Syncope Predicts the Outcome of Cardiomyopathy Patients. Analysis of the SCD-HeFT Study

Objectives: The outcome of congestive heart failure (CHF) patients with syncope is understood incompletely. Background: We analyzed data from patients enrolled in the SCD-HeFT (Sudden Cardiac Death Heart Failure Trial) to determine whether syncope predicted outcomes in patients with CHF. Methods: We compared outcomes (and associated clinical characteristics) in patients with and without syncope enrolled in SCD-HeFT. Results: In SCD-HeFT, 162 (6%) patients had syncope before randomization, 356 (14%) had syncope after randomization (similar incidence in each randomized arm), and 46 (2%) had syncope before and after randomization. A QRS duration ≥120 ms and absence of beta-blocker use predicted syncope during follow-up (hazard ratio [HR] 1.30 and 95% confidence interval [CI] 1.06 to 1.61, p = 0.014 and HR 1.25, 95% CI 1.01 to 1.56, p = 0.048, respectively). Syncope recurrence did not differ by randomization arm. However, in the implantable cardioverter-defibrillator (ICD) arm, syncope, before and after randomization, was associated with appropriate ICD discharges (HR 1.75, 95% CI 1.10 to 2.80, p = 0.019 and HR 2.91, 95% CI 1.89 to 4.47, p = 0.001, respectively). Post-randomization syncope predicted total and cardiovascular death (HR 1.41, 95% CI 1.13 to 1.76, p = 0.002 and HR 1.55, 95% CI 1.19 to 2.02, p = 0.001, respectively). The elevated relative risk of mortality for syncope versus nonsyncope patients did not vary significantly across treatment arms (ICD, HR 1.54, 95% CI 1.04 to 2.27; amiodarone, HR 1.33, 95% CI 0.91 to 1.93; and placebo, HR 1.39, 95% CI 0.96 to 2.02, test for difference p = 0.86). Conclusions: For CHF patients with ICDs, syncope was associated with appropriate ICD activations. Syncope was associated with increased mortality risk in SCD-HeFT regardless of treatment arm (placebo, amiodarone, or ICD). (SCD-HeFT Trial; NCT00000609).