Majority of ICD Patients Die of Heart Failure

Patients with implantable cardiac defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT-Ds) are likelier to die of heart failure (HF), according to a new study.

Researchers at Leiden University Medical Center (LUMC; The Netherlands) conducted a study involving 2,859 patients who underwent an ICD or CRT-D implantation at the LUMC between 1996 and 2010. The patients were divided into primary prevention ICD, secondary prevention ICD, and CRT-D patients. For patients who died during follow-up, the mode of death was retrieved from hospital and general practitioner records, and categorized according to a predetermined classification: HF death, other cardiac death, sudden death, noncardiac death, and unknown death.

The results showed that the cumulative incidence of all-cause mortality increased over time, going from 2% at 2 years to 40% after 8 years. The 8-year cumulative incidence for HF death was 8.6% among patients with an ICD for primary prevention, 9.6% among secondary prevention ICD patients, and 22.6% for those with a CRT-D. Conversely, the 8-year cumulative incidence of sudden death was 2.1% and 3.2% in the primary and secondary prevention ICD patients, and 3.6% in those with a CRT-D; in all, sudden death accounted for approximately 7-8% of all deaths. The most common causes of noncardiac death among the three groups were malignant neoplasm and infection, but there was a large number deaths for which the cause could not be determined. The study was published early online on April 18, 2012, in the journal HeartRhythm.

“For all patients, heart failure and noncardiac death are the most common modes of death,” concluded lead author Martin Schalij, MD, PhD, and colleagues of the department of cardiology. “The proportion of patients who died suddenly was low and comparable for primary and secondary ICD, and CRT-D patients.”
Defibrillator devices have been shown in large randomized trials to decrease mortality among primary prevention ICD patients, including those with ischemic and nonischemic heart disease at risk of sudden arrhythmic death. They also have been shown to have a mortality benefit in secondary prevention, including those who have survived life-threatening ventricular arrhythmias, mainly due to the addition of defibrillation capabilities.

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Leiden University Medical Center