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Analysis of deaths in patients with an implantable cardioverter defibrillator
T B Edel1, J D Maloney, S L Moore
1Cleveland Clinic Foundation, Ohio 44195-5064.
Insights
Implantable cardioverter-defibrillator (ICD) placement has a 4% operative mortality, primarily from ventricular arrhythmias. Poor left ventricular function and presentation as ventricular tachycardia are key predictors of worse outcomes after ICD implantation.
Area of Science:
- Cardiology
- Medical Devices
- Clinical Outcomes
Background:
- Implantable cardioverter-defibrillators (ICDs) are crucial for managing life-threatening arrhythmias.
- Assessing patient outcomes and predictors of mortality post-ICD implantation is vital for refining patient selection and management.
Purpose of the Study:
- To review the causes of death and clinical characteristics of patients who died after ICD placement.
- To compare outcomes between deceased and living patients following ICD implantation.
- To identify preoperative and device-related predictors of mortality.
Main Methods:
- Retrospective review of 171 patients undergoing ICD implantation.
- Comparison of clinical characteristics between 26 deceased and 145 living patients.
- Multivariate analysis to identify predictors of prognosis.
Main Results:
- Operative mortality was 4%, with higher rates for concomitant procedures. Late mortality was 11%, mainly due to progressive left ventricular dysfunction and arrhythmias.
- Sudden cardiac death accounted for 7 cases, with defibrillation system failures in some instances.
- Predictors of worse prognosis included presentation as ventricular tachycardia, poor left ventricular function, poor functional status, diuretic use, frequent device discharges, and antitachycardia pacing systems.
Conclusions:
- ICD implantation carries a significant but manageable risk, with specific patient characteristics predicting poorer outcomes.
- Defibrillation system failures and device programming (e.g., antitachycardia pacing) are critical factors influencing mortality.
- Identifying high-risk patients preoperatively can guide clinical decision-making and improve post-implantation management.
Abstract:
The cause of death and clinical characteristics of 26 patients that died after implantable cardioverter defibrillator placement were reviewed and compared to the 145 patients still living after a mean follow-up of 17 months. Operative mortality was 4% (7/171) and resulted from postoperative ventricular arrhythmias (four patients), heart failure (two patients), and respiratory failure (one patient). Operative mortality was significantly higher (1.7% vs 9.6%, P less than 0.05) following concomitant surgical procedures. Total late mortality was 11% (18/171). Thirteen deaths (75%) occurred in-hospital from progressive deterioration of left ventricular function (nine patients), arrhythmia (two patients), and noncardiac causes (two patients). Outpatient mortality was 3.5% (6/171) and resulted from presumed sudden cardiac death in five of six patients; two of the five had devices that were inactive, one had high defibrillation thresholds, and two had suspected bradyarrhythmic deaths. One postoperative death and one late in-hospital death were also considered sudden cardiac deaths for a total of seven patients with defibrillation system failures. By multivariant analysis, preoperative clinical characteristics associated with a worse prognosis following defibrillator implantation were identified: presentation as ventricular tachycardia (P less than 0.02), induction of sustained monomorphic ventricular tachycardia (P less than 0.05), poor left ventricular performance (P less than 0.01), poor functional status (P less than 0.001), and the use of diuretics (P less than 0.01). Frequent device discharges (P less than 0.001) and concomitant antitachycardia pacing systems (P less than 0.001) were markers for greater arrhythmia recurrence and were potent predictors of a worse prognosis and particularly sudden death.