PT  - JOURNAL ARTICLE
AU  - A. Englund
AU  - L. Bergfeldt
AU  - M. Rosenqvist
TI  - Disopyramide stress test: a sensitive and specific tool for predicting impending high degree atrioventricular block in patients with bifascicular block.
AID  - 10.1136/hrt.74.6.650
DP  - 1995 Dec 01
TA  - British Heart Journal
PG  - 650--655
VI  - 74
IP  - 6
4099  - http://heart.bmj.com/content/74/6/650.short
4100  - http://heart.bmj.com/content/74/6/650.full
SO  - Heart1995 Dec 01; 74
AB  - 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 < or = 30 beats/min for > or = 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.