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Inappropriate shock therapy in a heart failure defibrillator
T R Betts1, S Allen, P R Roberts
1Wessex Cardiothoracic Center, Southampton General Hospital, United Kingdom.
Pacing and Clinical Electrophysiology : PACE
|March 29, 2001
Summary
A patient with heart failure received an inappropriate shock from his defibrillator due to sensing issues. Reprogramming the device settings resolved the problem, preventing future shocks.
Area of Science:
- Cardiology
- Biomedical Engineering
Background:
- Implantation of biventricular defibrillators is a standard treatment for heart failure.
- Lead placement and device programming are critical for optimal function.
Observation:
- A patient experienced an inappropriate shock shortly after defibrillator implantation.
- Electrograms revealed far-field atrial sensing and double counting of ventricular signals.
Findings:
- Far-field atrial sensing by the coronary venous lead mimicked ventricular fibrillation.
- Widely split ventricular electrograms due to left bundle branch block contributed to detection issues.
- Adjusting the atrioventricular delay resolved sensing and pacing problems.
Implications:
- This case highlights potential sensing complications in biventricular defibrillators.
- Careful lead placement and programming are essential to avoid inappropriate shocks.
- Optimizing AV delay can improve device performance in patients with conduction delays.