[The QT-interval during "pressure-autotransfusion" with heparin and citrate (author's transl)].

Nine anaesthetized, splenectomized dogs, heparinized with 300 IU/kg heparin i.v. had one tenth of their blood volume returned to them by autotransfusion under pressure. The blood was mixed with 1:5 0,9% NaCl for the "Heparin-Autotransfusion", and with 1:5 ACD-B or CPD-stabilisor for the "Citrate-Autotransfusion". The blood was removed from an opening made in the left renal artery, and autotransfused with the Bentley-System. A Stathem-Element was used to monitor the aortic pressure and the tracing obtained was divided into four phases: V is at the end of the blood loss before autotransfusion, G is at the peak, S is at the trough and ST is at the phase when the aortic pressure becomes stable. In these four phases the heart rate was also measured in the normal way using needle electrodes in the extremities. Following the method of Colletti the QT intervals of the ECG (RR, QoTc, QTc, SaTc, SoTc) were measured. Immediately after the blood loss (phase V) we found no alteration in the heart rate, depolarisation, isoelectric phase or repolarisation of myocardium. In phase G during the increase in blood volume, the heart rate slowed slightly, but the QT interval was unchanged. In the following phase S, during Heparin-Autotransfusion the heart rate was slightly reduced whilst the ECG remained unchanged. During Citrate-Autotransfusion there was a reduction in heart rate, and a corresponding prolongation of the QTc and QoTc, significantly, without any relationship to the infused dose of citrate. The prolongation of the SaTc and especially of the SoTc correlated directly with the infused dose of citrate. In phase ST using CPD only SaTc and SoTc were prolonged.