Sudden cardiac death associated with hypoplasia of the coronary arteries and conduction system alteration.

We present a case of sudden cardiac death in a 24-year-old woman with evidence of hypoplasia of the left anterior descending (LAD) and posterior descending (PDA) coronary arteries. These vessels averaged 0.7 mm in internal diameter combined, in contrast to an average of 2.4 mm in control coronary arteries (p < 0.001). The myocardium exhibited areas of acute and chronic ischemic change. Also, the cardiac conduction system (CCS) had diffuse cellular enlargement, believed to be secondary to ischemia. The cells of the sinoatrial node (SAN) and the Purkinje cells of the proximal right bundle branch (RBB) averaged 28.5 and 25.6 microns, respectively. These were significantly larger than the SAN cells (21.6 microns, p = 0.002) and larger than the Purkinje cells (15.9 microns, p = 0.012) of control cases. We report that hypoplastic coronary artery disease is a cause of sudden death, is associated with varying degrees of ischemic change in the heart, and can be associated with condition system alteration.