QRS Duration Is a Predictor of Adverse Outcomes in Heart Failure With Preserved Ejection Fraction.

OBJECTIVES: This study examined the relationship between baseline QRS duration and clinical outcomes in subjects enrolled in the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist) trial.

BACKGROUND: Heart failure with preserved ejection fraction (HFPEF) is a heterogeneous clinical syndrome. Whether QRS duration identifies HFPEF subjects at an increased risk of adverse outcomes has not been well studied.

METHODS: QRS duration was analyzed as a dichotomous variable (≥120 ms or <120 ms) and as a continuous variable to determine its relation to the primary outcome (composite of cardiovascular death, aborted cardiac arrest, or HF hospitalization [HFH]) and to each component of the primary outcome. Multivariate analyses were conducted in the entire study cohort as well as in separate analyses for subjects enrolled only from North and South America, or from Russia and Georgia.

RESULTS: The QRS duration of ≥120 ms was independently associated with an increased risk of the primary outcome (p = 0.009) and HFH (p = 0.003) in the entire study cohort and in the subset enrolled in the Americas. There was a linear relation of QRS duration with risk of the primary outcome and HFH. No interaction was observed between treatment with spironolactone and QRS duration. The risk of adverse outcomes was increased independently of the type of conduction abnormality underlying prolonged QRS duration.

CONCLUSIONS: This post hoc analysis demonstrated that prolonged QRS duration identifies HFPEF subjects at a higher risk of adverse clinical outcomes and that spironolactone had a similar effect on outcomes independent of QRS duration. (Aldosterone Antagonist Therapy for Adults With Heart Failure and Preserved Systolic Function [TOPCAT]; NCT00094302).