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Cardiac conduction abnormalities during percutaneous balloon mitral or aortic valvotomy
M D Carlson1, I Palacios, J D Thomas
1Cardiac Unit, Massachusetts General Hospital, Boston 02114.
Insights
Percutaneous balloon valvotomy can prolong His-Purkinje conduction (HV interval) and QRS duration, potentially causing intraventricular conduction defects. However, complete heart block was not observed in this study of cardiac conduction changes.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Percutaneous balloon valvotomy is a common procedure for treating valvular heart disease.
- Understanding its impact on the cardiac conduction system is crucial for patient safety.
Purpose of the Study:
- To assess electrophysiologic changes in the cardiac conduction system during percutaneous mitral or aortic balloon valvotomy.
- To evaluate the incidence of conduction abnormalities post-procedure.
Main Methods:
- Prospective study of 19 patients undergoing percutaneous mitral/aortic balloon valvotomy.
- Recorded His bundle electrograms, measured AV node effective refractory period, and performed Holter monitoring.
- Follow-up ECGs were obtained to assess long-term changes.
Main Results:
- A significant prolongation of the maximum His-Purkinje conduction time (HV interval) was observed during valvotomy.
- Mean QRS complex duration increased significantly during and after the procedure, indicating intraventricular conduction delay.
- Five patients developed new intraventricular conduction defects or bundle branch blocks; four had persistent defects on follow-up.
Conclusions:
- Percutaneous balloon valvotomy can induce transient and sometimes persistent conduction abnormalities within the His-Purkinje system.
- While significant conduction delays occur, complete heart block was not observed in this patient cohort.
Abstract:
To evaluate the electrophysiologic changes in the cardiac conduction system that occur during percutaneous mitral or aortic balloon valvotomy, we prospectively studied the conduction system in 19 patients (10 mitral, 8 aortic, and 1 both) undergoing this procedure. A His bundle electrogram was recorded in all patients, and when sinus rhythm was present, the atrioventricular (AV) node effective refractory period was measured. Holter monitoring was performed during and for 24 hours after the procedure. Follow-up electrocardiograms (ECG) were available in 11 patients 2.3 +/- 1.5 months after the procedure. The AV node effective refractory period before (276 +/- 86 msec) and after valvotomy (298 +/- 85 msec) were not significantly different. The maximum His-Purkinje conduction time (HV interval) observed during valvotomy (66 +/- 20 msec) was significantly longer (p less than 0.01) than that measured before (57 +/- 10 msec) or after (60 +/- 18 msec) valvotomy. The mean HV intervals before and after valvotomy were not significantly different. The mean QRS complex duration increased from 95 +/- 28 to 112 +/- 28 msec during valvotomy and remained significantly prolonged (109 +/- 26 msec) 24 hours after the procedure (p less than 0.01). A new intraventricular conduction defect (QRS complex duration greater than 100 msec) or bundle branch block occurred in five of 13 patients who had normal QRS duration before the procedure. The change in HV interval did not correlate with the change in QRS complex duration. In four patients, the newly acquired intraventricular conduction defect was still present on follow-up ECG tracing. Complete heart block was not observed in any patient.(ABSTRACT TRUNCATED AT 250 WORDS)