Characteristics and clinical outcomes of patients hospitalized for acute heart failure who develop atrial fibrillation or convert to sinus rhythm

BackgroundAtrial fibrillation (AF) is the most common sustained arrhythmia in acute heart failure (AHF), with a prevalence of approximately 35%. However, little is known about the clinical characteristics and outcomes of in-hospital conversion from AF to sinus rhythm and vice versa.MethodsIn a post-hoc secondary analysis of the randomized, double-blind, placebo-controlled PROTECT trial in patients with AHF, we identified four groups of patients; AF at admission and in-hospital conversion to sinus rhythm (n=44), in-hospital development of AF (n=31), persistent AF (n=278) and continuous sinus rhythm (n=410).ResultsConversion from AF to sinus rhythm (13.7%) and from sinus rhythm to AF (7.0%) only occurred in a minority of patients. Patients with AF who converted to sinus rhythm more often had New York Heart Association class IV, higher heart rate and higher respiratory rate at hospital admission, whereas patients who developed AF were older, more likely to be female and had the highest ejection fraction, compared to continuous sinus rhythm (all P<0.05). Conversion to sinus rhythm or development of AF occurred mainly within the first 24 hours after hospital admission. Patients with persistent AF and those who developed AF had a longer median length of hospital stay (8 vs. 7 days; P<0.001 and 9 vs. 7 days; P<0.001 respectively), compared to continuous sinus rhythm. In both univariable and multivariable analysis, there was no significant association between the AF groups and the primary clinical outcomes of either 180-day all-cause mortality or 60-day death or readmission for heart failure.ConclusionIn patients hospitalized for AHF, only few converted from AF to sinus rhythm or sinus rhythm to AF. Although development of AF or persistent AF were associated with a longer length of hospitalization, mid-term mortality and readmission rates were similar between the groups.