Efficacy of serial electrical cardioversion therapy in patients with chronic atrial fibrillation after valve replacement and implications for surgery to cure atrial fibrillation

The Mid-Term Results of Patients who Underwent Radiofrequency Atrial Fibrillation Ablation Together with Mitral Valve Surgery

Objetive

Saline-irrigated radiofrequency ablation, which has been widely used for surgical treatment of atrial fibrillation in recent years, is 80-90% successful in achieving sinus rhythm. In our study, our surgical experience and mid-term results in patients who underwent mitral valve surgery and left atrial radiofrequency ablation were analyzed.

Methods

Forty patients (15 males, 25 females; mean age 52.05±9.9 years; range 32-74) underwent surgery for atrial fibrillation associated with mitral valvular disease. All patients manifested atrial fibrillation, which started at least six months before the surgical intervention. The majority of patients (36 patients, 90%) were in NYHA class III; 34 (85%) patients had rheumatic heart disease. In addition to mitral valve surgery and radiofrequency ablation, coronary artery bypass, DeVega tricuspid annuloplasty, left ventricular aneurysm repair, and left atrial thrombus excision were performed. Following discharge from the hospital, patients' follow-up was performed as outpatient clinic examinations and the average follow-up period of patients was 18±3 months.

Results

While the incidence of sinus rhythm was 85.3% on the first postoperative day, it was 80% during discharge and 71% in the 1^st year follow-up examination.

Conclusion

Radiofrequency ablation is an effective method when it is performed by appropriate surgical technique. Its rate for returning to sinus rhythm is as high as the rate of conventional surgical procedure.

Effects of Atrial Arrhytmias on the Regurgitation of a Monoleaflet Prosthetic Heart Valve

Many patients who receive a prosthetic heart valve also have or acquire cardiac arrhythmias. However, most in vitro studies of prosthetic valves examine them under normal rhythms. In this study, a monoleaflet prosthetic heart valve was tested in vitro under conditions that simulated normal sinus rhythm, first degree atrioventricular heart block, and atrial fibrillation (fixed and variable ventricular rates). Atrial contraction was simulated by an active atrial chamber. The timing between the atrium and ventricle was adjusted to simulate various types of arrhythmias. The closing, leakage, and total regurgitant volumes and fractions increased for each type of atrial arrhythmia when compared to normal sinus rhythm. The peak regurgitant flow increased for first degree atrioventricular heart block and atrial fibrillation with a fixed ventricular rate compared to normal sinus rhythm.

Radiofrequency ablation for atrial fibrillation: different approaches

The existing literature regarding radiofrequency ablation for the surgical treatment of atrial fibrillation was reviewed, analyzing the early and late results. A MEDLINE search supplemented with a manual bibliographic review was performed for all peer-reviewed English language articles regarding the use of radiofrequency ablation for the treatment of atrial fibrillation. Six studies were identified, with a total of 451 patients. None of the studies was completely randomized. All patients underwent radiofrequency ablation as an adjunct to a variety of cardiac surgical procedures. The hospital mortality rate was 2.7%. The overall survival rate was 97.1%, and freedom from atrial fibrillation was 76.3% +/- 5.1% after a mean follow-up period of 13.8 +/- 1.9 months. It was concluded that radiofrequency ablation should be considered a safe and effective means to cure atrial fibrillation in patients undergoing open heart surgery.

Sinus node function after cardiac surgery: is impairment specific for the maze procedure?

BACKGROUND

Maze surgery is a final solution for intractable atrial fibrillation (AF), but an adverse effect on postoperative sinus node function has been reported. Whether this also applies to other types of cardiac surgery is unclear.

METHODS

We assessed postoperative rhythm by means of repeated exercise tolerance testing, ambulatory electrocardiography, and non-invasive testing of autonomic function between 1 and 12 months after four types of cardiac surgery. Fourteen patients without structural cardiac disease and medically refractory AF underwent the maze III procedure, 11 patients with mitral valve disease and preoperative AF underwent valvar surgery combined with a (simplified) maze III procedure, and 8 patients with mitral valve disease in sinus rhythm (SR) underwent isolated valvar surgery. The control group consisted of eight patients with sinus rhythm who underwent coronary artery bypass surgery (CABG).

RESULTS

One month after surgery, the chronotropic response to exercise was depressed, mean heart rate was high, and heart rate variability (HRV) was low, especially after maze III, combined surgery, and isolated valvar surgery. Twelve months after surgery, moderate improvements were observed. After CABG, considerably fewer abnormalities were observed, and HRV parameters recovered to a large extent. Non-invasive testing of autonomic function indicated disturbed vagal modulation of heart rate in all three groups with atrial incision.

CONCLUSION

Thus, attenuation of HRV and vagal modulation of sinus node function are not confined to maze surgery but also apply to isolated mitral valve surgery. Atrial incision therefore appears to be crucial and presumably produces autonomic nervous damage followed by partial reinnervation. Nevertheless, cardiac surgery in general seems initially to impair sinus node function with partial recovery in the consecutive 12 months.

Surgical ablation of atrial fibrillation using the epicardial radiofrequency approach: mid-term results and risk analysis

BACKGROUND

The minor technical and time requirements with respect to the maze operation combined with a comparable efficacy has led to an increasing popularity of left atrial approaches to treat atrial fibrillation. We report our experience with a left atrial procedure based on extensive use of epicardial radiofrequency ablation in an effort to minimize cardiac arrest time.

METHODS

A total of 132 consecutive patients with atrial fibrillation (121 chronic, 11 paroxysmal) undergoing open heart surgery had combined intraoperative ablation. An original set of left atrial lesions was performed using a radiofrequency linear catheter. Most of the ablations were performed epicardially before aortic cross-damping. Patients with contraindications to the epicardial approach had the whole lesion set performed endocardially.

RESULTS

The mean cardiac arrest time spent for open heart ablations was significantly shorter (5.2 +/- 0.9 minutes with modem catheters) when the epicardial approach was used (107 of 132 patients, 81%). Hospital mortality was 0.8%. Freedom from atrial fibrillation was 77% 3 years after the operation. Of all the variables analyzed, only age at surgery and early postoperative arrhythmias increased the risk of recurrent atrial fibrillation. Overall 3-year survival was 94%. The 3-year actuarial freedom from stroke was 98%. No patient required implantation of a permanent pacemaker. Atrial contractility was recovered in all patients with stable sinus rhythm.

CONCLUSIONS

Left atrial radiofrequency ablation allows recovery of sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who undergo open heart surgery. The epicardial radiofrequency approach is a safe and effective means to cure atrial fibrillation with negligible technical and time requirements.

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.

Mini-maze suffices as adjunct to mitral valve surgery in patients with preoperative atrial fibrillation

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.

Mitral valve surgery and atrial fibrillation: is atrial fibrillation surgery also needed?

OBJECTIVE

Atrial fibrillation (AF) persisting after mitral valve surgery reduces survival due to heart failure and thrombo-embolisms, and impairs quality of life. Arrhythmia surgery for AF shows today very satisfying results and therefore mitral valve surgery with AF surgery appears appealing. This study explores whether combined surgery in view of today's results of mitral valve surgery is indicated.

METHODS AND RESULTS

An outcome analysis of the arrhythmia outcome of patients undergoing exclusive mitral valve surgery with or without tricuspid repair was done. Preoperative baseline characteristics including arrhythmia pattern, surgical methods and follow-up findings were reviewed. Postoperative management of AF was not protocolized. Between 1990 and 1993, 162 consecutive patients underwent mitral valve surgery; follow-up was a mean of 3.3+/-1.9 years. In-hospital and late mortality were 1 and 9%, respectively. Sinus rhythm was preserved in 40 of 57 (70%) patients with preoperative sinus rhythm whereas AF persisted in 58 of 68 (85%) of patients with preoperative chronic AF (>1 year present). Sinus rhythm without AF was observed in 10 of 29 (34%) patients with preoperative paroxysmal AF. The 4-year Kaplan-Meier survival did not differ between patients with preoperative sinus rhythm (95.2%), paroxysmal AF (89.2%) and chronic AF (82.9%) but AF persisting after surgery tended to determine survival (P=0.05). Gender, age and right ventricular pressure and tricuspid valve repair were risk factors for postoperative recurrence of AF in patients with sinus rhythm at discharge, relative risk 0.35, 1.06, 1. 04 and 2.9, respectively.

CONCLUSION

Current mitral valve surgery with or without tricuspid valve repair does not eliminate preoperative paroxysmal or chronic AF. Secondly, because preoperative AF did not determine survival after mitral valve surgery, whereas postoperatively persisting AF was weakly associated with survival, atrial arrhythmia surgery primarily aims to reduce morbidity due to AF. Some characteristics can identify patients with increased propensity for persisting AF after surgery. Randomized studies of AF surgery are needed to identify suitable candidates for combined surgery.

Observed and relative survival after aortic valve replacement

OBJECTIVES

We sought to evaluate the effects of a number of factors that can potentially determine the optimal time for aortic valve replacement (AVR) and the observed and relative survival after the operation.

BACKGROUND

Aortic valve replacement is performed in patients within a wide age span, but the proportion of elderly patients is increasing. In survival analyses, adjustment for the effects of age is therefore essential. Analysis of relative survival provides additional information on excess or disease-specific mortality and its risk factors.

METHODS

Survival was analyzed in 2,359 patients (1,442 without and 917 with concomitant coronary artery bypass graft surgery) undergoing their first AVR. By relating observed survival to that expected among the general Swedish population stratified by age, gender and five-year calendar period, the relative survival and disease-specific survival were estimated.

RESULTS

Early mortality after AVR (death within 30 days) was 5.6%. Relative survival rates (excluding early deaths) after 5, 10 and 15 years were 94.6%, 84.7% and 74.9%, respectively. There was an excess risk of dying during the entire follow-up period. Advanced New York Heart Association functional class, preoperative atrial fibrillation and pure aortic regurgitation were independent risk factors for observed and relative survival. Patients in the oldest age group showed decreased observed survival but excellent relative survival.

CONCLUSIONS

Old age was not a risk factor for excess mortality after AVR, whereas atrial fibrillation decreased relative survival substantially.

Atrial fibrillation in the elderly

Atrial fibrillation is the most common sustained arrhythmia seen in clinical practice. Although it occurs in any age patients, its frequency increases with age and is very common in the elderly. Atrial fibrillation causes substantial symptoms and morbidity and is an important cause of thromboembolism and stroke. The two approaches for therapy in those patients with intermittent or persistent atrial fibrillation are (1) maintenance of sinus rhythm with an antiarrhythmic drug or nonpharmacologic therapy, and (2) maintenance of atrial fibrillation with rate control. At the present time there are no data about the best approach and therapy must therefore be individualized.

Effects of atrial fibrillation on left ventricular function and geometry in mitral stenosis

This study shows that patients with mitral stenosis have depressed left ventricular ejection performance and spherical remodeling of the left ventricular cavity, which is more marked in those with atrial fibrillation. These changes have important clinical implications regarding treatment strategy in patients with mitral stenosis and chronic atrial fibrillation.