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AF Worsening Pre-existing HFrEF — EECC MCQ

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ModerateHeart FailureAF Worsening Pre-existing HFrEFEECC

A 58-year-old man with HFrEF (LVEF 25%) on optimal GDMT develops new-onset AF with rapid ventricular response (HR 140 bpm). His LVEF drops to 18%. After successful cardioversion and rate control, his LVEF returns to 28%. What does this demonstrate?

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Correct answer: D — AF-induced tachycardia-mediated worsening of pre-existing cardiomyopathy — the rapid ventricular rate caused additional reversible myocardial injury; both underlying HFrEF and the AF contribution must be treated to optimise LVEF

In patients with pre-existing cardiomyopathy, new-onset AF with uncontrolled rate causes ADDITIONAL reversible LV dysfunction layered on top of the baseline disease. This occurs through: (1) tachycardia-mediated injury (chronic rapid rate → metabolic depletion, calcium overload → impaired contractility); (2) loss of atrial contraction (reduces cardiac output by ~15-30%, more in stiff/non-compliant ventricles); (3) irregularity of RR intervals (reduces cardiac efficiency). After AF treatment (cardioversion or rate control), the REVERSIBLE component recovers (LVEF returns toward baseline), while the underlying cardiomyopathy persists. This is clinically important: (1) AF in HFrEF must be treated aggressively; (2) the CASTLE-AF trial showed AF ablation improves outcomes in HFrEF; (3) tachycardia-induced cardiomyopathy may coexist with other cardiomyopathies, making it essential to treat AF before concluding the LV dysfunction is irreversible.

Reference: ESC (2024): AF Guidelines; ESC (2023): HF Guidelines