Regressive Changes of the Myocardial Sleeves in Elderly Victims of Sudden Bathtub Death

Abstract

In Japan, most sudden deaths occurring during bathing happen in the winter, and predominantly to elderly people. One can infer a relation to physical conditions that are specific to aging. Atrial fibrillation, an arrhythmia, increases with age. This study examined histological changes in the pulmonary vein myocardial sleeves of sudden bathtub death victims and compared them with those of control individuals. We investigated 35 sudden deaths that occurred during bathing and 34 accidental deaths or deaths caused by diseases unrelated to cardiopathies. Pulmonary veins were excised cross-sectionally from the hilar side to the venoatrial junction. Then they were stained with hematoxylin and eosin, resorcin-fuchsin van Gieson, and Congo-red stains. Amyloid deposits in the pulmonary vein myocardial sleeves, as well as the range and severity of scarring, were graded microscopically on a scale of 0-3. In the sudden bathtub death victims, severe scarring was found in the myocardial sleeves of the four pulmonary veins (mean score, 2.0), which was significantly different (p < 0.05) from the control subjects (mean score, 1.4). Cardiomegaly was found in 28 out of the autopsied individuals. In subjects with cardiomegaly, the mean value of pulmonary vein myocardial sleeve scarring was 2.1. In subjects without cardiomegaly, the mean value was 1.8. Comparison revealed that cardiomegaly was associated significantly with scarring progression and degeneration of the myocardial sleeves. Scarring of the pulmonary vein myocardial sleeves was more advanced in victims of sudden bathtub death than in controls without heart disease. Elderly people with scarring of the pulmonary vein myocardial sleeves are likely to develop degenerative variations in their intra-atrial excitation conduction. These results demonstrate that taking hot baths might induce supraventricular arrhythmias such as atrial fibrillation.