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Perioperative electrocardiographic (ECG) recordings. a) Preoperative ECG. Sinus rhythm, 58 beats/min. Without QT prolongation (QTc, 440 msec). b) Two recordings of torsades de pointes episodes. Note the short-long-short phenomenon preceding the arrhythmia in the upper recording. c) Postoperative ECG. Sinus rhythm, 77 beats/min. With prolonged QT interval (QTc, 505 msec), best seen in aVF. In leads V1-V4, there are possible U waves merging into the P wave.
