Related Experiment Videos
Atrioventricular conduction in patients with clinical indications for transvenous cardiac pacing
Insights
His bundle studies reveal frequent distal conduction abnormalities in patients needing cardiac pacing. Some acutely ill patients with heart block showed restored atrioventricular conduction.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Cardiac pacing is indicated for various bradyarrhythmias and conduction disorders.
- Understanding atrioventricular (AV) conduction is crucial for appropriate pacing decisions.
Purpose of the Study:
- To analyze atrioventricular conduction using His bundle studies in patients with indications for cardiac pacing.
- To identify the location of conduction abnormalities (proximal vs. distal to His bundle).
Main Methods:
- His bundle electrophysiological study was performed in 80 patients indicated for cardiac pacing.
- Indications included high-grade AV block, sick sinus node syndrome, bradycardia-tachycardia syndrome, bilateral bundle-branch block, and ventricular irritability.
Main Results:
- Fifty percent (40/80) of patients exhibited distal conduction abnormalities by His bundle analysis.
- Mobitz II block was exclusively found distal to the His bundle.
- Sixty percent (48/80) of patients had intraventricular conduction disturbances on standard ECG.
- A notable finding was the re-establishment of normal AV conduction in some acutely ill patients with recent heart block.
Conclusions:
- His bundle studies are valuable for localizing conduction abnormalities in patients requiring cardiac pacing.
- Distal conduction abnormalities are common, influencing pacing strategies.
- ECG and electrophysiological findings highlight the complexity of AV conduction in these patients.
Abstract:
Eighty patients with clinical indications for cardiac pacing had atrioventricular conduction analysed by His bundle study. The indications for cardiac pacing included high grade atrioventricular block, sick sinus node syndrome without tachycardia, bradycardia-tachycardia syndrome, unstable bilateral bundle-branch block, and uncontrolled ventricular irritability. Complete heart block, Wenckeback block (Mobitz I), and 2:1 block were noted proximal and distal to the His bundle. Mobitz II block only occurred distal to the His bundle. Of special interest were the high incidence of distal conduction abnormalities by His bundle analysis (40/80, 50%), the re-establishment of normal atrioventricular conduction in acutely ill patients with recent evidence of heart block, and the high incidence of intraventricular conduction disturbances on standard electrocardiogram (48/80, 60%).