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Adding Defibrillation Therapy to Cardiac Resynchronization on the Basis of the Myocardial Substrate
Sérgio Barra1, Serge Boveda2, Rui Providência3
1Cardiology Department, Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom.
Insights
Patients with ischemic cardiomyopathy (ICM) benefit from an implantable cardioverter-defibrillator (ICD) alongside cardiac resynchronization therapy (CRT), improving survival. However, those with nonischemic dilated cardiomyopathy (DCM) show no significant survival difference with an ICD plus CRT.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Nonischemic dilated cardiomyopathy (DCM) patients may have lower ventricular arrhythmia risk than ischemic cardiomyopathy (ICM) patients.
- DCM predicts a positive response to cardiac resynchronization therapy (CRT).
Purpose of the Study:
- To investigate the impact of an implantable cardioverter-defibrillator (ICD) in addition to CRT.
- To analyze outcomes based on underlying heart disease in primary prevention heart failure patients.
Main Methods:
- Observational, multicenter European cohort study of 5,307 patients with DCM or ICM.
- Patients underwent CRT implantation with or without an ICD.
- Propensity-score and cause-of-death analyses were used to compare outcomes.
Main Results:
- ICM patients receiving CRT with an ICD showed improved survival compared to those without (HR: 0.76; p=0.005).
- DCM patients showed no significant survival difference with or without an ICD alongside CRT (HR: 0.92; p=0.49).
- Excess mortality in non-ICD recipients was linked to sudden cardiac death in 8.0% of ICM patients vs. 0.4% of DCM patients.
Conclusions:
- For heart failure patients indicated for CRT, additional primary prevention ICD therapy may not benefit those with DCM.
- ICM patients, however, may benefit from the addition of an ICD to CRT for primary prevention.
Background:
Patients with nonischemic dilated cardiomyopathy (DCM) may be at lower risk for ventricular arrhythmias compared with those with ischemic cardiomyopathy (ICM). In addition, DCM has been identified as a predictor of positive response to cardiac resynchronization therapy (CRT).
Objectives:
The aim of this study was to investigate the impact of an additional implantable cardioverter-defibrillator over CRT, according to underlying heart disease, in a large study group of primary prevention patients with heart failure.
Methods:
This was an observational, multicenter, European cohort study of 5,307 consecutive patients with DCM or ICM, no history of sustained ventricular arrhythmias, who underwent CRT implantation with (n = 4,037) or without (n = 1,270) a defibrillator. Propensity-score and cause-of-death analyses were used to compare outcomes.
Results:
After a mean follow-up period of 41.4 ± 29.0 months, patients with ICM had better survival when receiving CRT with a defibrillator compared with those who received CRT without a defibrillator (hazard ratio for mortality adjusted on propensity score and all mortality predictors: 0.76; 95% confidence interval [CI]: 0.62 to 0.92; p = 0.005), whereas in patients with DCM, no such difference was observed (hazard ratio: 0.92; 95% CI: 0.73 to 1.16; p = 0.49). Compared with recipients of defibrillators, the excess mortality in patients who did not receive defibrillators was related to sudden cardiac death in 8.0% among those with ICM but in only 0.4% of those with DCM.
Conclusions:
Among patients with heart failure with indications for CRT, those with DCM may not benefit from additional primary prevention implantable cardioverter-defibrillator therapy, as opposed to those with ICM.