebral block (PVB) [36].

Regardless of anesthetic technique, transcutaneous pacing/defibrillator pads are placed on the patient before beginning the procedure, and an external defibrillator with pacing capability should be immediately available (see "Perioperative management of patients with a pacemaker or implantable cardioverter-defibrillator", section on 'Placement of transcutaneous pacing/defibrillator pads'). Testing of an ICD by inducing ventricular fibrillation (VF) is occasionally performed after lead or device implantation to confirm that the newly implanted ICD can successfully terminate the arrhythmia. In the event of device failure, immediate defibrillation is accomplished via the transcutaneous defibrillator pads that were previously placed on the patient. Temporary hemodynamic support with vasopressor agents is initiated if initial defibrillation shocks are unsuccessful. In rare cases, cardiopulmonary resuscitation (CPR) and advanced cardiac life support (ACLS) are initiated by the interventional team until the patient has a stable cardiac rhythm and blood pressure. (See "Advanced cardiac life support (ACLS) in adults".)

CIED explantation or lead removal — Provision of general anesthesia is occasionally requested for removal of an infected CIED lead system and/or pulse generator [37]. Implanted leads older than three years may be difficult to extract; thus, these cases are typically managed with general anesthesia in the OR. (See 'General anesthesia with conventional ventilation' above and "Cardiac implantable electronic device lead removal".)

Complications — Procedural complications associated with CIED or lead implantation or explantation include traumatic injuries with bleeding (eg, perforation of the superior vena cava or other major blood vessel or heart, cardiac tamponade, hemothorax, pericardial effusion), as well as tricuspid regurgitation, pneumothorax, malignant arrhythmias, or embolization of thrombus or vegetation from the lead [37,38]. Typically, no testing of defibrillation thresholds by inducing VF to assess successful shock conversion is performed, as such testing can cause in cardiovascular collapse or refractory heart failure [39,40]. These complications are reviewed separately:

●(See "Cardiac implantable electronic device lead removal", section on 'Complications'.)

●(See "Cardiac implantable electronic devices: Periprocedural complications".)

●(See "Subcutaneous implantable cardioverter defibrillators", section on 'Potential complications'.)

Cardiothoracic surgical backup should be readily available for all transvenous lead extractions [37,38]. At some centers, low-risk extractions may be performed in the EP lab with a designated surgeon on standby in the hospital. However, other institutions schedule all lead extractions in a standard or hybrid OR, with the surgeon either scrubbed in or immediately available within the OR suite [37]. High-risk procedures (eg, transvenous lead extraction, ICD leads older than five years, or pacing leads older than 10 years) are typically performed in a hybrid OR with dedicated fluoroscopy, participation of a cardiothoracic surgeon, and general anesthesia. Preoperative RV dysfunction also confers high risk [41] . Invasive intra-arterial pressure monitoring and large bore IV access (eg, a femoral vein) is often employed during such high-risk cases, and some centers use TEE monitoring to immediately detect major complications [37,38].

Cardioversion — The anesthetic goal for cardioversion is to provide deep sedation with loss of consciousness (table 3), which should last for only the few seconds required for one or two cardioversion attempts, while avoiding apnea and the need for assisted ventilation.

In some cases, a TEE examination is performed prior to cardioversion (eg, history of inadequate anticoagulation conferring an increased risk of intracardiac thrombus and embolic stroke). Anesthetic techniques for TEE are described below. (See 'Transesophageal echocardiography procedures' below.)

Direct current cardioversion without TEE is a very brief procedure (seconds). Typically, small bolus doses of propofol (eg, 10 to 50 mg increments) are titrated to produce loss of response to verbal commands and loss of eyelash reflex. Small bolus doses of midazolam (eg, 1 to 2 mg) may be added. Prolonged apnea is avoided.

Although cardioversion procedures are brief, standard American Society of Anesthesiologists (ASA) monitors are employed (table 4) [7,8]. Oxygen may be administered via nasal cannulae and/or a mask prior to and during administration of sedatives or anesthetic agents. Capnography is employed to ensure that a prolonged period of apnea is avoided. Advanced airway equipment should be immediately available because temporary controlled ventilation with a bag and mask may be necessary in some cases, although laryngoscopy with endotracheal intubation is rare. (See 'Monitored anesthesia care' above.)

Most post-cardioversion arrhythmias are benign and temporary (eg, bradycardia, ectopic atrial beats). Occasionally, profound persistent post-cardioversion bradycardia necessitates pharmacologic treatment (eg, atropine or epinephrine) or mechanical intervention (eg, transcutaneous pacing or transvenous pacing if the patient has a CIED in place). Rarely, cardioversion may result in a reentrant atrial tachycardia with a rapid ventricular response or sustained VT or VF requiring defibrillation. The transcutaneous pads positioned on the patient for cardioversion serve as pacing and/or defibrillator pads. (See "Cardioversion for specific arrhythmias", section on 'Complications'.)

INTERVENTIONAL CARDIOLOGY PROCEDURES — In most patients, percutaneous coronary intervention (PCI) and other procedures in the cardiac catheterization laboratory are performed with minimal to moderate sedation administered by a credentialed nurse under the direction of the interventional cardiologist (see "Procedural sedation in adults outside the operating room"). Anesthesia personnel may be consulted to provide monitored anesthesia care (MAC) or general anesthesia in selected patients. (See 'Selection of anesthetic technique' above.)

Monitored anesthesia care — MAC techniques are similar to those described for electrophysiology (EP) procedures. (See 'Monitored anesthesia care' above.)

General anesthesia — In rare cases, general anesthesia may be requested by the interventional cardiologist. Monitoring and anesthetic agents and techniques are similar to those employed for patients undergoing EP procedures with conventional ventilation. (See 'General anesthesia with conventional ventilation' above.)

Complications requiring emergent anesthetic care — Complications during or immediately after a procedure in the interventional cardiology suite may require unplanned emergency assistance from anesthesia personnel to perform endotracheal intubation and/or to maintain hemodynamic stability. Examples include acute coronary syndrome, stroke, arrhythmias, perforation of the heart or a major vessel causing hemorrhage or hematoma, embolism of air or atherosclerotic debris, or allergic reactions. Information regarding the specific circumstances that led to the emergency (eg, current stage of the planned intervention, vascular access sites and function, administered medications) should be immediately and succinctly communicated to the anesthesiologist upon arrival. (See "Complications of diagnostic cardiac catheterization" and "Periprocedural complications of percutaneous coronary intervention".)

●Airway access — Typically, emergency endotracheal intubation is necessary. Access to the patient's head may be difficult due to the position of radiography equipment. The imaging table and fluoroscopy equipment can be temporarily repositioned to allow airway access. Placement of an endotracheal tube (ETT) is generally preferable to a laryngeal mask airway (LMA) because repositioning of the fluoroscopy equipment and/or performance of cardiopulmonary resuscitation (CPR) may dislodge an LMA. However, if the patient has a difficult airway and has received anticoagulant agents, attempts to intubate the trachea may result in oropharyngeal hemorrhage and increasing difficulty with intubation. In such cases, it is preferable to insert and secure a temporary LMA. (See "Complications of diagnostic cardiac catheterization".)

●Hemodynamic support — Hemodynamic support with infusion of a vasoconstrictor (eg, phenylephrine or vasopressin) or inotropic agent (eg, epinephrine or norepinephrine) may be necessary in some unstable patients (table 6). Central vascular access is preferred for administration of vasoactive infusions, but initiation of vasoactive infusions should not be delayed for placement of a central venous catheter (CVC). In this setting, emergent management of hemodynamic instability may be accomplished by infusing vasoactive agents through the side-arm of the femoral sheath previously inserted by the interventional cardiologist.

In all cases, frequent communication with the cardiologist regarding selection and dosing of vasoactive agents is necessary to determine whether ongoing interventional procedures are successful, and to rapidly recognize and treat new complications.

TRANSESOPHAGEAL ECHOCARDIOGRAPHY PROCEDURES

Considerations for patients with COVID-19 — Since transesophageal echocardiography (TEE) examination is an aerosol-generating procedure, it should be avoided in patients with known or suspected novel coronavirus disease 2019 (COVID-19) unless the findings are likely to be critically important [42-46]. Thus, elective TEEs are postponed and alternative imaging modalities are used in some urgent cases. For example, a cardiac computed tomography (CT) can be used to exclude a left atrial appendage thrombus prior to cardioversion for atrial fibrillation (AF). Important anesthetic considerations specific to patients with suspected or confirmed COVID-19 who do undergo endoscopy include the following (see "Transesophageal echocardiography: Indications, complications, and normal views", section on 'Transesophageal echocardiography in patients with suspected or confirmed COVID-19'):

●Whenever possible, TEE should be performed in a negative-pressure procedure room.

●During TEE examination, airborne, contact, and droplet personal protective equipment (PPE) should be worn to prevent infection, which consists of an N95 or higher level respirator or powered air purifying respirator, eye protection (eg, goggles or face shield that goes around the side of the face), gloves, disposable gown, operating room cap, and shoe covers (see "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control").

●Whenever possible, general anesthesia with endotracheal intubation rather than sedation with monitored anesthesia care (MAC) is employed.

●Some centers employ a sheath for the TEE probe to further reduce the risk of provider and environmental contamination [45], and/or cover the ultrasound system (controls) with a plastic barrier. Additional precautions include minimizing the number of personnel performing TEE examination, limiting TEE use by performing a focused examination, and using dedicated TEE equipment for COVID-19-positive patients.

After removal of the TEE probe at the conclusion of the cardiac surgical case, the probe is placed in a closed container and/or biohazard bag for cleaning and disinfection. All TEE equipment is thoroughly wiped with viricidal disinfectant. Personnel performing the TEE examination should carefully doff PPE according to a standardized process. (See "COVID-19: Perioperative risk assessment and anesthetic considerations, including airway management and infection control".)

General considerations — Common indications for TEE include evaluation of valvular pathology, urgent assessment of acute aortic pathology, and diagnosis of infectious endocarditis (see "Transesophageal echocardiography: Indications, complications, and normal views", section on 'Indications for TEE'). Also, TEE may be performed before a cardioversion or ablation procedure to reduce risk of embolic stroke due to undetected intracardiac thrombus. (See 'Cardioversion' above and 'Preparation and induction' above.)

Duration of the TEE examination varies (typically 10 to 30 minutes), and depends on the specific pathological findings, quality of the images obtained, and expertise of the physician performing the procedure.

In most patients, TEE examination is performed with local anesthesia applied to the posterior oropharynx and moderate sedation provided by credentialed nursing personnel under the direction of the echocardiographer. (See "Procedural sedation in adults outside the operating room".)

Deep sedation/anesthesia — In selected patients, anesthesia personnel may be consulted to provide deeper levels of sedation with MAC or general anesthesia with conventional ventilation (see 'Monitored anesthesia care' above and 'General anesthesia with conventional ventilation' above). The anesthetic goal is for the patient to maintain spontaneous respiration throughout the procedure, without need for additional airway support other than nasal cannulae for oxygen administration. High-flow nasal cannula oxygen is an option in patients with severe cardiorespiratory compromise [47] .

Insertion of the TEE probe is the most stimulating portion of the procedure because probe placement elicits upper airway and gag reflexes. These reflexes can be attenuated by topical oropharyngeal administration of lidocaine, typically 200 to 400 mg of a 4% solution sprayed into the mouth. Subsequently, a moderate dose of intravenous (IV) propofol is administered (eg, 20 to 100 mg) and the TEE probe is inserted.

Although the TEE examination is not painful after probe insertion, patients may experience chest pressure during manipulation of the probe, particularly when it is passed through the lower esophageal sphincter for acquisition of transgastric images. During the procedure, additional small doses of propofol (eg, 20 mg) are administered as necessary. An infusion of propofol (eg, 25 to 75 mcg/kg per minute) is a reasonable alternative to bolus dosing, although this is rarely needed unless the TEE examination is prolonged. In these instances, noninvasive ventilation techniques using masks designed to allow for insertion of an echocardiography probe have been employed to provide ventilatory support [48].

An alternative anesthetic technique is topical anesthesia of the oropharynx followed by small bolus doses of IV midazolam 1 to 2 mg, with or without small bolus doses of fentanyl 25 to 100 mcg.

General anesthesia with endotracheal intubation — General anesthesia may be requested by the echocardiographer (eg, for a patient with severe cardiovascular disease, gastric contraindications to a MAC technique, or inability to cooperate). Endotracheal intubation is necessary for airway control due to the presence of the oral TEE probe. Monitoring and anesthetic agents and techniques are similar to those employed for patients undergoing electrophysiology (EP) procedures with conventional ventilation. (See 'General anesthesia with conventional ventilation' above.)

Complications — Complications of TEE examination occasionally occur, including laryngospasm, aspiration, pharyngeal hematoma, or esophageal or gastrointestinal perforation with hemorrhage (particularly if the patient was receiving anticoagulant agents). Treatment of these complications often includes endotracheal intubation. (See "Rapid sequence induction and intubation (RSII) for anesthesia".)

Further management of TEE complications is described separately. (See "Transesophageal echocardiography: Indications, complications, and normal views", section on 'Safety of TEE examination'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Cardiac implantable electronic devices".)

SUMMARY AND RECOMMENDATIONS

●The off-site locations of the electrophysiology (EP), interventional cardiology, and transesophageal echocardiography (TEE) suites pose challenges for anesthesia personnel, including the need for transport and setup of anesthetic equipment in some institutions, fastidious communication with the interventional team to understand technical considerations for the proposed procedure, and possible radiation risks. (See 'Anesthetic challenges in off-site locations' above.)

●Several patient and procedure-related considerations affect anesthetic care for EP, interventional cardiology, or TEE procedures. (See 'Patient and procedure-related considerations' above.)

●After collaboration between the anesthesiologist and electrophysiologist or interventional cardiologist, monitored anesthesia care (MAC) or general anesthesia may be planned for selected patients (eg, severe anxiety, inability to lie supine, morbid obesity, difficult airway, or significant cardiovascular disease or comorbidities). Endotracheal intubation may be necessary if general anesthesia is selected. (See 'Selection of anesthetic technique' above.)

●Several sedative and/or opioid agents may be employed to provide moderate or deep sedation with MAC (eg, propofol infusion titrated at 25 to 75 mcg/kg per minute, often administered with remifentanil at 0.025 to 0.2 mcg/kg per minute). If the electrophysiologist requests minimal sedation so that catecholamine-mediated arrhythmias may be readily elicited, we use the lowest dose ranges of previously prepared infusions of sedative and analgesic agents, or small bolus doses of midazolam (0.5 to 2 mg) and fentanyl (50 to 100 mcg). (See 'Monitored anesthesia care' above.)

●Either inhalation or intravenous (IV) anesthetic agents may be employed during general anesthesia with conventional ventilation. Frequent temporary pauses in ventilation for 10 to 60 seconds may be necessary during critical periods of certain procedures (eg, EP ablation). (See 'General anesthesia with conventional ventilation' above.)

●When high frequency jet ventilation (HFJV) is employed for an EP procedure, general anesthesia is maintained with a total intravenous anesthesia (TIVA) technique, with neuromonitoring to minimize risk of awareness. Typical jet ventilator settings are (see 'General anesthesia with jet ventilation' above):

•Driving pressure – 30 pounds/square inch (psi)

•Frequency of respirations – 100 breaths/minute (bpm)

•Fraction of inspired oxygen (FiO₂) – 80 percent

•Inspiratory time – 30 percent

•Humidity – 50 percent

●Techniques for EP ablation procedures include (see 'Ablation of cardiac arrhythmias' above):

•Radiofrequency ablation (RFA) – Since RF energy heats myocardial tissue, esophageal temperature is continuously monitored to avoid burn injury and saline flushing via the ablation catheter is employed to cool the myocardium. Since several liters of fluid may be administered by such flushing, IV fluid administration is minimized and total fluid balance is calculated frequently (eg, at 30 minute intervals). Furosemide 20 mg IV is administered if necessary to treat overload.

•Cryoballoon ablation (CBA) – Cryothermal energy freezes myocardial tissue by insertion of a balloon-based catheter into each individual pulmonary vein; this catheter can expand and freeze the surrounding tissue. Phrenic nerve stimulation is used if cryoablation sites are near this nerve, necessitating avoidance of neuromuscular blockade.

●For endocardial ablation of recurrent ventricular tachycardia (VT) in a hemodynamically stable patient, deep sedation with MAC is typically employed. For patients with actual or potential hemodynamic instability and those undergoing epicardial ablation, general anesthesia is employed. (See 'Ventricular arrhythmias' above.)

●Before deep sedation for a TEE exam, upper airway and gag reflexes are attenuated by topical oropharyngeal administration of lidocaine, typically 200 to 400 mg of a 4% solution. Subsequently, a moderate dose of IV propofol is administered (eg, 20 to 100 mg) and the TEE probe is inserted. During the procedure, additional small doses of propofol (eg, 20 mg) may be administered if necessary. (See 'Transesophageal echocardiography procedures' above.)

●A TEE examination to detect intracardiac thrombus may be performed before cardioversion to reduce risk of embolic stroke. For patients undergoing cardioversion without TEE, small bolus doses of propofol (eg, 10 to 50 mg increments) are typically titrated to produce brief loss of response to verbal commands. Small bolus doses of midazolam (eg, 1 to 2 mg) may be added. Apnea is avoided. (See 'Cardioversion' above.)

ACKNOWLEDGMENT — The editorial staff at UpToDate would like to acknowledge Wendy L Gross, MD, who contributed to an earlier version of this topic review.