Effectiveness of Bi-atrial Pacing for Reducing Atrial Fibrillation after Coronary Artery Bypass Graft Surgery

Atrial fibrillation (AF) is common after cardiac surgery and adds significant cost and morbidity. The use of prophylactic pacing strategies to prevent post-operative AF has been controversial. We previously performed a pilot study which suggested that the combination of beta-blockers and bi-atrial pacing (BAP) may reduce AF after cardiac surgery.We prospectively randomized 118 patients to continuous BAP for up to 96 hours post-operatively versus standard therapy. All patients were treated with beta-blockers as tolerated. Patients were paced in the AAI mode at a rate of 100 pulses per minute. The primary endpoint of the study was the occurrence of sustained AF (>10 minutes).There was a significant reduction in the incidence of AF in the BAP group among patients undergoing coronary artery bypass graft surgery with or without aortic valve replacement (35% vs. 19% AF; OR=0.38, 95% CI 0.15, 0.93; p <0.05). Including patients undergoing isolated aortic valve surgery (n=7), there remained a strong trend toward a reduction of AF with pacing (no atrial pacing [NAP] vs. BAP; 35% vs. 21% AF; OR=0.48, 95% CI 0.21, 1.11; p=0.08). Patients age 70 or greater benefited most from pacing (NAP vs. BAP; 55 vs. 25% AF; p<0.05), while those less than 70 years of age did not (17 vs. 18% p=NS). There was a significant reduction in the amount of time spent in the intensive care unit among patients receiving BAP (50±40 vs. 37±25[emsp4 ]h; p<0.05).BAP together with beta-blockade after coronary artery bypass graft surgery reduces the incidence of post-operative atrial AF. Elderly patients (age 70 or greater) appear to benefit most, and may be a group to whom this therapy should be targeted.     

Temporary atrial epicardial pacing as prophylaxis against atrial fibrillation after heart surgery: a meta-analysis

INTRODUCTION: Recent studies have reported the use of temporary epicardial atrial pacing as prophylaxis for postoperative atrial fibrillation (AF). The aim of this study was to assess the effect of pacing therapies for prevention of postoperative AF using meta-analysis. METHODS AND RESULTS: Using a computerized MEDLINE search, eight pacing prophylaxis trials with 776 patients were included in the meta-analysis. Trials compared control patients to patients randomized to right atrial, left atrial, or biatrial pacing used in conjunction with either fixed high-rate pacing or overdrive pacing. Overdrive biatrial pacing (OR 2.6, CI 1.4-4.8), overdrive right atrial pacing (OR 1.8, CI 1.1-2.7), and fixed high-rate biatrial pacing (OR 2.5, CI 1.3-5.1) demonstrated a significant antiarrhythmic effect for prevention of AF after open heart surgery. Furthermore, studies investigating overdrive left atrial pacing and fixed high-rate right atrial pacing have been underpowered to assess efficacy. CONCLUSION: Biatrial overdrive and fixed high-rate pacing and right atrial fixed high-rate pacing reduced the risk of new-onset AF after open heart surgery, and the relative risk reduction is approximately 2.5-fold. These results imply that various pacing algorithms are useful as a nonpharmacologic method to prevent postoperative AF.     

Prediction of paroxysmal atrial fibrillation after aortic valve replacement in patients with aortic stenosis: identification of potential risk factors

BACKGROUND AND AIM OF THE STUDY: Paroxysmal atrial fibrillation (AF) is a frequent complication after cardiac surgery. The study aim was to identify preoperative predictors of risk for this condition in patients with aortic stenosis after aortic valve replacement. METHODS: The influence of clinical, echocardiographic and 24 h electrocardiogram (ECG) parameters on episodes of paroxysmal AF after aortic valve replacement (AVR) in 423 patients (156 women, 267 men; mean age 58 +/- 10 years) with aortic stenosis was analyzed. Episodes of postoperative paroxysmal AF were noted in 120 patients (28%). RESULTS: Univariate analyses identified the following variables as risk factors for arrhythmia: age, NYHA functional class, history of preoperative paroxysmal AF, left ventricular mass index, >300 supraventricular beats on 24h ECG before surgery, presence of supraventricular tachycardia (SVT), SVT of >5 beats or with a rate >120 beats/min. Concomitant coronary artery bypass (CABG) grafting and presence of enlarged left atrium had no impact. By multivariate analysis, four variables were identified as independent predictors: age (odds ratio 1.7; 95% CI 1.2-2.1); history of paroxysmal AF (OR 3.2; CI 1.4-7.3); presence of >300 supraventricular beats/24 h (OR 1.9; CI 1.1-3.4); and presence of SVT (OR 2.1; CI 1.3-3.4). Discriminatory analysis revealed that a model comprising these four parameters enabled risk prediction in 68% of patients. CONCLUSION: In patients with isolated aortic stenosis, age, past history of paroxysmal AF episodes, >300 supraventricular beats/24 h and presence of SVT during 24 h before AVR were predictors of postoperative paroxysmal AF episodes. Left atrial diameter and simultaneous CABG during AVR did not influence the likelihood of postoperative paroxysmal AF.     

Factors predicting success rate and recurrence of atrial fibrillation after first electrical cardioversion in patients with persistent atrial fibrillation

BACKGROUND: The recurrence rate of atrial fibrillation (AF) after elective cardioversion is high. HYPOTHESIS: The study aimed to identify clinical predictors for successful electrical cardioversion and maintenance of sinus rhythm after a first electrical cardioversion in patients with persistent AF without concomitant antiarrhythmic drugs of class I and III. METHODS: Consecutive outpatients (n = 166) with persistent AF for > 1 month, scheduled for elective cardioversion, were prospectively included in the study. A clinical investigation, echocardiographic assay, and Holter electrocardiogram (ECG) before and ECG 4 weeks after cardioversion, were performed in all patients. RESULTS: The mean age of the patients was 68 years (range 45-83) and duration of AF was 5 (1-48) months. Sinus rhythm was established in 124 (75%) patients. In multivariate analysis, only duration of AF < 6 months (p < 0.04, odds ratio [OR] 2.2, 95% confidence interval [CI] 1.1 to 4.7) and patients weight (p < 0.03, OR 2.3, 95% CI 1.1 to 4.8 for weight < 80 kg) were identified as independent predictors of successful cardioversion. At 4 weeks after cardioversion, only 46 (37%) of 124 patients maintained sinus rhythm. Independent factors for maintenance of sinus rhythm, in multivariate analysis, were AF <3 months (p < 0.04, OR 2.5, 95% CI 1.1 to 5.6), treatment with beta blockers (p < 0.00001, OR 7.0, 95% CI 3.0 to 16.3) or verapamil/diltiazem (p < 0.04, OR 3.6, 95% CI 1.1 to 12.1), and right atrial dimension < 37 mm (p < 0.02, OR 5.9, 95% CI 1.4 to 25.4). CONCLUSIONS: In patients with persistent AF, the patient's weight and the duration of AF are independent predictors for a successful cardioversion. Short duration of AF, treatment with beta blockers or verapamil/diltiazem, and right atrial area/dimension are independent predictors for maintenance of sinus rhythm.     

Predictors of very late recurrence of atrial fibrillation after circumferential pulmonary vein ablation

BACKGROUND: Early recurrence of atrial fibrillation (ERAF) after catheter ablation is common and has been thoroughly studied. However, very late recurrence of atrial fibrillation (VLRAF) is rarely researched, and its characteristics have not been determined. HYPOTHESIS: The aim of this study was to investigate the clinical characteristics of VLRAF after circumferential pulmonary vein ablation (CPVA), and to identify the risk factors for VLRAF. METHODS: We retrospectively studied 259 consecutive patients with atrial fibrillation (AF) who were referred for CPVA. Clinical variables were investigated and predictors of VLRAF were identified. RESULTS: A total of 249 patients were enrolled in this study. After a mean follow-up of 18.2 +/- 4.4 mo, 14 patients (5.6%) had VLRAF. Patients with VLRAF were more likely than those without recurrence to have ERAF (78.6% versus 17.8%, p = 0.000) and persistent AF (50.0% versus 13.0%, p = 0.000), but were less likely to achieve pulmonary vein (PV) isolation (78.6% versus 97.6%, p = 0.000). Bivariate analysis demonstrated that ERAF (odds ratio [OR] 8.148, 95% confidence interval [CI] 2.197-30.222; p = 0.002), persistent AF (OR 8.853, 95% CI 1.773-16.155; p = 0.003), and lack of PV isolation (OR 7.530, 95% CI 1.792-33.122; p = 0.006) were related to VLRAF. Multivariate logistic regression analysis only identified ERAF as a predictor of VLRAF after CPVA (OR 7.461, 95% CI 1.696-24.836; p = 0.006). CONCLUSIONS: Very late recurrence of AF is uncommon after CPVA. That occurs more commonly in patients with ERAF.     

Effective prevention of atrial fibrillation by continuous atrial overdrive pacing after coronary artery bypass surgery

OBJECTIVES: The present study was aimed to evaluate the efficacy of a specific algorithm with continuous atrial dynamic overdrive pacing to prevent atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery. BACKGROUND: Atrial fibrillation occurs in 30% to 40% of patients after cardiac surgery with a peak incidence on the second day. It still represents a challenge for postoperative prevention and treatment and may have medical and cost implications. METHODS: Ninety-six consecutive patients undergoing CABG for severe coronary artery disease and in sinus rhythm without antiarrhythmic therapy on the second postoperative day were randomized to have or not 24 h of atrial pacing through temporary epicardial wires using a permanent dynamic overdrive algorithm. Holter ECGs recorded the same day in both groups were analyzed to detect AF occurrence. RESULTS: No difference was observed in baseline data between the two study groups, particularly for age, male gender, history of AF, ventricular function, severity of coronary artery disease, preoperative beta-adrenergic blocking agent therapy or P-wave duration. The incidence of AF was significantly lower (p = 0.036) in the paced group (10%) compared with control subjects (27%). Multivariate analysis showed AF incidence to increase with age (p = 0.051) but not in patients with pacing (p = 0.078). It decreased with a better left ventricular ejection fraction only in conjunction with atrial pacing (p = 0.018). CONCLUSIONS: We conclude that continuous atrial pacing with an algorithm for dynamic overdrive reduces significantly incidence of AF the second day after CABG surgery, particularly in patients with preserved left ventricular function.     

Perceived health status in patients over 70 before and after open-heart operations

AIM: to evaluate improvement and predictors of improvement in patients' perceived health status after cardiac surgery in older patients. METHODS: three hundred and seventy-seven patients from three different departments of cardiac surgery completed the Nottingham Health Profile questionnaire before and 1 and 2 years after open-heart surgery. We analysed pre- and postoperative data and pre- and postoperative Nottingham Health Profile scores. RESULTS: the mean age was 74+/-3 years. The comparison between pre- and postoperative scores showed an improvement in all but the social isolation section. Logistic regression showed that the predictors of patients who became worse after surgery were (i) in the energy section: age over 75 [odds ratio (OR) = 1.8, 95% confidence interval (CI) = 1.02-3.2], coronary artery disease (OR = 2.4, 95% CI = 1.04-3.6) and postoperative events (OR = 1.9, 95% CI = 1.01-3.7); (ii) in the physical mobility section: diabetes mellitus (OR = 2.4, 95% CI = 1.2-4.7); and (iii) in the social isolation section: physical mobility impairment (OR = 3.4, 95% CI = 1.3-8.7). CONCLUSIONS: cardiac surgery improves perceived health status in patients over 70. This improvement is better for those undergoing aortic valve replacement than for those undergoing coronary artery bypass surgery. Comparison with reference scores for a standard population shows that, even when successful, cardiac surgery results in fatigue and persistent sleep disturbance in older patients.     

Hemodynamic effects and long-term outcome of percutaneous balloon valvuloplasty in patients with mitral stenosis and atrial fibrillation

BACKGROUND: The presence of atrial fibrillation (AF) has been identified as a predictor of a suboptimal result in some patients undergoing percutaneous balloon valvuloplasty in the treatment of symptomatic rheumatic mitral stenosis. HYPOTHESIS: Atrial fibrillation adversely affects the short- and long-term outcome of patients with mitral stenosis undergoing percutaneous balloon valvuloplasty. METHODS: A retrospective chart review of 104 consecutive patients with rheumatic mitral stenosis undergoing percutaneous balloon valvuloplasty was performed. A successful procedure was defined as a final mitral valve area > or = 1.5 cm2 and the absence of a complication. Endpoints included freedom from mitral valve replacement, death, and repeat balloon valvuloplasty at 5 years. RESULTS: A successful procedure was obtained in 89% of patients with sinus rhythm and in 78% of patients with AF (p = NS). Patients in sinus rhythm had a greater cardiac output resulting in a larger final valve area than patients in AF (1.8 vs. 1.6 cm2, p < 0.05). Freedom from valve replacement, death, and repeat balloon valvuloplasty at 5 years was 75% for patients in AF and 76% for patients in sinus rhythm (p = NS). Lower postprocedure mitral regurgitation grade and absence of prior commissurotomy were the only independent predictors of event-free survival. CONCLUSIONS: Patients with mitral stenosis and AF have lower cardiac outputs and gradients than patients with sinus rhythm, despite similar valve areas. The long-term outcome of balloon valvuloplasty is independent of the initial cardiac rhythm.     

Renal function is associated with risk of atrial fibrillation after cardiac surgery

BACKGROUND: Atrial fibrillation (AF) frequently occurs after cardiac surgery and is responsible for increased morbidity and resource use. The aim of the present study was to evaluate the association of impaired renal function and the development of postoperative AF. METHODS AND RESULTS: Patients undergoing elective cardiac surgery in the absence of significant left ventricular dysfunction (n=253; average age 65+/-11 years) were recruited to the present prospective study. Ninety-nine patients (39.1%) developed AF during the postoperative period. Creatinine clearance, estimated by the calculated glomerular filtration rate (GFR), was prospectively assessed to determine the association of baseline renal function and the development of postoperative AF. Baseline calculated GFR was assessed as a continuous and a categorical variable (normal: greater than 90 mL/min/1.73 m(2); mildly decreased: 60 mL/min/1.73 m(2) to 89 mL/min/1.73 m(2); and moderately to severely decreased: less than 60 mL/min/1.73 m(2)). Baseline creatinine clearance was 72+/-22.2 mL/min/1.73 m(2) and 78.8+/-23.5 mL/min/1.73 m(2) in patients with and without postoperative AF, respectively (P=0.02). There was an independent association between decreasing calculated GFR and the development of postoperative AF (OR for 10 mL decrease in calculated GFR: 1.21, 95% CI 1.02 to 1.39). In addition to calculated GFR, surgery for valvular heart disease (versus coronary artery bypass grafting [OR 2.23, 95% CI 1.09 to 3.14; P<0.01]), age (OR per 10-year increase in age 1.92, 1.18 to 2.59) and perioperative nonuse of beta-adrenergic blockers (OR 1.62, 95% CI 1.12 to 3.55; P<0.01) were identified as independent predictors of postoperative AF. CONCLUSIONS: In the setting of cardiac surgery, impaired calculated GFR is associated with an increased risk for the development of postoperative AF. These data provide additional evidence supporting the association between renal dysfunction and adverse cardiovascular outcomes.     

Clinical determinants of sinus conversion by radiofrequency maze procedure for persistent atrial fibrillation in patients undergoing concomitant mitral valvular surgery

The radiofrequency Maze procedure can effectively restore sinus rhythm in most patients with atrial fibrillation (AF) and mitral valve disease. AF after cardiac surgery is associated with increased morbidity and mortality. However, clinical determinants of long-term postoperative AF after the radiofrequency Maze procedure and concomitant mitral valve surgery are poorly defined. This study comprised 99 consecutive patients with persistent AF and mitral valve disease who underwent radiofrequency Maze procedures and concomitant mitral valvular operations. The predictive values of clinical variables for postoperative AF were examined. After a mean follow-up period of 46.1+/-24.6 months, 83 patients (83.8%) had sinus conversion after the Maze procedure, and 16 patients remained in persistent or paroxysmal AF. Multiple logistic regression analysis determined that predictors of sinus conversion were preoperative left atrial diameter (odds ratio [OR] 1.127 per 1-mm increment in left atrial diameter, 95% confidence interval [CI] 1.045 to 1.215, p<0.002) and the duration of AF (OR 1.022 per 1-month increment in duration of AF, 95% CI 1.009 to 1.035, p<0.001). Discriminant analysis showed that the sinus conversion rate was significantly lower in patients with preoperative left atrial diameters>56.8 mm (p<0.001) or AF duration>66 months (p<0.001) than in patients with preoperative left atrial diameters<56.8 mm or AF duration<66 months. In conclusion, the preoperative left atrial size and duration of AF are primary predictors of sinus conversion by the radiofrequency Maze procedure for patients with persistent AF and mitral valve disease.     

Significance of Atrial Fibrillation During Acute Myocardial Infarction, and its Current Management: Insights from the GUSTO-3 Trial

The Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO)-3 atrial fibrillation (AF) substudy assessed the prognostic significance of AF during acute myocardial infarction (AMI), the use of antiarrhythmic therapies, and whether different antiarrhythmic therapies were associated with different outcomes. The timing of the onset of AF relative to other post-AMI complications was recorded in the study. Of the 13,858 patients who were in sinus rhythm at the time of enrolment into GUSTO-3, 906 (6.5%) developed AF and 12,952 did not. Worsening heart failure, hypotension, third-degree heart block, and ventricular fibrillation were independent predictors of new-onset AF. The risks of 30-day and 1-year mortality were increased among patients with AF versus patients without AF before (odds ratio [OR] 2.74, 95% confidence interval [CI] 2.56-3.34; and OR 2.93, 95% CI 2.48-3.46, respectively) and after adjustment for baseline factors and pre-AF complications (OR 1.49, 95% CI 1.17-1.89; and OR 1.64, 95% CI 1.35-2.01, respectively). A total of 1,138 patients had data available on the management of their AF, including 117 with a history of paroxysmal AF and 138 with chronic AF prior to AMI. Of these 1,138 patients, 317 (28%) received antiarrhythmic therapies: class I antiarrhythmic drugs in 12%, sotalol in 5% and amiodarone in 15%. Electrical cardioversion was attempted in 116 patients (10%). Sinus rhythm was restored in 72% of patients given class I drugs, 67% of those given sotalol, 79% of those given amiodarone, and 64% of those who underwent electrical cardioversion. After adjustment for baseline characteristics and pre-AF complications, none of the specific antiarrhythmic therapies was associated with a higher chance of having sinus rhythm at discharge or before deterioration to in-hospital death. However, the use of class I antiarrhythmic drugs or sotalol was associated with lower unadjusted 30-day and 1-year mortality rates. After adjustment for baseline factors and pre-AF complications, the ORs for 30-day and 1-year mortality were 0.42 (95% CI 0.19-0.89) and 0.58 (95% CI 0.33-1.04), respectively, with class I agents, and 0.31 (95% CI 0.07-1.32) and 0.31 (95% CI 0.09-1.02), respectively, with sotalol. In contrast, there was no association between the use of amiodarone or electrical cardioversion and 30-day or 1-year mortality. New AF is often secondary to other post-AMI complications, but is in itself an independent predictor of a worse outcome. Clinical management of AF is variable, but in GUSTO-3 there was a strong trend towards lower mortality associated with the use of class I antiarrhythmic agents or sotalol. Randomized trials are needed to investigate this observation further.     

Cardiac resynchronization therapy: predictive factors of unsuccessful left ventricular lead implant.

AIMS: Cardiac resynchronization therapy is an established therapy for advanced heart failure. However, coronary sinus access and pacing is not achieved in about 5-10% of patients. The aim of this study was to identify predictive factors for failure of left ventricular (LV) lead transvenous implant. METHODS AND RESULTS: We evaluated 212 consecutive patients who received a cardiac resynchronization system. In 26 patients (12.3%), the attempt to pace the LV was unsuccessful. At univariate analysis, in patients with an unsuccessful implant a higher proportion of permanent atrial fibrillation (AF), valvular heart disease, and previous heart surgery were observed. Anteroposterior, longitudinal, and transversal left atrium diameters (LAD) were also larger among patients with an unsuccessful implant. The anteroposterior LAD (APLAD) with an optimal value to predict implant failure was 48.5 mm. At logistic regression analysis, the presence of permanent AF and APLAD were independent predictors of failed implant (OR 7.7, 95% CI 2.5-23.9, P=0.002 and OR 11.7, 95% CI 3.1-37.6, P<0.001, respectively). CONCLUSION: The presence of permanent AF and APLAD are factors that predict unsuccessful pacing from the LV.     

Amiodarone for atrial fibrillation following cardiac surgery: development of clinical practice guidelines at a university hospital

Atrial fibrillation (AF) usually develops within the first 72 h following cardiac surgery, and is often self-limiting. Within 48 h of acute onset of symptoms, approximately 50% of patients spontaneously convert to normal sinus rhythm. Thus, the relative risks and benefits of therapy must be carefully considered. The etiology of AF following cardiac surgery is similar to that in non-surgical patients except that pericardial inflammation and increased adrenergic tone play an increasingly important role. Further, AF after surgery may be associated with transient risk factors that resolve as the patient moves out from surgery, and the condition is less likely to recur compared to AF arising in other circumstances. Immediate heart rate control is important in preventing ischemia, tachycardia-induced cardiomyopathy, and left ventricular dilatation.At our institution, amiodarone is frequently used as a first-line drug for treating AF after cardiac surgery. Inconsistent prescribing practices, variable dosage regimens, and a lack of consensus regarding the appropriate use of amiodarone prompted the need for developing practice guidelines. Multidisciplinary collaboration between the departments of cardiac surgery, pharmacy, and anesthesiology led to the development of a protocol for postoperative AF. We review the clinical evidence from published trials and discuss our guidelines, defining amiodarone use for AF in the cardiac surgery setting.     

N-acetylcysteine for the prevention of postoperative atrial fibrillation: a prospective, randomized, placebo-controlled pilot study.

AIMS: Oxidative stress has recently been implicated in the pathophysiology of atrial fibrillation (AF). The aim of the present study was to evaluate the effects of antioxidant agent N-acetylcysteine (NAC) on postoperative AF. METHODS AND RESULTS: The population of this prospective, randomized, double-blind, placebo-controlled study consisted of 115 patients undergoing coronary artery bypass and/or valve surgery. All the patients were treated with standard medical therapy and were randomized to NAC group (n = 58) or placebo (saline, n = 57). An AF episode >5 min during hospitalization was accepted as endpoint. During follow-up period, 15 patients (15/115, 13%) had AF. The rate of AF was lower in NAC group compared with placebo group (three patients in NAC group [5.2%] and 12 patients in placebo group [21.1%] had postoperative AF; odds ratio [OR] 0.20; 95% confidence interval [CI] 0.05 to 0.77; P = 0.019). In the multivariable logistic regression analysis, independent predictors of postoperative AF were left atrial diameter (OR, 1.18; 95% CI, 1.06-1.31; P = 0.002) and the use of NAC (OR, 0.20; 95% CI, 0.04-0.91; P = 0.038). CONCLUSION: The result of this study indicates that NAC treatment decreases the incidence of postoperative AF.     

Prevalence and predictors of complications of radiofrequency catheter ablation for atrial fibrillation

Complications of Atrial Fibrillation Ablation. Introduction: Up to 6% of patients experience complications after radiofrequency catheter ablation (RFA) of atrial fibrillation (AF). The purpose of this study is to determine the prevalence and predictors of periprocedural complications after RFA for AF. Methods and Results: The subjects were 1,295 consecutive patients (age = 60 ± 10 years) who underwent RFA (n = 1,642) for paroxysmal (53%) or persistent AF (47%) from January 2007 to January 2010. A complication occurred in 57 patients (3.5%); a vascular access complication in 31 (1.9%); pericardial tamponade in 20 (1.2%); a thromboembolic event in 4 (0.2%); deep venous thrombosis in 1 (<0.01%); and pulmonary vein stenosis in 1 patient (<0.01%). There were no procedure‐related deaths. On multivariate analysis, female gender (OR = 2.27; ±95% CI: 1.31–2.57, P < 0.01) and procedures performed in July or August (OR = 2.10; ±95% CI: 1.16–3.80, P = 0.01) were independent predictors of any complication. For vascular complications, treatment with clopidogrel (OR = 4.40; ±95% CI: 1.43–13.53, P = 0.01), female gender (OR = 3.65; ±95% CI: 1.72–7.75, P < 0.01) and performing RFA in July or August (OR = 2.71; ±95% CI: 1.25–5.87, P = 0.01) were independent predictors. The only predictor of cardiac tamponade was prior RFA (OR = 3.32; ±95% CI: 0.95–11.61; P < 0.05). Conclusion: Prevalence of perioperative complications for RFA of AF is 3.5% and vascular access complications constitute the majority. The need for clopidogrel therapy should be carefully considered prior to RFA. At teaching institutions close supervision should be exercised during vascular access early in the year. Improvements in ablation technology and elimination of the need for repeat procedures may decrease the risk of pericardial tamponade . (J Cardiovasc Electrophysiol, Vol. 22, pp. 626‐631, June 2011)     

Impact of body mass index on early outcome and late survival in patients undergoing coronary artery bypass grafting or valve surgery or both

The influence of body mass on outcome after cardiac surgery remains controversial. The aim of this study was to analyze the impact of body mass index (BMI) on early and late outcomes in a large series of patients who underwent cardiac surgery. We retrospectively analyzed 5,950 consecutive patients who underwent cardiac surgery between January 1998 and September 2006. Patients were divided into 4 groups defined by BMI (weight divided by square of height [kilograms divided by meters squared]): underweight (20 to 25 to 30 kg/m2): 22%, n=1,292. Analysis was further refined by performing subgroup analysis according to the surgical procedure (valve surgery, coronary artery bypass grafting, and combined valve/coronary artery bypass grafting). Main outcome measure was the association between BMI and hospital mortality, postoperative morbidities, and late survival. Hospital mortality was 3.4% (n=203). There was no association between BMI and hospital mortality in the entire patient population. Multivariate analysis revealed obesity as an independent predictor of hospital mortality in patients who underwent valve surgery (odds ratio [OR] 2.3, 95% confidence interval [CI] 1.2 to 4.5, p=0.018). Obesity was associated with an increased risk for sternal infection (OR 1.8, 95% CI 1.1 to 2.9, p=0.013), whereas underweight correlated with postoperative bleeding (OR 2.0, 95% CI 1.1 to 3.6, p=0.017). Underweight was an independent predictor for decreased long-term survival (OR 1.8, 95% CI 1.3 to 2.5, p<0.001). In conclusion, cardiac surgery can be performed safely in both underweight and obese patients but carries a higher postoperative rate of major complications.     

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.     

Association between serum C-reactive protein elevation and atrial fibrillation after first anterior myocardial infarction

BACKGROUND: Elevated inflammatory markers have been found to correlate with higher risk for cardiac events in patients with acute myocardial infarction (AMI). It has been suggested that C-reactive protein (CRP) may be involved in the initiation process of atrial fibrillation (AF). However, the role of CRP levels in the occurence of AF in patients with AMI has not been studied. This study investigated whether CRP is a risk factor for AF in patients with acute anterior MI. METHODS: We prospectively evaluated 92 consecutive patients (25 women and 67 men; aged 58 +/- 11 y) with a first acute anterior wall MI. Blood samples were obtained at the time of admission to the hospital, and serum CRP levels were measured by an ultrasensitive immunonephelometry method. All patients were evaluated by echocardiography to measure the left ventricular (LV) diameter and functions. All patients were monitored continuously for the detection of AF in the coronary care unit. RESULTS: Atrial fibrillation occured in 19 (20%) of 92 patients. Univariate analysis showed that patients with AF had an advanced age (63 +/- 9.9 versus 56.7 +/- 11.7 y, p = 0.034), higher serum CRP level (2.95 +/- 2.5 versus 1.71 +/- 2.12 mg/dL, p = 0.034), larger LV end-systolic volume (74 +/- 15 versus 63 +/- 19, mL p = 0.02), higher LV ejection fraction (31.1 +/- 6.2 versus 38.4 +/- 10%, p = 0.001), and larger left atrial (LA) diameter (37.1 +/- 4.2 versus 34.7 +/- 3.3 mm, p = 0.01). In multivariate analysis, only age (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1-1.11, p = 0.036) and CRP levels (OR: 1.27, 95% CI: 1-1.59, p = 0.039) were independent predictors of AF. CONCLUSION: These results suggest that CRP may be a risk factor for AF in patients with acute anterior wall MI.     

Newly detected atrial fibrillation following dual chamber pacemaker implantation

Introduction: Pacemaker (PPM)-detected atrial high-rate episodes (AHREs) of even 5-minute duration may identify patients at increased risk for stroke and death. In this study, we sought to determine the incidence of newly detected atrial fibrillation (AF defined as an AHRE ≥5 minutes) in patients following dual-chamber PPM implantation and to define the clinical predictors of developing AF.
Methods and Results: We evaluated 262 patients (142 male; age 74 ± 12 years) without documented AF who underwent PPM implantation for sinus node dysfunction (n = 122) or atrioventricular block (n = 140). Information regarding patient demographics, cardiovascular diseases, and medication history was obtained. The cumulative percentages of ventricular pacing as well as the frequency, duration, and time to first episode of an AHRE were also determined. During follow-up of 596 ± 344 days, an AHRE ≥5 minutes was detected in 77 (29%) patients. Of these, 47 (61%) patients had an AHRE ≥1 hour, 22 (29%) patients had an AHRE ≥1 day, and 12 (16%) patients had an AHRE ≥1 week. An AHRE ≥5 minutes was seen in 24% and 34% of patients at 1 year and 2 years, respectively. Among patients with sinus node dysfunction, ≥50% cumulative ventricular pacing was the only significant predictor of an AHRE ≥5 minutes (HR 2.2; CI 1.0–4.7; P = 0.04).
Conclusions: Within 1 year of PPM implantation, AF is detected in 24% of patients without history of AF. In patients with sinus node dysfunction, ≥50% cumulative right ventricular pacing is associated with a 2-fold increase in risk of developing AF.     

Preoperative Statin Therapy Decreases Risk of Postoperative Renal Insufficiency

Introduction: Although current guidelines recommend withholding statins in perioperative patients, little information is available on whether perioperative statin use increases risk for postoperative renal failure. Aims: We examined the relation between preoperative statin therapy and postoperative risk for renal insufficiency in patients undergoing cardiac surgery. Methods: Retrospective cohort review from the Texas Heart Institute research database was performed. Patients were divided into two groups: those who received preoperative statins and those who did not. Primary outcome was the development of postoperative renal insufficiency (requiring dialysis or not). Outcomes were assessed in the entire cohort and in subgroups undergoing isolated coronary artery bypass grafting (CABG), isolated valve surgery, or combined CABG and valve surgery. Results: Of 3001 patients, 56% received preoperative statins. In multivariate logistic regression analysis, preoperative statins were associated with significant reductions in risk for postoperative renal insufficiency in the entire cohort (odds ratio [OR]= 0.60, 95% confidence interval [CI] 0.38–0.95) and in patients undergoing isolated CABG (OR = 0.34, 95% CI 0.17–0.68). In patients undergoing isolated valve surgery (OR = 1.35, 95% CI 0.61–2.96) or combined CABG and valve surgery (OR = 1.39, 95% CI 0.48–3.99), preoperative statins were not associated with decreased incidence of postoperative renal insufficiency. Age >65 years, preoperative renal insufficiency, history of congestive heart failure, preoperative intra‐aortic balloon pump insertion, and total cardiopulmonary bypass time >80 min were also independent predictors associated with increased risk for postoperative renal insufficiency. Conclusions: Preoperative statin therapy was associated with decreased incidence of postoperative renal insufficiency in patients undergoing cardiac surgeries, particularly in patients undergoing isolated CABG.