HealthDay News — For patients with left bundle branch block, the benefit of cardiac resynchronization therapy with defibrillator (CRT-D) over implantable cardioverter-defibrillator (ICD) alone persists with comorbidity, according to a study published in the May 16 issue of the Journal of the American College of Cardiology.

Emily P. Zeitler, MD, from Duke University Hospital in Durham, NC, and colleagues examined the correlation of multiple comorbidities with the benefits of CRT-D over ICD alone in 1,214 patients with left bundle branch block and zero, one, two, or three or more comorbidities.

The researchers identified an inverse correlation between comorbidity burden and improvements in left ventricular (LV) end-systolic volume, LV end-diastolic volume, LV ejection fraction, left atrial volume, and LV dyssynchrony. Regardless of treatment group, there was an increasing risk of death or nonfatal heart failure events with increasing comorbidity burden in an adjusted model (P<0.001). There was no interaction with respect to comorbidity burden and the benefit of CRT-D versus ICD only for death or nonfatal heart failure events during a mean follow-up of 4.65 years (interaction, P=0.943). The absolute risk reduction associated with CRT-D versus ICD alone was greater for groups with the greatest comorbidity burden versus those with less comorbidity burden (2 and ≥3 versus 0 and 1). 

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“The burden of comorbidity does not appear to compromise the clinical benefits of CRT-D compared with ICD alone,” the authors write.

Several authors disclosed financial ties to the pharmaceutical and medical device industries.

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