Characteristics and Clinical Outcomes of Patients Hospitalized for Acute Heart Failure Who Develop Atrial Fibrillation or Convert to Sinus Rhythm

Background: Atrial 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.

Methods: In a post hoc secondary analysis of the randomized, double-blind, placebo-controlled PROTECT trial in patients with AHF, we identified 4 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).

Results: Conversion from AF to sinus rhythm (13.7%) and from sinus rhythm to AF (7.0%) occurred only in a minority of patients. Patients with AF who converted to sinus rhythm were more often classified as being in New York Heart Association class IV, had higher heart rates and higher respiratory rates at hospital admission, whereas patients who developed AF were older, more likely to be female and had the highest ejection fractions 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 longer median lengths of hospital stay (8 vs 7 days; P < 0.001 and 9 vs 7 days; P < 0.001, respectively), compared to those with continuous sinus rhythm. In both univariable and multivariable analyses, 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.

Conclusion: In patients hospitalized for AHF, only few converted from AF to sinus rhythm or sinus rhythm to AF. Although development of AF or persistent AF was associated with longer lengths of hospitalization, midterm mortality and readmission rates were similar in the groups.