Blood pressure (BP), body weight, heart rate and systolic time intervals (STI) were measured every 6 months during 18 months in a group of 25 patients hemodialyzed with bicarbonate (B), as compared with 25 patients dialyzed with acetate (A). Dialysate Na remained at 140mmol/l. During the dialysis session, the decrease in BP were similar in the 2 groups but tachycardia was observed exclusively with A. The ratio between pre-ejection period (PEP) and left ventricular ejection time (LVET) increased during dialysis similarly in both groups. However predialytic PEP/LVET increased in the A group and decreased in the B group, becoming significantly lower in the Bi group at 18 months. With Bi, the loss of weight was significantly greater during the Hd session for the same decrease in blood pressure.
Conclusion: 1) During dialysis, the increase of PEP and PEP/LVET seems to be directly connected with the weight loss, and is the same in both groups. 2) The long term decrease of predialysis PEP and PEP/LVET seen with the B group can be explain by a greater degree of water inflation and by an improvement of myocardial contractility.