Atrial fibrillation after coronary artery bypass grafting: does the type of procedure influence the early postoperative incidence?

OBJECTIVE: Atrial fibrillation (AF), the common postoperative complication, has been observed after coronary artery bypass grafting (CABG) in 7--40% of patients. Cardiopulmonary bypass (CPB), eliminated in off-pump operations (OPCABG) may decrease the incidence of AF, whereas the combination of CABG with heart valve replacement may result in more frequent postoperative atrial fibrillation. The aim of our study was to compare the early postoperative AF incidence rate during ICU stay in three groups of patients: after CABG, OPCABG, and CABG combined with valve replacement. MATERIAL AND METHODS: A prospective study of 906 consecutive patients was carried out between January 1999 and January 2000. Clinical profile of 906 patients, including factors having potential influence on postoperative AF did not showed any significant differences between the groups. The presence of arrhythmia history was the reason of excluding 85 patients from the statistical analysis. The observation was performed in each case during ICU-stay, using a HP system for continuous automated arrhythmia analysis. Early postoperative incidence of AF was recorded and compared between three groups of patients: 650 after conventional CABG, 118 after OPCABG, and 53 after CABG combined with valve replacement. Chi-square and a Mann--Whitney tests, Statistica 5.0 PL were used for the statistical analysis. RESULTS: Atrial fibrillation occurred during the postoperative ICU stay in 9.8% of patients after CABG, in 10.2% after OPCABG, and in 21% after CABG combined with valve replacement. There was no significant difference between CABG and OPCABG groups (P=0.965). The confidence interval of the odds ratio ranges from 0.5 to 1.85. Consequently, an increased risk would be possible for both methods. We observed a statistically significant increase of the early postoperative atrial fibrillation incidence rate in patients after CABG combined with valve replacement, when compared with both CABG + OPCABG groups (P=0.005). CONCLUSIONS: (1) Atrial fibrillation is a common postoperative complication after myocardial revascularization procedures which prolongs ICU stay. (2) The study did not show that the incidence of postoperative AF is influenced by the technique of coronary artery bypass grafting: with or without CPB. (3) The prevalence of postoperative AF increase when CABG is combined with valve replacement.     

Human cytokine responses to coronary artery bypass grafting with and without cardiopulmonary bypass.

BACKGROUND: Coronary artery bypass grafting (CABG) is associated with a systemic inflammatory response. This has been attributed to cytokine release caused by extracorporeal circulation and myocardial ischemia. This study compares the inflammatory response after CABG with cardiopulmonary bypass and after minimally invasive direct coronary artery bypass grafting (MIDCABG) without cardiopulmonary bypass. METHODS: Cytokine release and complement activation (interleukin-6 and interleukin-8, soluble tumor necrosis factor receptors 1 and 2, complement factor C3a, and C1 esterase inhibitor) were determined in 24 patients before and after CABG or MIDCABG. The maximum body temperature, chest drainage, and fluid balance were recorded for 24 hours after operation. RESULTS: Release of interleukin-6, interleukin-8, and tumor necrosis factor receptors 1 and 2 was significantly higher (p < or = 0.005) in the CABG group than the MIDCABG group just after operation. After 24 hours, a significant increase in interleukin-6 was also found in the MIDCABG group (p = 0.001) compared with preoperative value. Body temperature and fluid balance were significantly higher after CABG (p < or = 0.001). CONCLUSIONS: Minimally invasive direct coronary artery bypass grafting represents a less traumatizing technique of surgical revascularization. The reduction in the inflammatory response may be advantageous for patients with a high degree of comorbidity.     

Predictors of atrial fibrillation after off-pump coronary artery bypass graft surgery

OBJECTIVE: Atrial fibrillation is the most common complication after coronary artery bypass graft surgery. This arrhythmia may lead to hemodynamic compromise, prolonged hospitalization, and increased risk for cerebral thromboembolism. Older age is the only variable consistently associated with the development of postoperative atrial fibrillation; however, no strong predictive model exists. The purpose of this study was to identify perioperative characteristics associated with new-onset atrial fibrillation in patients undergoing off-pump coronary artery bypass grafting. DESIGN: Prospective, observational. SETTING: University tertiary care hospital. PARTICIPANTS: One hundred sixty consecutive patients undergoing off-pump coronary artery bypass grafting. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Incidence of postoperative atrial fibrillation was the major outcome. Atrial fibrillation occurred in 33 patients (20.6%). Multivariate analysis identified reintervention (odds ratio 26.8), revascularization of the ramus medianus (odds ratio 3.9), and age (odds ratio 1.069 per year) as the only independent predictors of postoperative atrial fibrillation. All patients were in sinus rhythm at hospital discharge. One hospital death was noted. CONCLUSIONS: Despite the less invasive approach, the incidence of postoperative atrial fibrillation is high after off-pump coronary artery bypass grafting. Older age, grafting of the ramus medianus, and a redo operation were predictors of new-onset postoperative atrial fibrillation. It is possible that left atrial stretching with heart dislocation during revascularization of the lateral wall could lead to postoperative atrial fibrillation.     

Meta-analysis of short-term and mid-term outcomes following off-pump coronary artery bypass grafting

BACKGROUND: Uncertainty continues to surround the relative benefits and harms of conventional coronary artery bypass grafting (CABG) and off-pump coronary artery bypass grafting (OPCABG). Possible reasons are that high-quality studies have not comprehensively examined relevant patient outcomes and have enrolled a limited range of patients. Some studies may have been too small to detect clinically important differences in patient outcomes. The present study addresses these issues using meta-analysis. METHODS: We comprehensively retrieved randomized and nonrandomized controlled studies according to predetermined criteria. We performed meta-analyses for each outcome and empirically determined whether potential biases that might result from differences in study design or patient characteristics actually biased a study's results. We also conducted sensitivity analyses and tested for publication bias. RESULTS: Rates of perioperative myocardial infarction, stroke, reoperation for bleeding, renal failure, and mortality were lower after OPCABG than after CABG. Reductions in length of hospital stay, atrial fibrillation, and wound infection were also associated with OPCABG, but statistically significant differences among study results for these outcomes could not be explained by available information. Midterm (3 to 25 months) angina recurrence did not appear to differ between treatments; a trend was noticed toward lower reintervention rates with CABG, and a trend toward lower overall mortality with OPCABG, at least when performed at experienced centers. These midterm outcome results require confirmation. CONCLUSIONS: Off-pump coronary artery bypass grafting appears to reduce length of hospital stay, operative morbidity, and operative mortality relative to on-pump CABG. More studies are required before firm conclusions can be drawn concerning the effect of OPCABG on midterm mortality, angina recurrence, and repeat intervention.     

Cardioplegic arrest does not increase the risk of atrial fibrillation after coronary artery bypass surgery.

OBJECTIVE: Atrial fibrillation (AF) is the most common arrhythmia after coronary artery bypass grafting (CABG). It is a considerable source of morbidity, prolongs hospital stay and increases costs of treatment. Atrial cannulation, cardiopulmonary bypass and cardioplegic arrest have been suggested to play a role in the development of AF after CABG. The aim of this case-control study was to evaluate the role of cardiopulmonary bypass and cardioplegic arrest in the development of postoperative AF. METHODS: Data from 114 patients undergoing CABG without cardiopulmonary bypass and cardioplegic arrest (off-pump) between October, 1998 and December, 2002 were evaluated for the occurrence of postoperative AF. Each patient was individually matched by gender, age (+/-3 years), left ventricle ejection fraction (+/-5%), history of myocardial infarction, unstable angina, and beta-blocker medication with patients undergoing CABG with cardiopulmonary bypass and cardioplegic arrest (on-pump) during the same period. The data from off-pump and on-pump groups were compared. RESULTS: Off-pump and on-pump groups had similar preoperative characteristics. The number of distal anastomoses was lower in the off-pump (2.3+/-0.9) than in the on-pump (3.9+/-1.1, (P<0.001) group. However, the incidence of postoperative AF in the off-pump (36.8%) and the on-pump groups (36.0%) did not differ from each other. Old age was the only independent predictor of AF after CABG. CONCLUSIONS: Neither cardiopulmonary bypass nor cardioplegic arrest increases the risk of postoperative AF after CABG.     

Is atrial fibrillation caused by extracorporeal circulation?

BACKGROUND: Atrial fibrillation is the most common rhythm disturbance encountered after open heart operations, with a reported incidence up to 40%. Despite its high incidence and clinical relevance its etiology remains obscure. It has been hypothesized that atrial fibrillation might be related to extracorporeal circulation. We performed a retrospective study (January 1, 1997 to December 31, 1997) comparing the incidence of atrial fibrillation in 3 groups of patients revascularized with and without extracorporeal circulation. METHODS: The first group comprised patients with coronary artery disease operated on with standard revascularization technique with cardiopulmonary bypass (n = 685). The second group included patients who had minimally invasive coronary artery bypass grafting without the use of extracorporeal circulation (n = 19). Patients in the third group had off-pump transmyocardial laser revascularization (n = 19). RESULTS: There was no significant difference in the incidence of atrial fibrillation in the group that had conventional coronary artery bypass and the group that had minimally invasive coronary artery bypass without cardiopulmonary bypass. The incidence of atrial fibrillation was significantly lower in the transmyocardial laser group compared with the other two groups. CONCLUSIONS: The present study found that postoperative atrial fibrillation is not caused solely by extracorporeal circulation, but patients who had transmyocardial laser revascularization had a significantly lower incidence of atrial fibrillation.     

Off-pump coronary artery bypass grafting: initial experience at one community hospital

BACKGROUND: This study reports one cardiac surgical center's experience with off-pump coronary artery bypass (OPCAB) and compares clinical risk factors and outcomes with a group of patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass at the same institution. METHODS: Data on preoperative risk factors, intraoperative clinical markers, and postoperative outcomes were collected prospectively on all patients undergoing cardiac surgical procedures at our institution. From January 1, 1999, through October 7, 1999, 332 patients underwent OPCAB procedures at our institution. This group was compared with 445 consecutive patients undergoing CABG at the same institution during the period of January 1, 1998, through November 30, 1998. RESULTS: The two groups were similar with respect to preoperative clinical risk factors. Intraoperative data showed OPCAB patients tended to have fewer grafts performed and had a lower frequency of multiple grafts to obtuse marginal vessels. Outcomes showed no differences in the incidence of perioperative stroke, mediastinitis, reexploration for bleeding, pulmonary complications, new renal failure, postoperative atrial fibrillation, or transfusion of blood products. Patients in the OPCAB group had fewer perioperative myocardial infarctions and lower incidence of postoperative low cardiac output syndrome. A higher percentage of OPCAB patients had surgical lengths of stay of 5 days or less. The OPCAB group tended to have a lower in-hospital mortality rate but this difference did not reach statistical significance. CONCLUSIONS: Off-pump coronary artery bypass grafting with revascularization of all coronary artery segments is a safe and effective procedure that can be performed with equal or improved outcomes and shorter surgical lengths of stay compared with CABG with cardiopulmonary bypass.     

Anaesthesia for off-pump coronary artery bypass grafting surgery

Coronary artery bypass grafting (CABG) surgery may be undertaken with or without cardiopulmonary bypass (CPB) that is on- or off-pump. Although mortality and the incidences of coronary artery graft occlusion, myocardial infarction and stroke are equivalent, off-pump is associated with less blood loss, transfusion, requirement for inotropes, atrial fibrillation and chest infection compared with on-pump CABG surgery. Traditional high-dose opioid techniques of general anaesthesia should be avoided and either inhalation or total intravenous (IV) anaesthesia may be used. Meticulous monitoring, including electrocardiograph (ECG) and invasive arterial pressure measurement, is required. During grafting, good communication between anaesthetist and surgeon is essential. Maintenance of diastolic arterial pressure (DAP) is the key to preventing myocardial ischaemia and cardiovascular collapse. Surgical positioning for grafting to minimize hypotension is paramount and during grafting, IV fluid loading or vasoconstrictors and inotropes are effective treatments. Correction of bradycardia with atropine 0.3 mg IV or epicardial pacing also helps to maintain DAP. Persisting hypotension may require intra-aortic balloon pumping or conversion to on-pump CABG surgery. As there is less blood loss, there is a minimal requirement for cardiovascular support and early recovery of consciousness associated with off-pump compared with on-pump CABG surgery; patients in some institutions may be managed in a recovery room then transferred to a high-dependency unit, thus bypassing ICU.     

Benefit to quality of life after off-pump versus on-pump coronary bypass surgery

BACKGROUND: Whether the clinical outcome of off-pump coronary artery bypass graft (OPCABG) surgery is superior to on-pump coronary artery bypass graft (CABG) surgery is still a matter of debate. However with the considerable reduction of mortality associated with CABG surgery in recent years, more subtle outcome indicators such as quality of life (QOL) become more important. The aim of this study was to compare midterm QOL after OPCABG with that after CABG procedures and with an age- and sex-matched standard population. METHODS: Quality of life was assessed using the Short-Form 36 Health Survey Questionnaire for 504 consecutive patients after CABG (n = 438) and OPCABG (n = 66) operated on between June 1999 and November 2000 at our institution. RESULTS: Except for single-vessel disease, which was more frequent in OPCABG compared with CABG procedures (13.6% versus 6.8%; p <0.01), the preoperative variables were similar. Median EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 3.2 +/- 1.3 in the CABG group compared with 3.0 +/- 0.8 in the OPCABG group (p = not significant). After a mean follow-up of 10.8 +/- 0.5 months physical role function (73.5 +/- 38.3 versus 45.3 +/- 41.6; p <0.01) and emotional role function (75.3 +/- 40.3 versus 61.0 +/- 43.9; p <0.01) were significantly better in OPCABG than in CABG patients. Compared with a standard population, OPCABG patients were significantly impaired in emotional role function and CABG patients in physical and emotional role function. CONCLUSIONS: Midterm QOL after myocardial revascularization is fairly well preserved compared with an age- and sex-matched standard population and is superior after OPCABG compared with CABG. Whether this is only due to avoidance of cardiopulmonary bypass remains to be elucidated.     

二次冠状动脉旁路移植术的临床疗效

目的 评价二次冠状动脉旁路移植术的临床疗效.方法 51例病人(占医院同期进行冠状动脉旁路移植术病人的2.5%)进行二次冠状动脉旁路移植术,距首次手术(15.1±5.8)年.10例采用非体外循环冠状动脉旁路移植术(OPCABG),41例采用体外循环冠状动脉旁路移植术(CABG).正中切口43例,左胸侧切口8例.结果 3例行CABG病人手术后呼吸衰竭,需呼吸机辅助.所有病人住ICU(2.2±0.7)天,住院(9.2±2.4)天.术后死亡2例(3.9%),采用OPCABG和CABG者各1例,死亡原因分别为急性心肌梗死、低心排血量综合征和呼吸功能衰竭、重症肺炎.完全再血管化44例,其中行OPCABG者6例,CABG者38例.部分再血管化7例,行OPCABG者4例,CABG者3例.结论 CABG和OPCABG行二次冠状动脉旁路移植术均安全,疗效满意,能达到完全再血管化的目的.     

Influence of diabetes on mortality and morbidity: off-pump coronary artery bypass grafting versus coronary artery bypass grafting with cardiopulmonary bypass

BACKGROUND: Myocardial revascularization in diabetic patients is challenging with no established optimum treatment strategy. We reviewed our coronary artery bypass grafting experience to determine the impact of eliminating cardiopulmonary bypass on outcomes in diabetic patients relative to nondiabetic patients. METHODS: From January 1995 through December 1999, 9,965 patients, of whom 2,891 (29%) had diabetes, underwent isolated coronary artery bypass grafting. Diabetic and nondiabetic patients were further divided into groups on the basis of cardiopulmonary bypass use. Twelve percent (346 of 2,891) of diabetic patients and 12% (829 of 7,074) of nondiabetic patients underwent coronary artery bypass grafting without cardiopulmonary bypass; the remainder had coronary artery bypass grafting with cardiopulmonary bypass. Nineteen preoperative variables were compared among treatment groups by univariate analysis. RESULTS: Patients undergoing coronary artery bypass grafting without cardiopulmonary bypass compared with those having coronary artery bypass grafting with cardiopulmonary bypass had higher mean predicted mortalities (diabetic, 3.96% versus 3.72%, p = 0.83; nondiabetic, 3.03% versus 2.86%, p = 0.79). In nondiabetic patients, coronary artery bypass grafting without cardiopulmonary bypass provides an actual and risk-adjusted survival advantage over coronary artery bypass grafting with cardiopulmonary bypass (1.81% versus 3.44%, p = 0.0127; risk-adjusted mortality, 1.79% versus 3.61%, p = 0.007). This survival benefit of coronary artery bypass grafting without cardiopulmonary bypass was not seen in diabetic patients (2.89% versus 3.69%, p = 0.452; risk-adjusted mortality, 2.19% versus 2.98%, p = 0.42). Diabetic patients undergoing coronary artery bypass grafting without cardiopulmonary bypass had fewer complications, including decreased blood product use (34.39% versus 58.4%, p = 0.001), and reduced incidence of prolonged ventilation (6.94% versus 12.10%, p = 0.005), atrial fibrillation (15.90% versus 23.26%, p = 0.002), and renal failure requiring dialysis (0.87% versus 2.75%, p = 0.036). CONCLUSIONS: The survival advantage in nondiabetic patients treated with coronary artery bypass grafting without cardiopulmonary bypass is not apparent in diabetic patients. Coronary artery bypass grafting without cardiopulmonary bypass in diabetic patients is nevertheless associated with a significant reduction in morbidity.     

Coronary revascularization without cardiopulmonary bypass in patients with pectus excavatum.

BACKGROUND: Coronary revascularization in patients with pectus excavatum is technically difficult through a median sternotomy secondary to the posterior displacement of the sternum and the asymmetric angulation that it produces. The role of minimally invasive coronary artery bypass grafting (MIDCABG) in this subset of patients was evaluated. METHODS: In 1998, four patients with pectus excavatum underwent revascularization of the left anterior descending artery without cardiopulmonary bypass through a left anterior minithoracotomy. RESULTS: All patients underwent the procedure without intraoperative complications and postoperative angiography demonstrated adequate graft patency. CONCLUSIONS: The advantages of MIDCABG in patients with pectus excavatum is the superior exposure to the LAD and LIMA and avoidance of a median sternotomy and cardiopulmonary bypass. This procedure is deemed safe and effective in patients with such deformities of the chest wall.     

The effect of insulin cardioplegia on atrial fibrillation after high-risk coronary bypass surgery: a double-blinded, randomized, controlled trial

Atrial fibrillation after coronary bypass (CABG) surgery is an important cause of morbidity and increased resource utilization. Insulin-enhanced cardioplegia may reduce postoperative arrhythmias by improving aerobic myocardial metabolism and mitigating the deleterious effects of ischemia. We performed a double-blinded, randomized, controlled clinical trial to determine if insulin-enhanced cardioplegia decreases the risk of post-CABG atrial fibrillation in a high-risk patient population. We randomized 501 patients undergoing urgent CABG to receive insulin-enhanced (Humulin R 10 IU/L, Insulin group, n = 243) or standard (Control group, n = 258) blood cardioplegia during cardiopulmonary bypass. Patients were monitored by using continuous electrocardiography for a minimum of 3 days postoperatively. All standard cardiac medications, including beta-adrenergic blockers, were continued postoperatively. Insulin-enhanced cardioplegia did not result in a significant reduction in postoperative atrial fibrillation. Furthermore, we failed to detect a difference in the incidence of conduction defects, ventricular tachycardia, or pacemaker requirements between insulin and placebo patients. Atrial fibrillation was the most common arrhythmia, occurring in 31% of all patients. Independent predictors of atrial fibrillation were elderly age, preoperative atrial fibrillation, and renal insufficiency. Right bundle branch block was the most common conduction abnormality. Predictors of right bundle branch block were elderly age, female sex, and circumflex coronary artery disease. The incidence of postoperative ventricular tachycardia, left bundle branch block, and permanent pacemaker requirement was small. We conclude that insulin-enhanced cardioplegia does not reduce the incidence of postoperative atrial fibrillation in high-risk CABG patients. IMPLICATIONS: We conducted a double-blinded, randomized, placebo-controlled trial of insulin-enhanced cardioplegia in 501 patients undergoing urgent coronary bypass surgery. Insulin did not decrease the incidence of postoperative atrial fibrillation when compared with placebo. We also failed to demonstrate a difference in the incidence of other postoperative arrhythmias between the two groups of patients.     

Did the introduction of a minimally invasive technique change the incidence of atrial fibrillation after single internal thoracic artery-left anterior descending artery grafting?

OBJECTIVE: Atrial fibrillation after coronary artery bypass operations remains frequent and increases morbidity, as well as resource use. Its cause remains unclear. The introduction of a minimally invasive technique provides an opportunity to evaluate the effect of intraoperative factors, such as cardiopulmonary bypass, global myocardial ischemia, and myocardial protection technique, on the occurrence of this arrhythmia. METHODS: All the patients undergoing isolated left internal thoracic artery-left anterior descending artery grafting between January 1994 and December 1999 were reviewed. Twenty possible risk factors for postoperative atrial fibrillation, including the choice of operative technique--minimally invasive technique was introduced in January 1997--were entered into univariate and multivariable logistic regression analysis. RESULTS: Postoperative atrial fibrillation occurred in 36 (20%) of 183 patients. On univariate analysis, age (P <.001) and a history of supraventricular arrhythmia (P <.001) were found to be risk factors. In particular, 15 (22%) of 69 patients operated on with the minimally invasive technique had postoperative atrial fibrillation versus 21 (18%) of 114 in the standard group (P =.58). On multivariable analysis, including the operative technique, the same variables (P =.001 and.01, respectively) were identified as independent risk factors. CONCLUSIONS: The introduction of a minimally invasive technique for coronary artery bypass operations did not reduce the occurrence of postoperative atrial fibrillation in this study population. This suggests that prophylactic measures to reduce this arrhythmia should be focused on factors unrelated to cardiopulmonary bypass or myocardial preservation technique.     

Atrial fibrillation after coronary artery bypass graft surgery is unrelated to cardiac abnormalities detected by transesophageal echocardiography.

Atrial fibrillation is a common complication of coronary artery bypass graft (CABG) surgery that is associated with adverse patient outcomes. We evaluated whether preexisting abnormalities of cardiac structure or function detected with transesophageal echocardiography (TEE) are prevalent in patients later developing atrial fibrillation after CABG surgery. TEE imaging was performed after induction of general anesthesia, but before primary CABG surgery, in 62 consecutive patients without cardiac valvular disease or preexisting atrial fibrillation. Measurements included left atrial diameter, left ventricular wall thickness, left ventricular end-systolic and end-diastolic dimensions and fractional area change. Pulsed-wave Doppler measurements of pulmonary venous and trans-mitral blood flow velocity were obtained. Continuous monitoring with telemetry electrocardiography for the development of atrial fibrillation was performed. Eighteen patients (29%) developed postoperative atrial fibrillation. There were no significant differences in left atrial or left ventricular TEE variables or pulsed-wave Doppler pulmonary venous flow measurements between patients with and without postoperative atrial fibrillation. After adjusting for age and duration of aortic cross-clamping, there were no differences in the transmitral Doppler diastolic filling variables between these same groups. These data suggest that atrial fibrillation commonly occurs after CABG surgery in the absence of atrial enlargement or Doppler-derived cardiac functional abnormalities. The data imply that the use of TEE immediately before surgery would be an insensitive means for routine identification of patients susceptible to this arrhythmia. Implications: Transesophageal echocardiography performed immediately before coronary artery bypass graft (CABG) surgery is not useful for prediction of susceptibility to develop atrial fibrillation postoperatively. Postoperative atrial fibrillation commonly occurs after CABG surgery in the absence of preoperative atrial enlargement or Doppler derived functional abnormalities.     

Epicardial radiofrequency ablation for chronic atrial fibrillation undergoing simultaneous on-pump beating coronary artery bypass grafting

Off-pump coronary artery bypass grafting has become an attractive surgical alternative for myocar-dial revascularization because of the advantage of myocardial protection and other benefits of patients. However, it is still regarded as a controversial treatment for the coronary artery disease accompanied by atrial fibrillation (AF). A significant number of patients in need of coronary revascularization have chronic AF. Although the Cox-Maze III procedure is the gold standard for the surgical treatment of AF, few of these patients undergo AF operations at the time of their coronary bypass grafting. We report herein a case of the pulmonary vein isolation to eliminate the AF by means of epicardial radiofrequency ablation combined with 2 vessels coronary artery bypass grafting on the beating heart with the aid of cardiopulmonary bypass.     

Intravenous magnesium sulfate prophylaxis for atrial fibrillation after coronary artery bypass surgery

OBJECTIVE: Atrial fibrillation is a rhythm disorder commonly seen early after coronary artery bypass grafting, and it increases morbidity. METHODS: To investigate the effectiveness of magnesium sulfate in the prophylaxis of atrial fibrillation, we conducted a prospective, randomized, placebo-controlled clinical study on 200 consecutive patients in whom we performed elective and initial coronary artery bypass grafting operations. In each group 50% of patients underwent beating-heart operations. In the treatment group 100 patients (76 men and 24 women; mean age, 57.63 +/- 9.68 years) received 24.34 mEq (3 g) of magnesium sulfate in 100 mL of saline solution that was administered over 2 hours (50 mL/h) preoperatively, perioperatively, and at postoperative days 0, 1, 2, and 3. In the control group 100 patients (74 men and 26 women; mean age, 59.96 +/- 9.29 years) received only 100 mL of saline solution according to the same administration schedule as the treatment group. RESULTS: Atrial fibrillation developed in 15 patients from the treatment group and in 16 patients from the control group. The arrhythmia developed after 37.87 +/- 12.76 and 45.26 +/- 15.27 hours in the treatment and control groups, respectively. Although a significant relationship was found between low magnesium sulfate levels and increased incidence of atrial fibrillation (P <.05), when the incidence of postoperative atrial fibrillation is concerned, no significant difference was found between the 2 groups (P >.05). Also, no significant difference was found between operations with cardiopulmonary bypass and beating-heart operations in terms of atrial fibrillation incidence (P >.05). However, atrial fibrillation extended the duration of hospital stay in both groups (P <.05). CONCLUSION: Our findings indicate that magnesium sulfate infusion alone is not sufficient for the prophylaxis of atrial fibrillation.     

"Off-pump" coronary artery bypass grafting: the first one hundred cases of the Rose City experience.

BACKGROUND: In an effort to avoid the adverse effects of cardiopulmonary bypass, "off-pump" myocardial revascularization has been rediscovered and refined. This study reviews the first 100 off-pump coronary artery bypass procedures performed in Tyler, TX, and compares the results with those reported in the Seventh Annual Report of the Society of Thoracic Surgeons (STS) Cardiac Surgery Database. METHODS: Coronary artery bypass was performed on 100 patients without cardiopulmonary bypass over a 24-month period. Postoperative morbidity, mortality, and length of stay were recorded. RESULTS: Operative mortality was 3%. The incidences of postoperative complications for the off-pump group versus the STS database were as follows: reoperation for bleeding, 1% vs 2.2%; transfused patients, 15% vs 35%; atrial fibrillation, 5% vs 18.2%; infection, 2% vs 1.3%; neurologic, 0% vs 5.1%; renal failure, 0% vs 3.12%; ventilation more than 1 day, 0% vs. 5.69%. The postoperative length of stay for the off-pump group versus the STS group was 4.4 vs 6.6 days. CONCLUSIONS: Early results suggest that off-pump coronary artery bypass grafting is a safe and effective means of coronary revascularization with excellent short-term results and minimal morbidity.     

Fibrillation in patients subjected to coronary artery bypass grafting

OBJECTIVE: Atrial fibrillation is the most frequently encountered postoperative arrhythmic complication after coronary artery bypass grafting. Ischemic preconditioning has proved a potent endogenous factor in suppressing ischemia-reperfusion-induced arrhythmias. The protective effect of ischemic preconditioning on atrial fibrillation after coronary artery bypass grafting has not been studied. The purpose of the present study was to investigate whether ischemic preconditioning had an effect on postoperative atrial fibrillation in patients undergoing coronary artery bypass grafting. METHODS: Eighty-five patients undergoing coronary artery bypass grafting were randomized into ischemic preconditioning and control groups. Holter data from 24-hour electrocardiography were collected 1 day before the operation to the second postoperative day. Atrial fibrillation was registered as positive if any atrial fibrillation event occurred. RESULTS: The overall incidence of postoperative atrial fibrillation and sustained atrial fibrillation was 34.1% and 27.1%, respectively. The occurrence of atrial fibrillation was significantly lower in the ischemic preconditioning group (21.4% in patients undergoing ischemic preconditioning and 46.5% in control subjects, P =.015). Preoperative recent unstable angina did not influence the incidence of atrial fibrillation. Patients with atrial fibrillation had longer intensive care unit stays and compromised postoperative hemodynamic outcomes. Binary logistic regression analysis showed that ischemic preconditioning, preoperative mean heart rate, and postoperative pulmonary capillary wedge pressure were the independent predictors of atrial fibrillation. CONCLUSIONS: Postcoronary artery bypass grafting atrial fibrillation is associated with more complicated postoperative outcome. Higher preoperative heart rate and postoperative pulmonary capillary wedge pressure were the independent predictors of atrial fibrillation. Recent unstable angina is not related to the occurrence of postcoronary artery bypass grafting atrial fibrillation. Ischemic preconditioning significantly suppresses postcoronary artery bypass grafting atrial fibrillation, suggesting that ischemic preconditioning can be used as an effective prophylactic method for postoperative atrial fibrillation.     

Myocardial revascularization in the elderly using beating heart coronary artery bypass surgery

BACKGROUND: Beating heart or "off-pump" coronary artery bypass (OP-CAB) has become an accepted method of myocardial revascularization by reducing the perioperative morbidity related to cardiopulmonary bypass (CPB). However, the efficacy of OP-CAB has not been well established in the elderly patient population. METHODS: OP-CABs were performed in 53 patients aged 75 years and older, at Pitt County Memorial Hospital from January 1996 to October 1999, either through a median sternotomy or an anterior thoracotomy. These results were compared with 220 patients who underwent standard coronary artery bypass graft (CABG) operation using CPB during the same time period. RESULTS: Mean patient age for both groups was 79+/-0.5 years and preoperative risk factors were similar. There were no differences in postoperative myocardial infarction, atrial fibrillation, bleeding, neurologic complications, or renal failure. There were no deaths after OP-CAB, compared with the 7.6% operative mortality rate after CABG (p<0.05). The OP-CAB group had a significantly shorter postoperative length of stay (4.4+/-0.4 days vs. 8.4+/-0.6 days) and lower transfusion requirements (0.4+/-0.1 units packed red blood cells vs 1.9+/-0.2 units packed red blood cells) than the CABG group. CONCLUSIONS: Our data demonstrate that OP-CAB is a safe and efficacious method of myocardial revascularization in the elderly, and may actually be preferential in these patients when applicable.