Fluorodeoxyglucose positron emission tomography/computed tomography in Takotsubo cardiomyopathy complicated by sinus arrest and third-degree atrioventricular block: a case report.

BACKGROUND: Takotsubo cardiomyopathy (TTC) complicated by sinus arrest and third-degree atrioventricular block (AVB) is extremely rare. This case illustrates the utility of 18F-FDG PET/CT (fluorodeoxyglucose positron emission tomography/computed tomography) in characterizing myocardial stunning of TTC with dual nodal dysfunction and provides insights into long-term conduction outcomes.

CASE SUMMARY: A 77-year-old female presented with acute chest pain and palpitations due to emotional stress. Echocardiography showed left ventricular (LV) apical hypokinesis [global longitudinal strain (GLS) -14.8%], coronary computed tomography angiography revealed mild mid-left anterior descending artery stenosis, and cardiac biomarkers were elevated (troponin-T: 0.0803 ng/mL; N-terminal pro-B-type natriuretic peptide: 696.92 ng/L). Holter monitoring documented sinus arrest, third-degree AVB, and a minimum heart rate of 31 b.p.m. Fluorodeoxyglucose positron emission tomography/computed tomography showed increased glucose uptake in the LV apex (consistent with myocardial stunning/inflammation), while technetium-99m methoxyisobutylisonitrile SPECT/CT detected mild apical hypoperfusion. A dual-chamber pacemaker was implanted for refractory bradycardia. At 1-month follow-up, LV apical hypokinesis resolved (GLS -19.0%), with recovered AV nodal but persistent sinoatrial nodal dysfunction.

DISCUSSION: Fluorodeoxyglucose positron emission tomography/computed tomography is valuable for clarifying the metabolic basis of TTC-related myocardial dysfunction, complementing perfusion imaging. Early pacing evaluation is critical for TTC patients with sinoatrial nodal impairment-even with AV nodal recovery, persistent sinoatrial dysfunction may require long-term pacing support to prevent bradycardia-related adverse events.