Does rhythm matter? The prognostic importance of atrial fibrillation in heart failure.

Background: Atrial fibrillation (AF) and congestive heart failure (HF) often coexist, but there is conflicting data regarding the association of AF with outcome in HF. To examine this further we have evaluated the prognostic effect of AF in two complementary CHF populations; a population based data set of 55,106 patients admitted to hospital with CHF, and a cohort of 197 patients recruited after a hospital admission with HF into a management clinical trial.

Methods: Firstly, data for all hospital admissions in New Zealand from 1988 to 1997 were obtained. Using coding data, 55,106 first admissions for HF were identified, the presence of AF was determined by secondary diagnosis coding, and all cause mortality was obtained. Secondly, patients enrolled in the Auckland Heart Failure Management Study were evaluated for the presence or absence of AF, and for all cause mortality at three years.

Results: Mortality at 30 days, 6 and 12 months was significantly lower for AF patients compared to sinus rhythm (SR) in the national admissions cohort. In the clinical trial cohort the presence of AF was also associated with lower three-year mortality, although this difference was not seen when the groups were stratified by Doppler mitral filling pattern (a restrictive filling pattern was associated with reduced longevity compared to SR, non-restrictive or AF).

Conclusions: This data shows that the presence of AF in two general HF populations in New Zealand is not associated with an adverse prognosis. HF severity, and in particular a restrictive filling pattern, remain powerful predictors of mortality.