Complex arrhythmia is frequent in hemodialysis patients but it is not clear if this is a consequence of dialysis or uremia or is secondary to the hemodynamic and cardiovascular alterations often associated with chronic renal failure. The incidence of complex ventricular arrhythmia (frequent multiform premature beats, couplets, and runs) in 31 subjects who had their uremic status recently corrected by renal transplant (Group 1) and in 23 predialysis (Group 2) and 73 hemodialysis (Group 3) chronic renal failure patients were studied with 24-h Hotter monitoring. Patients were not receiving antiarrhythmic drugs or digitalis and significant coronary artery disease was excluded by clinical and noninvasive methods. Complex arrhythmia was two times more frequent in dialysis patients but the difference did not reach statistical significance (Group 1: 16%; Group 2: 17%; Group 3: 34%; chi(2) 4.9, P =.086). The stepwise model of logistic regression analysis identified systolic blood pressure (odds ratio 1.015, 95% confidence interval [CI] 1.001-1.027, P =.03) and left ventricular systolic dysfunction (odds ratio 7.04, 95% CI 1.3-36.7, P =.02) as the only factors that independently influenced the probability of complex arrhythmia. Age, gender, race, diabetes, smoking status, body mass index, diastolic blood pressure, serum creatinine, hematocrit, left Ventricular mass index, and use of diuretics, beta-blockers, angiotensin converting enzyme (ACE) inhibitors, sympatolytics, and calcium channel blockers did not influence the occurrence of complex arrhythmia. The data indicate that blood pressure and myocardial dysfunction are more important determinants of complex arrhythmia than dialysis or uremia in chronic renal disease patients. Am J Hypertens 1999;12:204-208 (C) 1999 American Journal of Hypertension, Ltd.