Influence of high-dose leucovorin and 5-fluorouracil chemotherapy regimen on P wave duration and dispersion.

Abstract

Although 5-fluorouracil (5-FU)-related cardiotoxicity is well known, atrial arrhythmia, as a potentially serious complication has not been studied in detail. The aim of this study was to determine the P max and Pd in the electrocardiograms (ECG) of patients receiving 5-FU treatment. Twenty-five patients (mean age: 62 years) receiving a 5-FU bolus plus continuous infusion with calcium leucovorin over 48 h and with normal pre-treatment cardiac physical examinations, ECG and echocardiography were enrolled. P maximum (P max), P minimum (P min) and P dispersion (Pd) (maximum minus minimum P wave duration) were measured from the 12-lead ECG at the 0th and 48th hour of the first chemotherapy cycle. Echocardiography was also obtained in all patients at the same times. Clinical cardiotoxicity was observed in two patients. P max and Pd were both significantly longer after 5-FU treatment at the 48th hour (P < 0.001). P min did not change (P > 0.05). Treatment with 5-FU based regimens may increase Pd and prolong the P max in cancer patients. These alterations may be predictive of patients at risk of atrial arrhythmias during 5-FU treatment.