Álvaro Albrecht

Randomized study of surgical isolation of the pulmonary veins for correction of permanent atrial fibrillation associated with mitral valve disease

OBJECTIVE Chronic permanent atrial fibrillation is often due to mitral valve disease. The Cox maze procedure is the gold standard for treating this arrhythmia. Simpler techniques and ablation methods should have their efficacy tested in clinical practice. Our objective was to evaluate the effectiveness of surgical pulmonary vein isolation as compared with the Cox maze procedure. METHODS Sixty patients were randomly assigned to control group, modified maze group (Cox maze III), and surgical isolation of the pulmonary veins (SPVI) group from July 1999 to October 2004. All patients had mitral valve lesions treated concomitantly. Preoperative characteristics were similar between groups. RESULTS There were 4 deaths: 3 in the Cox maze group and 1 in the SPVI group (P = .31). The Cox maze group presented longer times of extracorporeal circulation and myocardial ischemia (P < .001). The relative risk of late postoperative development of atrial fibrillation was 0.07 in the SPVI group (P < .001; 95% confidence intervals: 0.02-0.27) and 0.195 in the Cox maze group (P = .002; 95% confidence intervals: 0.07-0.56) as compared with the control group. No difference was found between the SPVI and Cox maze groups concerning prevention of atrial fibrillation recurrence (relative risk: 0.358; P = .215; 95% confidence intervals: 0.08-1.67). CONCLUSIONS The modified Cox maze procedure and surgical pulmonary vein isolation were similarly effective in restoring sinus or regular rhythm in permanent atrial fibrillation associated with mitral valve disease. These results favor the adoption of surgical isolation as a preferable technique, simpler and equally effective in controlling atrial fibrillation. The results also can bring further information for understanding the mechanisms involved in origins and treatment of chronic permanent atrial fibrillation.

Técnica cirúrgica simplificada pode ser eficaz no tratamento da fibrilação atrial crônica secundária a lesão valvar mitral

INTRODUCTION: Atrial fibrillation, nowadays, has been treated surgically by the maze procedure and its modifications. However, there is some evidence that points to the pulmonary vein ostia as trigger point for this arrhythmia. We postulate a surgical approach of pulmonary vein isolation or left atrial isolation in order to treat this disease. In this study we show the initial results of this technique in patients with chronic atrial fibrillation associated with mitral valve disease. MATERIAL AND METHODS: Seven patients were operated on by pulmonary vein isolation (IVP) and compared to the past results of the 57 patients in which the maze procedure had been done (Cox 3). RESULTS: Age - 49±8 years vs. 49±11 years (IVP vs. Cox 3), 71% and 72% (IVP vs. Cox 3) were female. Left atrium size was 5.5±0.7 cm vs. 6.0±1.1 cm (IVP vs. Cox 3). Ventricular EF 63±10% vs. 64±6% (IVP vs. Cox 3). Extracorporeal circulation time 91±33 min vs.104±29 min (IVP vs. Cox 3). Aortic cross-clamping 71±23 min vs. 83±26 min (IVP vs. Cox 3). Cardiac rhythm: sinusal / atrial n(%): 6(86) vs. 46(80) (IVP vs. Cox 3). Cardiac pace rhythm n(%):1 (14) vs. 4 (7) (IVP vs. Cox 3). Atrial fibrillation n(%):0 vs. 7 (13) (IVP vs. Cox 3). CONCLUSIONS: The initial results show sinus rhythm restoration and its maintenance. We have already started a double-blind randomized trial between these two surgical techniques.

Results of the surgical treatment of chronic atrial fibrillation

OBJECTIVE Report clinical experience in surgical treatment of atrial fibrillation (AF) by Cox-maze procedure. METHODS 61 patients underwent surgical treatment for AF. Two had primary AF and 59 AF secondary to heart disease (2 atrial septal defects, 57 mitral). Ages ranged from 20 to 74 years (mean = 49). There were 44 females (72%). The surgical technique employed was Cox 3 without cryoablation. The patients were follow-up in specific at patient clinics and underwent periodical ECG, exercise tests, echocardiogram and Holter monitoring. RESULTS In-hospital mortality was 4.9% and late mortality 1.6%. A temporary pacemaker was used in 28 (46%) and a definitive in 7 patients (11.4%). On hospital discharge, AF remained in 17%; 63.9% had sinus rhythm, 6.9% atrial rhythm, 1.7% junctional rhythm, and 10.3% had pacemaker rhythm. In the last evaluation, AF was present in 19.5%; (70.5% sinus rhythm, 4% atrial rhythm, 2% atrial tachycardia, and 4% pacemaker rhythm). There was no report of thromboembolic episodes. Chronotropic response was considered adequate in 19%, intermediate in 29%, and inadequate in 42%. In Holter monitoring, the mean heart rate was 82 +/- 8 bpm, with a minimum of 57 +/- 7 bpm and maximum of 126 +/- 23 bpm, with supraventricular extrasystoles in 2.3 +/- 5.5% of the total heartbeats and ventricular extrasystoles in 0.8 +/- 0.5%. In the echocardiogram, the A wave was present in the left atrium in 87.5%. CONCLUSION Maze procedure is effective and has acceptable surgical risk. Atrial or sinus rhythms remain stable with a small but remarkable frequency of atrial and ventricular arrhythmias. Left atrial contraction is present, although attenuated, as well as the chronotropic response to exercise.

Evaluation of the heart rate and arrhythmias following the Maze procedure for chronic atrial fibrillation

PURPOSE To assess the presence and the prevalence of arrhythmias and the variability of the heart rate in the medium-term postoperative period following the maze procedure for chronic atrial fibrillation (AF). METHODS Seventeen patients with a mean age of 51.7 +/- 12.9 years, who previously underwent the maze procedure without cryoablation for chronic atrial fibrillation, were evaluated with the 24 hour electrocardiogram (ECG)--Holter monitoring from the 6th month after the operation. Valvular and coronary procedures were concomitantly performed. RESULTS The mean heart rate during Holter monitoring was 82 +/- 8 bpm; the maximal heart rate was 126 +/- 23 bpm and the minimal heart rate 57 +/- 7 bpm. Sinus rhythm was found in 10 (59%) patients and atrial rhythm was found in 7 (41%). Supraventricular extrasystoles had a rate of 2.3 +/- 5.5% of the total number of heartbeats and occurred in 16 (94%) patients. Six (35%) patients showed nonsustained atrial tachycardia. Ventricular extrasystoles, with a rate of 0.8 +/- 0.5% of the total heartbeats, occurred in 14 (82%) patients. The chronotropic competence was normal in 9 (53%) patients and attenuated in 8 (47%). The atrioventricular conduction (AV) was unchanged in 13 (76%) patients and there were 4 (24%) cases of first degree atrioventricular block (AVB). CONCLUSION After the maze procedure, the values for the mean heart rate, AV conduction and chronotropic competence approach the normal range, although some cases show attenuation of the chronotropic response, first degree AV block or benign arrhythmias.

Análise comparativa dos resultados da cirurgia do labirinto (Cox-maze) para fibrilação atrial crônica em pacientes com doença valvar mitral reumática ou degenerativa

The results of maze procedure in rheumatic mitral valve disease are subject to debate. This paper reports medium term results in rheumatic and degenerative mitral valve surgery associated with maze procedure. From 1994 to 1997, 57 patients were operated on. They were divided into two Groups; R (rheumatic) 40 patients and D (degenerative) 17. Group R included 8 (20%) males and 32 (80%) females. Group D: 8 (47%) males and 9 (53%) females (NS). Age in R = 47 ± 11 and D 54 ± 17 years (p < 0.05). Left atrial size was 6.1 ± 1.1 cm in R and 5.9 ± 1.2 in D (NS). There were 3 hospital deaths, 1 (2.5%) in R and 2 (12%) in D. One D patient (7%) died late. Pacemakers were implanted in 4 (10%) R and 2 (17%) in D (NS). There were no significant differences regarding surgical duration of perfusion or myocardial ischemia, antiarrhythmic medications, immediate or late cardiac rythms and occurrence of arrythmias. Ergometric evaluation for measuring chronotropic response revealed a normal response in 6 (25%) R and 1 (10%) in D at a mean of 16.6 months PO. In the lower response group, 3 (12.5%) R and 6 (60%) D had intermediate values (p = 0.009) and 15 (62.5%) R versus 3 (30%) D had values below 75% of expected heart rate (p = 0.09). Rheumatic or degenerative ethiology of mitral valve disease does not influence the results of maze procedure in this patient population. Mean chronotropic response to exercise tends to be lower in degenerative patients.

Randomized study of surgical correction of permanent atrial fibrillation: preliminary results

OBJECTIVE: To analyze the results of techniques in the treatment of atrial fibrillation: the Maze procedure and Isolation of Pulmonary Veins were compared together with Control group, to establish the best treatment for this arrhythmia. METHOD: All patients were referred for surgery due for other cardiac lesions, which were treated concurrently. From July 1999 to September 2003, fifty-one patients where randomly allocated to the different groups. No cryoablation or other source of energy was used. The following variables were initially analyzed: total bypass time, aortic clamping time, sinus rhythm at discharge, and trans-operative and immediate post-operative complications. RESULTS: There were two intra-hospitalar deaths, one in the Maze group and one in the Isolation of Pulmonary Veins group. The Maze group had the longest bypass time (p<0,001). The duration of follow-up of 28.4 ±14 months was similar between the groups. The Isolation of Pulmonary Veins achieved the best results concerning reversion to sinus rhythm with 84.2% at hospital discharge and 88.9% after follow-up. In the Maze group, 78.5% of sinus rhythm was seen detected at discharge and 84.6% at the end of follow-up. In the Control group 87.5% of the patients have atrial fibrillation at discharge and after follow-up atrial fibrillation remained at 56.3% of the patients. There was no difference in the NYHA class between the groups after follow-up (p=0.56) and Control group patients had more complications (p=0.017). CONCLUSION: These results show that both techniques, the Maze and Isolation of Pulmonary Veins, have advantages over simple correction of cardiac lesions when associated to atrial fibrillation.