Biatrial pacing to prevent atrial fibrillation after coronary artery bypass

Between October 1999 and December 2000, 52 patients (37 male) undergoing coronary artery bypass surgery were selected for overdrive biatrial pacing to determine its effectiveness in reducing atrial fibrillation. A pacing wire was attached to the right atrial appendage and another to the roof of the left atrium behind the aorta. The atria were paced continuously in AAI mode at a rate of 90 pulses per minute or 10 pulses above the underlying rate (maximum rate < 140/min) for 3 days. The endpoint was the onset of atrial fibrillation during hospital stay. Results were compared with those of a control group of 52 matched patients. There were no significant differences in the occurrence of atrial fibrillation (30% in the paced group vs. 25% in the control group), morbidity, or length of hospital stay. Continuous biatrial pacing after coronary bypass surgery was safe and well tolerated, however, it did not prevent or lower the incidence of atrial fibrillation.     

Decreased right ventricular function after coronary artery bypass grafting

Decreased right ventricular function after coronary artery bypass grafting is a common and well-known (if not well-understood) phenomenon.We prospectively evaluated right ventricular function via echocardiographic tricuspid annular motion, tricuspid annular velocity, and right ventricular strain analysis before and after coronary artery bypass grafting. We also evaluated the effect of right coronary artery disease and revascularization on post-coronary artery bypass grafting, right ventricular function, and interventricular septal motion.We performed baseline echocardiography in 250 candidates for coronary artery bypass grafting, and we repeated echocardiography in 240 of those patients 1 year after coronary artery bypass grafting. We evaluated right ventricular function via tricuspid annular motion, tricuspid annular velocity, and right ventricular strain analysis, all measured at the right ventricular free wall.Right ventricular function as evaluated by tricuspid annular motion showed a significant reduction 1 year after coronary artery bypass grafting (21.7 vs 12.1 mm; P < 0.001) compared with preoperative measurements. Right ventricular tissue velocity (14.0 vs 7.0 cm/s; P < 0.001) and right ventricular strain (20.3% vs 11.6%; P < 0.001) were also significantly reduced after coronary artery bypass grafting. Interventricular septal motion was paradoxical in 97% of the patients 1 year after coronary bypass.Right ventricular function remained depressed for as long as 1 year after coronary artery bypass grafting. These findings were independent of the state of the right coronary artery and the graft. It is likely that the interventricular septum is recruited to maintain right ventricular stroke volume after coronary artery bypass grafting.     

Premature atrial beat eliciting atrial fibrillation after coronary artery bypass grafting

Of patients undergoing coronary artery bypass grafting 30% develop atrial fibrillation (AF) or flutter. To determine if AF is initiated from the right or left atrium, atrial electrograms were continuously recorded in patients undergoing this procedure. In addition, to study whether the prematurity index of premature atrial contractions (PACs) eliciting AF differs from PACs not provoking AF, the distribution of prematurity indices was evaluated from R-R interval analysis. The right and left atrial recording electrodes were first activated by the ectopic beat provoking AF in six and eight patients, respectively. The prematurity index of the PAC eliciting AF was located in the middle (in half of the patients) or to the left of the median distribution of prematurity indices. The variability in activation of the atrial electrodes suggests that the PAC provoking AF can have its origin in the right, the septal, or the left region of the atrium. The initiation of AF depends on the prematurity index of the PAC.     

Coronary artery-right ventricular fistula after coronary artery bypass grafting

Development of a coronary artery fistula rarely occurs after cardiac surgery. We report the appearance of a coronary artery-right ventricular fistula as a consequence of coronary artery bypass grafting. Possible mechanisms and consequences are discussed.     

冠状动脉旁路移植术后心房颤动的高危因素分析

目的　研究冠状动脉旁路移植术 (CABG)后心房颤动 (AF)的发病特点 ,分析AF的高危因素。方法　采用回顾性研究的方法 ,观察我院CABG患者 2 35例 ,监测手术前后心电图、2 4h动态心电图、心肌酶谱、心脏收缩功能、左心房内径、体外循环及主动脉阻断时间、和电解质变化等。结果　 2 35例患者CABG术后 4 2例 (17 9% )发生AF ,81%的AF发生于术后 1～ 3d ,持续 (12 0± 9 14 )h ,95 2 %患者 2 4h内恢复窦性心律 ;高龄 (≥ 70岁 )、低钾血症 (≤ 3 5mmol/L)、低镁血症 (≤ 0 70mmol/L)、左心功能不良[射血分数 (EF)≤ 0 4 0和 /或缩短分数 (FS)≤ 0 2 4 ]、左心房内径≥ 35mm、右冠状动脉狭窄≥ 70 %的患者术后AF发生率明显高于其他患者 (P分别为 0 0 0 1、0 0 0 9、0 0 16、0 0 30、0 0 36和 0 0 4 4 ) ;应用胺碘酮患者AF发生率明显降低。结论　低镁血症、左心房增大、右冠状动脉病变是术后AF的相关因素 ;高龄、左心室功能不良、低钾血症是术后AF的独立高危因素 ;预防应用胺碘酮能明显降低术后心室率 ,有效地抑制术后AF的发生 ,促进AF转复 ,明显改善左心室功能 ,并且具有较好安全性和耐受性 ,是术后AF的保护因素     

Left ventricular ejection power in coronary artery disease during atrial pacing.

Peak and mean left ventricular ejection power were measured during atrial pacing in 6 normal subjects (group I), 6 patients with coronary artery disease without myocardial infarction (group IIa), and 10 patients with coronary artery disease after myocardial infarction (group IIb). Pacing rates were 80 and 120/min. Power was determined by computer analysis of pressure, volume, and time. Data were normalised by end-diastolic volume and left ventricular muscle mass. Peak left ventricular ejection power normalised by end-diastolic volume values at a pacing rate of 120 min were significantly lower in group IIa and IIb than in normal subjects. Mean muscle mass in normal subjects was 179 g and in group IIa 216 g (P smaller than 0.05). Peak power normalised by muscle mass in normal subjects tended to increase at 120/min whereas in group IIa it declined by 26 per cent (P less than 0.001). These data indicate that the energy output of the left ventricle at rest may be the same in patients with significant coronary artery disease as in normal subjects. Increasing the heart rate from 80 to 120/min in a normal myocardium augments power but in coronary artery disease it remains static or falls.     

Left ventricular ejection power in coronary artery disease during atrial pacing.

Peak and mean left ventricular ejection power were measured during atrial pacing in 6 normal subjects (group I), 6 patients with coronary artery disease without myocardial infarction (group IIa), and 10 patients with coronary artery disease after myocardial infarction (group IIb). Pacing rates were 80 and 120/min. Power was determined by computer analysis of pressure, volume, and time. Data were normalised by end-diastolic volume and left ventricular muscle mass. Peak left ventricular ejection power normalised by end-diastolic volume values at a pacing rate of 120 min were significantly lower in group IIa and IIb than in normal subjects. Mean muscle mass in normal subjects was 179 g and in group IIa 216 g (P smaller than 0.05). Peak power normalised by muscle mass in normal subjects tended to increase at 120/min whereas in group IIa it declined by 26 per cent (P less than 0.001). These data indicate that the energy output of the left ventricle at rest may be the same in patients with significant coronary artery disease as in normal subjects. Increasing the heart rate from 80 to 120/min in a normal myocardium augments power but in coronary artery disease it remains static or falls.     

有、无体外循环冠状动脉旁路移植术后房颤原因的分析

目的:比较非体外循环下的冠状动脉旁路移植术(OPCABG)与体外循环下的冠状动脉旁路移植术(ECCABG)后房颤的发生率,并分析其原因。方法:OPCABG组75例,手术在全麻常温下进行;ECCABG组113例,手术在全麻低温体外循环下进行。结果:OPCABG组术后15例(20％)出现房颤,ECCABG组术后31例(27.4％)出现房颤。二组房颤发生率有显著差异(P<0.05)。结论:非体外循环下的冠状动脉旁路移植术术后房颤的发生率低于体外循环下的冠状动脉旁路移植术术后的房颤发生率,但仍有较高的发生率。房颤发生的原因可能是术后侧支循环逐渐关闭,改变心房的血液分布,诱发心房内及其周围组织产生局灶激动,从而发生房颤。     

Prediction of atrial fibrillation via atrial electromechanical interval after coronary artery bypass grafting

Objectives: We sought to analyze the value of measuring atrial electromechanical interval (AEMI) in predicting post coronary artery bypass grafting (CABG) atrial fibrillation (AF).Background: Atrial fibrillation is the most common arrhythmia after CABG with as many as 10–40%. Several predictors are associated with the development of AF after cardiac surgery.Methods: At least 30 patients; 18 males and 12 females (mean age 53 + 12 years) with ischemic heart disease diagnosed by coronary angiography and underwent CABG enrolled in the study. Pre-operative data were collected including laboratory, 12-lead ECG to measure P wave duration and P wave dispersion, trans-thoracic echocardiography to measure LV dimensions, ejection fraction, and LA volume. Pre-operative tissue Doppler imaging (TDI) was used to measure atrial electromechanical interval (AEMI) in milliseconds from the onset of P wave on the surface electrogram till the onset of atrial systole (Am).Results: Our patients were classified into two groups, group I with documented post CABG AF and group II with no AF. It was found that the mean value of AEMI in group I patients was significantly longer; 136 + 5.6 vs 93.7 + 19 ms in group II patients (P < 0.001). Using receiver operator characteristic (ROC) analysis, it was found that the cutoff value of AEMI as a predictor of post CABG AF was 120 ms which achieves 100% sensitivity and 99% specificity. It was found also significantly increased P wave duration and dispersion in group I patients compared to group II (97.7 ± 3 vs 94 ± 3.9 ms; P = 0.02 and 26 ± 4.7 vs 23 ± 4.7; P = 0.04, respectively).Conclusion: using AEMI as a predictor of post CABG AF is a valuable marker which carries high sensitivity and specificity.     

Risk predictors of new-onset atrial fibrillation after coronary artery bypass grafting

<正>Objective This study aims to determine the risk factors of new-onset atrial fibrillation (AF) in patients who underwent isolated coronary artery bypass grafting(CABG) to provide evidences for the prevention and treatment of new-onset AF after CABG. Methods Between January 2015 and May 2016,a total of 602     

Clinical prediction rule for atrial fibrillation after coronary artery bypass grafting

OBJECTIVES: This study was designed to devise and validate a practical prediction rule for atrial fibrillation/atrial flutter (AF) after coronary artery bypass grafting (CABG) using easily available clinical and standard electrocardiographic (ECG) criteria. BACKGROUND: Reported prediction rules for postoperative AF have suffered from inconsistent results and controversy surrounding the added predictive value of a prolonged P-wave duration. METHODS: In 1,851 consecutive patients undergoing CABG with cardiopulmonary bypass, preoperative clinical characteristics and standard 12-lead ECG data were examined. Patients were continuously monitored for the occurrence of sustained postoperative AF while hospitalized. Multiple logistic regression was used to determine significant predictors of AF and to develop a prediction rule that was evaluated through jackknifing. RESULTS: Atrial fibrillation occurred in 508 of 1,553 patients (33%). Multivariate analysis showed that greater age (odds ratio [OR] 1.1 per year [95% confidence intervals (CI) 1.0 to 1.1], p < 0.0001), prior history of AF (OR 3.7 [95% CI 2.3 to 6.0], p < 0.0001), P-wave duration >110 ms (OR 1.3 [95% CI 1.1 to 1.7], p = 0.02), and postoperative low cardiac output (OR 3.0 [95% CI 1.7 to 5.2], p = 0.0001) were independently associated with AF risk. Using the prediction rule we defined three risk categories for AF: <60 points, 61 of 446 (14%); 60 to 79 points, 330 of 908 (36%); and >or=80 points, 117 of 199 (59%). The area under the receiver-operator characteristic curve for the model was 0.69. CONCLUSIONS: These data show that post-CABG AF can be predicted with moderate accuracy using easily available patient characteristics and may prove useful in prognostic and risk stratification of patients after CABG. The presence of intraatrial conduction delay on ECG contributed least to the prediction model.     

Early pharmacologic conversion of atrial fibrillation after off-pump coronary artery bypass grafting

BackgroundThe aim of this study was to evaluate the efficacy of early amiodarone-based pharmacological cardioversion for postoperative atrial fibrillation (POAF) following off-pump coronary bypass grafting (OPCAB).MethodsA total of 507 patients who underwent OPCAB between 2015 and 2017 were categorized into POAF (n=94) and no-POAF (n=413) groups. Patients in the POAF group were treated according to the following institutional protocol: 150 mg loading dose of intravenous amiodarone, followed by oral administration with sequential maintenance doses at 600, 400, and 200 mg per day. If sinus rhythm was restored before discharge, patients were discharged without amiodarone or anticoagulants, except for dual antiplatelets.ResultsBefore discharge at index hospitalization, 97.8% of POAF patients had restored sinus rhythm. Independent risk factors for POAF were age, unstable angina, prior percutaneous transluminal coronary angioplasty, and left atrial diameter. The mean follow-up duration was 41.1±12.8 months. Freedom from overall mortality and composite events, including mortality, major bleeding requiring admission and cerebrovascular events, were similar between the 2 groups. Results were consistent after propensity-score matching.ConclusionsAmiodarone-based rapid pharmacological cardioversion of POAF resulted in a high sinus rhythm conversion rate (97.9%). Rate of late adverse cardiovascular events including stroke, were low even without anticoagulation. As optimal treatment and anticoagulation guidelines for POAF after OPCAB have not yet been established, amiodarone-based treatment protocols may be considered as a useful option.