The following is a summary of “Relative Contribution of Atrial Fibrillation to Outcomes of Patients With Cardiomyopathy Based on Severity of Left Ventricular Dysfunction,” published in the July 2023 issue of the Cardiovascular Disease by Ayub et al.
In individuals experiencing left ventricular (LV) dysfunction, the likelihood of mortality or hospitalizations due to heart failure (HFHs) escalates as the ejection fraction (EF) deteriorates. The extent to which atrial fibrillation (AF) impacts outcomes in patients with lower ejection fraction remains uncertain. The current study sought to examine the relative impact of atrial fibrillation on the prognosis of patients with cardiomyopathy based on the severity of left ventricular dysfunction. This observational study analyzed data from 18,003 patients with an ejection fraction of 50% or less who were treated at a prominent academic medical center from 2011 to 2017.
The patients were categorized based on quartiles of ejection fraction as follows: EF less than 25% for quartile 1, EF between 25% and less than 35% for quartile 2, EF between 35% and less than 40% for quartile 3, and EF greater than or equal to 40% for quartile 4. and progressed to the terminal stage of mortality or hospitalization for health failure. The outcomes of patients with atrial fibrillation were compared to those without AF within each quartile of ejection fraction. Over a median follow-up period of 3.35 years, 8,037 patients (45%) experienced mortality, while 7,271 patients (40%) developed at least one hospitalization for heart failure. The incidence of heart failure and mortality from any cause demonstrated an upward trend as the ejection fraction declined.
The hazard ratios (HRs) of death or hospitalization for heart failure in patients with atrial fibrillation compared to patients without AF increased progressively as the ejection fraction increased (HR of 1.22, 1.27, 1.45, 1.50 for quartiles 1, 2, 3, and 4, respectively, P=0.045). This increase was primarily driven by the risk of HFH (HR of 1.26, 1.45, 1.59, 1.69 for quartiles 1, 2, 3, and 4, respectively, P=0.045). In summary, among individuals with left ventricular dysfunction, the adverse impact of atrial fibrillation on the likelihood of heart failure hospitalization is particularly noticeable in those with a higher degree of preserved ejection fraction. Mitigation strategies for atrial fibrillation to reduce heart failure hospitalizations may significantly impact patients with a higher degree of preserved left ventricular function.