CAM 20205

Intracardiac Electrophysiologic Studies

Category:Medicine   Last Reviewed:March 2020
Department(s):Medical Affairs   Next Review:March 2999
Original Date:March 1996    

Intracardiac electrophysiologic (EP) studies refer to percutaneous techniques that directly assess the electrical activity of the heart and can be used in the diagnosis and management of selected cardiac arrhythmias. EP studies have been used mainly for identifying the mechanism, site and severity of brady- or tachyarrhythmias. They have also been used in the preparation for catheter ablation procedures, to assess response to drug therapy and to determine indications for implantable cardioverter defibrillators (ICDs).

EP procedures are performed in an electrophysiology lab, with the patient under conscious sedation. Vascular access is obtained, most commonly through the femoral vein. Multiple electrode catheters are positioned in the heart, with the number and location depending on the intent of the study and the location of the suspected abnormality. These catheters are used to stimulate specific areas of the heart and record the electrical responses to stimulation.

The specific techniques used in EP studies vary according to the intent and indications for the study. The general categories of intracardiac electrophysiologic studies are: 

  1. Recordings from the sinoatrial (SA) node, the His bundle and the coronary sinus in order to assess the basic integrity of the cardiac conduction system; 
  2. Programmed electrical stimulation, which consists of pulsed stimulation and the insertion of premature contractions, to assess the inducibility of arrhythmias and/or to terminate a specific arrhythmia; 
  3. Mapping techniques to determine tachycardia pathways. Mapping involves a detailed analysis of electrical activity at a specific site of interest, and can be an important decision-making tool in the approach to catheter ablations. 

Complications of EP studies are uncommon, with serious complications occurring in the range of 1-2%. The most common complications are related to the percutaneous catheterization. These include bleeding or hematoma at the access site, thrombophlebitis, infection and arterial damage/dissection. Complications related to the intracardiac stimulation vary depending on the placement and stimulation techniques. These could include perforation of the cardiac chamber and tamponade, coronary sinus perforation, myocardial infarction or arrhythmias induced by the procedure. Radiofrequency ablation is associated with an additional number of complications, which are addressed in specific policies for catheter ablation (see 20201 Catheter Ablation for Cardiac Arrhythmias and 20219 Catheter Ablation of the Pulmonary Veins as Treatment for Atrial Fibrillation).

Electrophysiologic studies are considered MEDICALLY NECESSARY for patients with:

  • Coronary artery disease and symptoms suggestive of ventricular tachycardia or fibrillation
  • Coronary artery disease, nonsustained ventricular tachycardia and left-ventricular ejection fraction less than 40 percent
  • Unexplained recurrent syncope in the presence of structural heart disease
  • In preparation for, or as part of, catheter ablation procedures
  • Severe, unexplained symptoms suggestive of an undocumented arrhythmia, where noninvasive clinical testing has failed to adequately diagnose, localize or fully characterize the arrhythmia

Policy Guidelines
These tests are invasive and carry attendant risks; thus, their use is generally reserved for situations in which other less invasive testing cannot provide the needed clinical information

Benefit Application
Blue Card®/National Account Issues
None identified.

Supraventricular Tachyarrhythmias
The majority of supraventricular tachyarrhythmias can be diagnosed by a resting electrocardiogram (ECG) and/or an ambulatory event monitor. For these patients, EP studies are not needed for diagnosis. (2) In some patients, however, the mechanism of the arrhythmia is uncertain based on ECG tracings. EP studies can successfully characterize the origin, location and mechanism of the arrhythmia in nearly all cases. (3)

The greatest utility of EP studies in supraventricular arrhythmias is in preparation for catheter ablation procedures. Currently, a large proportion of patients with supraventricular tachyarrhythmias in the U.S. are treated with ablation, and virtually all ablation procedures are accompanied by EP testing. (2) EP studies are used to confirm the abnormal foci, determine the precise location and conduction characteristics of the arrhythmia, and to direct the ablation catheter. For supraventricular arrhythmias, the EP study and ablation procedure are usually performed at the same time.

Ventricular Tachyarrhythmias
In the past, inducibility of arrhythmias on EP studies was commonly used for risk stratification of patients with ventricular arrhythmias and/or sudden death. While the results of EP studies do have modest predictive value in risk stratification, the sensitivity and negative predictive value are suboptimal. (3) As a result, information from EP testing may not influence clinical decision making, as the negative predictive value is not high enough to forego treatment in patients with a negative test.

The best evidence on the predictive value of inducibility comes from post hoc analysis of implantable cardioverter defibrillator (ICD) trials in which patients underwent EP testing, and both patients with inducible and noninducible arrhythmias were followed for outcomes. In the early trials of ICD use, such as the Multicenter Automatic Defibrillator Implantation Trial one (MADIT I), inducibility on EP studies was an eligibility criterion, and patients excluded from the study were not systematically followed. In the Multicenter Unsustained Tachycardia Trial (MUSTT), (4) inducibility was a requirement for enrollment, but patients excluded from the trial were also followed for mortality outcomes. In this trial, the mortality rate in patients with noninducible versus inducible arrhythmias was somewhat lower (21 percent vs. 28 percent, respectively). The relatively high mortality in patients without inducible arrhythmias raised suggestion that even in these patients, arrhythmias might benefit from ICD treatment.

The MADIT-II study was the first trial of ICD use that did not require EP studies as part of the decision-making process for an ICD. (5) Although patients enrolled in MADIT-II were not required to undergo EP studies, they were encouraged to do so in order to evaluate the predictive value of inducibility for ventricular arrhythmias, and 82 percent did undergo EP studies. A follow-up study was subsequently published that specifically looked at inducibility as a predictor of ICD discharges for ventricular tachycardia or ventricular fibrillation. (6) In this analysis, patients who had an inducible arrhythmia had only a slightly higher risk of ICD discharge at two years than patients who were not inducible (29.4 percent vs. 25.5 percent, respectively; p=0.02).

Following MADIT-II, the use of EP study results as a factor in ICD implantation has fallen out of favor. Currently, the decision to implant an ICD is more dependent on other risk factors, such as the presence of coronary artery disease (CAD) and/or low ejection fraction. The most recent guidelines do not recommend EP testing for risk stratification of all patients with ventricular arrhythmias. The following specific guidelines regarding electrophysiological testing in patients with ventricular arrhythmias and CAD were published by the American College of Cardiology (ACC) and the American Heart Association (AHA) in 2006 (7):

Class I Recommendations

  1. Diagnostic evaluation of patients with remote MI (myocardial infarction) with symptoms suggestive of ventricular tachyarrhythmias, including palpitations, presyncope and syncope (Level of Evidence: B)
  2. To guide and assess the efficacy of ventricular tachycardia ablation (Level of Evidence: B)
  3. Diagnostic evaluation of wide-QRS-complex tachycardias of unclear mechanism. (Level of Evidence: C)

Class IIa Recommendations:
Risk stratification in patients with remote myocardial infarction, nonsustained ventricular tachycardia and left-ventricular ejection fraction equal to or less than 40 percent. (Level of Evidence: B)

For patients with ventricular arrhythmias due to nonischemic cardiomyopathy, the yield of EP studies is lower, and EP studies are not diagnostic in the majority of patients, and, thus, EP studies have a more limited role. In general, EP studies are of use in nonischemic cardiomyopathy when other noninvasive methods for diagnosing and characterizing a suspected arrhythmia are not successful. (7)

The two main classes of bradyarrhythmias for which EP studies are considered are sinus node dysfunction and atrioventricular (AV) node dysfunction. In the majority of patients, ECG tracings can adequately diagnose and characterize the type and severity of these bradyarrhythmias.

For patients with bradyarrhythmias that are correlated with symptoms, and in whom there is unequivocal ECG evidence of sinus node or AV node dysfunction on ECG, EP studies are not of benefit. (1) In some patients, in whom the correlation between symptoms and bradycardia is uncertain, or in whom the ECG is not definitive, EP studies may be of benefit to further characterize the arrhythmia and determine whether a pacemaker is indicated. (7)

Similarly, for patients with documented symptomatic second- or third-degree AV node block, EP studies are not needed, as these patients require a pacemaker regardless of EP study results. (1) EP studies may be helpful in situations in which the correlation between AV block and symptoms is uncertain. EP studies can also be helpful in patients with signs and symptoms of AV block, but in whom AV block has not been documented. Finally, for some patients, the type and/or site of the AV block cannot be determined by surface tracings, and EP studies can be helpful in further characterizing the type of AV block in determining whether a pacemaker is indicated. (7)

Syncope of Undetermined Etiology
The etiology of syncope can be determined for the majority of patients on the basis of history, physical examination, ECG and laboratory testing. However, in some patients, the origin remains elusive after standard workup. These patients are often considered for EP studies in order to determine the likelihood that occult arrhythmias are the cause of syncope. The 2006 ACC/AHA guidelines include the following recommendations (7):

Class I Recommendations:
EP testing is recommended in patients with syncope of unknown cause with impaired left-ventricular function or structural heart disease. (Level of Evidence: B)

Class IIa Recommendations:
EP testing can be useful in patients with syncope when bradyarrhythmias or tachyarrhythmias are suspected and in whom noninvasive diagnostic studies are not conclusive. (Level of Evidence: B)

Catheter Ablation
EP studies are commonly used in preparation for catheter ablation procedures. (7) They are commonly performed at the same time as the ablation procedure, although in some circumstances they may precede the ablation procedure. The intent of EP studies is to provide precise localization and mapping of the arrhythmia in order to guide the ablation procedure. Specific techniques for EP studies in these procedures vary according to the clinical diagnosis and ablation approach. Further information on specific ablation procedures are discussed as separate policy statements (see 20202 Catheter Ablation for Cardiac Arrhythmias; 70114 Open and Thoracoscopic Approaches to Treat Atrial Fibrillation).

Other Conditions
Conditions for which the ACC/AHA guidelines conclude that EP testing is not indicated or controversial include dilated cardiomyopathy, long QT syndrome, Brugada syndrome, hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy and outflow tract ventricular tachycardia. (7) For these conditions, EP testing may sometimes be indicated when there is the need to establish a precise diagnosis or to further characterize the arrhythmia when this cannot be accomplished by other tests. In addition, EP studies may be required to guide curative catheter ablation in selected patients with these conditions and ventricular arrhythmias.

Guidelines have also been published by the ACC/AHA on the clinical competence required for clinicians to perform EP studies. (8) These guidelines include the minimal training required, the potential routes for acquisition of training and the maintenance of competence.

Electrophysiologic (EP) studies are used to diagnose and characterize cardiac arrhythmias and are most useful in the evaluation of ventricular arrhythmias for patients with CAD. For other types of arrhythmias, EP studies may be valuable as a diagnostic tool when non-invasive studies are not diagnostic. They are also used in the evaluation of unexplained syncope and in preparation for catheter ablation procedures. Since these tests are invasive and carry attendant risks, their use is generally reserved for situations in which other less invasive testing cannot provide the needed clinical information. In addition, EP studies are used in conjunction with catheter ablation procedures to confirm the location and type of arrhythmia and direct the catheter ablation procedure.


  1. Zipes DP, Dimarco JP, Gillette PC et al. Guidelines for clinical intracardiac electrophysiological and catheter ablation procedures. J Am Coll Cardiol 1995; 26(2):555-73.
  2. Blomstrom-Lundqvist C, Scheinman MM, Aliot EM et al. ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias – Executive summary. J Am Coll Cardiol 2003; 42(8):1493-531.
  3. Thomas KE, Josephson ME. The role of electrophysiology study in risk stratification of sudden cardiac death. Prog Cardiovasc Dis 2008; 51(2):97-105.
  4. Buxton AE, Lee KL, Fisher JD et al. A randomized study of the prevention of sudden death in patients with coronary artery disease. Multicenter unsustained tachycardia trial investigators. N Engl J Med 1999; 341(25):1882-90.
  5. Moss AJ, Zareba W, Hall WJ et al. Prophylactic implantation of a defibrillator in patients with myocardial infarction and reduced ejection fraction. N Engl J Med 2002; 346(12):877-83.
  6. Daubert JP, Zareba W, Hall WJ et al. Predictive value of ventricular arrhythmia inducibility for subsequent ventricular tachycardia or ventricular fibrillation in multicenter automatic defibrillator implantation trial (MADIT) II patients. J Am Coll Cardiol 2006; 47(1):98-107.
  7. Zipes DP, Camm AJ, Borggrefe M et al. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. J Am Coll Cardiol 2006; 48(5):e247-e346.
  8. Tracy CM, Akhtar M, DiMarco JP et al. American College of Cardiology/American Heart Association 2006 update of the clinical competence statement on invasive electrophysiology studies, catheter ablation, and cardioversion. Circulation 2006; 114(15):1654-68

Coding Section

Codes Number Description
CPT 93600-93644 Intracardiac electrophysiological procedures code range
ICD-9 Procedure 37.26 Cardiac electrophysiological stimulation and recording studies
  37.27 Cardiac mapping
  37.29 Other diagnostic procedures on heart and pericardium (includes HIS bundle recording)
ICD-9 Diagnosis 426.6 Other heart block (intraventricular)
  426.7 Anomalous atrioventricular excitation (Wolfe-Parkinson-White syndrome)
  427.1 Paroxysmal ventricular tachycardia
  427.31 Atrial fibrillations
  427.32 Atrial fibrillation and flutter, atrial flutter
  427.41 Ventricular fibrillation
  427.81 Sinoatrial node dysfunction
  427.89 Other specified cardiac dysrhythmias (supraventricular tachycardia)
  780.2 Syncope and collapse
HCPCS No Code  
ICD-10-CM (effective 10/01/15) I45.5 Other specified heart block 
  I45.6 Pre-excitation syndrome (includes Wolff-Parkinson-White syndrome)
  I47.0-I47.9 Paroxysmal tachycardia code range (includes ventricular tachycardia and supraventricular tachycardia)
  I48.0-I48.1 Atrial fibrillation and flutter 
  I49.01-I49.9 Other cardiac arrhythmias code range (includes ventricular fibrillation)
  I50.1-I50.9 Heart failure code range 
  R55 Syncope and collapse
ICD-10-PCS (effective 10/01/15)   ICD-10-PCS codes are only used for inpatient services. There is no specific ICD-10-PCS code for this procedure. 
  4A023FZ Measurement & monitoring, physiological systems, measurement, cardiac, percutaneous, rhythm 
  02K80ZZ, 02K83ZZ, 02K84ZZ Surgical, heart & great vessels, map, conduction mechanism, code by approach (open, percutaneous or percutaneous endoscopic) 
  02JA0ZZ, 02JA3ZZ, 02JA4ZZ Surgical, heart & great vessels, inspection, conduction mechanism, code by approach (open, percutaneous or percutaneous endoscopic) 
  0WJD0ZZ, 0WJD3ZZ, 0WJD4ZZ Surgical, anatomical regions, inspection, pericardial cavity, code by approach (open, percutaneous or percutaneous endoscopic) 
Type of Service Medicine  
Place of Service Inpatient/Outpatient  

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross and Blue Shield Association technology assessment program (TEC) and other non-affiliated technology evaluation centers, reference to federal regulations, other plan medical policies and accredited national guidelines.

"Current Procedural Terminology© American Medical Association.  All Rights Reserved" 

History From 2014 Forward     


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