Temporary Atrial Pacing in the Prevention of Postoperative Atrial Fibrillation

Background: Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting (CABG). Since its prevention with prophylactic drug therapy has limited success, alternative approaches are desirable. This study examined the efficacy of atrial or biatrial pacing, compared with no pacing, on the incidence of AF after isolated CABG.
Methods: From August 2002 to September 2004, 240 patients underwent CABG. After surgery, right and left atrial epicardial pacing wires were implanted for 72 hours of temporary pacing. Patients were randomly assigned to one of three groups: no pacing (control group), right atrial (RA), and biatrial (BiA) pacing. Cardiac rhythm was monitored continuously during intensive care, or daily on the ward. The primary endpoints of this study were an episode of AF occurring up to 72 hours after CABG and the risk factors correlated with this event.
Results: Atrial and BiA pacing significantly lowered the incidence (1.25% vs 25%, P = 0.001) of AF episodes, and were both correlated (odd ratio 0.038; 95% confidence interval 0.005–0.29) with a decrease in rates of postoperative AF. Multivariable analysis identified older age (odd ratio 1.074; 95% confidence interval 1.024–1.12) and no pacing as independent risk factors of postoperative AF.
Conclusions: Temporary right atrial or biatrial pacing after CABG significantly decreased the postoperative incidence of AF. Multivariable analysis identified older age and no pacing as predictors of AF occurrence .     

Prophylactic Amidarone Treatment for Atrial Fibrillation After Coronary Artery Bypass Surgery

In this study we performed a retrospective chart review to evaluate the efficacy of short-term postoperative oral amiodarone therapy on postoperative atrial fibrillation (POAF) after coronary artery bypass surgery. The incidence of POAF in 372 patients (60.6%) without prophylactic amiodarone therapy was compared with that in 240 patients (39.4%) receiving the medication immediately after the surgery. Patients who received prophylactic amiodarone developed significantly less POAF than those without prophylactic treatment (17.0% versus 25.9%, P = .01), with relative and absolute risk reductions of 0.7% and 8.9%, respectively. Postoperative oral amiodarone therapy is simple to administer and may be a valuable adjunct therapy for patients after coronary artery bypass surgery.     

Atrial High Rate Episodes in Patients with Dual‐Chamber Cardiac Implantable Electronic Devices: Unmasking Silent Atrial Fibrillation

Assessment of the prevalence of silent paroxysmal atrial fibrillation (AF) represents a challenge, since the arrhythmia may be brief, completely asymptomatic, and difficult to detect. Lack of symptoms from AF should not be equated to lack of risk of thromboembolic complications. Today's cardiac implantable electronic devices (CIED) diagnostics include system diagnostics accurately revealing asymptomatic cardiac arrhythmias as atrial high rate episodes (AHRE). The presence of AHRE has been related to increased risk of stroke and systemic embolism. The application of anticoagulation therapy in patients with device‐detected AHRE is yet unclear and challenging in the absence of randomized studies. Until further studies are available, anticoagulation therapy should be individualized and promoted attending to the CHADS₂ score. Future guidelines should deal with this peculiar AF scenario to make professionals who routinely perform CIED follow‐ups aware of these relevant episodes and their clinical implications.     

Left‐Sided Atrial Flutter Originating in the Coronary Sinus after Radiofrequency Ablation of Atrial Fibrillation

We describe a case of atypical atrial flutter presenting 1 year after radiofrequency ablation for atrial fibrillation (AF). Electrophysiologic study showed a reentry circuit involving the inferolateral aspect of the mitral annulus and the coronary sinus (CS); however, a mitral isthmus line did not terminate the arrhythmia. Participation of the proximal CS musculature in the circuit suggested a possible target for ablation. Radiofrequency energy applications from within the CS terminated the tachycardia. Mapping and ablation within the CS should be considered in patients with post‐AF ablation arrhythmias, particularly when the mitral annulus appears to be involved in the tachycardia circuit. (PACE 2010; 33:e96–e99)     

Factors Predisposing to the Development of Atrial Fibrillation

Atrial fibrillation (AF) is in most patients (approximately 70%) associated with organic heart disease including valvular heart disease, coronary artery disease, hypertension, hypertrophic cardiomyopathy, dilated cardiomyopathy, and congenital heart disease, mostly atrial septal defect in adults. In many chronic conditions, determining whether AF is the result or is unrelated to the underlying heart disease, remains unclear. The list of possible etiologies also include cardiac amyloidosis, hemochromatosis and endomyocardial fibrosis. Other heart diseases, such as mitral valve prolapse (without mitral regurgitation), calcifications of the mitral annulus, atrial myxoma, pheochomocytoma, and idiopathic dilated right atrium may present with AF. Atrial fibrillation may occur in the absence of detectable organic heart disease, the so-called “lone AF”, in about 30% of cases. The term “idiopathic AF” implies the absence of any detectable etiology including hyperthyroidism, chronic obstructive lung disease, overt sinus node dysfunction, and overt or concealed preexcitation (Wolff-Parkinson-White syndrome), only to mention a few of other uncommon causes of AF. The autonomous nervous system may contribute to the occurrence of AF in some patients. AF occurs commonly. In patients with valvular heart disease, AF is common, particularly when the mitral valve is involved. The occurrence of AF is unrelated to the severity of mitral stenosis or mitral regurgitation but is more common in patients with enlarged left atrium and congestive heart failure. In patients with coronary artery disease, AF occurs predominantly in older patients, males, and patients with left ventricular dysfunction. Important predictive factors of AF include hypertension, left ventricular hypertrophy and diabetes. The risk of the development of AF, in an individual patient, is often difficult to assess. Increasing age, presence of valvular heart disease, and congestive heart failure increase the risk of atrial fibrillation.     

Impact of treatment crossovers on clinical outcomes in the rate and rhythm control strategies for atrial fibrillation: Insights from the AFFIRM (Atrial Fibrillation Follow‐up Investigation of Rhythm Management) trial

We investigated the rates and reasons for crossover to alternative treatment strategies and its impact on mortality in patients who were enrolled in the Atrial Fibrillation Follow‐up Investigation of Rhythm Management (AFFIRM) trial. Over a mean follow‐up period of 3.5 years, 842 patients underwent crossover to the alternative treatment arms in AFFIRM. The rate of crossover from rhythm to rate control (594/2,033, 29.2%) was more frequent than the rate of crossover from rate to rhythm control (248/2,027, 12.2%, P < 0.0001). The leading reasons for crossover from rhythm to rate control were failure to achieve or maintain sinus rhythm (272/594, 45.8%) and intolerable adverse effects (122/594, 20.5%). In comparison, the major reasons for crossover from rate to rhythm control were failure to control atrial fibrillation symptoms (159/248, 64.1%) and intolerable adverse effects (9/248, 3.6%). This difference in crossover pattern was statistically significant (P < 0.0001). There was a significantly decreased risk of all‐cause mortality (adjusted HR: 0.61, 95% CI: 0.48–0.78, P < 0.0001) and cardiac mortality (adjusted hazard ratio [HR]: 0.61, 95% confidence interval [CI]: 0.43–0.88, P = 0.008) in the subgroup of patients who crossed over from rhythm to rate control as compared to those who continued in rhythm control. There was a nonsignificant trend toward decreased all‐cause (adjusted HR: 0.76, 95% CI: 0.53–1.10, P = 0.14) and cardiac mortality (adjusted HR: 0.70, 95% CI: 0.42–1.18, P = 0.18) in patients who crossed over from rate to rhythm control as compared to those who continued rate control.