Survival of implantable cardioverter-defibrillator recipients: role of left ventricular function and its relationship to device use
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1Arrhythmia and Pacemaker Service, Eastern Heart Institute, Passaic, N.J.
Insights
Implantable cardioverter-defibrillator (ICD) therapy shows similar survival benefits for ventricular tachycardia in patients with moderate to severe left ventricular dysfunction. However, cardiac mortality is significantly higher in severe dysfunction patients, regardless of ICD shocks.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- The efficacy of implantable cardioverter-defibrillator (ICD) therapy for malignant ventricular tachyarrhythmia in patients with varying degrees of left ventricular dysfunction remains incompletely understood.
- Left ventricular dysfunction (LVD) is a critical factor influencing outcomes in patients with ventricular arrhythmias.
Purpose of the Study:
- To evaluate the patterns of ICD use and survival rates in patients with moderate to severe left ventricular dysfunction.
- To compare outcomes between patients with moderate LVD (LVEF >30%) and severe LVD (LVEF ≤30%).
Main Methods:
- A cohort of 112 patients with moderate to severe LVD were divided into two groups based on left ventricular ejection fraction (LVEF).
- Group 1: 57 patients with moderate LVD (LVEF >30%). Group 2: 55 patients with severe LVD (LVEF ≤30%).
- Follow-up ranged from 1 to 78 months, with actuarial analysis used for survival calculations.
Main Results:
- At 3 years, ICD activation for ventricular tachycardia was similar in both groups (65% vs. 71%).
- Four-year mortality from arrhythmia or sudden death was comparable (5% vs. 9%).
- However, cardiac mortality was significantly higher in the severe LVD group at 2 years (40% vs. 12%, p=0.05) and 4 years (43% vs. 15%, p<0.01).
- No significant difference in cardiac mortality was observed based on appropriate ICD shocks within either group.
Conclusions:
- ICD therapy provides comparable survival benefits for ventricular tachyarrhythmia in patients with moderate and severe left ventricular dysfunction.
- Patients with severe left ventricular dysfunction face a substantially higher risk of cardiac mortality, irrespective of ICD intervention.
- Further research may be needed to optimize management strategies for severe LVD patients experiencing ventricular arrhythmias.
Abstract:
The quantitative benefit of ICD therapy in patients with malignant ventricular tachyarrhythmia with different degrees of left ventricular dysfunction is unclear. We evaluated patterns of ICD use and survival in 112 patients with moderate to severe left ventricular dysfunction. Group 1 included 57 patients with moderate left ventricular dysfunction (defined as left ventricular ejection fraction greater than 30%) and group 2 comprised 55 patients with severe left ventricular dysfunction (defined as ejection fraction equal to or less than 30%). The follow-up period ranged from 1 to 78 months. Age, incidence of coronary artery disease, and presenting arrhythmia in the two groups were similar. The mean left ventricular ejection fraction in group 1 was 44.6 +/- 8.2% and in group 2 was 21.6 +/- 6% (p < 0.0001). At 3 years of follow-up 65% of the patients in group 1 and 71% in group 2 (p = NS) had ICD activation for presumed ventricular tachycardia. Survival was calculated by means of actuarial analysis. Arrhythmia or sudden death mortality at 4 years of follow-up was 5% in group 1 and 9% in group 2 (NS). Cardiac mortality was higher in patients with severe left ventricular dysfunction reaching levels of statistical significance at 2 years of follow-up. At 2 years of follow-up it was 12% in group 1 and 40% in group 2 (p = 0.05), and at 4 years of follow-up it was 15% in group 1 and 43% in group 2 (p < 0.01). In both groups there was no difference in cardiac mortality in patients who did and did not have appropriate ICD shocks.(ABSTRACT TRUNCATED AT 250 WORDS)