The heart in uremia: An electrocardiographic and pathologic study

1. 1. Twenty-seven fatal cases of uremia are presented and their electrocardiographic and anatomic changes are described. 2. 2. The sole demonstrable characteristic anatomic lesion is pericarditis, which was present in 41 per cent of the series and which frequently extended into the adjacent myocardium. 3. 3. The myocardial changes are those attributed to hypertensive heart disease with additional diffuse fatty degeneration, cloudy swelling of myocardial fibers, and interstitial edema. While the fatty degeneration was probably caused by concomitant anemia, the cloudy swelling and interstitial edema can be attributed to the uremic intoxication but cannot be considered diagnostic of uremia. There is no evidence to support the existence of a specific so-called uremic myocarditis. 4. 4. The factors responsible for the changes in the electrocardiogram of patients with uremia are chronic left heart strain, myocardial changes due to coronary artery disease, diffuse pericarditis, and changes in the electrolyte balance which give rise to hypocalcemia and hyperpotassemia. Because of the opposite effect of some of these factors on the electrocardiogram, the changes tend to obscure or balance each other, as revealed by serial electrocardiograms. 5. 5. Evidence of hyperpotassemia was found in six cases. Tall narrow T waves, which are the early sign of potassium poisoning, were seen in five cases; additional intraventricular and auriculoventricular conduction disturbances, a later sign of potassium poisoning, were present in one case. The terminal stages of potassium poisoning which are characterized by auricular standstill and final ventricular standstill or ventricular fibrillation were not observed, since no tracings were obtained immediately before death. 6. 6. T-wave changes indicative of hyperpotassemia were observed in one case as long as nine weeks before death. 7. 7. The effect of hyperpotassemia on the electrocardiographic pattern of left heart strain is emphasized. 8. 8. The combination of a prolonged electrical systole of the hypocalcemic type with narrow tall T waves indicative of potassium poisoning is the most characteristic electrocardiographic feature of uremia. 9. 9. Potassium poisoning seems to be the immediate cause of death in at least one-fifth of the cases of uremia in man; the electrocardiogram is of valve for the diagnosis of hyperpotassemia and thus may give a hint as to the immediate prognosis in patients with uremia.