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His bundle electrograms in patients with congestive cardiomyopathy
European Journal of Cardiology
|January 1, 1975
Summary
His bundle electrograms reveal previously undetected atrioventricular conduction abnormalities in patients with congestive cardiomyopathy. These findings expand understanding of the electrophysiologic characteristics of this condition.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Congestive cardiomyopathy (CCM) can affect cardiac conduction.
- Standard electrocardiography (ECG) may not fully reveal underlying conduction disturbances.
Purpose of the Study:
- To investigate atrioventricular (AV) conduction abnormalities in patients with CCM using His bundle electrograms.
- To correlate electrophysiologic findings with standard ECG and clinical presentation.
Main Methods:
- His bundle electrograms were recorded at rest and during atrial pacing in 16 CCM patients.
- Analysis included A-H intervals, H-V intervals, and intraventricular conduction times.
- Patients' medication, including digitalis, was noted.
Main Results:
- All patients showed progressive A-H interval prolongation with increased heart rate during pacing.
- Three patients on digitalis developed second-degree AV block (A-H block) at paced rates below 130/min.
- Conduction delays were identified proximal to, within, and distal to the His bundle, including left bundle branch block and isolated H-V prolongation.
Conclusions:
- His bundle electrography is crucial for detecting subtle AV conduction abnormalities in CCM.
- These abnormalities are more prevalent than suggested by standard ECG.
- Findings enhance the understanding of electrophysiologic derangements in congestive cardiomyopathy.