Is prolongation of the QTc interval during isoflurane anaesthesia more prominent in women pretreated with anthracyclines for breast cancer?

BACKGROUND

Inhalation anaesthetics and anthracycline chemotherapeutic drugs may both prolong the QT interval of the electrocardiogram. We investigated whether isoflurane may induce or augment QTc prolongation in patients who had previously received cancer chemotherapy including anthracycline drugs.

METHODS

Forty women undergoing surgery for breast cancer were included in the study. They were divided into two groups: (A) women previously treated with anthracyclines (n=20); and (B) women not treated with antineoplastic drugs (n=20). All patients received a standardized balanced anaesthetic in which isoflurane 0.5 vol% was used. The QT and corrected QT intervals were measured before anaesthesia, after induction and tracheal intubation, after 1, 5, 15, 30, 60 and 90 min of anaesthesia, and during recovery.

RESULTS

In both groups we observed a tendency to QTc prolongation, but statistically significant differences among baseline values and values observed during isoflurane-containing anaesthesia were seen only in group A. During anaesthesia, significant differences in QTc values between the two groups were observed.

CONCLUSION

In female patients pretreated with anthracyclines for breast cancer, the tendency to QTc prolongation during isoflurane-containing general anaesthesia was more strongly expressed than in patients without previous chemotherapy.