Hemodialysis patients have low 5-year survival rates of approximately 60%, and the most common cause of death is cardiovascular diseases. Their population may be considered, therefore, as an accelerated model in analyzing the risk factors for cardiovascular diseases. We previously reported the role of blood pressure, one of the most important risk factors for cardiovascular diseases, in determining the prognosis of hemodialysis patients. In this study, we examined the effect of cardiomegaly detected on chest roentgenogram or electrocardiogram before initiating hemodialysis therapy on survival after introduction to maintenance hemodialysis. One hundred and sixty hemodialysis patients who had no history of ischemic heart disease or arrhythmia were followed up for 88.9 +/- 4.0 months, among whom 69 died. Heart enlargement, defined on chest roentgenogram, was detected in 104 patients, and left ventricular hypertrophy, defined on electrocardiogram, was detected in 105 patients. The presence of either finding shortened their survival. However, Cox's proportional hazards model and logistic multiple regression analysis identified only left ventricular hypertrophy as one of the significant determinants for survival, but heart enlargement was not independent. Correction of systolic hypertension on the maintenance phase had no significant favorable effect on survival in patients with left ventricular hypertrophy, while it improved in those with heart enlargement. This finding, together with those above from Cox's model and logistic analysis strongly suggests that risk from left ventricular hypertrophy is independent of, but one from heart enlargement is dependent on hypertension.