Clinical, electrocardiographic, and electrophysiologic characteristics of patients with a fasciculoventricular pathway: The role of PRKAG2 mutation

BACKGROUND The ECG, clinical, and electrophysiologic profiles of patients with a fasciculoventricular pathway are well described. Fasciculoventricular pathways occurring in the setting of glycogen storage cardiomyopathy possess unique features. OBJECTIVE The purpose of this study was to compare the clinical, ECG, and electrophysiologic characteristics of patients with a fasciculoventricular pathway, with or without glycogen storage cardiomyopathy. METHODS Two groups of patients with a fasciculoventricular pathway were compared: group A consisted of 10 patients with the PRKAG2 mutation (Arg302gln), and group B consisted of 9 patients without the mutation. RESULTS Thirty percent of group A patients had left ventricular hypertrophy, and none had an additional accessory pathway. Group B patients had no structural heart disease, and 33% had an additional accessory pathway. Group A patients had a slower resting heart rate (56 +/- 7 vs 75 +/- 10 bpm, P<0.0001), a wider QRS complex (0.15 +/- 0.01 vs 0.11 +/- 0.02 ms, P<.0004), and a longer HV interval (34 +/- 1 vs 25 +/- 3 ms, P = .0003). During long-term follow-up, 50% of group A patients developed complete AV block versus none in group B. Eighty percent of group A patients developed atrial flutter and/or atrial fibrillation. No Group B patient had any arrhythmia during follow-up after successful ablation of additional arrhythmia circuits. No sustained ventricular arrhythmia was induced in any patient from either group. CONCLUSION Patients with a fasciculoventricular pathway associated with the PRKAG2 mutation have distinct clinical, ECG, and electrophysiologic profiles and should be correctly identified because of their ominous long-term prognosis. Patients without the mutation have an excellent arrhythmia-free prognosis after treatment of additional circuits.