Disopyramide stress test: a sensitive and specific tool for predicting impending high degree atrioventricular block in patients with bifascicular block.

Abstract

Objective-To study the value of intravenous disopyramide as part of an invasive electrophysiological study in predicting impending high degree atrioventricular block in patients with bifascicular block. Design-An invasive electrophysiological study was performed in the basal state and after the infusion of disopyramide (2 mg/kg body weight). The progression to high degree atrioventricular block was assessed by bradycardia-detecting pacemakers or repeated 12-lead electrocardiogram recordings, or both. Patients-73 patients with bifascicular block were included, of whom 25 had a history of unexplained syncope. The remaining 48 patients had no arrhythmia related symptoms and were included as controls. All patients had an ejection fraction of > 35%. Results-After a mean follow up of 23 months, seven patients in the syncope group and three in the non-syncope group had a documented high degree atrioventricular block or pacemaker-detected bradycardia of < 30 beatsimin for > 6 s. The sensitivity of the disopyramide test was 71% and the specificity 98%. The corresponding figures for an abnormal electrophysiological study in the basal state were 14% and 91%, respectively. Conclusions-The sensitivity of an invasive electrophysiological study in patients with bifascicular block and syncope can be markedly increased by the use of intravenous disopyramide. A positive test is a highly specific finding and warrants pacemaker implantation. (Br Heart J 1995;74:650-655) Keywords: disopyramide stress test, atrioventricular block, bifascicular block, electrophysiological study Bifascicular block, defined as left bundle branch block or right bundle branch block with left anterior or posterior fascicular block, has a prevalence of between 1% and 1-5% in an adult population.'-3 Up to 25% of patients with bifascicular block have a history of syncope3 and the management of these patients is a common clinical problem. The overall yearly incidence of progression to high degree atrioventricular block is only 1-4%3-5 and the strategy of pacemaker implantation in all symptomatic patients can thus be questioned. No non-invasive test has been found to be useful in predicting subsequent high degree atrioventricular block, and an invasive electrophysiological study is often of limited value.47 Findings with a high specificity, such as an HV interval of > 100 ms and a His-Purkinje block during atrial pacing, are rare and hence have a low sensitivity.5 8In order to increase the sensitivity of an electrophysiological study, a pharmacological stress test of the His-Purkinje system has been proposed, and ajmaline,9 10 procainamide,"-13 and disopyramide'4 '5 have been used for this purpose. The clinical value of these tests has, however, not been well defined, primarily because of the lack of appropriate controls and the lack of sensitive tools for detecting intermittent high degree atrioventricular block.The aim of this study was to evaluate prospectively the value of intravenous disopyramide as part of an invasive electrophysiological study...

Is there a prognostic relevance of electrophysiological studies in bundle branch block patients?

“…Total mortality and cardiac These findings were underlined by studies from the 1980s and '90s. [6][7][8] In their study, Martí-Almor and colleagues demonstrated a similar follow-up period of 4.5 years. 9 Their patient cohort was of comparable age (73 AE 9 years vs 75 AE 9 years, respectively) but included more women (33% vs 17%, respectively).…”

“…This is supported by the fact that nearly half of the patients with negative EP study (45%) later display arrhythmias in the implantable loop recorder. These findings were underlined by studies from the 1980s and ’90s …”

Dispersion in Ventricular Repolarization in Patients with Severe Intraventricular Conduction Disturbances

“…They were studied with the purpose of identifying substrates for brady-and tachyarrhythmia. 31,32 Patients without syncope were included to assist the definition of the specificity of the applied protocols. Prior to the invasive electrophysiological study, all patients underwent careful history taking, a physical examination, routine laboratory tests, a chest X ray, a symptom-limited bicycle exercise test, and an echo-Doppler examination including assessment of the left ventricular ejection fraction.…”

Acquired Atrioventricular Block:

“…Phase 4 block is always infranodal and can be evaluated with His‐bundle recordings by producing bradycardia and pauses by the electrical induction of atrial or ventricular premature beats. However, a positive response to pharmacological challenge with drugs such as procainamide according to published criteria should probably be a class II indication in symptomatic patients without previously documented AV block 20 , 2 …”

“…However, a positive response to pharmacological challenge with drugs such as procainamide according to published criteria should probably be a class II indication in symptomatic patients without previously documented AV block. 20,21 Acute Myocardial Infarction The ACC/AHA/NASPE 2002 guidelines (and the 1999 ACC/AHA guidelines for the treatment of acute myocardial infarction) advocate "persistent and symptomatic AV block" after acute myocardial infarction (MI) as a class I indication for pacing. 1,22 This vague statement ignores the simple fact that any form of AV block in acute MI can be symptomatic before it resolves completely as in inferior MI.…”