Medium-term results after the modified Cox/Maze procedure combined with other cardiac surgery

Human Tissue Analysis of Left Atrial Adipose Tissue and Atrial Fibrillation after Cox Maze Procedure

Cardiac adipose tissue is a well-known risk factor for the recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation, but its correlation with maze surgery remains unknown. The aim of this study was to investigate the correlation between the recurrence of AF and the adipose component of the left atrium (LA) in patients who underwent a modified Cox maze (CM) III procedure. We reviewed the pathology data of resected LA tissues from 115 patients, including the adipose tissue from CM-III procedures. The mean follow-up duration was 30.05 ± 23.96 months. The mean adipose tissue component in the AF recurrence group was 16.17% ± 14.32%, while in the non-recurrence group, it was 9.48% ± 10.79% (p = 0.021), and the cut-off value for the adipose component for AF recurrence was 10% (p = 0.010). The rates of freedom from AF recurrence at 1, 3, and 5 years were 84.8%, 68.8%, and 38.6%, respectively, in the high-adipose group (≥10%), and 96.3%, 89.7%, and 80.3%, respectively, in the low-adipose group (<10%; p = 0.002). A high adipose component (≥10%) in the LA is a significant risk factor for AF recurrence after CM-III procedures. Thus, it may be necessary to attempt to reduce the perioperative adipose portion of the cardiac tissue using a statin in a randomized study.

Does Surgical Ablation of Atrial Fibrillation Benefit Patients Undergoing Bioprosthetic Valve Replacement?

The benefit of avoiding lifelong anticoagulation therapy in patients with bioprosthetic heart valve implantation may potentially be offset by atrial fibrillation (AF); however, clinical impact of surgical AF ablation in such patients remains controversial. We enrolled 426 patients (aged 72.0 ± 7.8 years) with AF who underwent left-side valve replacement with bioprostheses between 2001 and 2018. Of these, 297 underwent concomitant surgical ablation (ablation group) and 129 underwent valve replacement alone (non-ablation group). Clinical outcomes were compared, and mortality was considered as a competing risk factor against valve-related complications. Inverse-probability weighting (IPTW) was adopted to reduce selection bias. The ablation group had lower baseline risk profiles than the non-ablation group. In crude analysis, early mortality rates were 3.4% and 7.0% in the ablation and non-ablation groups, respectively (P = 0.104). During follow-up (1521.9 patient-years), the ablation group showed lower AF-recurrence (P < 0.001) and anticoagulant medication rate (P = 0.021), and lower overall mortality risk (subdistribution hazard ratio [SHR], 0.63; 95% confidence interval [CI], 0.42-0.94), but higher risk of permanent pacemaker implantation (SHR, 4.67; 95% CI, 1.36-16.05). No significant difference in the risk of stroke (SHR, 1.27; 95% CI, 0.55-2.95) was observed between the groups. After baseline IPTW-adjustment, findings of the clinical outcomes were analogous to those from crude analyses. In patients undergoing bioprosthetic valve replacement, the addition of surgical ablation was associated with improved rhythm outcomes and survival but at the expense of a higher risk of pacemaker implantation. The underlying mechanism of improved survival by AF ablation needs further investigation.

Sick Sinus Syndrome After the Maze Procedure Performed Concomitantly With Mitral Valve Surgery

Background

To characterize the development of sick sinus syndrome (SSS) after the additive maze procedure (MP) during mitral valve surgery.

Methods and Results

Follow‐up data (median, 3.6 years) of 750 patients with a prevalence of rheumatic cause of 57.6% were analyzed. SSS occurred in 35 patients with a time‐dependent increase: the incidence rates at 1, 2, and 4 years after surgery were 2.9%, 3.7%, and 4.3%, respectively. The additive MP showed higher risks of SSS development (hazard ratio, 7.44; 95% confidence interval, 3.45–16.05; P<0.001) and pacemaker implantation (hazard ratio, 3.61; 95% confidence interval, 1.95–6.67; P<0.001). Patients who developed SSS showed higher 4‐year rates of clinical events (death, stroke, and hospital admission) (67.5±8.5% versus 33.0±1.9%; P<0.001). After adjustment for age and preoperative peak systolic pulmonary artery pressure, the lesion extent (biatrial versus left atrial MP), not the underlying cause (rheumatic versus nonrheumatic), was independently associated with SSS development (hazard ratio, 3.58; 95% confidence interval, 1.08–11.86; P=0.037). The adverse effect of the biatrial MP was confirmed in patients with trivial or mild preoperative tricuspid regurgitation showing higher SSS incidence (4.6±1.4% versus 1.0±0.7%; P=0.023), not in those with moderate‐to‐severe tricuspid regurgitation (6.8±1.7% versus 3.8±3.8%; P=0.337). Recurrence of atrial fibrillation was not associated with the lesion extent of the MP.

Conclusions

After the additive MP, the ongoing risk of SSS development should be acknowledged irrespective of the underlying cause. Considering additive risk of biatrial MP with similar atrial fibrillation recurrence rate, minimizing lesion extent is warranted.

2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the management of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Both the incidence and prevalence of AF are increasing, and the burden of AF is becoming huge. Many innovative advances have emerged in the past decade for the diagnosis and management of AF, including a new scoring system for the prediction of stroke and bleeding events, the introduction of non-vitamin K antagonist oral anticoagulants and their special benefits in Asians, new rhythm- and rate-control concepts, optimal endpoints of rate control, upstream therapy, life-style modification to prevent AF recurrence, and new ablation techniques. The Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology aimed to update the information and have appointed a jointed writing committee for new AF guidelines. The writing committee members comprehensively reviewed and summarized the literature, and completed the 2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the Management of Atrial Fibrillation. This guideline presents the details of the updated recommendations, along with their background and rationale, focusing on data unique for Asians. The guidelines are not mandatory, and members of the writing committee fully realize that treatment of AF should be individualized. The physician's decision remains most important in AF management.

Freedom from atrial fibrillation after cox maze III ablation during follow-up

Background:

Nearly 60% of patients undergoing mitral valve (MV) operations are affected by atrial fibrillation (AF). Cox Maze III ablation is one of the effective ways for restoring sinus rhythm for patients undergoing open heart surgery. The aim of present study was to evaluate efficacy of Maze III ablation procedure for restoring sinus rhythm among patients who had underwent open heart surgery.

Materials and Methods:

During present descriptive-analytic prospective study 114 patients with chronic AF had undergone open heart surgery for their valvular or coronary artery diseases in Educational-Medical centres of Tabriz University of Medical Sciences (Tabriz, Iran) 2006-2012, were included in the study. For all patients Maze III ablation was done. Patients were evaluated by 12 lead electrocardiography (ECG) and 24 hours ambulatory ECG monitoring after 3-6 years (mean 4.8) of follow-up.

Result:

Patients' rhythm before Cox Maze III surgery was chronic AF in all patients. All patients were discharged from operating room with sinus rhythm. During intensive care unit (ICU) hospitalization, rhythm of 34 patients changed to AF and 80 patients had sinus rhythm. Sixteen patients had undergone electrical cardioversion for restoring sinus rhythm which was successful in 12 patients. Ninety-two patients had sinus rhythm when discharged from the hospital. After termination of follow-up, freedom from atrial fibrillation was 51%. Patients with AF during follow-up on surface ECG didn't have episodes of sinus rhythm in their ambulatory monitoring. One patient implanted cardiac pacemaker due to persistent sinus bradycardia.

Conclusion:

Based on the results of this study, Cox Maze III ablation procedure is an effective and safe way for restoring sinus rhythm among patients who are candidate for open heart surgery, while no significant complication was seen among patients.

Operative techniques in association with arrhythmia surgery in patients with congenital heart disease

Arrhythmia surgery in patients with congenital disease is challenged by the range of anatomic variants, arrhythmia types, and intramyocardial scar location. Experimental and clinical studies have elucidated the mechanisms of arrhythmias for accessory connections, atrial fibrillation, atrial reentry tachycardia, nodal reentry tachycardia, focal or automatic atrial tachycardia, and ventricular tachycardia. The surgical and transcatheter possibilities are numerous, and the congenital heart surgeon should have a comprehensive understanding of all arrhythmia types and potential methods of ablation. The purpose of this article is to introduce resternotomy techniques for safe mediastinal reentry and to review operative techniques of arrhythmia surgery in association with congenital heart disease.

Radiofrequency ablation for treatment of atrial fibrillation

INTRODUCTION

Atrial Fibrillation (AF) is the most common cardiac arrhythmia which represents a major public health problem. The main purpose of this research is to evaluate the Radiofrequency (RF) ablation effects in the patients with chronic AF scheduled for cardiac surgery because of different heart diseases.

METHODS

The descriptive and prospective study was conducted on 60 patients with AF scheduled for surgery along with RF ablation. The data were collected by questionnaire and included: patients' age, sex, NYHA class, operation type, past medical history, type and cause of valvular heart disease, preoperative ECG (electrocardiogram), duration of surgery, clamping time, cardiopulmonary bypass, and RF ablation time. RF ablation was followed by the main operation. The follow up examination, ECG, and echocardiography were performed 3 and 6 months after operation.

RESULTS

The mean age of patients was 48±10 years (18-71 years). Forty one patients had permanent AF and 19 had the persistent AF. The left ventricular ejection fraction was 48.27±9.75 percent before operation, and reached to 56.27±7.87 percent after the surgery (P<0.001). The mean NYHA class before the surgery was 2.83±0.68 which decreased to 1.34±0.46 6 months after the surgery with RF ablation (P<0.001). One patient (1.6%) died after surgery. Complete relief and freedom from AF recurrence was observed in 70% of patients in the mean follow up in 7 months after the surgery. The sinus rhythm with efficient atrial contraction was established in 100% of discharged patients.

CONCLUSION

RF ablation is an effective procedure to cure atrial fibrillation in patients undergoing cardiac surgeries.

Ablation of atrial fibrillation: comparison of catheter-based techniques and the Cox-Maze III operation

BACKGROUND

Catheter-based ablation is often recommended for treatment of atrial fibrillation (AF), but there are no data that directly compare late results to those of the Cox-Maze procedure. Although catheter ablation avoids operation, lack of reliable transmurality may reduce effectiveness. We compared clinical outcomes of the cut-and-sew Cox-Maze procedure with catheter ablation.

METHODS

Between January 1993 and October 2007, 97 patients aged 25 to 80 years underwent an isolated cut-and-sew Cox-Maze procedure. Patients were matched 1:2 according to age, sex, and AF type, with 194 patients undergoing catheter-based ablation for lone AF.

RESULTS

At last follow-up, 82% of patients who underwent the Cox-Maze procedure were free of AF and had stopped taking antiarrhythmic medications compared with 55% of patients who underwent ablation (p<0.001). When analyzed as a time-related event, freedom from recurrent AF was 87% 5 years after the Cox-Maze procedure compared with 28% after catheter ablation (p<0.001). Late warfarin anticoagulation was required in 12% of patients who underwent the Cox-Maze procedure compared with 55% of patients who underwent ablation (p<0.001), and use of antiarrhythmic medications during follow-up was significantly higher in patients who underwent ablation (68% versus 15%, p<0.001). Forty-one patients (24%) required repeated ablation procedure and 9 required a second repeated ablation.

CONCLUSIONS

Compared with catheter-based ablation, the Cox-Maze procedure results in greater freedom from AF and less medical treatment with antiarrhythmic drugs and warfarin anticoagulation during follow-up.

Atrial fibrillation: cure or treat?

Controversies exist with regard to the optimal management of atrial fibrillation (AF). Restoration and maintenance of sinus rhythm is a desirable goal in AF patients because the prevention of recurrences may improve cardiac function, relieve symptoms and should reduce the likelihood of adverse events. Pharmacological therapy for AF has been disappointing with unacceptable rates of AF recurrence and other proarrhythmic sequelae. Recent studies suggested that potential benefit of sinus-rhythm maintenance with respect to mortality may have been neutralized by harmful effects of currently available antiarrhythmic therapies. Because of the inefficacy and dangers with nonablative therapies currently available for maintaining sinus rhythm, alternative treatments are certainly desirable. Curative treatment of atrial fibrillation with catheter ablation is now a legitimate option for a large number of patients. In several studies AF ablation has consistently been demonstrated to be superior to antiarrhythmic medications for the maintenance of sinus rhythm. Nevertheless, many aspects of the therapy are still controversial and large-scale prospective studies are needed to confirm the efficacy and safety of this approach.

Three-dimensional spectral map of atrial fibrillation by a 64-channel magnetocardiogram

We verified the significance of 3-dimensional (3D) spectral mapping during atrial fibrillation (AFIB) using a 64-channel magnetocardiogram (MCG). The study consisted of 16 patients with valvular heart disease who had chronic AFIB. All 16 patients had surgical pulmonary vein (PV) isolation followed by valvular repair. We performed spectral mapping by fast Fourier transform analysis in nonaveraged 64-channel MCG data. The 3D spectral map was superimposed on a 3D heart polygon. At 1 year after surgical PV isolation for AFIB, followed by valve repair, 7 patients had restoration to sinus rhythm, and 9 patients remained in persistent AFIB. The preoperative mean 3D frequency of AFIB was 6.1 +/- 0.9 Hz in patients with restored sinus rhythm and 7.2 +/- 0.7 Hz in patients with sustained AFIB after PV isolation (P = .02). In addition, the preoperative 3D spectrum was distributed on the right side of the heart in patients with persistent AFIB. In conclusion, 3D spectral mapping using 64-channel MCG may represent a meaningful noninvasive strategy for patients with AFIB who receive an interventional procedure.

Surgical ablation of atrial fibrillation: the Columbia Presbyterian experience

BACKGROUND

The Maze III procedure is an effective surgical treatment for atrial fibrillation (AF). However, it is not widely applied due to its complexity, increased operative times, and the risk of bleeding. Various energy sources have been introduced to simplify the traditional "cut and sew" approach.

METHODS

This study involves patients undergoing surgical atrial fibrillation ablation (SAFA) at a single institution from 1999 to 2005. Type of concomitant procedures, preoperative clinical characteristics, and chronicity of AF were evaluated in overall patient population. Parameters including surgical approach, lesion pattern, and energy source used were collected intraoperatively. Clinical outcomes examined were postoperative rhythm success, stroke, early mortality, and long-term survival.

RESULTS

Three hundred thirty-nine patients were identified. Three hundred twenty-eight (96.8%) patients had associated cardiac disease and underwent concomitant procedures; 75.8% of patients had persistent AF. Energy sources used were microwave (49.8%), radiofrequency (42.2%), and laser (8.0%). In 41.9% of cases a pulmonary vein encircling lesion was the only lesion created. Combination lesion sets were performed in the remaining cases. Rhythm success rates at 3, 6, 12, and 24 months were 74.1%, 68.2%, 74.5%, and 71.1%, respectively. Patients who underwent surgical removal of left atrial appendage by means of stapling or simple excision had no early postoperative stroke. Early mortality was 4.9%. Postoperative survival rates at 1, 3, and 5 years were 89.6%, 83.1%, and 78.0%.

CONCLUSIONS

Surgical ablation of atrial fibrillation is a safe and effective procedure in restoring sinus rhythm with excellent postoperative survival rates. Further advancements in the field will eventually result in minimally invasive procedures with higher success rates.

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.

Ten-year Experience With the Cox-Maze Procedure for Atrial Fibrillation: How Do We Define Success?

BACKGROUND

The Cox-maze procedure is the standard to which other surgical treatments of atrial fibrillation (AF) are compared. However, evaluation of new devices and lesion sets is difficult because of variable methods of reporting success in eliminating AF. We analyzed 10-year outcome with the "cut and sew" Cox-maze procedure and present rhythm at last follow-up, interval contact, and actuarial AF freedom.

METHODS

Between March 1993 and December 2002, 335 patients (211 men) underwent the Cox-maze procedure (age, 22 to 83 years; median, 62 years). Atrial fibrillation was chronic (CAF) in 175 patients and paroxysmal (PAF) in 160.

RESULTS

Concomitant mitral valve procedures were performed in 59%, coronary artery bypass grafting in 19%, and tricuspid valve repairs in 7%. Early mortality was 0.9%. During hospitalization, transient AF occurred in 29% of patients and 10% required implantation of a new permanent pacemaker (PPM). Dismissal electrocardiogram was normal sinus rhythm in 64%, junctional rhythm in 18%, AF in 11%, and PPM in 7%. At last follow-up (mean 42 +/- 6 months), 88% of patients were free of AF. However, when analyzed by the Kaplan-Meier method, freedom from AF was lower for patients with preoperative lone PAF (5 years, 90%; 10 years, 64%), preoperative lone CAF (5 years, 80%; 10 years, 62%), and patients undergoing combined maze-mitral valve surgery (5 years, 68%; 10 years, 41%).

CONCLUSIONS

Ten-year results with the standard Cox-maze procedure confirm high effectiveness, but reporting methods should be standardized to account for patients who have transient atrial arrhythmias during long-term follow-up.

Combined Atrial Septal Defect Surgical Closure and Irrigated Radiofrequency Ablation in Adult Patients

BACKGROUND

Atrial arrhythmias are relatively common among patients over 40 years old with atrial septal defect (ASD) and are a precipitating cause of heart failure. Surgical closure of the ASD in these patients is feasible and is associated with a low mortality rate and a beneficial effect on the clinical status; however the occurrence of atrial arrhythmia does not decrease after surgery. We present the results of our preliminary experience with surgical ASD closure combined with intraoperative irrigated radiofrequency (IRF) ablation in adult patients.

METHODS

During a 26-month period between September 2002 and December 2004, 15 patients more than 40 years old with ASD and atrial arrhythmia underwent elective surgical closure of the defect and intraoperative IRF ablation. All patients had supraventricular arrhythmias: 8 had permanent atrial fibrillation, whereas 7 had previous episodes of atrial flutter or intra-atrial reentry tachycardia. The biatrial approach (Cox-Maze III procedure) was used in 7 patients and a right-sided Maze procedure (ablation lines on the right atrium only) was carried out in the remaining 8 patients.

RESULTS

All patients survived the procedure. Fourteen patients left the operating room in sinus rhythm and 1 had a pacemaker implanted. There were no complications resulting from the IRF ablation. All 15 patients survived over the average follow-up period of 24 months. Thirteen patients were still in sinus rhythm, 1 had pacemaker rhythm, and only 1 (1 of 15; 6.5%) suffered a recurrence of atrial fibrillation 3 months after the procedure.

CONCLUSIONS

We suggest adding intraoperative IRF ablation during surgical closure of an ASD in all adult ASD patients with arrhythmias. The IRF ablation is easy to perform, safe, and effective.

Surgical ablation as treatment for the elimination of atrial fibrillation: A meta-analysis

OBJECTIVE

The maze procedure is recognized as the most effective surgical treatment of atrial fibrillation. In the last few years, new surgical ablation techniques were developed involving the left atrium only and modifications of the maze procedure in ablating both atria. For this study, we evaluated the evidence regarding the effectiveness of the surgical ablation procedures (biatrial and left atrial) in reducing postoperative atrial fibrillation and subsequent survival.

METHODS

MEDLINE was searched for English-language studies using the terms "maze," "atrial fibrillation," and "surgical treatment" for 1995 through August 2005. Primary outcomes of interest were postoperative survival and postoperative freedom from atrial fibrillation. Survival data were collected at 1-, 2-, and 3-year intervals. Freedom from atrial fibrillation was collected at 3 months and at 1-, 2-, and 3-year intervals.

RESULTS

Sixty-nine studies were included in this analysis. Five thousand eight hundred eighty-five total patients were involved. Patients undergoing surgical ablation (range, 90.4-85.4) demonstrated significantly greater rates of freedom from atrial fibrillation compared with those seen in control patients (range, 47.2-60.9). Survival rates among patients with biatrial surgical procedures (range, 94.9-92.8) were similar to those who had left atrial procedures only (range, 93.9-89.4). However, patients undergoing biatrial ablation (range, 92.0-87.1 vs 86.1-73.4) demonstrated superior freedom from atrial fibrillation at all time points.

CONCLUSION

Biatrial ablation surgical procedures were more effective in controlling atrial fibrillation than procedures confined to the left atrium. To encourage the use of future meta-analysis within the surgical literature, we suggest the more frequent reporting of either through Kaplan-Meier survival analyses and the reporting of rates for specific time intervals.

An Innovative Balloon-Type Surgical Device for Atrial Fibrillation

BACKGROUND

The maze procedure and its modifications are the surgical treatment for atrial fibrillation. In an attempt to achieve a less invasive operation, we developed a balloon-type device for electric pulmonary vein isolation and evaluated its effectiveness macroscopically and microscopically.

METHODS

We created a left heart system model from 20 pigs. Based on a mold, a balloon was made with silicone resin. When this balloon was inflated, all pulmonary vein orifices were pressed and ablated by probes using radiofrequency and cryotherm as energy sources. Macroscopic and microscopic evaluations were performed.

RESULTS

Complete circular ablation by radiofrequency was confirmed in 2 of 3 veins. The transmural denaturation was pathologically confirmed in all areas ablated at 80 degrees for 2 minutes. The complete circular ablation line and the transmural denaturation were macroscopically and microscopically confirmed after cryoablation at -100 degrees for 2 minutes using liquid nitrogen.

CONCLUSIONS

This study proved that the balloon is effective in simplifying pulmonary vein isolation and has potential to become an instrument that contributes to less invasive operations in the near future.

Construction of a Three-dimensional Outline of the Heart and Conduction Pathway by Means of a 64-channel Magnetocardiogram in Patients with Atrial Flutter and Fibrillation

BACKGROUND

Magnetocardiography (MCG) has the potential for collecting three-dimensional (3D) intracardiac electric information, because the magnetic field is unaffected by the shape of the lungs and torso. In the present study, we report on the generation of a 3D heart outline and conduction pathway by means of a current density map using a 64-channel SQUID system, and an evaluation of its significance in patients with atrial flutter (AFL) and atrial fibrillation (AFIB).

METHODS

The subjects consisted of 20 healthy volunteers, and 3 patients with AFL and 4 patients with AFIB. A 64-channel MCG was recorded after digitization at 500 Hz, and a 3D current density was reconstructed from the magnetic fields using a space filter in conjunction with the minimum normalization method of Tikhonov. A 3D heart outline was generated from the integrated current density by the space filter. The conduction pathway was superimposed on a heart outline generated by a magnetic field. The heart outline was verified by the silhouette on the magnetic resonance (MR) images. An MCG was recorded pre- and post interventional therapy, and therapeutic efficacy was evaluated.

RESULTS

The 3D heart outline of the atrium and ventricle corresponded to the silhouette of the right atrium and left ventricle, respectively, on an MR image. The serial conduction pathway of the QRS segment superimposed on the 3D heart outline map demonstrated the conduction pattern generated within the heart. The MCG revealed a counter-clockwise rotation in patients with AFL, and random micro-reentry in the case of AFIB. After interventional therapy, restoration of the sinus rhythm was verified in patients with both AFL and AFIB.

CONCLUSIONS

A 64-channel MCG was used to evaluate the 3D heart outline and conduction pathway in patients with AFL and AFIB without the need for MR images. Condensed Abstract A 64-channel MCG was used to evaluate the 3D heart out line and conduction pathway in patients with AFL and AFIB.

Future Directions

The recommendations put forth in these guidelines for the management and prevention of atrial fibrillation (AF) after cardiac surgery are based on information available at the time of the final literature review. As a result, they will become dated as new information and results from new trials becomes available. The maintenance of clinical practice guidelines is an evolving process requiring the alteration of recommendations over time, based on new studies and new results. The current set of guidelines attempts not only to identify new therapeutic options for AF after cardiac surgery but also to develop a strategy to indicate how and when to update the guidelines themselves.

Long-term follow-up after the mini-maze procedure

BACKGROUND

Atrial fibrillation (AF) is associated with significant morbidity and mortality. The standard to treat AF surgically is the Cox maze III procedure but owing to its complexity it is not performed on a regular basis. Meanwhile several maze variants have been developed but their long-term results are still not well known.

METHODS

From November 1995 until May 2002 a mini-maze procedure was performed upon 77 patients aged 64 +/- 8.7 years with chronic symptomatic AF. Electrophysiological evaluation, magnetic resonance imaging, echocardiography and electrocardiographic evaluations were performed after 3 and 12 months. After a mean follow-up of 50 +/- 2.6 months a standard questionnaire was sent to all patients.

RESULTS

Early and late mortality was 1.2% and 9.3% respectively. Actuarial survival was 91%, 90%, and 87% after 1, 3, and 5 years respectively. Left bundle branch block was an independent risk factor for late death (p = 0.02). Patients who were in sinus rhythm at follow-up had significantly better survival rate as compared with the patients still in AF. Seventy-one percent of patients were in sinus rhythm or paced by an atrial pacemaker. Predictors for restoration of sinus rhythm were absence of preoperative mitral insufficiency (p = 0.03) and larger left atrium (p = 0.04). The presence of preoperative tricuspid insufficiency (p = 0.03) and larger right atrium (p = 0.017) were predictors for postoperative pacemaker implantation.

CONCLUSIONS

The mini-maze procedure can be carried out with satisfactory early and long-term results regarding mortality and restoration of sinus rhythm. Prophylactic implantation of biventricular pacemakers in patients with left bundle branch block may decrease late mortality. Every effort should be done to cure AF as it affects long-term survival.

A New Solution for an Old Problem? Effects of a Nurse-led, Multidisciplinary, Home-based Intervention on Readmission and Mortality in Patients With Chronic Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF), the most common chronic cardiac dysrhythmia, is an important cause of cardiovascular morbidity and mortality. However, there is a paucity of studies examining the potential benefits of optimizing the postdischarge management of patients with chronic AF.

RESEARCH OBJECTIVE

To examine the effects of a nurse-led, multidisciplinary, home-based intervention (HBI) on the pattern of recurrent hospitalization and mortality in patients with chronic AF in the presence and absence of chronic heart failure (HF). PATIENT COHORT AND METHODS: Health outcomes in a total of 152 hospitalized patients (53% male) with a mean age of 73 +/- 9 years and a diagnosis of chronic AF who were randomly allocated to either HBI (n = 68) or usual postdischarge care (UC: n = 84) were examined. Specifically, the pattern of unplanned hospitalization and all-cause mortality during 5-year follow-up were compared on the basis of the presence (n = 87) and absence (n = 65) of HF at baseline.

RESULTS

Patients with concurrent HF exposed to HBI (n = 37) had fewer readmissions (2.9 vs 3.4/patient), days of associated hospital stay (22.7 vs 30.5: P = NS) and fatal events (51 % vs 66%) relative to UC (n = 50): P = NS for all comparisons. In the absence of HF, morbidity and mortality rates were significantly lower but still substantial during 5-year follow-up. In these patients, HBI was associated with a trend towards prolonged event-free survival (adjusted RR = 0.70; P = .12) and fewer fatal events (29% vs 53%, adjusted RR = 0.49; P = .08). HBI patients (n = 31) also had fewer readmissions (2.1 vs 2.6/patient) and days of associated hospital stay (16.3 vs 20.3/patient), although this did not reach statistical significance. On the basis of these data, it was calculated that a randomized study of an AF-specific HBI would require 250 patients followed for a median of 3 years to detect a 25% variation in recurrent hospital stay relative to UC.

CONCLUSIONS

These unique data provide sufficient preliminary evidence to support the hypothesis that the benefits of HBI in relation to the management of HF may extend to "high risk" patients with chronic AF in whom morbidity and mortality rates are also unacceptably high. Further, appropriately powered studies are required to confirm these benefits.

Cox/Maze III operation versus radiofrequency ablation for the surgical treatment of atrial fibrillation: a comparative study

BACKGROUND

The purpose of this study was to evaluate the efficacy of radiofrequency (RF) ablation in the treatment of atrial fibrillation, by comparatively analyzing the outcomes of the patients who underwent RF ablation with those of patients who underwent Cox/Maze III surgery.

METHODS

Between April 1995 and June 2002, 70 patients underwent surgery for atrial fibrillation and open-heart surgery at the Department of Cardiovascular Surgery of the University of Bologna: 30 patients underwent the surgical Cox/Maze III procedure (group 1), and 40 patients underwent the RF ablation according to the Maze III configuration at least on the left atrium (group 2). There were 14 males and 56 females, with a mean age of 61.5 +/- 12.5 years (range 22 to 80 years old).

RESULTS

Groups 1 and 2 did not differ in terms of baseline characteristics. The perioperative mortality rate was not significantly different between the two groups (6.6% in group 1 vs 7.5% in group 2). The overall cumulative rates of sinus rhythm were 68.9% in group 1 and 88.5% in group 2 (not statistically significant). Biatrial contraction was assessed by transthoracic echocardiography in 70.4% of the patients in group 1 and 76.5% of the patients in group 2 (p = 0.65).

CONCLUSIONS

The RF ablation procedure offers as good results as the Cox/Maze III operation, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent open heart surgery; it is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements.

Surgery for atrial fibrillation using radiofrequency catheter ablation

OBJECTIVE

We present the results obtained in 40 patients with chronic atrial fibrillation using direct intraoperative radiofrequency to perform atrial fibrillation surgery.

METHODS

Between April 2001 and June 2002, 40 patients underwent surgery for atrial fibrillation using radiofrequency ablation and cardiac surgery at the Department of Cardiovascular Surgery of the University of Bologna [corrected]. There were 8 men and 32 women with a mean age of 62 +/- 11.6 years (range: 20 to 80 years).

RESULTS

Concomitant surgical procedures were: mitral valve replacement (n = 13), mitral valve replacement plus tricuspid valvuloplasty (n = 11), combined mitral and aortic valve replacement (n = 8), and combined mitral and aortic valve replacement plus tricuspid valvuloplasty (n = 5). Moreover, 1 patient underwent tricuspid valvuloplasty plus atrial septal defect repair, another required aortic valve replacement plus coronary artery bypass graft, and a third underwent aortic valve replacement. After the mean follow-up time of 16.5 +/- 2.5 months survival was 92.8% and the overall cumulative rate of sinus rhythm was 88.5%.

CONCLUSIONS

We conclude that the radiofrequency ablation procedure is a safe and effective means of curing atrial fibrillation with negligible technical and time requirements, allowing recovery of the sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who underwent cardiac surgery (88.5% of our study population).

Validity and reliability of the NYHA classes for measuring research outcomes in patients with cardiac disease

The New York Heart Association (NYHA) functional classification system was developed to help physicians in clinical practice evaluate the effect of cardiac symptoms on a patient's daily activities. Over time, the role of the NYHA classification system has expanded, and it is now frequently used in clinical research. This review of the literature was undertaken to explore whether the NYHA classes have sufficient validity and reliability to serve as a functional outcome measure in research studies. After exploring its strengths and limitations, we conclude that the NYHA classes are a valid measure of functional status, a concept that is distinct from functional capacity and functional performance. The reproducibility of the NYHA functional classification system has not been established in the literature. Researchers are urged to report the methods for determining NYHA class, the training of raters, and the intra-rater or inter-rater reliability in studies that have multiple raters or measurements. Until the reliability of the NYHA functional classification system is determined, it is prudent to refrain from using the NYHA classes as the sole outcome measure of change in function in research studies of cardiac patients.

Left atrial versus bi-atrial Maze operation using intraoperatively cooled-tip radiofrequency ablation in patients undergoing open-heart surgery: safety and efficacy

OBJECTIVES

We sought to determine whether limited left atrial Maze surgery encircling each of the pulmonary veins, using cooled-tip radiofrequency (RF) ablation, is as effective as the bi-atrial approach?

BACKGROUND

The original Cox/Maze operation effectively restores sinus rhythm (SR) in patients with atrial fibrillation (AF). Ablation procedures aimed at eliminating pulmonary vein foci have produced promising short-term success.

METHODS

This was a prospective analysis of patients with chronic AF undergoing open-heart surgery in addition to the Maze operation, using intraoperatively cooled-tip RF ablation either in the left atrium alone (group A) or in both atria (group B).

RESULTS

Patients in group A (n = 21) and group B (n = 49) did not differ in terms of their baseline characteristics. Concomitant open-heart surgical procedures included mitral valve replacement (3 vs. 25), mitral valve plasty (0 vs. 2), mitral and aortic valve replacement (1 vs. 1), aortic valve replacement (4 vs. 6) and coronary artery bypass grafting (13 vs. 15) in groups A and B, respectively. Follow-up ranged from 1 to 50 months. The overall cumulative rates of SR were 82% in group A and 75% in group B, without a statistically significant difference (p = 0.571). Bi-atrial contraction was revealed in 92.3% of patients in SR in group A and in 79.2% in group B. The cumulative survival rates were 90.5% in group A and 77.9% in group B (p = 0.880).

CONCLUSIONS

A left or bi-atrial Maze operation using intraoperatively cooled-tip RF ablation can safely be combined with open-heart surgery. A left atrial Maze procedure seems to be as effective as the bi-atrial procedure and restores SR in 82% of patients.

Survival and sinus rhythm maintenance after modified Cox/maze procedure and mitral valve operation in patients with chronic atrial fibrillation

OBJECTIVE

Sinus rhythm gained after the Cox/maze procedure concomitant with mitral valve operation has demonstrated long-term attrition during the follow-up, no information exists on whether the type of mitral valve operation--(repair vs. replacement)--affects this sinus rhythm maintenance rate. We retrospectively studied patients undergoing concomitant mitral valve operation and Cox/maze procedure to answer this question.

METHODS

Between April 1993 and August 1995, 87 consecutive patients--35 men and 52 women (mean age: 59.3 years)--with chronic atrial fibrillation and mitral valve disease underwent the modified Cox/maze procedure and concomitant mitral valve operation, with 56 having mitral valve repair (repair group) and 31 mitral valve replacement (replacement group). Patients were followed up and changes in rhythm studied retrospectively.

RESULTS

Follow-up for a mean 51.3 +/- 11.6 months was completed in 82 of 83 long-term survivors (99%). Repair group surgery survival was 98.1 +/- 1.9% at 1 year and 94.2 +/- 3.2% at 5 based on the Kaplan-Meier method. Replacement group surgery survival was 85.7 +/- 5.9% at 1 year and 82.9 +/- 6.4% at 5. Probability in sinus rhythm maintenance for the repair group at 1 year was 88.6 +/- 5.4% and at 5 years was 67.6 +/- 9.1%. Probability in sinus rhythm maintenance for the replacement group at 1 year was 95.7 +/- 4.3% and at 5 years was 65.0 +/- 11.1%.

CONCLUSIONS

Medium-term results after the Cox/maze III procedure concomitant with mitral valve operation are good. The attrition of sinus rhythm maintenance appears similar by the completion of 5-year follow-up.