Effects of Left and Right Pneumonectomy on Time- and Frequency-Domain Parameters of Heart Rate Variability

The incidence and outcome of ventricular arrhythmias after noncardiac thoracic surgery

Atrial arrhythmias are common after thoracic surgery, but the incidence and significance of ventricular arrhythmias early after such surgery are not well established. Our goal was to determine the incidence and outcome of this complication from a continuing prospective database in 412 patients who had lobectomy (n = 243) or pneumonectomy (n = 169) and were continuously monitored with Holter recorders for 72-96 h postoperatively. The primary end point of the study was the occurrence of ventricular tachycardia (VT) defined as three or more consecutive wide complexes. Sixty-one of 412 patients (15%) developed 1 or more episode of VT. There were no episodes of sustained (>30 s) VT and no patient required treatment for hemodynamic compromise associated with any VT episode. Patients with VT had a more frequent incidence of a preoperative left bundle branch block (P = 0.01) but did not differ in other clinical characteristics, operative data, or core temperature on arrival to the postanesthesia care unit, when compared with those without VT. Patients who developed VT had significantly more atrial premature contractions (P < 0.001), ventricular premature contractions (P < 0.001), ventricular couplets (P < 0.001), and postoperative atrial fibrillation, 21 of 61 (34%) versus 58 of 351 (17%), P = 0.001, than those without VT, respectively. Multivariate logistic regression analysis revealed that only postoperative atrial fibrillation occurrence was independently associated with VT (relative risk 2.6, 95% confidence intervals 1.4 to 4.8, P = 0.002). We conclude that nonsustained VT after noncardiac thoracic surgery occurs frequently but is not associated with poor outcome. The strong association of atrial and ventricular arrhythmogenesis with VT suggests that vagal withdrawal and/or adrenergic hyperactivity may have a role in precipitating these events in the early postoperative period.

IMPLICATIONS

In 412 patients, we determined that the incidence of nonsustained ventricular tachycardia after major thoracic surgery is 15% and is not associated with poor outcome.

Effects of diltiazem prophylaxis on the incidence and clinical outcome of atrial arrhythmias after thoracic surgery

OBJECTIVES

We sought to determine whether early prophylaxis with an L -type calcium channel blocker reduces the incidence and morbidity associated with atrial fibrillation/flutter and supraventricular tachyarrhythmia after major thoracic operations.

METHODS

In this randomized, double-blind, placebo-controlled study, 330 patients were given either intravenous diltiazem (n = 167) or placebo (n = 163) immediately after lobectomy (> or =60 years) or pneumonectomy (> or =18 years) and orally thereafter for 14 days. The primary end point with respect to efficacy was a sustained (> or =15 minutes) or clinically significant atrial arrhythmia during treatment.

RESULTS

Postoperative atrial arrhythmias (atrial fibrillation/flutter = 60; supraventricular tachyarrhythmias = 5) occurred in 25 (15%) of the 167 patients in the diltiazem group and 40 (25%) of the 163 patients in the placebo group (P = .03). When compared with placebo, diltiazem nearly halved the incidence of clinically significant arrhythmias (17/167 [10%] vs. 31/163 [19%], P = .02). The 2 groups did not differ in the incidence of other major postoperative complications or overall duration or costs of hospitalization. No serious adverse effects caused by diltiazem were seen.

CONCLUSIONS

After major thoracic operations, prophylactic diltiazem reduced the incidence of clinically significant atrial arrhythmias in patients considered at high risk for this complication.