ACQUIRED QT INTERVAL CHANGES AND NECK DISSECTIONS

Study Objective: To determine if acquired long QT syndrome following r ight or left, radical or modified, neck dissections result in malignan t an arrhythmias or deaths. Design: Prospective study. Setting: Inpati ent head and neck service of the Massachusetts Eye and Ear Infirmary. Patients: 69 patients who underwent extensive neck surgery, without co ngenital long QT syndrome, medications Known to prolong the QT interva l, preoperative ventricular arrhythmias, or electrolyte abnormalities. Interventions: None. Measurements and Main Results: Preoperative and postoperative electrolytes were evaluated. Preoperative and postoperat ive electrocardiograms and QT intervals were evaluated. Continuous int raoperative and 10- to 12-hour postoperative monitoring of lead II or V5 were evaluated. Twenty-six patients (Group 1) underwent either righ t radical neck dissection or modified right radical neck dissection, 2 5 patients (Group 2) underwent either left radical neck dissection or modified left neck dissection, and 18 patients (Group 3) underwent ext ensive neck surgery without radical or modified neck dissection. Posto peratively, 38 patients (19 Group 1, 11 Group 2, and 8 Group 3 patient s) developed a QT interval corrected for heart rate (QTc) of greater t han 440 milliseconds. Repeated measures analysis of variance, comparin g preoperative and postoperative QTc showed a statistically significan t preoperative to postoperative change, but no significant difference among the three groups. No malignant arrhythmias or deaths were record ed in any of the three groups. Conclusions: Acquired long QT syndrome following radical neck dissection, without congenital, metabolic, or p harmacologic disturbance, is unlikely to trigger malignant arrhythmias , as previously reported for right radical neck dissection.