Cardiac conduction system involvement in sudden death of obese young people

Abstract Involvement of the conduction system in the sudden death of obese young people has not been documented in the literature. We therefore studied the conduction system by serial section examination in 7 subjects, 5 obese and 2 mild to moderately obese, who died suddenly at ages 6, 11, 14, 16, 20, 30, and 32 years of age (5 males, 4 black and 1 white; two females, 1 black and 1 white). Three had a history of sleep apnea. The heart was hypertrophied and enlarged in 6; all 6 had a distinct ventricular septal bulge and epicardial coronary arteries were normal. All had focal mononuclear cells in and around the sinoatrial node and/or its approaches, with marked fat throughout the conduction system in 3, fibrosis of the atrioventricular (AV) bundle and/or the left bundle branch in 5, and the branching bundle sandwiched between the bulbar muscle and the summit of the ventricular septum in 5 (2 with left-sided bundle, 1 with loop formation, and 1 with a markedly fragmented bundle). The AV node was partly within the central fibrous body and/or the atrial septum in 6 patients; focal mononuclear cells were present to a varying degree, with focal fibrosis of the ventricular septum in 6 patients, arteriolosclerosis in 4, and myocardial disarray in 3. The mild to moderately obese patients demonstrated lesser amounts of fat with more fibrosis when compared with the markedly obese. In summary, there are significant pathologic findings in the conduction system in the sudden death of obese young people. The findings were more marked in patients with obesity of long-standing duration and a history of obstructive sleep apnea. We believe these findings may, indeed, produce arrhythmias that may be silent in nature but may form a milieu for an arrhythmic event that may end fatally during an altered physiologic state.