Preliminary Results of a Limited Thoracotomy: New Approach to Treat Atrial Fibrillation

The Society of Thoracic Surgeons 2023 Clinical Practice Guidelines for the Surgical Treatment of Atrial Fibrillation

The Society of Thoracic Surgeons 2023 Clinical Practice Guidelines for the Surgical Treatment of Atrial Fibrillation incorporate the most recent evidence for surgical ablation and left atrial appendage occlusion in different clinical scenarios. Substantial new evidence regarding the risks and benefits of surgical left atrial appendage occlusion and the long-term benefits of surgical ablation has been produced in the last 5 years. Compared with the 2017 clinical practice guideline, the current update has an emphasis on surgical ablation in first-time, nonemergent cardiac surgery and its long-term benefits, an extension of the recommendation to perform surgical ablation in all patients with atrial fibrillation undergoing first-time, nonemergent cardiac surgery, and a new class I recommendation for left atrial appendage occlusion in all patients with atrial fibrillation undergoing first-time, nonemergent cardiac surgery. Further guidance is provided for patients with structural heart disease and atrial fibrillation being considered for transcatheter valve repair or replacement, as well as patients in need of isolated left atrial appendage management who are not candidates for surgical ablation. The importance of a multidisciplinary team assessment, treatment planning, and long-term follow-up are reiterated in this clinical practice guideline with a class I recommendation, along with the other recommendations from the 2017 guidelines that remained unchanged in their class of recommendation and level of evidence.

Neuromodulation therapy for atrial fibrillation

Atrial fibrillation has a multifactorial pathophysiology influenced by cardiac autonomic innervation. Both sympathetic and parasympathetic influences are profibrillatory. Innovative therapies targeting the neurocardiac axis include catheter ablation or pharmacologic suppression of ganglionated plexi, renal sympathetic denervation, low-level vagal stimulation, and stellate ganglion blockade. To date, these therapies have variable efficacy. As our understanding of atrial fibrillation and the cardiac nervous system expands, our approach to therapeutic neuromodulation will continue evolving for the benefit of those with AF.

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.

Neuroscientific therapies for atrial fibrillation

The cardiac autonomic nervous system (ANS) plays an integral role in normal cardiac physiology as well as in disease states that cause cardiac arrhythmias. The cardiac ANS, comprised of a complex neural hierarchy in a nested series of interacting feedback loops, regulates atrial electrophysiology and is itself susceptible to remodelling by atrial rhythm. In light of the challenges of treating atrial fibrillation (AF) with conventional pharmacologic and myoablative techniques, increasingly interest has begun to focus on targeting the cardiac neuraxis for AF. Strong evidence from animal models and clinical patients demonstrates that parasympathetic and sympathetic activity within this neuraxis may trigger AF, and the ANS may either induce atrial remodelling or undergo remodelling itself to serve as a substrate for AF. Multiple nexus points within the cardiac neuraxis are therapeutic targets, and neuroablative and neuromodulatory therapies for AF include ganglionated plexus ablation, epicardial botulinum toxin injection, vagal nerve (tragus) stimulation, renal denervation, stellate ganglion block/resection, baroreceptor activation therapy, and spinal cord stimulation. Pre-clinical and clinical studies on these modalities have had promising results and are reviewed here.

Catheter Ablation of Long-standing Persistent Atrial Fibrillation: a Reckless Challenge or a Way to Real Cure?

Long-standing persistent atrial fibrillation (L-PeAF) is a category in which rhythm control is attempted while atrial fibrillation (AF) is maintained for more than 1 year. Because AF is a progressive disease and L-PeAF accompanies significant electrical and structural remodeling of atria, it is difficult to restore and maintain sinus rhythm in patients with L-PeAF. Nonetheless, the rhythm outcome is being increasingly improved by the development of sophisticated mapping devices, highly efficient catheters, and evidence-based ablation strategies, and the rational choice of patient selection criteria. This review discusses the evolution of the rhythm control outcome of L-PeAF and its future direction of development.

Left atrial function after epicardial pulmonary vein isolation in patients with atrial fibrillation

Purpose

Epicardial pulmonary vein isolation has become an increasingly used therapy for medically resistant atrial fibrillation. The purpose of the present study was therefore to evaluate if epicardial pulmonary vein isolation combined with ganglionated plexi ablation affects the size and mechanical function of the left atrium, and whether the effects are dependent on the extensiveness of the ablation applications.

Methods

A total of 42 patients underwent an echocardiographic examination prior to and 6 months after a minimal invasive epicardial pulmonary vein isolation procedure for the assessment of the effects on left atrial size and function. In 27 patients, who had sinus rhythm both at baseline and follow-up, was a comparison of atrial size and function possible at these time intervals. Fractional area changes were obtained from the left atrial end-systolic and end-diastolic areas in the apical four-chamber view. Pulsed-Doppler was used to assess the transmitral flow velocities to evaluate mechanical function.

Results

Left atrial size and function at 6-month follow-up had not changed significantly from those at baseline as indicated by left atrial maximal area (17.1 ± 4.6 vs. 18.7 ± 5.3, p = 0.118), minimal area (12.5 ± 3.8 vs. 13.4 ± 4.7, p = 0.248), fractional area change (27.4 ± 8.2 vs. 28.7 ± 10.6, p = 0.670), and E/A ratio (1.49 ± 0.47 vs. 1.54 ± 0.67, p = 0.855).

Conclusions

Radiofrequency ablation for epicardial pulmonary vein isolation combined with ganglionated plexi ablation has no major effects on atrial function or size. A preserved atrial function for those maintaining sinus rhythm may have important implications for thromboembolic risk after surgery, but warrants confirmation in larger trials.

Assessment of the effect of left atrial cryoablation enhanced by ganglionated plexi ablation in the treatment of atrial fibrillation in patients undergoing open heart surgery

BACKGROUND

The aim of our study was to investigate, whether enhancement of left atrial cryoablation by ablation of the autonomic nervous system of left atrium leads to influencing the outcomes of surgical treatment of atrial fibrillation in patients with structural heart disease undergoing open-heart surgery.

METHODS

The observed patient file consisted of 100 patients, who have undergone a combined open-heart surgery at our department between July 2012 and December 2014. The patients were indicated for the surgical procedure due to structural heart disease, and suffered from paroxysmal, persistent, or long-standing persistent atrial fibrillation. In all cases, left atrial cryoablation was performed in the extent of isolation of pulmonary veins, box lesion, connecting lesion with mitral annulus, amputation of the left atrial appendage and connecting lesion of the appendage base with left pulmonary veins. Furthermore, 35 of the patients underwent mapping and radiofrequency ablation of ganglionated plexi, together with discision and ablation of the ligament of Marshall (Group GP). A control group was consisted of 65 patients without ganglionated plexi intervention (Group LA). The main primary outcome was establishment and duration of sinus rhythm in the course of one-year follow-up.

RESULTS

Evaluation of the number of patients with a normal sinus rhythm in per cent has shown comparable values in both groups (Group GP - 93.75%, Group LA - 86.67%, p = 0.485); comparable results were also observed in patients with normal sinus rhythm without anti-arrhythmic treatment in the 12th month (Group GP - 50%, Group LA - 47%, p = 0.306). We have not observed any relation between the recurrence of atrial fibrillation and the presence of a mitral valve surgery, or between the presence of a mitral and tricuspid valves surgery and between the left atrial diameter > 50 mm.

CONCLUSIONS

Enhancement of left atrial cryoablation by gangionated plexi ablation did not influence the outcomes of surgical ablation due to atrial fibrillation in our population in the course of 12-month follow-up.

TRIAL REGISTRATION

The study was approved retrospectively by the Ethics Committee of the University Hospital Ostrava ( reference number 867/2016).

Thoracoscopic Ablation With Appendage Ligation Versus Medical Therapy for Stroke Prevention: A Proof-of-Concept Randomized Trial

OBJECTIVE

Atrial fibrillation (AF) has a demonstrable effect on quality of life (QOL). Recurrent stroke occurs in 10% of patients with AF. The objective of this study was to demonstrate proof of concept that thoracoscopic pulmonary vein isolation and atrial appendage ligation (TPVIAL) could prevent recurrent stroke and could potentially improve QOL in patients with AF with a previous stroke.

METHODS

The study was a National Institutes of Health-funded single-center proof-of-concept design that randomized 23 patients with AF-related stroke to TPVIAL (n = 12) or to medical management (n = 11). Quality of life was the primary outcome variable; secondary end points included restoration of rhythm, recurrent stroke, and surgical morbidity.

RESULTS

Quality-of-life subscores at 3 and 6 months revealed improvements in energy and decreases in fatigue in the TPVIAL arm [baseline, 33 (19.8); 3 months, 49.5 (20.6), P = 0.01; 6 months, 55.5 (14.4), P = 0.03]. At 12-month follow-up, there were no recurrent strokes in the TPVIAL group. In the medically treated arm, two patients at 6 months (P = 0.22) and three total patients at 12 months (P = 0.09) had recurrent ischemic stroke. There was one death in the medical management arm. In the TPVIAL arm, no AF recurrence occurred in patients with paroxysmal AF, and one patient had recurrence of persistent and long-standing AF. Seven patients in the TPVIAL arm discontinued warfarin therapy for secondary stroke prevention.

CONCLUSIONS

This small proof-of-concept study showed that TPVIAL improved QOL on two subscores and restored normal sinus rhythm in all but one patient, and it showed the potential to prevent secondary stroke. A larger study will be needed.

The Society of Thoracic Surgeons 2017 Clinical Practice Guidelines for the Surgical Treatment of Atrial Fibrillation

EXECUTIVE SUMMARY

Surgical ablation for atrial fibrillation (AF) can be performed without additional risk of operative mortality or major morbidity, and is recommended at the time of concomitant mitral operations to restore sinus rhythm. (Class I, Level A) Surgical ablation for AF can be performed without additional operative risk of mortality or major morbidity, and is recommended at the time of concomitant isolated aortic valve replacement, isolated coronary artery bypass graft surgery, and aortic valve replacement plus coronary artery bypass graft operations to restore sinus rhythm. (Class I, Level B nonrandomized) Surgical ablation for symptomatic AF in the absence of structural heart disease that is refractory to class I/III antiarrhythmic drugs or catheter-based therapy or both is reasonable as a primary stand-alone procedure, to restore sinus rhythm. (Class IIA, Level B randomized) Surgical ablation for symptomatic persistent or longstanding persistent AF in the absence of structural heart disease is reasonable, as a stand-alone procedure using the Cox-Maze III/IV lesion set compared with pulmonary vein isolation alone. (Class IIA, Level B nonrandomized) Surgical ablation for symptomatic AF in the setting of left atrial enlargement (≥4.5 cm) or more than moderate mitral regurgitation by pulmonary vein isolation alone is not recommended. (Class III no benefit, Level C expert opinion) It is reasonable to perform left atrial appendage excision or exclusion in conjunction with surgical ablation for AF for longitudinal thromboembolic morbidity prevention. (Class IIA, Level C limited data) At the time of concomitant cardiac operations in patients with AF, it is reasonable to surgically manage the left atrial appendage for longitudinal thromboembolic morbidity prevention. (Class IIA, Level C expert opinion) In the treatment of AF, multidisciplinary heart team assessment, treatment planning, and long-term follow-up can be useful and beneficial to optimize patient outcomes. (Class I, Level C expert opinion).

Novel Percutaneous Epicardial Autonomic Modulation in the Canine for Atrial Fibrillation: Results of an Efficacy and Safety Study

BACKGROUND

Endocardial ablation of atrial ganglionated plexi (GP) has been described for treatment of atrial fibrillation (AF). Our objective in this study was to develop percutaneous epicardial GP ablation in a canine model using novel energy sources and catheters.

METHODS

Phase 1: The efficacy of several modalities to ablate the GP was tested in an open chest canine model (n = 10). Phase 2: Percutaneous epicardial ablation of GP was done in six dogs using the most efficacious modality identified in phase 1 using two novel catheters.

RESULTS

Phase 1: Direct current (DC) in varying doses (blocking [7-12 μA], electroporation [300-500 μA], ablation [3,000-7,500 μA]), radiofrequency ablation (25-50 W), ultrasound (1.5 MHz), and alcohol (2-5 mL) injection were successful at 0/8, 4/12, 5/7, 3/8, 1/5, and 5/7 GP sites. DC (500-5,000 μA) along with alcohol irrigation was tested in phase 2. Phase 2: Percutaneous epicardial ablation of the right atrium, oblique sinus, vein of Marshall, and transverse sinus GP was successful in 5/6 dogs. One dog died of ventricular fibrillation during DC ablation at 5,000 μA. Programmed stimulation induced AF in six dogs, preablation and no atrial arrhythmia in three, flutter in one, and AF in one postablation. Heart rate, blood pressure, effective atrial refractory period, and local atrial electrogram amplitude did not change significantly postablation. Microscopic examination showed elimination of GP, and minimal injury to atrial myocardium.

CONCLUSION

Percutaneous epicardial ablation of GP using DC and novel catheters is safe and feasible and may be used as an adjunct to pulmonary vein isolation in the treatment of AF in order to minimize additional atrial myocardial ablation.

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%).

Elimination Of Triggers Without An Additional Substrate Modification Is Not Sufficient In Patients With Persistent Atrial Fibrillation

Atrial fibrillation (AF) is a multifactorial disease with complex pathophysiology. Although restoring sinus rhythm delays the progression of atrial remodeling, non-pharmacologic intervention, such as radiofrequency catheter ablation (RFCA), should be done based on the background pathophysiology of the disease. While circumferential pulmonary vein isolation (CPVI) has been known to be the cornerstone of AF catheter ablation, a clinical recurrence rate after CPVI is high in patients with persistent AF (PeAF). Step-wise linear ablation, complex fractionate atrial electrogram (CFAE)-guided ablation, rotor ablation, ganglionate plexus ablation, and left atrial appendage isolation may improve the ablation success rate after CPVI. But, there are still substantial AF recurrences after such liberal atrial substrate ablation, and current ablation techniques regarding substrate modification still have limitations. Therefore, more understanding about AF pathophysiology and early precise intervention may improve clinical outcome of AF management. Keeping in mind "more touch, more scar," operators should generate most efficient substrate modification to achieve better long-term clinical outcome.

Cardiac Autonomic Denervation for Ablation of Atrial Fibrillation

The influence of the autonomic nervous system (ANS) on triggering and perpetuation of atrial fibrillation (AF) is well established. Ganglionated plexi (GP) ablation achieves autonomic denervation by affecting both the parasympathetic and sympathetic components of the ANS. GP ablation can be accomplished endocardially or epicardially, i.e. during the maze procedure or thoracoscopic approaches. Recent evidence indicates that anatomic GP ablation at relevant atrial sites appears to be safe and improves the results of pulmonary vein isolation in patients with paroxysmal and persistent AF.

Outflow tract premature ventricular depolarizations after atrial fibrillation ablation may reflect autonomic influences

PURPOSE

Autonomic modulation following catheter ablation of atrial fibrillation may promote the development of catecholamine-sensitive arrhythmias, such as outflow tract (OT) ventricular premature depolarizations (VPDs). The purpose of this study was to determine the incidence and prognostic significance of OT VPDs occurring in patients after atrial fibrillation (AF) ablation.

METHODS

We prospectively examined 53 consecutive patients undergoing wide-area circumferential antral pulmonary vein (PV) isolation; no patients had evidence of OT VPDs on 24 h of preprocedural telemetry monitoring. Cases (OT+) had postprocedure telemetry monitoring with >30 continuous beats or >3/min OT VPDs. Clinical follow-up included transtelephonic monitoring at 6 weeks, 6 months, and 1 year.

RESULTS

The incidence of OT VPDs in this population was 11% (6/53). There was no difference in AF recurrence at 1 year between those with or without OT VPDs (17 vs 28%, p = 0.6). There was a strong association with higher immediate postprocedure heart rate (HR) in OT+ compared to OT- patients (86 vs 76, p = 0.03); this difference persisted at 1 year (79 vs 60, p < 0.01). OT VPDs resolved in 5/6 of the OT+ patients over the 1-year follow-up. In a multivariable linear regression model, OT VPDs were associated with higher HR (odds ratio (OR) 1.14 [1.10-1.18], p < 0.001) despite adjustment for medication dose.

CONCLUSIONS

A minority of patients undergoing antral PV isolation develops OT VPDs associated with a sustained increase in mean heart rate; this effect may result from the modulation of adjacent autonomic ganglia.

Treatment of lone atrial fibrillation: minimally invasive pulmonary vein isolation, partial cardiac denervation and excision of the left atrial appendage

Since 1999, my colleagues and I have diligently pursued a minimally invasive surgical, beating-heart, left atrial isolation technique that is offered to patients with lone atrial fibrillation (AF). We began clinical cases in 2003. In 2005, we reported our initial experience with video-assisted bilateral pulmonary vein (PV) isolation and left atrial appendage (LAA) exclusion for the minimally invasive treatment of AF (Wolf technique). From our experience in over 1,000 cases there have been many lessons learned in the evaluation, selection and minimally invasive surgical treatment of patients with lone AF. In our experience we have had zero mortality and no conversions to sternotomy. Recently we reviewed 157 patients who are now 1 to 9 years out from the Wolf technique. The patients' ages ranged from 15 to 87 years old. The AF-free rate for paroxysmal AF was 92%, for persistent AF 85%, and for long-standing persistent AF 75%. The follow-up included 7-day continuous monitoring. There were no deaths (personal review). The Wolf technique is a safe and effective treatment for selected patients with lone AF.

A hybrid procedure for atrial fibrillation using total thoracoscopic ablation and post-procedural electrophysiological confirmation of ablation lines

Atrial fibrillation (AF) is the most common chronic arrhythmia in the world, and it is associated with an increased long-term risk of stroke, heart failure, and all-cause mortality. To overcome the limitations of transvenous radiofrequency (RF) ablation for AF, total thoracoscopic ablation (TTA) has evolved as a new technique. TTA has several advantages over transvenous RF ablation and is known to produce better outcomes, especially in patients with persistent AF. Herein, we report 2 cases of successful TTA followed by an electrophysiological study confirming satisfactory ablation lines; the first such procedure reported in Korea.

Identification of left atrial ganglionated plexi by dense epicardial mapping as ablation targets for the treatment of concomitant atrial fibrillation

Background

Autonomic ganglionated plexi (GPs) play a significant role in the initiation and maintenance of atrial fibrillation (AF). GPs are key targets for a maze procedure. The purpose of this study was to identify the location of the left atrial GPs based on dense epicardial mapping during a maze procedure in patients with concomitant AF.

Methods

Sixteen patients (age, 68 ± 10 years; 11 males, 69%) with heart failure and concomitant AF (duration 55 ± 86 months) underwent intraoperative epicardial electrophysiological mapping and a GP ablation using the maze procedure at our institution. Twenty-four-site, high-frequency stimulation (1,000/min; output, 18 V; pulse width, 0.75 ms) was performed by placing tweezers directly onto the potential GP sites on the left atrial epicardium.

Results

Active GPs were found in 13 (81%) of the 16 patients, and 12 (92%) of 13 patients had active GPs between the right pulmonary veins (PVs) and the interatrial groove. For those patients with active locations, a 7-day event-loop recording demonstrated that 12 (92%) of 13 patients were maintained in sinus rhythm 3 months after the operation.

Conclusion

Dense epicardial mapping in the potential GP areas identified active GP locations in a high percentage of patients. GPs between the PVs and interatrial groove have a high potential as ablation targets for treatment of concomitant AF.

A minimally invasive cox-maze procedure: operative technique and results

OBJECTIVE

The Cox-Maze procedure (CMP) for the surgical treatment of atrial fibrillation (AF) traditionally has required a median sternotomy and cardiopulmonary bypass. This study describes a method using ablation technologies to create the full Cox-Maze lesion set through a 5- to 6-cm right minithoracotomy.

METHODS

Twenty-two consecutive patients underwent a CMP through a right mini-thoracotomy and cardiopulmonary bypass. All patients were followed prospectively with electrocardiogram and 24-hour Holter monitoring at 3, 6, and 12 months. The CMP lesion set was created using bipolar radiofrequency energy and cryotherapy.

RESULTS

There was no operative mortality or major complications.Two patients required a permanent pacemaker. Five patients (23%) had early atrial tachyarrhythmias. At last follow-up(mean, 18 ± 12 months), all the patients (n=22) were free from atrial dysrhythmias. At 3 months (n=19), 84% of patients were off antiarrhythmic drugs. At 6 months (n=18), 94% of patients were free from AF and off antiarrhythmic medications. At 12 months (n=16), 81% of patients were free from AF and off antiarrhythmic drugs and three patients remained on warfarin for a mechanical mitral valve.

CONCLUSIONS

A full CMP can be performed through a right mini-thoracotomy with outstanding short-term results. This less invasive procedure can be offered to patients without compromising efficacy.

The intrinsic autonomic nervous system in atrial fibrillation: a review

The procedure of catheter ablation for the treatment of drug resistant atrial fibrillation (AF) has evolved but still relies on lesion sets intended to isolate areas of focal firing, mainly the myocardial sleeves of the pulmonary veins (PVs), from the rest of the atria. However the success rates for this procedure have varied inversely with the type of AF. At best success rates have been 20 to 30% below that of other catheter ablation procedures for Wolff-Parkinson-White syndrome, atrioventricular junctional re-entrant tachycardia and atrial flutter. Basic and clinical evidence has emerged suggesting a critical role of the ganglionated plexi (GP) at the PV-atrial junctions in the initiation and maintenance of the focal form of AF. At present the highest success rates have been obtained with the combination of PV isolation and GP ablation both as catheter ablation or minimally invasive surgical procedures. Various lines of evidence from earlier and more recent reports provide that both neurally based and myocardially based forms of AF can separately dominate or coexist within the context of atrial remodeling. Future studies are focusing on non-pharmacological, non-ablative approaches for the prevention and treatment of AF in order to avoid the substantive complications of both these regimens.

Surgery for atrial fibrillation: recent progress and future perspective

Development and introduction of radiofrequency ablation devices allowed the maze procedures to be performed safely and easily, further enabling off-pump pulmonary vein isolation through a mini-thoracotomy or thoracoscope. The effects of the maze procedure include prevention of stroke and other complications related to atrial fibrillation, improved cardiac performance, and relief of symptoms. Indications for the maze procedure have been discussed on the basis of the evidence. Pulmonary vein isolation has been shown to be effective in most patients with paroxysmal atrial fibrillation and can be performed with endocardial catheter ablation and minimally invasive epicardial ablation. These two modalities should be compared in terms of the success rate, occurrence of cerebral microembolic signals, capability of additional lesions indicated for persistent or long-standing persistent atrial fibrillation, and closure of the left atrial appendage. Noncontinuous or nontransmural lines of conduction block as a result of incomplete ablation can result in recurrence of atrial fibrillation and induction of atrial tachycardia. Intraoperative verification of conduction block across the ablation lines is recommended to prevent these complications. Volume reduction of the enlarged left atrium or a boxlesion to isolate the entire posterior left atrium may be effective in patients with a dilated left atrium, but the potentially impaired atrial transport function should be considered. Mapping of active ganglionated plexi and their ablation may improve the outcome of the procedure, but the long-term effect on atrial fibrillation and autonomic nerve activities should be examined.

Initial experience of sequential surgical epicardial-catheter endocardial ablation for persistent and long-standing persistent atrial fibrillation with long-term follow-up

BACKGROUND

Patients with long-standing persistent (LSP) atrial fibrillation (AF) who have previously undergone catheter ablation represent a challenging patient population. Repeat catheter ablation in these patients is arduous and associated with a high failure rate, whereas surgical ablation can be complicated by multiple flutters. We sought to determine if minimally-invasive surgical ablation, followed by catheter ablation of all inducible flutters, would improve success rates over repeat catheter ablation alone.

METHODS

Fifteen patients (Sequential) with persistent or LSP AF who failed at least one catheter ablation and one anti-arrhythmic drug (AAD) underwent surgical ablation, followed by planned endocardial evaluation and catheter mapping with ablation during the same hospitalization. Sequential patients were matched to 30 patients who had previously failed at least one catheter ablation and underwent a repeat catheter ablation (catheter-alone). The primary end point was event-free survival of any documented AF recurrence or AAD use.

RESULTS

All patients underwent uncomplicated surgical ablation and electrophysiology procedure. Five Sequential patients had seven inducible flutters that were mapped and ablated. After a mean follow-up of 20.7±4.5 months, 13/15 (86.7%) Sequential patients, but only 16/30 (53.3%) catheter-alone patients, were free of any atrial arrhythmia and off of AAD (p=0.04). On AAD, 14/15 (93.3%) Sequential patients were free of any atrial arrhythmia recurrence, compared to 17/30 (56.7%) catheter-alone patients (p=0.01).

CONCLUSIONS

For patients with atrial fibrillation who have failed catheter ablation, Sequential minimally invasive epicardial surgical ablation, followed by endocardial catheter-based ablation, has a higher early success rate than repeat catheter ablation alone.

Left atrial ganglion ablation as an adjunct to atrial fibrillation surgery in valvular heart disease

BACKGROUND

Our aim was to evaluate early results of ganglionic plexus (GP) ablation with modified Cox maze lesion sets for concomitant atrial fibrillation (AF) during corrective valve surgery.

METHODS

Between December 2006 and April 2008, 20 patients (7 men; median age, 65 years; range, 52 to 82 years) with valvular heart disease and AF (intermittent in 12 [60%]) underwent corrective valve surgery with maze and GP ablation. Patients were then compared with a case-matched control cohort who underwent radiofrequency ablation maze alone.

RESULTS

Procedures included mitral valve repair in 7 patients (35%), multivalve procedures in 5 (25%), mitral valve replacement in 4 (20%), aortic valve replacement in 3 (15%), and valve-sparing aortic root replacement in 1 (5%). All patients underwent concomitant AF ablation procedures (biatrial maze in 11 [55%], left-sided maze in 9 [45%]). Ganglionic plexus stimulation was performed in all patients. Sites at which the R-R interval doubled were considered active and were ablated. There were no early deaths. Freedom from AF at 1 year was significantly higher (90% versus 50%; p=0.01) and mean New York Heart Association functional class was better (1 versus 1.7; p<0.001) in the group that underwent maze and GP ablation compared with maze alone.

CONCLUSIONS

Active left atrial GP are frequently present in patients with AF and valvular heart disease, and GP ablation can be safely performed as an adjunct to AF ablation during valve surgery. Early results are promising and may yield higher freedom from AF compared with radiofrequency ablation maze alone.

Anatomy of the Pericardial Space and Mediastinum: Relevance to Epicardial Mapping and Ablation

The pericardial space is a fairly new portal for interventional cardiac electrophysiologists to access the heart and requires an understanding of its anatomic peculiarities to maneuver safely around the epicardial surfaces of the heart and great veins. Subxiphoid puncture should allow the diaphragm and fibrous pericardium to be crossed without entering the right ventricle, which is the most anteriorly situated cardiac chamber. The phrenic nerves descend on the fibrous pericardium bilaterally. The right nerve is related to the superior caval vein and the superior right pulmonary vein, whereas the left nerve takes variable courses over the left atrial appendage and the left ventricle. Related to the fibrous pericardium overlying the posterior wall of the left atrium is the esophagus.