Complexities of treating co-morbidities in heart failure with preserved ejection fraction.

Atrial fibrillation and heart failure with preserved ejection fraction (HFpEF) are frequent concomitant diseases sharing several pathophysiological mechanisms leading to structural remodelling of both atria and ventricles. We present a case of an HFpEF patient with rapid atrial fibrillation who remained symptomatic even after successful cardioversion, initiation of antiarrhythmic therapy, and treatment of comorbidities. Due to asymmetric septal hypertrophy, the stress test was performed to exclude outflow tract obstruction and revealed a low basal heart rate with significant chronotropic insufficiency. In addition to SGLT2 initiation, the beta-blocker dose was reduced, and amiodarone was discontinued. This therapy modification led to a marked improvement in exercise capacity, significant reduction of palpitations, reduction of NT-proBNP, and signs of a decreased left ventricular filling pressure with reverse remodelling of LA. This case shows the importance of both individual tailoring of medical therapy and chronotropic insufficiency in HFpEF patients.