Clinical Electrophysiology -> SVT/AVNRT/WPW/AT: -> Epidemiology of Cardiac Arrhythmias/ Epidemiology D-PO04 - Poster Session IV (ID 15) Poster

D-PO04-231 - Cardiac Involvement In Facioscapulohumeral Muscular Dystrophy (ID 1244)


Background: Facioscapulohumeral muscular dystrophy (FSHD) is one of the most common muscular dystrophies and predominantly affects facial and shoulder girdle muscles. Previous case reports and few cohort studies identified cardiac abnormalities in some FSHD patients, but their nature, frequency, and correlation with genotype remain largely unknown.
Objective: To understand the history and extent of cardiac involvement, as well as possible relationship with genotype in FSHD.
Methods: We reviewed cardiac involvement in 104 patients with genetically confirmed FSHD evaluated in the past two decades at Mayo Clinic.
Results: Median age at time of evaluation was 46 years (interquartile range 29-60); 59% were males. Cardiac symptoms were reported by 32% of patients with dyspnea being the most frequent (23%). ECGs were abnormal in 50% of the 64 patients in whom they were obtained. The most common rhythm and conduction abnormalities were incomplete or complete bundle branch block (11%), atrial fibrillation (4%), atrioventricular block (8%) with 1st degree AV block (4%), 2:1 AV block (2%), and complete heart block (2%). Holter monitoring obtained in 11 patients revealed non-sustained or sustained ventricular tachycardia in 5 and 1 patients, respectively. Echocardiograms were obtained in 42 patients, demonstrating mitral valve prolapse (12%), tricuspid regurgitation (5%), aortic regurgitation (2%), aortic stenosis (2%), and bicuspid aortic valve (2%). Two patients had a reduced ejection fraction, each with symptoms of heart failure. There were no associations between cardiac conduction abnormalities and patients’ age, degree of muscle weakness, or size of the chromosome 4q35 deletion (p≥0.05). Structural abnormalities were associated with advancing age, but not with the degree of muscle weakness or size of the 4q35 deletion.
Conclusion: Our findings indicate a higher than expected frequency of cardiac conduction abnormalities in FSHD relative to the general population and a higher than expected frequency of mitral valve prolapse in FSHD. These findings indicate the need for screening and monitoring FSHD patients for cardiac conduction abnormalities, as conduction abnormalities could not be predicted on clinical or genetic grounds.