An Intriguing Family with Type 2 Diabetes Mellitus and Complete Heart Block

Chronic hyperglycaemia of Type 2 Diabetes Mellitus (T2DM) causes long term damage to heart resulting in coronary artery disease (CAD), myocardial infarction (MI), congestive heart failure (CHF), and sudden death from arrhythmias. A 62 year old male presented to our emergency with complaint of sudden onset giddiness from last 2 hours. This was followed by loss of consciousness. Patient was a known case of T2DM since last 1 year. Family history- patient has two brothers who also have T2DM and both of them also developed Complete Heart Block (CHB) spontaneously. The patient's mother also had T2DM and she also developed CHB. On examination of the cardiovascular system, pulse rate was 36 per minute and a variable intensity of first heart sound was present. Rest of the cardiovascular examination and other system examination was within normal limits. Routine investigations were within normal limits and ECG showed CHB. Echocardiography revealed normal ventricular function with no evidence of ischemic heart disease. This was a case of Type 2 DM and spontaneous onset CHB with a strong family history. This case underscores the fact that CHB can occur spontaneously in Type 2 diabetics without ischemic heart disease. The cause of CHB was most likely Cardiac Autonomic Neuropathy (CAN), which is determined not only by poor glycaemic control, metabolic derangements and duration of diabetes but also by genetic factors (likely maternal).