Can paroxysmal atrial fibrillation (Afib) cause heart failure with reduced ejection fraction (HFrEF)?

Paroxysmal Atrial Fibrillation Can Cause Heart Failure with Reduced Ejection Fraction

Yes, paroxysmal atrial fibrillation can cause heart failure with reduced ejection fraction (HFrEF) through multiple pathophysiological mechanisms, particularly via tachycardiomyopathy. 1

Pathophysiological Mechanisms

• Atrial fibrillation (AF) and heart failure (HF) have a bidirectional relationship, often described as "AF begets HF and HF begets AF" 1
• Paroxysmal AF can lead to the development and deterioration of left ventricular dysfunction and systolic heart failure through several mechanisms 1:
  • Rapid and irregular ventricular rates during AF episodes can directly decrease cardiac output 1
  • Rhythm irregularity during AF, independent of heart rate, can decrease cardiac output by approximately 0.8 L/min 1
  • Loss of atrial kick (atrial contribution to ventricular filling) impairs ventricular filling 1

Tachycardiomyopathy

• AF-mediated tachycardiomyopathy is a well-recognized complication where rapidly conducting AF serves as a reversible cause of HF 1
• The hallmark of tachycardiomyopathy is partial or complete reversibility once the arrhythmia is controlled 1
• AF is the most common cause of tachycardiomyopathy in adults 1
• The diagnosis of AF-mediated tachycardiomyopathy should always be considered in patients with new-onset or worsening HF with AF and rapid ventricular response, particularly without prior history of structural heart disease 1

Clinical Evidence

• Patients with paroxysmal AF have a higher risk of heart failure hospitalization compared to those without AF (HR: 1.34; 95% CI: 1.19 to 1.51; p < 0.001) 2
• Many patients with severe HFrEF gain rapid hemodynamic improvement with immediate cardioversion, demonstrating the causal relationship 1
• Some patients remain symptomatic during AF despite sufficient rate control and improve with restoration of sinus rhythm, further supporting the causal relationship 1
• New-onset AF is associated with the greatest risk of adverse outcomes including heart failure hospitalization (HR: 2.11; 95% CI: 1.58 to 2.81) 2

Management Implications

• For patients with HFrEF when AF is suspected to significantly contribute to low blood pressure, restoring sinus rhythm may be a reasonable approach 1
• Catheter ablation for AF in patients with HFrEF has shown superiority in improving survival, quality of life, ventricular function, and reducing heart failure hospitalizations compared with antiarrhythmic drugs and rate control therapies 3
• The 2016 ESC guidelines provide a Class IIa-B recommendation for catheter ablation in patients with concomitant HF and AF, particularly for symptomatic paroxysmal or persistent AF and AF-mediated tachycardiomyopathy 1
• Factors favoring AF ablation in HFrEF patients include recent onset HF, recent onset AF with fast ventricular rates, and idiopathic cardiomyopathy 1

Clinical Pearls and Caveats

• The prevalence of AF among patients with HF ranges from 10-57% depending on age, onset, and severity of HF 1
• Conversely, the rate of HF ranges between 40-55% in patients with persistent and long-standing persistent AF 1
• When both conditions coexist, they synergistically confer worse outcomes compared to either condition alone 1
• Early rhythm control therapy is associated with better cardiovascular outcomes among patients with recent AF and cardiovascular conditions, including those with HF 4
• Careful patient selection for AF ablation is crucial, as not all patients will benefit from ablation-based rhythm control, particularly those with extensive atrial/ventricular remodeling or advanced age 1