Peri toneal dialysis has been utilized extensively in the management of patients with acute and chronic renal failure and in acute drug intoxication. Although many of the hazards of this procedure have been discussed in detail,1-6 the occurrence of vagal-induced bradycardia and hypotension have been mentioned only briefly.2,7,8 That serious and life-threatening arrhythmias may be produced by peritoneal dialysis-induced vagotonia has not been emphasized. This report stresses the potentially serious nature of such arrhythmias observed during the performance of peritoneal dialysis in three patients. Patient Summaries Patient 1.\p=m-\A54-year-old woman was admitted to the Portsmouth Naval Hospital in December 1969 following the onset of pericarditis associated with chronic renal failure. Physical examination showed the blood pressure to be 136/92 mm Hg and the pulse rate, 94 beats per minute. Moderate cardiomegaly and a typical three-component pericardial friction rub were present. Pitting edema was present in the lower extremities. The blood urea nitrogen (BUN) value was 58 mg/100 ml and the serum creatinine value, 8.0 mg/100 ml. An electrocardiogram demon¬ strated increased left ventricular voltage and nonspecific ST-segment changes. The chest roentgenogram showed generalized cardiomegaly.Peritoneal dialysis was performed via a stylet catheter. The procedure, which was uneventful, was repeated ten days later.The serum electrolyte level was normal at that time. Incomplete drainage of dialysate from the abdomen led to progressive abdominal distention during the second dialysis. While the dialysis catheter was being repositioned, the patient complained of abdominal pain and became cyanotic and acutely short of breath. Concomitantly, the radial pulse decreased from 80 to 15 beats per minute and be¬ came irregular. Intravenous adminis¬ tration of 0.5 mg of atropine sulfate accel¬ erated the pulse rate to 100 beats per minute within 30 seconds. An electro¬ cardiogram subsequently demonstrated a sinus tachycardia. The results of physical examination and the chest roentgenogram were unchanged. The dialysis was contin¬ ued, after replacement of the catheter, without any immediate cardiac ar¬ rhythmia. The patient suffered a cardiac arrest later that day and died. No evi¬ dence of a myocardial infarction or pul¬ monary embolus was found at post¬ mortem examination. The heart was en¬ larged and revealed fibrinous pericarditis and moderate focal coronary arterio¬ sclerosis. Patient 2.-A 19-year-old woman was admitted to the Portsmouth Naval Hospi¬ tal in February 1970 because of abdominal pain and intractable vomiting. Physical examination showed the blood pressure to be 142/92 mm Hg and the pulse rate, 94 beats per minute. Extensive exudates were present in the optic fundi. The re¬ sults of the remainder of the examination were unremarkable. At the time of admis¬ sion the BUN value was 107 mg/100 ml and the serum creatinine level was 16 mg/100 ml.Peritoneal dialysis was performed twice using a stylet catheter. Following the s...