Acute electrocardiographic changes induced by amsacrine

The ECG effect of amsacrine (m-AMSA) was evaluated in 12 consecutive patients with leukemia. m-AMSA induced a significant prolongation of the Q-T interval (msecs, mean ± SE) before (448 ± 13) and 1 hour after (512 ± 12) treatment (P . 0.0001), paired t test), without concomitant changes in the P-R interval, QRS duration, and heart rate. This selective cardiotoxic effect appeared to be transient and was noted towards the end of the iv drug administration, but was not present 24 hours later. No cardiac arrhythmias were noted during continuous monitoring. Nevertheless, it is assumed that the prolongation of the Q-T interval may represent a stage of increased vulnerability to rhythm disturbances. Special care should be taken to avoid factors that may prolong the Q-T interval (hypokalemia, ischemia, or premedication with phenothiazine) during the administration of m-AMSA.