The Maze operation for treatment of atrial fibrillation. Early clinical experience in a Scandinavian institution

Surgical treatment of atrial fibrillation : a systematic review

BACKGROUND

The recently published overwhelming number of publications on the surgical treatment of AF, using a wide variety of techniques, blurred any precise appreciation of the nowadays surgical treatment of AF. As a consequence, the "state of the art" of the surgical technique of AF is ill-defined.

OBJECTIVES

In this review the efficacy of the alternative sources of energy (radiofrequency-microwave and cryoablation; (group I) and the classical "cut and sew" Cox-Maze III (group II), which claims a 97-99% sinus rhythm (SR) success rate, were evaluated in the surgical treatment of atrial fibrillation (AF).

METHODS

A computerized search in the PubMed and Medline database was conducted. Only original, English written, clinical manuscripts on the surgical treatment of atrial fibrillation citing the clinical outcome, including the postoperative sinus rhythm, were included. The following data were registered: the absolute numbers and percentages of treated patients, gender (male versus female) distribution, the type of arrhythmia (permanent or paroxysmal AF), type of surgery (mitral or non-mitral valve or a lone AF surgical procedure), postoperative morbidity (bleeding, the use of an intra-aortic balloon pump, cerebral vascular accident), postoperative pacemaker implantations, 30-day mortality, survival and sinus rhythm conversion. The mean values for age (years), left atrial diameter (mm), preoperative duration of AF (years) and left ventricular ejection fraction (%) were also recorded.

RESULTS

Forty-eight studies were included comprising 3832 patients: 2279 in group I and 1553 in group II. The mean duration of AF, left atrial diameter and LVEF were 5.4 versus 5.5 years (p=0.90), 55.5 versus 57.8 mm (p=0.23) and 57 versus 58% (p=0.63). The postoperative SR rates for group I and II were 78.3 versus 84.9% (p=0.03). However, the "cut and sew" Cox-Maze III was conducted in younger patients (55.0 versus 61.2 years; p=0.005), more often to treat paroxysmal (22.9 versus 8.0%) and lone AF (19.3 versus 1.6%). Alternative sources of energy were predominantly used to treat permanent AF (92.0%), almost always as a concomitant surgical procedure (98.4%) and increasingly in combination with non-mitral valve surgery (18.5%). After correction for these variations, the postoperative SR conversion rates for group I and II did not differ significantly anymore.

CONCLUSIONS

We could not identify any significant difference in the postoperative SR conversion rates between the classical 'cut and sew' and the alternative sources of energy, which were used to treat atrial fibrillation.

Atrial Arrhythmias After Surgical Maze

OBJECTIVES

We describe the clinical and electrophysiologic characteristics and management of post "cut and sew" Maze arrhythmias in symptomatic patients.

BACKGROUND

The Cox Maze procedure was developed as a surgical treatment of atrial fibrillation. Until recently, invasive electrophysiologic studies in patients with symptomatic post-operative arrhythmias in this patient population have not been described.

METHODS

The management and clinical course of consecutive patients with post-Maze arrhythmias refractory to antiarrhythmic drugs (AADs) between January 2000 and December 2003 are presented.

RESULTS

Twenty-three patients (15 men) presented 14 +/- 14 months after Maze surgery for treatment of atrial fibrillation (AF). Eight patients underwent "cut and sew" Maze for lone AF with no other surgical indication. Fifteen patients underwent the "cut and sew" Maze procedure in addition to another surgical procedure: mitral valve surgery (11 patients) and coronary artery bypass graft surgery (4 patients). Eight patients (35%) had recurrent AF secondary to recovered conduction around the lines encircling the pulmonary veins. Five patients were documented to have focal atrial tachycardia, which was mapped to the coronary sinus in 3 patients, to the posterolateral right atrium in 1 patient, and to the left atrial (LA) septum in 1 patient. Four patients had right atrium incisional atrial flutter (AFL), and 6 had LA incisional AFL, which was mapped around the mitral valve annulus in 4 patients and around the right pulmonary veins in 2 patients. Twenty-two of the 23 patients were treated successfully with radiofrequency ablation. At 1-year follow-up, 19 patients were arrhythmia-free and taking no AADs.

CONCLUSIONS

After surgical "cut and sew" Maze, approximately one-third of patients experiencing atrial arrhythmias have AF secondary to pulmonary vein-left atrium conduction recovery. Moreover, incisional AFL seems to be a common finding in this group of patients. Catheter-based mapping and ablation of these arrhythmias seems to be feasible and effective.

Electrophysiological Evaluation of the Sinus Node and the Cardiac Conduction System Following the Maze Procedure for Atrial Fibrillation

Transient sinus node dysfunction has been demonstrated by noninvasive methods following the maze procedure for atrial fibrillation (AF). However, extensive data from invasive electrophysiological studies have not been previously reported. Thirty-seven patients, mean age 54 +/- 10 years, underwent the maze (III) procedure. Electrophysiological studies with recordings of SNRT, CSNRT, AVN-ERP, point of Wenckebach block, AH, PA, and HV interval, were performed preoperatively and 6 and 15 months postoperatively. Induction of atrial flutter/AF was attempted postoperatively. Based on electrophysiological study evaluation, the maze (III) procedure did not cause permanent damage to the sinus node in any patient with a documented normal sinus node function preoperatively (CSNRT max 541 +/- 210 vs 587 +/- 437 ms, P = 0.26). Postoperative AV node function was normal in all patients with a documented normal AV node function before surgery. One patient had an iatrogenic third degree AV block. There was no difference in PA or HV interval after surgery. Sustained atrial tachyarrhythmias could be induced in 5 patients, of whom 4 developed permanent AF/atrial flutter late after surgery. At late follow-up, (mean 45 months), 27 (73%) patients were in sinus rhythm, 5 (13%) patients had permanent pacing, and 5 patients had recurrent AF requiring His bundle ablation (n = 2) or medical treatment (n = 3). Based on electrophysiological studies, the maze (III) procedure does not cause permanent damage to the sinus or AV nodes or to the right atrial and His-Purkinje conduction systems. Electrophysiological study evaluation may predict the need for postoperative pacemaker. Induction attempts of atrial arrhythmias may predict future recurrences and guide therapeutic efforts.

Elevations in antidiuretic hormone and aldosterone as possible causes of fluid retention in the Maze procedure

BACKGROUND

Reduced levels of atrial natriuretic peptide (ANP) has been suggested as a cause of fluid retention after combined Maze and valvular surgery. This study aimed to assess hormonal activation in the perioperative setting of isolated Maze procedures.

METHODS

Changes in ANP, brain natriuretic peptide (BNP), antidiuretic hormone (ADH), aldosterone, and angiotensin II were measured in 16 patients (mean age 53+/-9 years) without concomitant heart disease undergoing the Maze (III) procedure. Ten matched patients (mean age 56+/-9 years) undergoing multivessel coronary artery bypass grafting served as controls. Measurements with hemodynamic correlates were obtained at baseline and after ventricular pacing (100 stimulations/minute), directly preoperatively, postoperatively and the first postoperative day. Weight gain and diuretic requirements were recorded.

RESULTS

The major differences in hormonal response were significantly higher plasma levels of ADH (Maze preoperative 1.1+/-0.4, postoperative 24.9+/-16.7 pmol/L; controls preoperative 1.1+/-0.1, postoperative 3.7+/-3.5 pmol/L) and aldosterone (Maze preoperative 106+/-94, postoperative 678+/-343 pmol/L; controls preoperative 124+/-79, postoperative 171+/-93 pmol/L) in the Maze group on the first postoperative day (p < 0.001). Preoperative baseline plasma levels of ANP and pulmonary capillary wedge pressures (PCWP) were higher in the Maze group but this difference was abolished by pacing, and postoperatively, ANP levels changed in parallel to the PCWP in both groups. Diuretic requirements were significantly higher in the Maze group.

CONCLUSIONS

Substantial increases in ADH and aldosterone were observed after the Maze procedure, indicating these hormones as important determinants in postoperative fluid retention. The role for ANP in this setting may be a less prominent than previously reported.