[Holter monitoring of patients treated with cytostatic agents]

After cytostatic treatment severe arrhythmias, the development of angina pectoris and even the development of acute myocardial infarction and sudden death were observed. Therefore we made in 42 patients with malignant haematological disease treated with cytostatics 96 Holter monitorings of the electrocardiographic signal. The monitoring was made during the administration of cytostatics as well as during the time interval between the administration of combinations of cytostatics. In both instances (during the administration and during the interval between administration) we recorded a surprisingly high, mean all-day as well as maximal, heart rate. In the group monitored during administration of chemotherapeutic drugs we observed 5-8 hours after administration of cytostatics serious ventricular arrhythmias [incl. ventricular tachycardia], denivelization of the ST segment, paroxysms of supraventricular tachycardia. In the group monitored during the interval between administration of cytostatics the sick-sinus syndrome was recorded, as well as a passive nodal rhythm, disorders of the intraventricular conduction. The described changes are explained by the release of vasoactive substances after administration of cytostatics, by a change of the transmembrane calcium transport leading to an increased excitability of the heart muscle and possibly to coronary spasms and direct irreversible damage of the conduction system.