[Monitoring of cardiac function during doxorubicin therapy in metastasized breast cancer. Measuring systolic time interval].

Assessment of systolic time interval represents an uncomplicated, sufficiently precise and cheap possibility in clinical practice of cardiac monitoring during treatment with doxorubicin (adriamycin) if the ratio between pre-ejection period interval (PEPI) and left ventricular ejection time interval (LVETI) ("Weissler index") for evaluation of left ventricular cardiac function is used. In an investigation of 352 female patients with metastatic carcinoma of the breast statistically ascertained dose-response relationships could be established as regards electrocardiographic disorders of repolarisation and the systolic time interval (P less than 0.001). Pre-irradiated patients showed more ECG changes (P less than 0.001) and higher PEPI : LVETI values (P less than 0.001) than patients without prior irradiation. There was no general influence of cytostatic treatment on systolic and diastolic blood pressure values. The upper limit of a therapeutic risk in evaluation of the systolic time interval for cardiac monitoring of doxorubicin treatment should be 0.45-0.50 for PEPI : LVETI. Above this borderline value precise cardiac evaluation including invasive methods should be attempted if continuation of treatment is indicated. This regime could help prevent the occurrence of life-threatening cardiac crises during treatment with doxorubicin.