Can Atrial Fibrillation (Afib) cause Congestive Heart Failure (CHF)?

Does Atrial Fibrillation Cause Congestive Heart Failure?

Yes, atrial fibrillation can directly cause heart failure through a condition called tachycardia-mediated cardiomyopathy (also known as AF-mediated cardiomyopathy), which is potentially reversible with adequate rhythm or rate control. 1, 2

Mechanisms by Which AF Causes Heart Failure

AF compromises cardiac function through three distinct pathophysiological mechanisms:

• Loss of atrial mechanical contraction ("atrial kick"): The absence of synchronous atrial activity can decrease cardiac output by up to 15-20%, particularly devastating in patients with impaired diastolic filling, hypertension, mitral stenosis, hypertrophic cardiomyopathy, or restrictive cardiomyopathies 3

• Irregular ventricular rhythm: Even at normal mean heart rates, the irregularity alone reduces cardiac output by 9-15% compared to regular rhythm due to force-interval relationships and variations in cycle length 3

• Persistently rapid ventricular rate: AF with rates ≥130 bpm can produce dilated ventricular cardiomyopathy through myocardial energy depletion, ischemia, abnormal calcium regulation, and ventricular remodeling 3, 2

Diagnosing AF-Mediated Cardiomyopathy

The hallmark of tachycardia-mediated cardiomyopathy is partial or complete reversibility once the arrhythmia is controlled. 2

To establish this diagnosis:

• Suspect AF-mediated cardiomyopathy in any patient with new-onset or worsening heart failure in the setting of AF with rapid ventricular response 2

• Attempt strict rhythm control for at least 6-8 weeks to determine if AF is contributing to ventricular dysfunction 1

• Document improvement in left ventricular systolic function after rhythm control to confirm the causal link 1, 2

• Important caveat: Not only rapid but also normal irregular ventricular responses can cause tachycardiomyopathy, so pharmacological rate control alone may be insufficient for diagnosis or treatment 1, 2

Evidence for Reversibility with Treatment

Multiple randomized controlled trials demonstrate that AF ablation in heart failure patients results in significant improvements in left ventricular ejection fraction:

• CAMERA-MRI trial (2017): Showed LVEF improvement of +18% in the ablation group versus +4% in rate control, with 58% achieving LVEF normalization ≥50% compared to only 9% with rate control 1

• CAMTAF trial (2014): Demonstrated LVEF improvement of +8% with ablation versus -3% with pharmacological rate control 1

• PABA-CHF trial (2008): Showed absolute LVEF increase of +8% versus -1% when comparing AF ablation to biventricular pacing plus AV node ablation 1

Bidirectional Relationship

While AF can cause heart failure, the relationship is bidirectional:

• Heart failure also promotes AF: Ventricular dysfunction activates the renin-angiotensin-aldosterone system, causes atrial structural remodeling, volume retention, increased atrial pressure, atrial stretch, and functional mitral regurgitation—all facilitating AF initiation and maintenance 2

• Synergistic worsening: The coexistence creates synergistically worse outcomes, with almost 3-fold higher risk for stroke/TIA and almost 2-fold higher heart failure-related and overall mortality compared to cardiomyopathy patients without AF 2

Clinical Implications

Freedom from AF recurrence and absence of ventricular late gadolinium enhancement on cardiac MRI predict improvement of left ventricular dysfunction after AF ablation. 1

This evidence strongly supports that AF is not merely a marker of heart failure severity but can be a direct causative factor, particularly when:

• The ventricular rate is persistently elevated (≥130 bpm) 3
• There is new-onset cardiomyopathy in the setting of AF 2
• Cardiac MRI shows absence of significant ventricular fibrosis (negative LGE) 1