CHAPTER 82: INVASIVE DIAGNOSTIC ELECTROPHYSIOLOGY

Dinesh Sharma; Srinivas R. Dukkipati

INTRODUCTION

Electrophysiology studies (EPS) are minimally invasive procedures utilized for the diagnosis and treatment of cardiac arrhythmias. They can provide insight into the mechanism underlying a variety of cardiac rhythm disorders when noninvasive testing has been unrevealing. Abnormal findings often require device therapy or catheter ablation, which is often performed concomitantly with EPS.

INVASIVE DIAGNOSTIC ELECTROPHYSIOLOGY STUDIES

Indications for Electrophysiology Studies

EPS is recommended when noninvasive investigations do not establish the diagnosis or etiology of arrhythmia and the result will change the clinical management. It is indicated for the evaluation of documented or suspected bradyarrhythmias and tachyarrhythmias, syncope, and for risk stratification of individuals at risk for sudden cardiac death (SCD).^1,2 Indications are summarized in Table 82–1. EPS should not be performed in patients who have unstable angina, systemic infection, deep venous thrombosis in the region of venous access, or any other medical condition where the risks of the procedure outweigh the benefits derived from testing.

TABLE 82–1.Indications for Diagnostic Electrophysiology Studies

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TABLE 82–1. Indications for Diagnostic Electrophysiology Studies

Bradyarrhythmias: For the diagnosis and management of suspected or documented bradyarrhythmias when noninvasive testing has been inconclusive.

Evaluation of sinus node function in patients with suspected sick sinus syndrome—suggested by the presence of a prolonged SNRT (> 1500 ms) and inappropriate sinus bradycardia.
Assessment of the level of AV conduction abnormality in patients with bifascicular or intermittent AV block—induction of infra-nodal block (either intra- or infra-Hisian), or an HV interval > 100 ms are abnormal findings.

Tachyarrhythmias: For the diagnosis and management when noninvasive testing has been inconclusive.

Delineate of the mechanism of narrow-complex tachycardia.
Delineate the mechanism of wide-complex tachycardia.
Define of the mechanism of narrow- or wide-complex tachycardia for catheter ablation.

Syncope

Assessment sinus node function and AV conduction in patients with syncope.
Evaluation for tachyarrhythmias (SVT or VT) as a potential cause of syncope in patients presenting with palpitations associated with syncope.
Evaluation of syncope in patients with structural heart disease.
Evaluation of syncope of unclear etiology.
Evaluation of syncope in high-risk occupations—airline pilots, bus drivers, etc.

Risk Stratification

Patients with coronary artery disease, depressed LVEF (< 40%), and nonsustained VT—induction of sustained VT or VF is an indication for ICD.
Brugada syndrome—the role of electrophysiology study for VT/VF induction and risk stratification is controversial.
Wolff-Parkinson-White syndrome—when pre-excitation persists with exercise on stress testing.

Other

Assessment for VT or VF in patients with a suspected risk of arrhythmic sudden death.
Survivors of sudden cardiac death without a clear cause.

Abbreviations: AV, atrioventricular; HV, His deflection to the earliest ventricular signal; ICD, implantable cardioverter-defibrillator; LVEF, left ventricular ejection fraction; SNRT, sinus node recovery time; SVT, supraventricular tachycardia; VF, ventricular fibrillation; VT, ventricular tachycardia.

Technique

EPS involves placing catheters equipped with electrodes at the tip in ...

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