Continuous ambulatory ECG monitoring during fluorouracil therapy: a prospective study.

Abstract

Although there have been anecdotal reports of cardiac toxicity associated with fluorouracil (5-FU) therapy, this phenomenon has not been studied in a systematic fashion. We prospectively performed continuous ambulatory ECG monitoring on 25 patients undergoing 5-FU infusion for treatment of solid tumors in order to assess the incidence of ischemic ST changes. Patients were monitored for 23 +/- 4 hours before 5-FU infusion, and 98 +/- 9 hours during 5-FU infusion. Anginal episodes were rare: only one patient had angina (during 5-FU infusion). However, asymptomatic ST changes (greater than or equal to 1 mm ST deviation) were common: six of 25 patients (24%) had ST changes before 5-FU infusion v 17 (68%) during 5-FU infusion (P less than .002). The incidence of ischemic episodes per patient per hour was 0.05 +/- 0.02 prior to 5-FU infusion v 0.13 +/- 0.03 during 5-FU infusion (P less than .001); the duration of ECG changes was 0.6 +/- 0.3 minutes per patient per hour before 5-FU v 1.9 +/- 0.5 minutes per pati...