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Is inappropriate therapy a resolved issue with current implantable cardioverter defibrillators?
1Arrhythmia Unit, University of Barcelona, Spain.
The American Journal of Cardiology
|March 25, 1999
Summary
Implantable cardioverter-defibrillators (ICDs) may deliver inappropriate shocks due to misidentifying arrhythmias. New detection criteria improve accuracy for supraventricular tachycardias and ventricular tachycardias, enhancing patient safety.
Area of Science:
- Cardiology
- Biomedical Engineering
- Electrophysiology
Background:
- Implantable cardioverter-defibrillators (ICDs) can deliver inappropriate therapies when misinterpreting non-ventricular electrical activity as ventricular.
- Supraventricular tachycardias and artifacts are common causes of inappropriate ICD therapy.
Purpose of the Study:
- To evaluate the effectiveness of enhanced detection criteria in third-generation ICDs for distinguishing between supraventricular and ventricular arrhythmias.
- To optimize ICD programming for accurate tachycardia detection and appropriate therapy delivery.
Main Methods:
- Analysis of tachycardia episodes in patients with ICDs, focusing on arrhythmias detected in the ventricular tachycardia zone.
- Evaluation of specific detection criteria, including sudden onset and stability, and their impact on sensitivity and specificity.
- Comparison of different algorithms to identify the optimal combination for accurate arrhythmia detection.
Main Results:
- A significant proportion of detected ventricular tachycardia episodes were actually supraventricular (193/690).
- Sudden onset criteria effectively detected sinus tachycardia (65/67), and stability criteria detected atrial fibrillation (31/32).
- Ventricular tachycardia detection sensitivity was initially 90%, improving to 100% with sustained, rate-duration criteria, but specificity decreased from 96% to 83%.
Conclusions:
- The algorithm combining sudden onset (>9%) and stability (<40 msec) demonstrated the best specificity and sensitivity.
- Programming ICDs with sudden onset and stability criteria, along with a sustained, rate-duration safety net, ensures appropriate device management for most patients.