Repetitive ventricular response. Its incidence, inducibility, reproducibility, mechanism, and significance.

Open Access
Publisher Website
Google Scholar
Abstract
Using His bundle electrograms and the ventricular extrastimulus technique (single premature stimulus during sinus rhythm.sbd.S1 method; single premature stimulus during ventricular pacing.sbd.S1S2 method; and 2 premature stimuli during ventricular pacing.sbd.S1S2S3 method), the occurrence of repetitive ventricular responses was tested in 51 patients. Of 51 patients, 32 had organic heart disease and 19 of 51 patients (37%) had no evidence of heart disease. No patient had spontaneous or exercise-induced ventricular tachycardia, sudden death or a recent myocardial infarction (less than 6 mo.). Repetitive ventricular responses were induced in 38 of 51 patients. In 33 of 51 patients (65%) the repetitive ventricular responses were reproducible. In 26 patients (5), they were caused by local re-entry and in 28 patients (55%) by bundle-branch re-entry. In addition, 16 patients had reproducible repetitive ventricular responses resulting from both bundle-branch and local re-entry. Repetitive ventricular responses caused by local re-entry were induced by the S1 method in only 1 patient (4%), by the S1S2 method in 7 of 26 patients (27%) and by the S1S2S3 method in 24 of 26 patients (92%) and were reproducible in 86% of patients. The incidence of repetitive ventricular responses caused by local re-entry was significantly higher in patients with organic heart disease vs. those without organic heart disease. Repetitive ventricular responses caused by bundle-branch re-entry were induced only in 1 patient (2.5%) by the S1 method, in 21 of 28 patients (75%) by the S1S2 method and in 12 of 28 patients (42%) by the S1S2S3 method. There was no significant difference between the occurrence of repetitive ventricular responses resulting from bundle-branch re-entry and the presence or absence of organic heart disease. All patients without repetitive ventricular responses were followed for 6-17 mo. (average = 12 mo.) with 24 h ambulatory ECG recordings. None of the patients with repetitive ventricular responses caused by local re-entry and bundle-branch re-entry developed ventricular tachycardia and/or sudden cardiac cardiac death. Repetitive ventricular responses caused by local re-entry can be induced in a significant number of patients with organic heart disease unlike bundle-branch re-entry; the S1S2S3 method is the most sensitive for induction of repetitive ventricular responses caused by local re-entry while the S1S2 method is the most sensitive for the induction of repetitive ventricular responses caused by bundle-branch re-entry. The S1 method is the least sensitive for the induction of both local re-entry and bundle-branch re-entry. Though repetitive ventricular responses caused by local re-entry may suggest electrical instability, follow-up studies disclosed that it is not a predictor of sudden death.