CONGRESS ABSTRACT

A 75-year-old woman with no known cardiovascular disease was admitted for acute decompensated heart failure. She reported months of progressive exertional dyspnea. Electrocardiography revealed atrial fibrillation with rapid ventricular response (~140 bpm). Transthoracic echocardiography showed reduced left ventricular ejection fraction (LVEF 40%) with diffuse hypokinesia, severe atrial dilation with atrial functional moderate-to-severe mitral and tricuspid regurgitation, pulmonary hypertension and left pleural effusion. Laboratory tests showed reduced TSH (0.26 μIU/mL) with normal free thyroid hormones, and no liver or kidney damage. During hospitalization, multiple attempts at rate control were performed using high-dose beta-blockers (metoprolol up to 200 mg/day, followed by propranolol up to 160 mg/day) and digoxin, with poor ventricular rate control. After exclusion of left atrial appendage thrombosis, electrical cardioversion successfully restored sinus rhythm, with rapid improvement of LVEF to 52%, consistent with tachycardiomyopathy. The patient was discharged in sinus rhythm (60 bpm) on metoprolol 100 mg/die, flecainide 100 mg/die, anticoagulation, diuretics, canreonate and antithyroid therapy (metimazole 5 mg/die); catheter ablation of AF was scheduled. Within 24 hours, she was readmitted with syncope. On admission, she was hypotensive (70/50 mmHg) with sinus bradycardia (45 bpm), severe metabolic derangement (lactate 7.4 mmol/L), and acute kidney injury (creatinine 3.4 mg/dL). Echocardiography showed severe functional mitral and tricuspid regurgitation with global hypokinesia and LVEF 40%. Iatrogenic beta-blocker–induced hemodynamic collapse was suspected. She required inotropes and withdrawal of negative chronotropic drugs. Hemodynamics progressively improved, and serial echocardiography demonstrated complete recovery of LVEF (60%) and marked reduction of valvular regurgitation. Coronary angiography was normal. At 3-month follow-up, her echocardiogram showed persistence of normal LVEF together with mild mitral and tricuspid regurgitation. She underwent successful AF ablation. Conclusion This case illustrates the vulnerability of patients with AF-related tachycardiomyopathy and thyroid dysfunction. Even after apparent recovery and restoration of sinus rhythm, beta-blockers may precipitate cardiogenic shock. Early rhythm-control strategies, cautious pharmacological therapy and prolonged in-hospital observation are crucial in this population.