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Predictors of outcome in patients with implantable transvenous cardioverter defibrillators
J Tebbenjohanns1, B Schumacher, W Jung
1Department of Cardiology, University of Bonn, Germany.
Insights
Identifying patients for implantable cardioverter defibrillator (ICD) therapy is key. Lower ejection fraction and inducible sustained monomorphic ventricular tachycardia predict appropriate ICD discharges, aiding patient selection.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Implantable cardioverter defibrillator (ICD) therapy is crucial for preventing sudden cardiac death.
- Identifying patients who will benefit most from ICDs remains a significant clinical challenge.
Purpose of the Study:
- To determine if clinical variables, signal-averaged electrocardiogram (SAECG), and electrophysiologic study (EPS) predict appropriate ICD discharges and mortality.
- To identify predictors of appropriate ICD therapy in patients receiving transvenous ICDs.
Main Methods:
- A follow-up study of 76 patients after transvenous ICD implantation.
- Analysis of clinical variables (ejection fraction), SAECG, and EPS findings.
- Comparison of patients with appropriate ICD discharges versus those without.
Main Results:
- A lower mean ejection fraction (35.4% vs 45.1%, p < 0.05) predicted appropriate ICD discharges.
- Inducible sustained monomorphic ventricular tachycardia (75.9% vs 21.2%, p < 0.01) was a significant predictor.
- Inducible ventricular fibrillation was less likely in patients with appropriate discharges (10.3% vs 25.5%, p < 0.05).
- SAECG abnormalities were more frequent but not statistically significant.
- Overall mortality was 7.8%.
Conclusions:
- Lower ejection fraction and inducible sustained monomorphic ventricular tachycardia are significant predictors of future appropriate ICD discharges.
- Transvenous ICD implantation demonstrates excellent survival rates.
- Further long-term follow-up is needed to fully define predictors of overall mortality.
Abstract:
The identification of patients who benefit most from implantable cardioverter defibrillator (ICD) therapy is of great interest. To find out if clinical variables, the signal-averaged electrocardiogram, and electrophysiologic study predict occurrence of appropriate ICD discharges and death, we followed-up on 76 patients after implantation of a transvenous ICD. During a mean follow-up period of 18.2 +/- 6.4 months, 29 patients (38.6%) experienced at least one appropriate episode. When these patients were compared with those who had either no therapy or inappropriate episodes, three variables were found to be significant in the identification of patients who experienced appropriate discharges: (1) The mean ejection fraction of patients who received appropriate discharges was 35.4% +/- 13.5% versus 45.1% +/- 15.3% in the other group (p < 0.05); (2) patients with appropriate therapy had sustained monomorphic ventricular tachycardia that was more likely to be inducible (75.9% vs 21.2%, p < 0.01); and (3) in patients with appropriate therapy ventricular fibrillation was less likely to be inducible (10.3% vs 25.5%, p < 0.05). The signal-averaged electrocardiograms were more often abnormal, but the differences were not significant. The total mortality rate in our patient group was 7.8%, with nonsudden cardiac death in four patients, noncardiac death in one patient, and sudden death in one patient. In our patient group a lower ejection fraction and inducible sustained monomorphic ventricular tachycardia were predictors of future ICD discharge after implantation. The survival rate after transvenous ICD implantation is excellent; a longer follow-up period is necessary to further define predictors of total mortality rate.