Predictors and risk of pacemaker implantation after the Cox-maze IV procedure

Epicardial and endocardial surgical ablation of atrial fibrillation: outcomes from CASE-AF Registry

OBJECTIVES

The German CArdioSurgEry Atrial Fibrillation Registry is a prospective, multicentric registry analysing outcomes of patients undergoing surgical ablation for atrial fibrillation as concomitant or stand-alone procedures. This data sub-analysis of the German CArdioSurgEry Atrial Fibrillation Registry aims to describe the in-hospital and 1-year outcomes after concomitant surgical ablation, based on 2 different ablation approaches, epicardial and endocardial surgical ablation.

METHODS

Between January 2017 and April 2020, 17 German cardiosurgical units enrolled 763 consecutive patients after concomitant surgical ablation. In the epicardial group, 413 patients (54.1%), 95.6% underwent radiofrequency ablation. In the endocardial group, 350 patients (45.9%), 97.7% underwent cryoablation. 61.5% of patients in the epicardial group and 49.4% of patients in the endocardial group presenting with paroxysmal atrial fibrillation. Pre-, intra- and post-operative data were gathered.

RESULTS

Upon discharge, 32.3% (n = 109) of patients after epicardial surgical ablation and 24.0% (n = 72) of patients after endocardial surgical ablation showed recurrence of atrial fibrillation. The in-hospital mortality rate was low, 2.2% (n = 9) in the epicardial and 2.9% (n = 10) in the endocardial group. The overall 1-year procedural success rate was 58.4% in the epicardial and 62.2% in the endocardial group, with significant symptom improvement in both groups. The 1-year mortality rate was 7.7% (n = 30) in epicardial and 5.0% (n = 17) in the endocardial group.

CONCLUSIONS

Concomitant surgical ablation is safe and effective with significant improvement in patient symptoms and freedom from atrial fibrillation. Adequate cardiac rhythm monitoring should be prioritized for higher quality data acquisition.

Concomitant ablation of atrial fibrillation: New pacemakers and early rhythm recovery

OBJECTIVE

New permanent pacemaker (PPM) implantation after concomitant atrial fibrillation (AF) ablation has been associated with surgical ablation (SA). We sought to determine factors for PPM use as well as early rhythm recovery.

METHODS

From 2004 through 2019, 6135 patients underwent valve surgery and were grouped: No AF (n = 4584), AF no SA (n = 346), and AF with SA (n = 1205) to evaluate predischarge PPM and 3-month rhythm recovery (intrinsic heart rate >40 beats per minute).

RESULTS

Overall, 282 (4.6%) patients required a predischarge PPM: atrioventricular node dysfunction in 75.3%, sick sinus syndrome in 19.1%, both (5%), and indeterminate (0.7%). Patients with AF had more PPMs: AF with SA (7.9%) versus AF no SA (6.9%) versus No AF (3.6%) (P < .001). For patients with AF, PPM rates were not significantly higher for ablation patients (7.6% SA vs 6.9% AF no SA; P = .56). There were differences in PPM by SA lesion set (biatrial 12.8%; left atrial only 6.1%; pulmonary vein isolation 3.0%; P < .001). Among patients with AF treated with 3-month PPM follow-up, rhythm recovery was common (35 out of 62 [56.5%]) and did not differ by lesion set. Rhythm recovery was seen in 63 out of 141 (44.7%) in the atrioventricular node dysfunction group versus 24 out of 35 (68.6%) in the sick sinus syndrome group (P = .011). In propensity score-matched groups, late survival was similar (P = .63) for new PPM patients.

CONCLUSIONS

Avoiding conduction system trauma and delaying implantation reduces the need for postoperative PPM. Rhythm recovery within 3 months is frequent, especially for patients with sick sinus syndrome. A conservative approach to the implantation of a new PPMs is warranted.

Incidence of and risk factors for pacemaker implantation after the modified Cryo-Maze procedure for atrial fibrillation

OBJECTIVES

The Maze procedure is a well-established treatment for atrial fibrillation. However, it is sometimes associated with bradycardia requiring pacemaker implantation. We assessed the rates of in-hospital and late-onset pacemaker implantation after the modified Cryo-Maze procedure and explored the risk factors for pacemaker implantation.

METHODS

This study enrolled a series of 751 patients who underwent the modified Cryo-Maze procedure at our institution between 2001 and 2020. Multivariable Fine-Gray regression was used to analyze the risk factors for late-onset pacemaker implantation.

RESULTS

Twelve patients (1.6%) underwent in-hospital pacemaker implantation, and 55 patients (7.3%) underwent late-onset pacemaker implantation during a median follow-up of 4.5 years (interquartile range, 1.4-10.0). The most common primary indication for pacemaker implantation was sick sinus syndrome (56 patients [7.5%]), followed by complete atrioventricular block (11 patients [1.5%]). The cumulative incidence of late-onset pacemaker implantation with death as a competing risk was 2.8% at 1 year, 7.7% at 5 years, and 10.8% at 10 years. Risk factors for late-onset pacemaker implantation included a longer preoperative atrial fibrillation duration (hazard ratio, 1.14; P < .001) and an older age (hazard ratio, 1.05; P = .001). The mortality, cumulative incidence of cerebrovascular accidents, and rate of atrial fibrillation recurrence were not significantly different between patients with and without pacemaker implantation.

CONCLUSIONS

Longer preoperative atrial fibrillation duration and older age are risk factors for late-onset pacemaker implantation after the modified Cryo-Maze procedure. However, the incidence of pacemaker implantation is not associated with increased morbidity or atrial fibrillation recurrence.

Multicenter randomized study evaluating the outcome of ganglionated plexi ablation in maze procedure

OBJECTIVE

The benefit of adding ganglionated plexi ablation to the maze procedure remains controversial. This study aims to compare the outcomes of the maze procedure with and without ganglionated plexi ablation.

METHODS

This multicenter randomized study included 74 patients with atrial fibrillation associated with structural heart disease. Patients were randomly allocated to the ganglionated plexi ablation group (maze with ganglionated plexi ablation) or the maze group (maze without ganglionated plexi ablation). The lesion sets in the maze procedure were unified in all patients. High-frequency stimulation was applied to clearly identify and perform ganglionated plexi ablation. Patients were followed up for at least 6 months. The primary endpoint was a recurrence of atrial fibrillation.

RESULTS

The intention-to-treat analysis included 69 patients (34 in the ganglionated plexi ablation group and 35 in the maze group). No surgical mortality was observed in either group. After a mean follow-up period of 16.3 ± 7.9 months, 86.8% of patients in the ganglionated plexi ablation group and 91.4% of those in the maze group did not experience atrial fibrillation recurrence. Kaplan-Meier atrial fibrillation-free curves showed no significant difference between the two groups (P = .685). Cox proportional hazards regression analysis indicated that left atrial dimension was the only risk factor for atrial fibrillation recurrence (hazard ratio: 1.106, 95% confidence interval 1.017-1.024, P = .019).

CONCLUSION

The addition of ganglionated plexi ablation to the maze procedure does not improve early outcome when treating atrial fibrillation associated with structural heart disease.

Atrial fibrillation management during septal myectomy for hypertrophic cardiomyopathy: A systematic review

INTRODUCTION

Atrial fibrillation is common in patients with hypertrophic cardiomyopathy, and significantly impacts mortality and morbidity. In patients with atrial fibrillation undergoing septal myectomy, concomitant surgery for atrial fibrillation may improve outcomes.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies reporting the outcomes of combined septal myectomy and atrial fibrillation surgery were included.

RESULTS

A total of 10 observational studies were identified, including 644 patients. Most patients had paroxysmal atrial fibrillation. The proportion with prior unsuccessful ablation ranged from 0 to 19%, and preoperative left atrial diameter ranged from 44 ± 17 to 52 ± 8 mm. Cox-Maze IV (n = 311) was the most common technique used, followed by pulmonary vein isolation (n = 222) and Cox-Maze III (n = 98). Patients with persistent or longstanding atrial fibrillation more frequently received Cox-Maze III/IV. Ranges of early postoperative outcomes included: mortality 0 to 7%, recurrence of atrial tachyarrhythmias 4.4 to 48%, cerebrovascular events 0 to 1.5%, and pacemaker insertion 3 to 21%. Long-term data was limited. Freedom from atrial tachyarrhythmias at 1 year ranged from 74% to 96%, and at 5 years from 52% to 100%. Preoperative predictors of late atrial tachyarrhythmia recurrence included left atrial diameter >45 mm, persistent or longstanding preoperative atrial fibrillation and longer atrial fibrillation duration.

CONCLUSION

In patients with atrial fibrillation undergoing septal myectomy, the addition of ablation surgery adds low overall risk to the procedure, and likely reduces the risk of recurrent atrial fibrillation in the long term. Future randomised studies comparing septal myectomy with or without concomitant AF ablation are needed.

The Impact of the Cox-Maze Technique on Freedom From Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia observed with concomitant cardiac surgery. Surgical options include a cut-and-sew technique Maze (CAS) and a cryoablation/bipolar technique Maze (CB). There are limited data comparing the long-term outcomes of these 2 techniques.

METHODS

All patients who underwent either CAS or CB Maze between 2011 and 2018 were included in the study. Chi-square test and Fisher's exact test or Student's t test were used to compare differences between baseline characteristics. Kaplan-Meier survival curves were generated for each group. Cumulative incidence functions were generated for AF recurrence and Fine-Gray competing-risk regression was used to determine predictors for AF recurrence.

RESULTS

A total of 482 patients underwent open surgical ablation. Of those, 287 had CAS and 198 had CB. All procedures were concomitant with cardiac surgery. There was similar long-term mortality between the CAS and CB cohorts (22.3% vs 17.4%; log-rank P = .91). There was no difference in pacemaker implantation (11.1% vs 11.3%; P = .813) or long-term freedom from AF recurrence (73.3% vs 78.2%; P = .294). On Fine-Gray competing-risk regression, New York Heart Association functional class IV (hazard ratio [HR], 2.07; P = .03), concomitant aortic valve replacement (HR, 3.02; P = .01), and concomitant CABG + valve (HR, 2.36; P = .02) were significant independent predictors for AF recurrence; Maze type was not a predictor.

CONCLUSIONS

These data indicate no difference between the CAS vs CB with respect to freedom from long-term AF. Both techniques may be appropriate based on surgeon experience and patient characteristics.

Inter/Intra-Atrial Dissociation in Patients With Maze Procedure and Its Clinical Implications: Pseudo-Block and Pseudo-Ventricular Tachycardia

Background

Severe conduction delay and inter/intra‐atrial dissociation may occur in patients who undergo an extensive catheter ablation or a maze procedure for atrial tachyarrhythmia. We report a series of patients with inter/intra‐atrial dissociation that mimicked complete atrioventricular block or ventricular tachycardia.

Methods and Results

We retrospectively reviewed the medical records of 7 patients who were referred for the evaluation of atrioventricular block (patients 1–6) or ventricular tachycardia (patient 7) that occurred after biatrial maze procedure and valvular surgery. During the electrophysiologic study, slow atrial or junctional escape rhythm dissociated from isolated atrial activity mimicked complete atrioventricular blocks. Intra‐atrial dissociation of the right atrium or left atrium was observed. Atrioventricular nodal conduction from the nondissociated atrium to the ventricle was preserved in all patients, while the conduction from the dissociated atrium was blocked. In patient 7, the pacing of the ventricle by tracking of atrial tachycardia from the nondissociated left atrium/coronary sinus mimicked ventricular tachycardia during pacemaker interrogation. A total of 5 patients received new permanent pacemaker implantations during the index hospitalization for the surgery (n=2) or as a deferred procedure (n=3) according to the treatment for sick sinus syndrome.

Conclusions

Pseudo‐atrioventricular block or pseudo‐ventricular tachycardia may occur because of inter/intra‐atrial dissociation after a maze procedure. The selection of patients for permanent pacemaker implantation should be determined based on the patient’s symptoms and the status of the escape pacemaker and not on the apparent atrioventricular block. Proper diagnosis is important to avoid unnecessary implantation of a pacemaker or a defibrillator.

Efficacy, safety, and long-term survival of concomitant valve replacement and bipolar radiofrequency ablation in patients aged 70 years and older: a comparative study with propensity score matching from a single-Centre

Background

Concomitant bipolar radiofrequency ablation and valve replacement in the elderly remains controversial. In the current study, we aimed to compare the outcomes of concomitant valve replacement and bipolar radiofrequency ablation with valve replacement alone in elderly patients with atrial fibrillation (AF).

Methods

This was a retrospective study of patients aged ≥70 years who underwent valve replacement with or without bipolar radiofrequency ablation in a single-centre between January 2006 and March 2015. The early postoperative results and long-term clinical outcomes were compared after propensity score matching.

Results

A total of 34 pairs of patients (73.94 ± 2.64 years old; 34 in the AF with ablation group and 34 in the AF without ablation group) were enrolled in the propensity score matching analysis. There were no significant differences between the two matched groups in terms of surgical mortality (5.88% vs. 2.94%, P = 0.555) and major postoperative morbidity. Kaplan–Meier analysis revealed a significantly better overall survival in the AF with ablation group compared to the AF without ablation group (P = 0.009). Cumulative incidence curves showed a lower incidence of cardiovascular death in the AF with ablation group (P = 0.025, Gray’s test). Patients in the AF with ablation group had a reduced incidence of stroke compared to patients in the AF with ablation group (P = 0.009, Gray’s test). The freedom from AF after 5 years was 58.0% in the AF with ablation group and 3.0% in the AF without ablation group.

Conclusions

The addition of bipolar radiofrequency ablation is a safe and feasible procedure, even in patients aged ≥70 years, with a better long-term survival and a reduced incidence of stroke compared to valve replacement alone. These findings suggest that bipolar radiofrequency ablation should always be considered as a concomitant procedure for elderly patients with AF who require cardiac surgery. However, a large-scale, prospective, multi-centre, randomized study should be performed in the future to fully validate our findings.

Pacemaker Implantation After Mitral Valve Surgery With Atrial Fibrillation Ablation

BACKGROUND

The incidence of permanent pacemaker (PPM) implantation is higher following mitral valve surgery (MVS) with ablation for atrial fibrillation (AF) compared with MVS alone.

OBJECTIVES

This study identified risk factors and outcomes associated with PPM implantation in a randomized trial that evaluated ablation for AF in patients who underwent MVS.

METHODS

A total of 243 patients with AF and without previous PPM placement were randomly assigned to MVS alone (n = 117) or MVS + ablation (n = 126). Patients in the ablation group were further randomized to pulmonary vein isolation (PVI) (n = 62) or the biatrial maze procedure (n = 64). Using competing risk models, this study examined the association among PPM and baseline and operative risk factors, and the effect of PPM on time to discharge, readmissions, and 1-year mortality.

RESULTS

Thirty-five patients received a PPM within the first year (14.4%), 29 (83%) underwent implantation during the index hospitalization. The frequency of PPM implantation was 7.7% in patients randomized to MVS alone, 16.1% in MVS + PVI, and 25% in MVS + biatrial maze. The indications for PPM were similar among patients who underwent MVS with and without ablation. Ablation, multivalve surgery, and New York Heart Association functional (NYHA) functional class III/IV were independent risk factors for PPM implantation. Length of stay post-surgery was longer in patients who received PPMs, but it was not significant when adjusted for randomization assignment (MVS vs. ablation) and age (hazard ratio [HR]: 0.81; 95% confidence interval [CI]: 0.61 to 1.08; p = 0.14). PPM implantation did not increase 30-day readmission rate (HR: 1.43; 95% CI: 0.50 to 4.05; p = 0.50). The need for PPM was associated with a higher risk of 1-year mortality (HR: 3.21; 95% CI: 1.01 to 10.17; p = 0.05) after adjustment for randomization assignment, age, and NYHA functional class.

CONCLUSIONS

AF ablation, multivalve surgery, and NYHA functional class III/IV were associated with an increased risk for permanent pacing. PPM implantation following MVS was associated with a significant increase in 1-year mortality. (Surgical Ablation Versus No Surgical Ablation for Patients With Atrial Fibrillation Undergoing Mitral Valve Surgery; NCT00903370).

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.

Comparison of two radiofrequency ablation devices for atrial fibrillation concomitant with a rheumatic valve procedure

BACKGROUND

Perioperative and median-term follow-up outcomes have not been compared among procedures using radiofrequency ablation devices for permanent atrial fibrillation with concomitant rheumatic valve disease. We compared the sinus rhythm restoration efficacy of "non-irrigation" ablation forceps and an "irrigation" ablation device in patients with rheumatic valve disease undergoing a modified Cox maze radiofrequency ablation procedure due to permanent atrial fibrillation.

METHODS

Data of 278 patients with rheumatic valve disease from the Cardiac Surgery Department of Sichuan Provincial People's Hospital who underwent the modified Cox maze radiofrequency ablation procedure between May 2013 and May 2017 were reviewed. The procedure was performed using "non-irrigation" ablation forceps (AtriCure, group A) in 149 patients and an "irrigation" ablation device (Medtronic, group M) in 129 patients. Data were collected prospectively, and follow-up was documented and compared between the groups.

RESULTS

The radiofrequency procedure duration was 28.9 ± 3.8 min in group A and 29.5 ± 2.8 min in group M (t = 1.623, P = 0.106). The predicted radiofrequency time to the left atrium diameter was (Ya = 0.4964 X + 0.3762, R = 0.74) in group A and (Ym = 0.4331 X + 4.3563, R = 0.8435) in group M. The sinus rhythm (SR) conversion rate without use of anti-arrhythmic drugs was similarly good in groups A and M, with 75.2%, 72.5%, and 70.5% vs. 73.6%, 71.3%, and 69.8% at discharge, 6 and 12 months, respectively (F = 0.084, F = 0.046, F = 0.046, P > 0.05, respectively).

CONCLUSION

Two types of radiofrequency ablation devices characteristic of "non-irrigation" and "irrigation" bipolar ablation forceps were similarly efficient at SR restoration.

The long-term efficacy of concomitant maze IV surgery in patients with atrial fibrillation

Background

Atrial fibrillation (AF) is the most common cardiac arrhythmia, and associated with increased risk of morbidity and mortality. AF surgery is widely used for rhythm control of AF, but previous studies have shown varying results. This study sought to investigate the long-term efficacy of concomitant maze IV (CMIV) surgery in an unselected AF population and identify predictors of late AF recurrence.

Methods

In total 144 consecutive patients, who underwent CMIV between January 2006 and December 2010 were enrolled. By data from electronic medical records, registers, and rhythm prints, late AF recurrences and heart rhythm at latest follow-up were retrospectively registered. All patients still alive were invited to an ambulant follow-up to update rhythm status.

Results

During a median (IQR) follow-up of 7.39 (2.67) years, 114 (79.2%) patients had recurrence. The cumulative incidence of sinus rhythm (SR) without antiarrhythmic drugs (AADs) was 52.3% after 1 year. Long-term results after 2, 5 and 7 years were 47.9%, 32.6% and 25.1%, respectively. At latest follow-up 34.7% were in SR off AADs. No difference in 10-year event-free survival stratified by recurrence were found (p = 0.678). Contrary, time to death (5.40 vs. 3.43 years, p = 0.004) revealed death as competing risk event. The Fine-Gray model identified preoperative sustained AF (SAF) (SHR 3.54, 95%CI [2.35;5.32], p < 0.001), AF duration (1.08, [1.05;1.11], p < 0.001), and postoperative atrial tachyarrhythmia (ATA) (2.29, [1.21;4.35], p = 0.011) as predictors.

Conclusion

CMIV in the present cohort provided limited long-term success in obtaining SR. SAF, longer AF duration, and postoperative ATA were associated with late AF recurrence.

Predictors of the need for pacemaker implantation after the Cox maze IV procedure for atrial fibrillation

PURPOSE

The Cox maze IV (CMIV) procedure is being used increasingly frequently for surgical ablation of atrial fibrillation (AF). This study aimed to identify the risk factors of the need for postoperative pacemaker implantation (PMI) after CMIV.

METHODS

Preoperative, intraoperative, and postoperative data were retrospectively collected from 67 consecutive patients who underwent CMIV at our institution; 7 (10.4%) required PMI (as a treatment of brady AF or sick sinus syndrome).

RESULTS

Patients who needed PMI tended to have lower preoperative heart rates than those who did not on a 12-lead electrocardiogram (ECG; 68.7 ± 11.6 vs. 79.1 ± 18.5 bpm, p = 0.07) and a 24-h ECG (94,772 ± 9800 vs. 109,854 ± 19,078 beats/day, p = 0.03). A multivariate analysis identified a low amplitude of the fibrillatory wave on preoperative ECG as a risk factor of PMI necessity after CMIV [odds ratio = 14.7; 95% confidence interval (CI) 1.9-324.7; p = 0.007] and internal use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEIs/ARBs) as a negative risk factor (odds ratio = 0.16; 95% CI 0.02-0.99; p = 0.049).

CONCLUSIONS

A low amplitude of the fibrillatory wave was identified as a risk factor of PMI necessity, whereas the internal use of ACEIs/ARBs diminished the need for PMI. These factors should be considered before CMIV is performed.

Concomitant ablation for atrial fibrillation during septal myectomy in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVE

The appearance of atrial fibrillation is associated with significant clinical deterioration in patients with obstructive hypertrophic cardiomyopathy; therefore, maintenance of sinus rhythm is desirable. Guidelines and most articles have reported the results of catheter ablation and pharmacologic atrial fibrillation treatment; nevertheless, data regarding concomitant procedures during septal myectomy are limited. The aim of this study was to assess the outcomes of concomitant atrial fibrillation treatment in patients with obstructive hypertrophic cardiomyopathy.

METHODS

Between 2010 and 2013 in our clinic, 187 patients with obstructive hypertrophic cardiomyopathy underwent extended myectomy. In 45 cases, concomitant Cox-Maze IV procedure was performed; however, obstructive hypertrophic cardiomyopathy was the primary indication for surgery. Atrial fibrillation was paroxysmal in 26 patients (58%) and nonparoxysmal in 19 patients (42%). The mean age of patients was 52.8 ± 14.2 years (range, 22-74 years). Mean peak gradient was 90.7 ± 24.2 mm Hg, and interventricular septum thickness was 26.1 ± 4.3 mm. Mean atrial fibrillation duration was 17.3 ± 8.5 months.

RESULTS

There were no early deaths. No procedure-related complications occurred with regard to ablation procedure. Complete atrioventricular block was achieved in 2 patients (4.0%). Mean crossclamping time was 61 ± 36 minutes. Peak left ventricular outflow tract gradient was 12.6 ± 5.5 mm Hg based on transesophageal echocardiography. The Maze IV procedure was used for ablation in all patients (radiofrequency ablation with bipolar clamp + cryolesion for mitral and tricuspid lines). Because of the atrial wall thickness (5-6 mm), applications were performed 8 to 10 times on each line. There were no cases of pacemaker implantation due to sinus node dysfunction. All patients were discharged in stable sinus rhythm. Mean follow-up was 23.7 ± 1.3 months. The rate of atrial fibrillation freedom was 100% (45 patients) at 6 months, 89% (40 patients) at 1 year, and 78% (35 patients) at 24 months.

CONCLUSIONS

Concomitant ablation atrial fibrillation during septal myectomy in patients with obstructive hypertrophic cardiomyopathy is a safe and effective procedure and should be considered carefully in this patient group.

Surgery for Atrial Fibrillation

Atrial fibrillation is the most common cardiac arrhythmia, and its treatment options include drug therapy or catheter-based or surgical interventions. The surgical treatment of atrial fibrillation has undergone multiple evolutions over the last several decades. The Cox-Maze procedure went on to become the gold standard for the surgical treatment of atrial fibrillation and is currently in its fourth iteration (Cox-Maze IV). This article reviews the indications and preoperative planning for performing a Cox-Maze IV procedure. This article also reviews the literature describing the surgical results for both approaches including comparisons of the Cox-Maze IV to the previous cut-and-sew method.

The totally thoracoscopic maze procedure for the treatment of atrial fibrillation

The purpose of this study was to update the current evidence regarding the efficacy and safety of the totally thoracoscopic maze (TT-maze) procedure for the treatment of atrial fibrillation (AF). Fourteen studies published between 2011 and 2016 and comprising 1171 patients were included as follows: 545 (46%) patients had paroxysmal AF (pAF), 268 (23%) persistent AF (persAF) and 358 (31%) longstanding persistent AF (LSPAF). Fixed- and random-effect models were used to calculate the pooled overall freedom from atrial arrhythmias. The 1- and 2-year pooled overall antiarrhythmic drug (AAD) free (off-AAD) success rates were 78% (95% confidence interval (CI): 72-83%, n = 13) and 77% (95% CI: 64-86%, n = 6), respectively. The 1- and 2-year pooled on-AAD success rates were 84% (95% CI: 78-89%, n = 5) and 85% (95% CI: 78-90%, n = 3), respectively. Subanalysis regarding the different types of AF revealed a 1-year pooled off-AAD success rate of 81% (95% CI: 73-86%, n = 7) for pAF, 63% (95% CI: 57-69%, n = 5) for persAF and 67% (95% CI: 52-79%, n = 3) for LSPAF. The overall in-hospital complication rate was <3% (n = 36). We conclude that the TT-maze is an effective strategy for the treatment of AF with maintained efficacy at the 2-year follow-up. Furthermore, the TT-maze has demonstrated similar efficacy to the Cox Maze IV procedure at the midterm follow-up with a lower complication rate. Extended follow-up research is needed to determine whether the high success rates after TT-maze will be stable over time.

Acute Sinus Node Dysfunction after Atrial Ablation: Incidence, Risk Factors, and Management

BACKGROUND

Many patients with atrial fibrillation (AF) or atrial flutter (Aflutter) have concomitant sinus node dysfunction (SND). Ablation may result in injury to the sinus node complex or its blood supply resulting in sinus arrest and need for temporary pacing. We sought to characterize patients who develop acute SND (ASND) during/immediately after AF/Aflutter ablation.

METHODS

We performed a retrospective analysis of AF/Aflutter ablation patients between January 1, 2010 and February 28, 2015 to characterize those who required temporary pacemaker (TPM) implantation due to ASND (sinus arrest, sinus bradycardia <40 beats/min, or junctional rhythm with hemodynamic compromise) following atrial ablation.

RESULTS

Of 2,151 patients, eight patients (<0.5%) with ASND manifesting as sinus arrest (n = 2), severe sinus bradycardia (n = 2), and junctional rhythm with hemodynamic compromise (n = 4) were identified (all male, age 66 ± 9.9 years, 4/8 [50%] persistent AF). AF ablation was performed in four, atypical Aflutter in one, and AF/Aflutter in three patients. The ablation set consisted of: pulmonary vein (PV) isolation (n = 6), roof line ablation (n = 6), mitral annulus-left inferior PV line ablation (n = 5), left atrial appendage-mitral annulus ablation (n = 1), cavotricuspid isthmus ablation (n = 5), and isolation or ablation near the superior vena cava (SVC, n = 4). Patients with peri-SVC ablation were more likely to develop ASND (P = 0.03). All patients received TPM; six received permanent pacemaker before discharge, performed 3.5 days postablation (range 2-6 days). At 3-month device interrogation, all patients were atrially paced >50%.

CONCLUSION

ASND is a rare complication of atrial ablation. It may be more common when peri-SVC ablation is performed and may necessitate permanent pacemaker implantation.

Early Results of the Modified Right Atrial Lesion Set for the Cox-Cryomaze Procedure

Objective

The standard right atrial lesion (RAL) set, as originally outlined in the Cox-Maze III procedure, can be technically challenging when using a cryoprobe to create the lesions. We report our initial experience with an alternative set of RALs for the surgical treatment of atrial fibrillation (AF).

Methods

Between September 2011 and January 2015, a total of 112 patients underwent a CryoMaze procedure with biatrial lesions using argon-based cryoablation (cryoprobe temperature, −160°C). Although the standard left atrial lesion set was used, the RAL pattern was modified in this cohort of patients. The intracaval superior vena cava-inferior vena cava lesion was performed as in the pattern described for the standard Cox-Maze III procedure. In addition, a horizontal atriotomy incision (the “T” lesion) in the mid free wall of the right atrium was based roughly in the midintercaval line and extended medially as a linear cryolesion to the lateral tricuspid annulus at the so-called 2-o'clock position as in the Cox-Maze III lesion pattern. Ordinarily, a linear cryolesion would be placed from the tip of the right atrial appendage (RAA) to the anterior tricuspid annulus at the so-called 10-o'clock position to prevent macro re-entry around the base of the RA appendage. Our modification consisted of, instead, a linear cryolesion directed perpendicularly from the mid portion of the atriotomy (T lesion) to the tip of the RA appendage, which simply interrupted RAA re-entry at another point.

Results

The mean ± standard deviation age was 72.7 ± 10.6 years, 56.3% were males, and 63.1% had long-standing persistent AF. There were three operative deaths (2.6% with an observed over expected of 0.58), all in the concomitant procedures with associated cardiac disease. Overall follow-up was 91.3%. Freedom from AF at discharge, 1-, 3-, 6-, 12-, 24-month, and last follow-up [16.1 ±11.3 months (range, 0.4–43 months)], was 100%, 76.3%, 84.2%, 98.3%, 89.5%, 89.2%, and 90.5%, respectively. Similarly, freedom from antiarrhythmic drugs was 74% and 81%, whereas freedom from anticoagulants was 72% and 78% at 12 and 24 months, respectively.

Conclusions

These results suggest the modified RAL set to be an effective alternative to the traditional RALs of Cox-Maze III. By substituting this lateral RAA lesion for the more technically difficult medial lesion, the procedure becomes easier to perform and favorably impacts operative time while achieving comparable results in reducing AF burden.

Predictors of Late-Onset Atrial Fibrillation Following Isolated Mitral Valve Repairs in Patients With Preserved Ejection Fraction

BACKGROUND

We sought to determine the incidence of and risk factors for late-onset atrial fibrillation (LOAF) in patients with preserved ejection fractions undergoing mitral valve repair

METHODS

We included patients undergoing isolated mitral valve repair (MVR) for degenerative disease between 1997-2014 at our institution with EF ≥60%. Patients who had AF preoperatively were excluded from the final analysis. Our primary outcome, LOAF, was defined as AF occurring after discharge following MVR (≥9 days).

RESULTS

223 patients were included in the study with a mean follow-up of 4.8 ± 4.6 years. A total of 25 patients developed LOAF, and freedom from LOAF was 93.9% at one year, and 87.3% at five years. Patients developing LOAF were of similar mean age (58 vs. 63 years in controls, p = 0.08) and had similar preoperative comorbidities, but did show a trend toward larger left atrial diameter (5.1 vs. 4.7 cm, p = 0.11). After risk adjustment with Cox regression analysis, only increasing left atrial size was associated with LOAF (HR 1.63, p = 0.04). On follow-up, 29 patients (10.8%) developed moderate or greater mitral regurgitation at a mean of 2.2 years. Using a mixed-effects model, we were unable to detect an association between recurrent mitral regurgitation following MVR and LOAF (OR 1.36, p = 0.42).

CONCLUSIONS

LOAF occurs in about 13% of preserved ejection fraction patients undergoing MVR by five years. Increasing left atrial diameter is an independent predictor of LOAF. Concomitant anti-arrhythmic procedures may warrant further investigation in patients with preserved ejection fraction and enlarged left atria undergoing MVR. doi: 10.1111/jocs.12774 (J Card Surg 2016;31:486-492).

Development Of A Novel Scoring System That Determines The Success Of Atrial Fibrillation Ablation As Part Of Cardiac Surgery

BACKGROUND

Radiofrequency ablation therapy for the treatment of atrial fibrillation (AF) can be performed as a concomitant procedure alongside cardiac surgery, but carries the risks of increased bypass time and damage to the sinoatrial node. This study aims to assess the efficacy of concomitant surgical AF ablation and develop a novel scoring system to predict post-procedural return to sinus rhythm.

METHODS

A review of the Leeds General Infirmary surgical database was conducted to list all patients who had undergone valvular or coronary bypass surgery with concomitant AF ablation between Jan 2012 - Dec 2013 (n = 76). Follow-up was obtained retrospectively using patient notes, clinic letters and echocardiographic data. Primary outcome was freedom from AF at median follow up (383 days). A novel scoring system was created through analysis of previous literature and evaluated using a receiver operating characteristic (ROC) curve.

RESULTS

At median follow up 50.9% of patients undergoing the procedure were free from AF. The novel scoring system was shown to adequately predict post-procedural return to sinus rhythm (ROC AUC = 0.7708).

CONCLUSION

A novel scoring system was shown to predict procedural success in patients undergoing concomitant AF ablation alongside cardiac surgery. These results can be further validated using larger patient cohorts.

Surgical Treatment of Atrial Fibrillation

Atrial fibrillation (AF) is the most common chronic arrhythmia in the adult population. Ablation lines have largely replaced the historical and challenging cut and sew techniques. Surgical ablation of AF is commonly performed in cases with other indications for cardiac surgery and less commonly as a stand-alone therapy. Pulmonary vein isolation is the cornerstone of this procedure. Extended left atrial ablation lines may increase efficacy in cases with longstanding persistent or permanent AF. Additional efficacy by adding right atrial ablation is controversial but is often performed in cases undergoing right atrial or atrial septal surgery. Left atrial volume reduction is recommended in cases with large left atria and AF undergoing another cardiac surgery. Arrhythmia recurrence is not uncommon after surgical ablation of AF and varies among studies due to heterogeneity in patient population, lesion set and endpoints. Freedom from AF recurrence was 65-87% at 12 months and 58-70% at 2 years follow-up. Long-term monitoring is recommended due to an increased prevalence of asymptomatic recurrences. The strongest predictors of AF recurrence are longstanding or persistent AF and a large left atrium. The most common mechanisms of recurrence are pulmonary vein reconnection, nonpulmonary vein triggers, and gaps in the ablation lines. About 20% of atrial tachyarrhythmia recurrences are atrial flutter or atrial tachycardia. There are not enough data in the surgical literature to support withdrawal of anticoagulation after surgical AF ablation. Patients selected for stand-alone surgical ablation usually have low risk profiles and low postoperative mortality rates (0.2%).

Effectiveness of Surgical Ablation in Patients With Atrial Fibrillation and Aortic Valve Disease

BACKGROUND

In patients with atrial fibrillation (AF), the addition of surgical ablation to aortic valve replacement (AVR) does not increase procedural morbidity or mortality. However, efficacy in this population has not been carefully evaluated. This study compared outcomes between patients undergoing stand-alone Cox-Maze IV with those undergoing surgical ablation and concomitant AVR.

METHODS

From January 2002 to May 2014, 188 patients received a stand-alone Cox-Maze IV (n = 113) or surgical ablation with concomitant AVR (n = 75). In the concomitant AVR group, patients underwent Cox-Maze IV (n = 58), left-sided Cox-Maze IV (n = 3), or pulmonary vein isolation (n = 14). Thirty-one perioperative variables were compared. Freedoms from AF on and off antiarrhythmic drugs were evaluated at 3, 6, 12, and 24 months.

RESULTS

Follow-up was available in 97% of patients. Freedom from AF on and off antiarrhythmic drugs in patients receiving a stand-alone Cox-Maze IV versus concomitant AVR was not significantly different at any time point. The concomitant AVR group had more comorbidities, paroxysmal AF, pacemaker implantations (24% vs 5%, p = 0.002), and complications (25% vs 5%, p < 0.001). Freedoms from AF off antiarrhythmic drugs for patients receiving an AVR and pulmonary vein isolation at 1 year was only 50%, which was significantly lower than patients receiving an AVR and Cox-Maze IV ( 94%, p = 0.001).

CONCLUSIONS

A Cox-Maze IV with concomitant AVR is as effective as a stand-alone Cox-Maze IV in treating AF, even in an older population with more comorbidities. Pulmonary vein isolation was not as effective and is not recommended in this population. A Cox-Maze IV should be considered in all patients undergoing AVR with a history of AF.

Comparing energy sources for surgical ablation of atrial fibrillation: a Bayesian network meta-analysis of randomized, controlled trials

Simplified maze procedures involving radiofrequency, cryoenergy and microwave energy sources have been increasingly utilized for surgical treatment of atrial fibrillation as an alternative to the traditional cut-and-sew approach. In the absence of direct comparisons, a Bayesian network meta-analysis is another alternative to assess the relative effect of different treatments, using indirect evidence. A Bayesian meta-analysis of indirect evidence was performed using 16 published randomized trials identified from 6 databases. Rank probability analysis was used to rank each intervention in terms of their probability of having the best outcome. Sinus rhythm prevalence beyond the 12-month follow-up was similar between the cut-and-sew, microwave and radiofrequency approaches, which were all ranked better than cryoablation (respectively, 39, 36, and 25 vs 1%). The cut-and-sew maze was ranked worst in terms of mortality outcomes compared with microwave, radiofrequency and cryoenergy (2 vs 19, 34, and 24%, respectively). The cut-and-sew maze procedure was associated with significantly lower stroke rates compared with microwave ablation [odds ratio <0.01; 95% confidence interval 0.00, 0.82], and ranked the best in terms of pacemaker requirements compared with microwave, radiofrequency and cryoenergy (81 vs 14, and 1, <0.01% respectively). Bayesian rank probability analysis shows that the cut-and-sew approach is associated with the best outcomes in terms of sinus rhythm prevalence and stroke outcomes, and remains the gold standard approach for AF treatment. Given the limitations of indirect comparison analysis, these results should be viewed with caution and not over-interpreted.

Surgery for atrial fibrillation

Atrial fibrillation is the most common cardiac arrhythmia, and its treatment options include drug therapy or catheter-based or surgical interventions. The surgical treatment of atrial fibrillation has undergone multiple evolutions over the last several decades. The Cox-Maze procedure went on to become the gold standard for the surgical treatment of atrial fibrillation and is currently in its fourth iteration (Cox-Maze IV). This article reviews the indications and preoperative planning for performing a Cox-Maze IV procedure. This article also reviews the literature describing the surgical results for both approaches including comparisons of the Cox-Maze IV to the previous cut-and-sew method.

Illustrated techniques for performing the Cox-Maze IV procedure through a right mini-thoracotomy

The Cox-Maze IV procedure has replaced the "cut-and-sew" technique of the original Cox-Maze operation with lines of ablation created using bipolar radiofrequency (RF) and cryothermal energy devices. In select patients, this procedure can be performed through a right mini-thoracotomy. This illustrated review is the first to detail the complete steps of the Cox-Maze IV procedure performed through a right mini-thoracotomy with careful attention paid to operative anatomy and advice. Pre- and post-operative management and outcomes are also discussed. This should be a practical guide for the practicing cardiac surgeon.