Cardiac magnetic resonance diagnosis of septal acute myocardial infarction secondary to first septal perforator occlusion causing complete atrioventricular block

A 66-year-old woman presenting with syncope following chest pain was admitted to the intensive care unit. The electrocardiogram displayed a complete atrioventricular block with a left-bundle block branch appearance (Panel A). She was pain free upon admission and physical exam was normal. Hs-troponin I was elevated at 13276 ng/L (N < 54). Potassium level was normal at 3.6 mM (N > 3.5). Transthoracic echocardiography revealed preserved left-ventricle ejection fraction without wall motion abnormality. Given the rise in troponin level and the prior chest pain, a coronary-angiography was performed and was considered unremarkable (Panel B). A cardiac magnetic resonance (CMR) was then performed and revealed a basal-septal myocardial infarction (MI). Myocardial rest perfusion sequences showed a basal-septal perfusion defect (Panel C.1). T2-mapping images displayed myocardial oedema in the basal and mid-septal region (Panel C.2). T1-weighted late gadolinium enhancement (LGE) images revealed...