Figure 3. Electrocardiogram obtained from patient 3. Superposition of ST and T changes (ST segment analysis) during isoflurane and halothane anesthesia. Flattening of the T wave is evident during isoflurane anesthesia; after isoflurane was changed to halothane, the T wave morphology normalized. ECG calibration: gain 1.0 = 10 mm = 1 mV.