A Patient of Limb-girdle Muscular Dystrophy Type 1B Presenting with Heart Failure and Cardiac Conduction Defects: A Case Report

Background: Limb-girdle muscular dystrophy type 1B (LGMD1B) are characterised by cardiac dysrhythmias, late-onset cardiomyopathy, slowly progressive skeletal myopathy and contractures of the neck, elbows and ankles. The causative mutation is in lamin A/C gene (autosomal dominant LGMD1B). Objective: To assess the clinical outcome of a patient of limb-girdle muscular dystrophy type 1B with heart failure and cardiac conduction defects. The case: We report a case of 47-yr-old male with proximal muscle weakness who presented with repeated exertional dyspnea and repeated presyncope. ECG revealed junctional bradycardia. Echocardiography revealed global wall motion abnormality with EF 48%. EMG showed myopathic pattern. Next genome sequencing showed that the patient has a missense mutation in exon 4 region of LMNA gene (c.G662A/p.Arg221His). Cardiac involvement is very common in this disease which includes AV block, bradycardia, atrial tachycardia, atrial fibrillation and ventricular dysrhythmia causing sudden death. Our patient presented with symptomatic junctional bradycardia which necessitates implantation of permanent pacemaker. Conclusion: Cardiologists should be aware of these unusual genetic diseases with conduction defects, especially in young adults. Bangladesh Med Res Counc Bull 2022; 48(1): 76-80