Esmolol versus verapamil in the acute treatment of atrial fibrillation or atrial flutter

The effects of esmolol, an ultrashort-acting beta blocker, and verapamil were compared in controlling ventricular response in 45 patients with atrial fibrillation or atrial flutter, in a randomized, parallel, open-label study. Patients with either new onset (less than 48 hours, n = 31) or old onset (greater than 48 hours, n = 14) of atrial fibrillation or flutter with rapid ventricular rate were stratified to receive esmolol (n = 21) or verapamil (n = 24). Drug efficacy was measured by ventricular rate reduction and conversion to sinus rhythm. The heart rate declined with esmolol from 139 to 100 beats/min (p less than 0.001) and with verapamil from 142 to 97 beats/min (p less than 0.001). Fifty percent of esmolol-treated patients with new onset of arrhythmias converted to sinus rhythm, whereas only 12% of those who received verapamil converted (p less than 0.03). Mild hypotension was observed in both treatment groups. Esmolol compares favorably with verapamil with respect to both efficacy and safety in acutely decreasing ventricular response during atrial fibrillation or flutter. Moreover, conversion to sinus rhythm is significantly more likely with esmolol.     

Pulmonary vein firing triggering atrial fibrillation after open heart surgery

We report the case of a 44-year-old woman with obstructive hypertrophic cardiomyopathy without history of prior arrhythmias who underwent surgical myectomy. She developed symptomatic postoperative atrial fibrillation (AF) that was refractory to antiarrhythmic therapy and could not be adequately rate controlled. AF always was preceded by short and fast runs of atrial tachycardia. In the electrophysiology laboratory, this arrhythmia appeared to originate from the right superior pulmonary vein and conducted with variable degrees of exit block. Pulmonary vein isolation guided by circular mapping was performed, and no further episodes of either atrial tachycardia or AF were noted. This case highlights the potential role of the pulmonary veins in the pathophysiology of postoperative AF.     

Efficacy of landiolol hydrochloride for atrial fibrillation after open heart surgery

It is important to establish effective treatment for postoperative atrial fibrillation (AF), the most common complication after cardiac surgery. We evaluated the efficacy and safety of landiolol hydrochloride for rhythm conversion in patients with postoperative AF. Among 134 patients who developed new-onset AF after open heart surgery between 2007 and 2009, 69 patients who received landiolol hydrochloride for treatment of postoperative AF were enrolled. The AF conversion rate, the percentage of patients with 20 % reduction of the ventricular rate, and the factors related to successful treatment were evaluated. Then, the landiolol group was compared with 65 patients who had postoperative AF and did not receive landiolol hydrochloride. Landiolol hydrochloride was the first-line treatment in 46 patients and the only therapy in 26 patients. Reversion to sinus rhythm was achieved in 51 patients, while the conversion rate in patients without landiolol hydrochloride was only 56.8 % (p < 0.05). A 20 % reduction of the ventricular rate was achieved more frequently in the landiolol group. Although landiolol hydrochloride was highly effective in patients who had undergone off-pump coronary artery bypass grafting, patients with cardiopulmonary bypass did not respond as well. The heart rate was reduced from 130 ± 26 to 81 ± 12 (p < 0.05) after landiolol administration, while blood pressure did not decrease significantly. Landiolol hydrochloride was effective for conversion of postoperative AF. This ultra-short-acting β-blocker is a safe first-line treatment for postoperative AF after open heart surgery, and is most effective in patients who have undergone off-pump coronary artery bypass grafting.     

静脉地尔硫治疗快速房颤、房扑的疗效分析

为检验静脉地尔硫艹卓控制房颤、房扑心室率的有效性和安全性，对４７例快速房颤、房扑患者一次静脉注射０．２５ｍｇ／ｋｇ地尔硫艹卓后以５ｍｇ／ｈ～１０ｍｇ／ｈ微泵维持，平均起效时间５．２±２．７ｍｉｎ，总有效率９３．６％，心功能较用药前明显改善（Ｐ＜０．０５），对血压无明显影响，副作用发生率为１０．６％，均不严重。结果提示地尔硫艹卓是一种能迅速、安全、有效控制房颤、房扑患者心室率的药物     

Amiodarone versus sotalol for the treatment of atrial fibrillation after open heart surgery: the Reduction in Postoperative Cardiovascular Arrhythmic Events (REDUCE) trial

Objectives

This prospective, randomized, double-blind, placebo-controlled study compared the efficacy and safety of amiodarone and sotalol in the prevention of atrial fibrillation (AF) following open heart surgery.

Background

The incidence of supraventricular arrhythmias following open heart surgery ranges from 20% to 40%, with AF being the most common. Both amiodarone and sotalol have been shown to be effective in reducing postoperative arrhythmias, but no direct comparison of these agents has been conducted.

Methods

A total of 160 patients were randomized, of whom 134 underwent coronary artery bypass graft surgery (CABG) alone, 17 underwent CABG and concomitant aortic valve replacement surgery (AVR), 9 underwent AVR only, and 1 patient's surgery was canceled. Patients with signs or symptoms of congestive heart failure (CHF), ejection fraction ≤30%, estimated creatinine clearance <30 mL/min, or serum creatinine ≥2.5 mg/dL were excluded. Patients were randomized to receive either sotalol 80 mg 2 times per day (n = 76) or intravenous amiodarone 15 mg/kg over 24 hours followed by oral amiodarone 200 mg 3 times per day (n = 83). Study drug was started at the time of surgery and continued for 7 days or until discharge, whichever came first.

Results

AF occurred in 17% of patients randomized to amiodarone and 25% of the patients randomized to sotalol (P = .21). However, the duration of AF was significantly shorter in amiodarone-treated patients (169 ± 224 min) compared to sotalol treated patients (487 ± 505 min; P = .04). In a subgroup analysis, the incidence of AF in patients undergoing AVR or CABG with AVR was significantly less with amiodarone (1/15, 7%) compared to sotalol (9/11, 82%) (P < .001). Blood pressure was lower immediately after surgery with amiodarone but comparable to sotalol at 24 hours. Of the hemodynamic indices measured, only stroke volume was significantly lower in patients randomized to sotalol at 24 hours (P = .035).

Conclusions

Amiodarone and sotalol share similar efficacy and safety in reducing postoperative AF. Hemodynamic effects were similar between both drugs at 24 hours, with the exception that stroke volume was lower in sotalol-treated patients. In patients undergoing more complex surgery, postoperative AF occurred more frequently with sotalol than with amiodarone.     

Pharmacokinetics and pharmacodynamics of intravenous diltiazem in patients with atrial fibrillation or atrial flutter.

BACKGROUND. Diltiazem, a calcium channel blocker, has been shown to be safe and effective in the treatment of patients in atrial fibrillation and/or atrial flutter. However, there have been no pharmacokinetic/pharmacodynamic studies of diltiazem in these patients. METHODS AND RESULTS. The pharmacokinetics and pharmacodynamics of intravenous diltiazem were determined in 32 patients with atrial fibrillation or atrial flutter (mean +/- SD age, 66 +/- 7 years; mean baseline heart rate, 131 +/- 10 beats per minute) after 20 mg or 20 mg followed by 25-mg bolus doses and a 10 and 15 mg/hr infusion for 24 hours. After the 10 and 15 mg/hr infusions of diltiazem, mean +/- SD elimination half-life was 6.8 +/- 1.8 and 6.9 +/- 1.5 hours, volume of distribution was 411 +/- 151.8 and 299 +/- 70.8 I, and systemic clearance was 42 +/- 12.4 and 31 +/- 8.3 l/hr, respectively. Percentages of the plasma concentrations of the principal metabolites desacetyldiltiazem and N-desmethyldiltiazem to diltiazem were < 15% and < 10%, respectively. Thirty of 32 patients maintained response throughout the 24-hour infusion of diltiazem. Using a sigmoidal Emax pharmacodynamic model, a strong relation (mean +/- SD r2, 0.78 +/- 0.2) was observed between plasma diltiazem concentration and percent heart rate reduction. Mean +/- SD Emax (maximum percent reduction in heart rate from baseline) and EC50 (plasma diltiazem concentration that achieves half Emax) were 52 +/- 17% and 110 +/- 84 ng/ml, respectively. The model predicts that mean plasma diltiazem concentration of 79, 172, and 294 ng/ml are required to produce a 20%, 30%, and 40% reduction in heart rate, respectively. A relation between plasma diltiazem concentration and percent change in systolic blood pressure (SBP) or diastolic blood pressure (DBP) from baseline was not observed (mean +/- SD r2, SBP/DBP: 0.35 +/- 0.24/0.36 +/- 0.2). There were no untoward side effects observed. CONCLUSIONS. First, the pharmacokinetics of diltiazem in patients with atrial fibrillation or atrial flutter is nonlinear with an apparent dose-dependent decrease in systemic clearance with increasing infusion rate. Second, using a sigmoidal Emax model, there is a strong relation between plasma diltiazem concentration and percent heart rate reduction. Third, the plasma concentrations of the principal metabolites desacetyldiltiazem and N-desmethyldiltiazem are low and are not expected to contribute significantly to the pharmacodynamics of intravenous diltiazem in these patients.     

Thoracic epidural anesthesia does not influence the incidence of postoperative atrial fibrillation after beating heart surgery

BACKGROUND: At least 20 - 30 % of patients undergoing coronary artery bypass graft surgery (CABG) or beating-heart surgery develop postoperative atrial fibrillation (AF). We evaluated the effect of thoracic epidural anesthesia (TEA) on the occurrence of postoperative AF in patients submitted to CABG without cardiopulmonary bypass (OPCABG). METHODS: We performed a retrospective analysis of 125 patients undergoing myocardial revascularization. Early postoperative incidence of AF was compared between three groups of patients - 50 after conventional CABG, 45 after OPCABG, and 30 after OPCABG combined with TEA intraoperatively and postoperatively. Clinical profile of the patients, including factors with a potential influence on postoperative AF was matched for groups. RESULTS: Postoperative AF occurred in 13.3 % of the TEA-treated patients, in 17.7 % of the patients in the OPCABG group, and in 26 % of the patients in the CABG group. This difference did not carry any statistical significance. Risk factors and incidence of postoperative complications were comparable in all groups. CONCLUSION: TEA has no effect on the incidence of postoperative AF in patients undergoing beating-heart surgery.     

心脏直视手术下行仿改良迷宫Ⅲ术射频消融治疗心房颤动

目的 评价心脏直视下行盐水冲洗射频消融仿改良迷宫Ⅲ手术(IRFMM)治疗心脏瓣膜病合并心房颤动(房颤)的安全性及有效性.方法 回顾分析63例心脏瓣膜病合并持续性房颤病例,其中31例行瓣膜置换同期行IRFMM手术治疗房颤(治疗组),32例行瓣膜置换而未同期行IRFMM术(对照组)的治疗结果和早期随访资料.结果 治疗组18例术后立即恢复窦性心律,3例术后使用临时起搏器,于术后5 d内恢复窦性心律,7例术后由交界区心律转为窦性心律,3例仍为房颤.术后随访2～19个月,出院时90.3%(28/31)为窦性心律,随访半年以上91.3%(21/23)维持窦性心律,随访1年以上85.7%(12/14)维持窦性心律.对照组术后仅3例短暂转复为窦性心律,出院时全转为房颤.32例随访2～19个月,未转为窦性心律者,两组相比差异有统计学意义(P＜0.01).结论 使用美敦力公司Cardioblate盐水冲洗射频消融系统代替切割、冷冻施行迷宫术治疗房颤安全简便有效.     

Double-blind crossover randomized trial of intravenously administered verapamil. Its use for atrial fibrillation and flutter following open heart surgery

Fourteen patients with onset of atrial fibrillation (11) or flutter (three) and ventricular rate over 120 beats per minute following cardiac surgery were treated with intravenous (IV) doses of verapamil hydrochloride or placebo in a double-blind crossover protocol. Patients with poor left ventricular function, hypotension, atrioventricular block, and taking beta-blockers and disopyramide were excluded. The dosages were 0.075 mg/kg and 0.15 mg/kg given 15 minutes apart, with termination of study on achieving an end point (conversion to sinus rhythm or slowing of ventricular rate to below 100 beats per minute). None reached the end point with placebo but all with verapamil. Baseline ventricular rate was 144 +/- 20 beats per minute, after placebo 143 +/- 16 beats per minute, and after verapamil 89 +/- 7 beats per minute (mean +/- SD). Thus, IV verapamil briefly slows the ventricular rate of atrial tachyarrhythmias following cardiac surgery.     

Quantitative electrocardiography for predicting postoperative atrial fibrillation after cardiac surgery

Background

Atrial fibrillation (AF) after cardiac surgery is a common marker of poor outcomes. Quantitative electrocardiographic (ECG) measurements may be valuable predictors of postoperative AF.

Methods

We evaluated clinical and ECG predictors of postoperative AF in 13 356 patients who underwent cardiac surgery in sinus rhythm.

Results

A total of 4724 patients (35%) developed postoperative AF. P-wave amplitude in leads aVR and V₁ were the strongest ECG predictors. A less negative P-wave amplitude in lead aVR was associated with increased risk for postoperative AF (odds ratio, 1.46; 95% confidence interval, 1.32-1.61), as was a more positive or a more negative P-wave amplitude in lead V₁ (odds ratio, 1.25; 95% confidence interval, 1.16-1.36) after adjusting for clinical and procedural predictors of postoperative AF. Reclassification analysis showed a 7% discrimination improvement (P < .0001).

Conclusions

P-wave amplitude in lead aVR and lead V₁ are powerful predictors of postoperative AF and, in combination with other clinical predictors, can guide application of prophylactic interventions.     

Left atrial flutter after radiofrequency catheter ablation of focal atrial fibrillation

We report an arrhythmic complication in two patients in whom a procedure directed at isolating one or two pulmonary veins had been performed. The complication was related to pulmonary vein disconnection scars after ablation. Both patients developed new clinical tachycardia (atypical atrial flutter) secondary to a reentrant phenomena in the vicinity of a previously ablated pulmonary vein.