Acquired QT interval changes and neck dissections.

STUDY OBJECTIVE: To determine if acquired long QT syndrome following right or left, radical or modified, neck dissections result in malignant arrhythmias or deaths.

DESIGN: Prospective study.

SETTING: Inpatient head and neck service of the Massachusetts Eye and Ear Infirmary.

PATIENTS: 69 patients who underwent extensive neck surgery, without congenital long QT syndrome, medications known to prolong the QT interval, preoperative ventricular arrhythmias, or electrolyte abnormalities.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Preoperative and postoperative electrolytes were evaluated. Preoperative and postoperative electrocardiograms and QT intervals were evaluated. Continuous intraoperative and 10- to 12-hour postoperative monitoring of lead II or V5 were evaluated. Twenty-six patients (Group 1) underwent either right radical neck dissection or modified right radical neck dissection, 25 patients (Group 2) underwent either left radical neck dissection or modified left neck dissection, and 18 patients (Group 3) underwent extensive neck surgery without radical or modified neck dissection. Postoperatively, 38 patients (19 Group 1, 11 Group 2, and 8 Group 3 patients) developed a QT interval corrected for heart rate (QTc) of greater than 440 milliseconds. Repeated measures analysis of variance, comparing preoperative and postoperative QTc showed a statistically significant preoperative to postoperative change, but no significant difference among the three groups. No malignant arrhythmias or deaths were recorded in any of the three groups.

CONCLUSIONS: Acquired long QT syndrome following radical neck dissection, without congenital, metabolic, or pharmacologic disturbance, is unlikely to trigger malignant arrhythmias, as previously reported for right radical neck dissection.