Non-invasive assessment of cardiac function in poisoning with drugs

Systolic time intervals (STI) have been used in evaluating cardiac function in 21 patients who had taken an overdose of drugs. Registrations were made in all patients on arrival at the hospital and on the third day. On arrival STI was abnormal in 16 patients (76%). At the second registration it was still abnormal in ten (48%). Prolongations of total electromechanical systole (QS2) and preejection period (PEP) were the most frequent findings. The patients with abnormal STI at the first registration showed a significant improvement in QS2 (p less than 0.01) and PEP (p less than 0.05) from the first to the third day. Two of the four patients who had taken amitriptyline in a slow release form showed a prolongation of PEP and an increase in PEP/LVET from the first to the third day, and on patient has a further prolongation of the fifth day. The findings may be explained by a reduction of cardiac contractility caused by the membrane-stabilizing effect of the drugs.