Amiodarone with or without N-Acetylcysteine for the Prevention of Atrial Fibrillation after Thoracic Surgery: A Double-blind, Randomized Trial.

BACKGROUND: Postoperative atrial fibrillation may identify patients at risk of subsequent atrial fibrillation, with its greater risk of stroke. This study hypothesized that N-acetylcysteine mitigates inflammation and oxidative stress to reduce the incidence of postoperative atrial fibrillation. METHODS: In this double-blind, placebo-controlled trial, patients at high risk of postoperative atrial fibrillation scheduled to undergo major thoracic surgery were randomized to N-acetylcysteine plus amiodarone or placebo plus amiodarone. On arrival to the postanesthesia care unit, N-acetylcysteine or placebo intravenous bolus (50 mg/kg) and then continuous infusion (100 mg/kg over the course of 48 h) was administered plus intravenous amiodarone (bolus of 150 mg and then continuous infusion of 2 g over the course of 48 h). The primary outcome was sustained atrial fibrillation longer than 30 s by telemetry (first 72 h) or symptoms requiring intervention and confirmed by electrocardiography within 7 days of surgery. Systemic markers of inflammation (interleukin-6, interleukin-8, tumor necrosis factor α, C-reactive protein) and oxidative stress (F2-isoprostane prostaglandin F2α; isofuran) were assessed immediately after surgery and on postoperative day 2. Patients were telephoned monthly to assess the occurrence of atrial fibrillation in the first year. RESULTS: Among 154 patients included, postoperative atrial fibrillation occurred in 15 of 78 who received N-acetylcysteine (19%) and 13 of 76 who received placebo (17%; odds ratio, 1.24; 95.1% CI, 0.53 to 2.88; P = 0.615). The trial was stopped at the interim analysis because of futility. Of the 28 patients with postoperative atrial fibrillation, 3 (11%) were discharged in atrial fibrillation. Regardless of treatment at 1 yr, 7 of 28 patients with postoperative atrial fibrillation (25%) had recurrent episodes of atrial fibrillation. Inflammatory and oxidative stress markers were similar between groups. CONCLUSIONS: Dual therapy comprising N-acetylcysteine plus amiodarone did not reduce the incidence of postoperative atrial fibrillation or markers of inflammation and oxidative stress early after major thoracic surgery, compared with amiodarone alone. Recurrent atrial fibrillation episodes are common among patients with postoperative atrial fibrillation within 1 yr of major thoracic surgery.

Preoperative Echocardiographic Indices of Diastolic Dysfunction and Brain Natriuretic Peptide in Predicting Postoperative Atrial Fibrillation After Noncardiac Surgery.

BACKGROUND: We have shown previously that either echocardiographic indices of diastolic dysfunction or increased preoperative brain natriuretic peptide (BNP) predict postoperative atrial fibrillation (POAF). Because these 2 predictors of POAF have not been evaluated together, our goal was to further elucidate their concurrent role in patients undergoing noncardiac thoracic surgery. METHODS: We retrospectively identified 191 patients who had a preoperative transthoracic echocardiogram and serum BNP level collected as part of routine care before major lung or esophageal resection. Clinical and echocardiographic data were compared between patients who did or did not develop POAF (>5 minutes), and prognostic factors for POAF were identified. RESULTS: Univariate associations with POAF (41 of 191; 22% patients) included older age (P = .04), male sex (P = .01), hypertension (P = .03), increased body mass index (P = .01), and prolonged transmitral flow deceleration time (P < .0001), whereas BNP was not statistically significant (P = .07). Stepwise logistic regression analysis showed that both increasing transmitral flow deceleration time (continuous data log base 2 transformed; odds ratio, 16.05; 95% confidence interval, 3.74-68.96; P = .0002) and left atrial diastolic volume index (continuous data log base 2 transformed; odds ratio, 3.29; 95% confidence interval, 1.22-8.91; P = .02) were independent risk factors of POAF (area under the receiver operating characteristic curve = 0.73). There was no significant interaction between BNP and the 2 independent variables (P = .60, and P = .90), respectively. CONCLUSIONS: In a cohort of patients who had echocardiography and BNP measurements before undergoing major thoracic surgery, this study showed that when evaluated together greater preoperative left atrial diastolic volume index and transmitral flow deceleration time but not BNP levels were independent predictors for POAF.

Cardiac metastases from head and neck cancer mimicking a myocardial infarction.

Cardiac metastases from head and neck cancer are rare. We present 2 patients with primary head and neck cancer found to have cardiac metastases. Electrocardiograms showed a persistent acute infarction pattern due to myocardial tumor infiltration. No cardiac symptoms were present. Both patients died of metastatic disease.

Preoperative left atrial dysfunction and risk of postoperative atrial fibrillation complicating thoracic surgery.

OBJECTIVE: Postoperative atrial fibrillation complicating general thoracic surgery increases morbidity and stroke risk. We aimed to determine whether preoperative atrial dysfunction or other echocardiographic markers are associated with postoperative atrial fibrillation. METHODS: In 191 patients who had undergone anatomic lung or esophageal resection, preoperative clinical and echocardiographic data were compared between patients with and without postoperative atrial fibrillation. Presence of postoperative atrial fibrillation lasting more than 5 minutes during hospitalization was detected using continuous telemetry or 12-lead electrocardiography. Maximal left atrial volume and indices of left atrial function were assessed. RESULTS: Patients with postoperative atrial fibrillation (33/191, 17%) were older (71 ± 5 years vs 64 ± 12 years, P < .0001), were taking ß-blockers more often, had greater left atrial volume, had decreased left atrial emptying fraction, and had lower E' and A' septal velocities compared with patients without postoperative atrial fibrillation. The incidence of postoperative atrial fibrillation in patients with left atrial volume 32 mL/m(2) or greater was 37% (11/30) and greater than in those with left atrial volume less than 32 mL/m(2) (14%, 22/160, P = .002). Length of hospital stay was significantly increased in patients with postoperative atrial fibrillation compared with patients without (P = .04). Older age was significantly associated with greater ß-blocker use and left atrial volume and lower left atrial emptying fraction. On multivariate analysis, lower left atrial emptying fraction (odds ratio, 1.03 per unit decrement; 95% confidence interval, 1.002-1.065; P = .04) and preoperative use of ß-blockers (odds ratio, 2.82; 95% confidence interval, 1.18-6.77; P = .02) were the only independent risk factors associated with postoperative atrial fibrillation. CONCLUSIONS: These data show that an echocardiogram before major thoracic surgery, increased use of preoperative ß-blockers, and decreased left atrial emptying fraction were associated with postoperative atrial fibrillation. Echocardiographic predictors of left atrial mechanical dysfunction may prove clinically useful in risk stratifying patients in whom postoperative atrial fibrillation is more likely to develop and to benefit from prevention strategies aimed at mitigating atrial function before surgery.

Preoperative exercise echocardiography and perioperative cardiovascular outcomes in elderly patients undergoing cancer surgery.

Limited information is available on the value of exercise echocardiography (EE) for identifying operative risk in elderly patients undergoing noncardiac surgery. The authors investigated the outcome in 221 consecutive patients 75 years and older who had EE before intermediate- or high-risk cancer surgery. Baseline clinical data, postoperative adverse cardiovascular events (PACE), and 30-day mortality were collected from the medical records and the Social Security Death Index. The mean age +/- SD of the group was 78.9+/-3.5 years; 57% were men. Significant cardiovascular abnormalities (by echocardiography) were present in 71.5%. Mean metabolic equivalents +/- SD achieved during exercise was 4.9+/-1.9. EE identified 50 (22.6%) patients with ischemia and/or infarction. Perioperative beta-blockers were used in 80% of patients with coronary artery disease vs 48.5% without coronary artery disease (P<.0001). There were 31 PACE in 26 (11.8%) patients. Atrial fibrillation was the most common PACE, seen in 18 (8.1%) patients, followed by congestive heart failure in 8 (3.6%), acute coronary syndrome in 2 (0.9%), and cardiac arrest in 1 (0.5%). Thirty-day mortality was only 0.9%. Hospital lengths of stay for patients with and without PACE were 16.8+/-14.9 and 8.5+/-4.8 days (P< or =.0001), respectively. An abnormal EE predicted PACE (22% vs 8.8%; P< .025). Perioperative beta-blockers reduced the incidence of postoperative atrial fibrillation (4.9% vs 12.2%; P=.052). In conclusion, EE is feasible in very elderly patients. There is a high prevalence of cardiac abnormalities in the elderly. An abnormal EE predicts PACE, which, in turn, is associated with increased length of stay.

The incidence and outcome of ventricular arrhythmias after noncardiac thoracic surgery.

UNLABELLED: 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.

Older age is the strongest predictor of postoperative atrial fibrillation.

BACKGROUND: Identification of patients vulnerable for atrial fibrillation (AF) after major thoracic surgery will allow targeting those most likely to benefit from prophylactic therapy. The goal of the current study was to evaluate the accuracy of easily available clinical characteristics for the prediction of this complication. METHODS: Patients undergoing major elective thoracic surgery were chosen from an ongoing prospective database. RESULTS: Postoperative in-hospital AF occurred in 79 (15%) of 527 patients Using cut-point methodology and logistic regression, the authors identified two preoperative risk factors independently associated with AF: age 60 yr or older (P = 0.0007) and heart rate 74 beats/min or greater on preadmission electrocardiogram (P = 0.005). The odds of developing AF increased by a factor of 2.5 (95% confidence interval, 1.7-3.4; P < 0.0001) between incremental age categories (< 60 yr, 60-69 yr, > or = 70 yr) and by a factor of 2.3 (95% confidence interval, 1.4-3.8; P < 0.0007) between heart rate categories (< 74 beats/min, > or = 74 beats/min). The combination of age 60 yr or older and preoperative heart rate 74 beats/min or greater predicted AF with a sensitivity of 73% and specificity of 57%. Maximum P-wave duration as measured from standard electrocardiogram did not differentiate patients who did or did not develop AF. Patients who developed AF had a higher incidence of postoperative pneumonia (14 vs. 4%; P = 0.001), acute respiratory failure (8 vs. 1.6%; P = 0.01), greater hospital stay (17 +/- 17 vs. 10 +/- 9 days; P = 0.001) and 30-day mortality (11 vs. 3%; P = 0.001) when compared with those who did not develop AF, respectively. CONCLUSIONS: Advanced age and preoperative heart rate identify patients at high risk for development of AF after thoracic surgery. Postoperative AF occurs more frequently in patients with greater postoperative morbidity and length of hospitalization.