Cardiac arrhythmias in patients with small cell lung cancer and cardiac disease before, during and after doxorubicin administration. An evaluation of acute cardiotoxicity by continuous 24-hour Holter monitoring.

Cardiac arrhythmias have been reported during doxorubicin infusion. The aim of the present study was to investigate the prevalence of arrhythmias and elucidate whether previous cardiac disease might increase the probability of treatment-related ectopic activity. In 18 patients with small cell lung cancer, 11 with concomitant heart disease, electrocardiogram (ECG) was continuously registered by a portable tape recorder 24 h before, during and 24 h after doxorubicin infusion (Holter monitoring). The only significant finding was an increased number of bigeminal ventricular extrasystoles after doxorubicin infusion. A trend of increased number of ventricular extrasystoles was also observed. The study suggests that pretreatment arrhythmias do not dispose for increased cardiac irritability and that bolus injections of doxorubicin do not seriously influence the ectopic activity in patients with and without heart disease.