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[Clinical evaluation of a dual chamber implantable cardioverter-defibrillator]
J Kazmierczak1, R Tavernier, J De Sutter
1Kliniki Kardiologii Pomorskiej AM w Szczecinie.
Insights
Dual-chamber implantable cardioverter-defibrillators (ICDs) improve detection of ventricular arrhythmias and reduce inappropriate shocks from atrial fibrillation. This technology enhances AV synchrony, potentially improving outcomes for patients with heart failure.
Area of Science:
- Cardiology
- Biomedical Engineering
- Electrophysiology
Background:
- Single-chamber ICDs reduce sudden cardiac death but have high rates of inappropriate therapy (up to 34%) due to supraventricular tachyarrhythmias.
- Many ICD patients (up to 20%) require antibradycardia pacing, highlighting the need for improved pacing and arrhythmia discrimination.
Purpose of the Study:
- To evaluate the clinical performance of dual-chamber ICDs in discriminating between ventricular and supraventricular tachyarrhythmias.
- To assess the impact of dual-chamber ICDs on inappropriate therapy rates and atrioventricular (AV) synchrony.
Main Methods:
- A preliminary clinical experience with 20 patients implanted with dual-chamber ICDs was described.
- In-hospital induced ventricular tachycardia/ventricular fibrillation (VT/VF) and atrial fibrillation (AF) episodes were recorded and analyzed.
- Tachycardia episodes during a mean follow-up of 10 months were monitored for detection accuracy.
Main Results:
- Dual-chamber ICDs demonstrated 100% sensitivity and 82% specificity for VT/VF detection.
- Of 22 recorded AF episodes, 18 were correctly identified; 4 were misclassified as VT/VF, leading to 2 instances of antitachycardia pacing and 2 shocks.
- The device improved discrimination of atrial from ventricular tachyarrhythmias, reducing inappropriate therapy events.
Conclusions:
- Dual-chamber ICDs enhance the ability to differentiate atrial from ventricular tachyarrhythmias, significantly decreasing inappropriate shocks.
- Maintaining AV synchrony with dual-chamber ICDs may improve hemodynamic status, potentially leading to better survival and quality of life, especially in patients with compromised left ventricular function.
Abstract:
Single-chamber ventricular cardioverter-defibrillator (ICD) has been shown to significantly reduce the incidence of sudden cardiac death due to malignant ventricular arrhythmias. However, inappropriate therapy due to supraventricular tachyarrhythmias (mainly atrial fibrillation) affects up to 34% of patients. Moreover, it has been estimated that up to 20% of ICD patients are in the need of physiological antibradycardia pacing. Use of dual-chamber ICD offers an atrial signal for better ability to discriminate atrial from ventricular tachyarrhythmias as well as a maintenance of AV synchrony, what may be of critical importance for patients with a compromised left ventricular function. In the present study we describe our preliminary clinical experience with a dual-chamber ICD's implanted in 20 patients. During the implantation and in-hospital testing, 95 induced VT/VF episodes were correctly diagnosed by ICD, as well as 28 induced FA episodes. Over a mean follow-up period of 10 +/- 6 months, 98 tachycardia episodes were recorded. All 76 VT/VF episodes were correctly diagnosed, as were 18 of 22 FA. Four FA episodes were diagnosed as VT/VF and treated by antitachycardia pacing in 2 cases and by shock in 2. Thus, sensitivity and specificity of VT/VF detection are 100% and 82% respectively. A dual-chamber ICD appears to improve discrimination of atrial from ventricular tachyarrhythmias without loss of sensitivity and to decrease occurrence of inappropriate therapy. AV synchrony, by improving the hemodynamic status of the patient (mainly in those with impaired left ventricular function), may demonstrate better survival and comfort of life.