Pramod Theetha Kariyanna¹, Apoorva Jayarangaiah², Abdullah Mahmood³, Mitchell Hare⁴, Nicholas Taklalsingh¹, Isabel M. McFarlane^1,

Idiopathic inflammatory myopathy (IIM) is a rare autoimmune myopathy that includes polymyositis, dermatomyositis, inclusion body myositis and autoimmune necrotizing myositis. Cardiac involvement was considered a rare occurrence in IIM however, recent reports suggests that cardiac involvement is a common feature and portends poor prognosis as it is usually encountered in advanced disease. IIM leads to myocarditis with subsequent development of myocardial fibrosis, cardiac conduction system disease and cardiomyopathy resulting in both systolic and diastolic heart failure. Conduction abnormalities such as first, second and third degree atrioventricular blocks, right and left bundle branch blocks associated with IIM have been reported. We present a case of a 44-year-old woman with biopsy proven-IIM whose left ventricular ejection fraction (LVEF) and electrocardiogram (ECG) were recorded as normal two years prior. On presentation to our hospital ECG revealed atrial tachycardia and 2D echocardiogram revealed heart failure with reduced ejection fraction (20-30%). Patient quickly progressed to complete heart block. A cardiac resynchronization therapy-defibrillator (CRT-D) insertion was planned but patient succumbed to sepsis.

idiopathic inflammatory myopathy, atrial tachycardia, heart failure with reduced ejection fraction