Sudden Death in 14 Month Old Due to Fibromuscular Dysplasia of Atrioventricular Nodal Artery

Abstract

Fibromuscular dysplasia is a non-atherosclerotic, non-inflammatory vascular disease that is most commonly found in the renal arteries of pre-menopausal women. However, this disease entity has rarely been described in the coronary arteries and small cardiac conduction arteries. To our knowledge, there is no recorded case of fibromuscular dysplasia in small cardiac conduction arteries in infants/children. In this report, we present a case of unexplained death of a 14 month old wherein routine histologic examination failed to reveal a cause of death, but subsequent submission of the cardiac conduction system (atrioventricular [AV] and sinoatrial [SA] node regions) demonstrated the presence of isolated AV nodal artery fibromuscular dysplasia, which was considered the cause of death. The case serves to emphasize the potential importance of evaluating the cardiac conduction system in cases where routine gross and microscopic autopsy fails to reveal an adequate explanation for death.

Histologic Examination of the Heart in the Forensic Autopsy

“…It is typified by nonatherosclerotic luminal narrowing of this small artery by intimal and medial thickening (Image 54). Several studies have concluded that severe (>75%) narrowing of the AV nodal artery is significant enough to explain sudden cardiac death, with a proposed mechanism of AV nodal ischemia (32, 33).…”

Lesions of the Cardiac Conduction System and Sudden Death

“…Burke and Virmani 28 have emphasized that most sudden deaths attributed to FMD of the AV node artery occur during exercise. The youngest reported case of death from FMD of the atrioventricular node artery occurred in a 14-month-old patient 30 . Zack et al 31 have called into question the significance of this lesion, but they do not consider the degree of narrowing of the artery.…”

“…The youngest reported case of death from FMD of the atrioventricular node artery occurred in a 14-month-old patient. 30 Zack et al 31 have called into question the significance of this lesion, but they do not consider the degree of narrowing of the artery.…”