Cardiac arrhythmias in hemodialysis patients. A study of incidence and contributory factors.

Cardiac arrhythmias were evaluated in 100 patients undergoing regular maintenance hemodialysis for chronic renal failure by Holter ECG monitoring a 72-hour period beginning on the day of hemodialysis. Clinically significant ventricular arrhythmias (more than 700 beats/24 h) were found in 18 patients (the frequent group) in whom premature ventricular contractions (PVCs) were recorded frequently during and for 4 h after hemodialysis. In the frequent group, the values of the serum calcium concentration times those of phosphorus were significantly higher than those of patients without PVCs (the no arrhythmia group) or those with fewer PVCs (less than 700 beats/day; sporadic group) (54.9 +/- 3.5 vs. 43.8 +/- 3.2, 43.0 +/- 1.8, respectively; p less than 0.005). Also, in the frequent group, the percent fractional shortening of the left ventricle, as measured by two-dimensional echocardiography, was significantly lower than those in the no arrhythmia and sporadic groups (30.7 +/- 1.8% vs. 40.7 +/- 1.9%, 37.7 +/- 1.1%, respectively; p less than 0.01). On the other hand, in those with frequent premature atrial contractions, the left atrial end-diastolic dimension was significantly enlarged (42.1 +/- 1.2 mm vs. 36.5 +/- 1.1 mm, 38.1 +/- 0.9 mm, respectively; p less than 0.01). From these results, we conclude that impaired cardiac performance and a high calcium phosphate product predialysis may be correlated with an increased incidence of ventricular arrhythmias in uremic patients.