Mini‐Maze and Mitral Valve Surgery. Introduction: After mitral valve (MV) surgery, preoperative atrial fibrillation (AF) often recurs while cardioversion therapy generally fails. Additional Cox maze ...surgery improves postoperative arrhythmia outcome, but the extensive nature of such an approach limits general appliance. We investigated the clinical outcome of a simplified, less extensive Cox maze procedure (“mini‐maze”) as adjunct to MV surgery.
Methods and Results: Thirteen patients with MV disease and preoperative AF were treated with combined surgery (group 1). Nine control patients without previous AF underwent isolated MV surgery (group 2). We retrospectively compared the results to findings in 23 patients with preoperative AF who had undergone isolated MV surgery (group 3). In group 1, mini‐maze took an additional 46 minutes of perfusion time. One 75‐year‐old patient died of postoperative multiple organ failure. Seven patients showed spontaneously converting (within 2 months) postoperative AF. After 1 year, 82% were in sinus rhythm (SR). No sinus node dysfunction was observed. In group 2, all patients were in SR after 1 year. In group 3, only 53% were in SR after 1 year, despite serial cardioversion and antiarrhythmic drug therapy. Exercise tolerance and heart rate were comparable for groups 1 and 2. Left atrial function was present in all but one patient in group 1 and in all patients in group 2 (after MV reconstruction).
Conclusion: Adding a relatively simple mini‐maze to MV surgery improves arrhythmia outcome in patients with preoperative AF without introducing sinus node dysfunction or persistent absence of left atrial function. The results of this type of combined surgery are encouraging and deserve further attention.
Chronic atrial fibrillation (AF) occurs often in the setting of mitral and aortic valve disease. Eventually, these patients undergo valve replacement which improves cardiac function but does not ...prevent AF. This study investigates which patient may benefit from additional surgery for the cure of AF performed in combination with valve surgery. Seventy-four patients were retrospectively included from our prospective database of patients referred for serial cardioversion therapy between 1986 and 1993. All these patients had chronic AF after valve replacement. After the first electrical cardioversion, patients did not receive antiarrhythmic drugs. Relapses were managed by repeated cardioversions, and then antiarrhythmic drugs were instituted. After a median follow-up of 7 years (range 1.3 to 23), 39 patients had intractable AF. Multivariate analysis revealed that patients with a history of chronic AF before surgery (risk ratio 5.4, confidence intervals 2.5 to 11.3, p = 0.0001) had a poor arrhythmia outcome. In addition, Kaplan-Meier survival analysis demonstrated a lower success rate (p = 0.0017) in patients with mitral valve disease than in those with aortic valve disease. Congestive heart failure (41% vs 6%, p = 0.0007) and cardiovascular mortality (23% vs 9%, p = 0.09) were seen most often in patients with an unsuccessful cardioversion strategy. Thus, patients scheduled for mitral valve surgery with a history of chronic AF should be considered candidates for additional surgery for AF concomitantly performed during valve surgery.
Alamethicin is an amphipathic alpha-helical peptide that forms ion channels. An early event in channel formation is believed to be the binding of alamethicin to the surface of a lipid bilayer. ...Molecular dynamics simulations are used to compare the structural and dynamic properties of alamethicin in water and alamethicin bound to the surface of a phosphatidylcholine bilayer. The bilayer surface simulation corresponded to a loosely bound alamethicin molecule that interacted with lipid headgroups but did not penetrate the hydrophobic core of the bilayer. Both simulations started with the peptide molecule in an alpha-helical conformation and lasted 2 ns. In water, the helix started to unfold after approximately 300 ps and by the end of the simulation only the N-terminal region of the peptide remained alpha-helical and the molecule had collapsed into a more compact form. At the surface of the bilayer, loss of helicity was restricted to the C-terminal third of the molecule and the rod-shaped structure of the peptide was retained. In the surface simulation about 10% of the peptide/water H-bonds were replaced by peptide/lipid H-bonds. These simulations suggest that some degree of stabilization of an amphipathic alpha-helix occurs at a bilayer surface even without interactions between hydrophobic side chains and the acyl chain core of the bilayer.
Serial electrical cardioversion is often used for treatment of atrial fibrillation, but its long-term efficacy has not been determined prospectively.
To determine the long-term success rate of the ...serial electrical cardioversion approach in patients with chronic atrial fibrillation, to identify factors that predict its success, and to assess the efficacy and safety of oral anticoagulation in these patients.
Patients with chronic (> 24 hours) atrial fibrillation received anticoagulant therapy for at least 4 weeks prior to electrical cardioversion. No prophylactic antiarrhythmic agent was given after the first shock. Relapses were managed by using repeated cardioversions, after which serial antiarrhythmic drug therapy was started. Treatment with anticoagulants was withdrawn after 4 weeks of sinus rhythm.
Two hundred thirty-six patients were followed up for a mean +/- SD of 3.7 +/- 1.6 years. The actuarial cumulative percentages of patients who maintained sinus rhythm after serial cardioversion treatment was 42% and 27% after 1 and 4 years, respectively. Multivariate analysis showed that factors that were associated with failure of this approach included duration of atrial fibrillation that exceeded 36 months (risk ratio, 5.0; P < .001), poor exercise tolerance (functional class III; risk ratio, 1.8; P = .001), and age older than 56 years (risk ratio, 1.5; P = .04). The anticoagulation level (international normalized ratio, 2.4-4.8) was associated with an incidence of thromboembolic events and bleeding complications of 0.2% and 1.5%, respectively.
Many patients with chronic atrial fibrillation failed to respond to the serial electrical cardioversion strategy. However, in younger patients with a fair exercise tolerance and a duration of atrial fibrillation shorter than 36 months, this approach may be worthwhile. In addition, thromboembolic events were infrequent in the patients who were subjected to this regimen.
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