Impact of age and medical comorbidity on the effectiveness of implantable cardioverter-defibrillators for primary prevention.

Background: Although implantable cardioverter-defibrillators (ICDs) reduce mortality in primary prevention patients with left ventricular systolic dysfunction, recent studies have questioned their overall role in clinical practice, especially in older patients and those with major comorbid conditions.

Methods And Results: In a prospective cohort of 965 patients with ischemic and nonischemic cardiomyopathies (ejection fraction or=75), ischemic etiology, ejection fraction (>25% versus 0.05). Incremental cost-effectiveness ratios for ICD therapy were similar between patients aged >or=75 years and younger patients but rose slightly in those with multiple comorbid conditions.

Conclusions: Routine use of ICDs in primary prevention patients with left ventricular systolic dysfunction was associated with lower all-cause mortality, even among older patients and those with major comorbid conditions. Although their use needs to be individualized, our findings suggest that these groups should not be routinely excluded from ICD treatment.