A Study of Heart Block in Man Using His Bundle Recordings

Abstract

The technique of recording His bundle electrograms in man by a tripolar electrode catheter was applied in a study of patients with first, second, and third-degree heart block. In all patients with first-degree heart block (congenital, acquired, or induced by atrial pacing), the delay in A-V conduction occurred proximal to the His bundle as evidenced by a prolonged P-H interval. The enhancement of A-V conduction (shortening the P-H interval) due to isoproterenol was qualitatively similar in the three forms of first-degree block. In cases of Wenckebach phenomenon the P-H interval progressively increased until a dropped beat occurred. The nonconducted P wave was not followed by a His deflection, indicating block proximal to the His bundle. Cases of 2:1 and 3:1 block occurring proximal to the His bundle were also studied. The usefulness of His-bundle recordings in the diagnosis of cases of complete and incomplete bilateral bundle-branch block is also demonstrated.

Electrocardiographic manifestations: diagnosis of atrioventricular block in the Emergency Department

“…This finding is explained by its association with bundle branch block (20,21). His bundle recordings indicate that the block is never localized to the His bundle; instead, 20% of cases occur in the common bundle and 80% in the bundle branches (5).…”

American College of Cardiology/American Heart Association 2006 Update of the Clinical Competence Statement on Invasive ElectrophysiologyStudies,CatheterAblation,andCardioversion

“…Initially, data from EPS were used to determine the mechanisms of spontaneously occurring arrhythmias, including atrioventricular (AV) conduction abnormalities, premature complexes, and a variety of tachycardias (6,7). Subsequently, techniques for programmed electrical stimulation were developed, which permitted the reproducible initiation of both supraventricular (7,8) and ventricular (9 -11) arrhythmias in the laboratory.…”

Amiodarone versus Sotalol and Propafenone for prevention of immediate recurrence of atrial fibrillation after internal cardioversion: Importance of P wave analysis

“…External and intra-atrial shocks are given in an attempt to convert AF to SR with a higher acute success rate of intra-atrial shocks but similar long-term recurrence rates of AF [1]. Despite successful conversion of AF to SR, immediate recurrence of AF (IRAF) after cardioversion is a major and largely unpredictable clinical problem and, little is known about preventive strategies of IRAF following the use of either one of these techniques [2][3][4][5].…”