A study has assessed the relationship between atrial fibrillation and outcomes in the TOPCAT ( Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist ) trial, to evaluate whether atrial fibrillation can modify the treatment response to Spironolactone and whether Spironolactone can influence post-randomization atrial fibrillation.
Atrial fibrillation is common in heart failure with preserved ejection fraction ( HFpEF ) and likely contributes to increased risk of adverse outcomes.
A total 1,765 patients enrolled in TOPCAT trial in North and South America were divided into 3 groups: no known atrial fibrillation, history of atrial fibrillation without atrial fibrillation at enrollment, and atrial fibrillation found on the electrocardiogram ( ECG ) at enrollment.
Researchers have assessed outcomes and treatment response to Spironolactone in all groups, and the association between post-randomization atrial fibrillation and outcomes in patients free of atrial fibrillation at baseline.
The primary outcome of the TOPCAT trial was a composite of cardiovascular mortality, aborted cardiac arrest, or heart failure hospitalization.
Seven hundred sixty patients ( 43% ) had a history of atrial fibrillation ( 18% ) or atrial fibrillation on ECG at enrollment ( 25% ).
The highest adjusted risk was associated with atrial fibrillation at enrollment ( primary outcome, hazard ratio: 1.34; 95% confidence interval: 1.09 to 1.65; p = 0.006; and an increased early risk of secondary outcomes ).
Neither history of atrial fibrillation nor atrial fibrillation at enrollment modified the beneficial treatment effect of Spironolactone.
Post-randomization atrial fibrillation, which occurred in 6.3% of patients, was not influenced by Spironolactone treatment, but was associated with an increased early risk of the primary outcome ( hazard ratio: 2.32; 95% confidence interval: 1.59 to 3.40; p less than 0.0001 ) and secondary outcomes.
In conclusion, atrial fibrillation at enrollment was associated with increased cardiovascular risk in HFpEF patients in the TOPCAT study.
Post-randomization atrial fibrillation, which was associated with an increased risk of morbidity and mortality, was not influenced by Spironolactone. ( Xagena )
Cikes M et al, JACC Heart Fail 2018; Epub ahead of print