Radiofrequency ablation of atrial flutter with 1:1 accessory pathway conduction improved cardiac function in a patent with PRKAG2 Cardiomyopathy. Insights with 68Ga-FAPI PET/CT imaging.

PRKAG2 syndrome is an autosomal dominant cardiac glycogenosis caused by mutations in the PRKAG2 gene, clinically characterized by the triad of ventricular hypertrophy, conduction disease, and ventricular pre-excitation, along with a high propensity for supraventricular arrhythmias. This report describes a young male carrier of the R302Q mutation who developed wide QRS tachycardia due to atrial flutter with 1:1 conduction via an accessory pathway. Electrophysiological study revealed atrial flutter activation in a counterclockwise direction around the tricuspid annulus, coexisting with a left-sided accessory pathway. Following radiofrequency ablation, the patient's left ventricular ejection fraction markedly improved from 16% to 60%. Furthermore, 68Ga-FAPI PET/CT imaging, performed for the first time in this disease, revealed enhanced fibroblast activity in the left ventricular endocardial and mid-myocardial layers, consistent with the distribution of late gadolinium enhancement on cardiac magnetic resonance but extending beyond it. This finding indicates that FAPI PET/CT detects active myocardial remodeling before irreversible fibrosis develops. Thus, ⁶⁸Ga‑FAPI PET/CT provides a complementary molecular imaging tool to assess disease activity and potentially guide early intervention in PRKAG2 cardiomyopathy.