Ethanol infusion in the vein of Marshall: Adjunctive effects during ablation of atrial fibrillation

Chemical mapping as a predictor of vein of Marshall ethanol ablative effects

PURPOSE

The aim of this study was to test regional pharmacological effects of an antiarrhythmic agents to predict ablative effects.

BACKGROUND

The vein of Marshall (VOM) providing vascular access to myocardial tissue has been used for ablative purposes using ethanol.

METHODS

A total of 35 patients (male 21, 63.2 ± 7.8 years old) were included. A balloon-tipped infusion catheter was inserted into the VOM. Endocardial ultrahigh-resolution mapping was performed along the VOM region to record the change in atrial electrograms (AEs) after VOM injection of cibenzoline of 3.5 mg during sustained atrial fibrillation (AF). Subsequently, ethanol was infused into the VOM and ablative region was mapped.

RESULTS

In 17 patients (49 %), cibenzoline reduced AEs amplitude by >50%, all of which had also complete elimination of AEs following ethanol (Group A). In 18 patients (Group B), cibenzoline failed to eliminate AEs; yet, in 13 of 18 AEs were eliminated by ethanol. In the remaining five patients, ethanol did not eliminate AE.

CONCLUSIONS

Cibenzoline into the VOM could reliably predicts the results of subsequent ethanol infusion into the VOM using ultrahigh-resolution mapping system, which leads to avoid unnecessary permanent lesion creation by ethanol infusion.

Vein of Marshall ethanol infusion for persistent atrial fibrillation: VENUS and MARS clinical trial design

BACKGROUND

Although pulmonary vein isolation (PVI) is effective in the treatment of paroxysmal atrial fibrillation (AF), its success rates in persistent AF are suboptimal. Ablation strategies to improve outcomes including additional lesions beyond PVI have not consistently shown benefit. Recurrence as perimitral flutter (PMF) is a common form of ablation failure. The vein of Marshall (VOM) contains myocardial connections and abundant sympathetic and parasympathetic innervation implicated in the genesis and maintenance of AF, and is anatomically co-localized with the mitral isthmus, the ablation target of PMF. VOM ethanol infusion is effective in targeting these arrhythmia substrates.

OBJECTIVE

To test the safety and efficacy of VOM ethanol infusion when added to PVI in patients undergoing either de novo ablation of persistent AF or after a previous ablation failure.

STUDY DESIGN

VENUS-AF and MARS-AF are prospective, multicenter, randomized, controlled trials. VENUS-AF will enroll patients undergoing their first catheter ablation of persistent AF. MARS-AF will enroll patients undergoing ablation after previous ablation failure(s). Patients (n = 405) will be randomized to PVI alone or in combination with VOM ethanol infusion. The primary endpoints include procedural safety and freedom from AF or atrial tachycardia (AT) of more than 30 seconds on 30-day continuous event monitors at 6 and 12 months after randomization procedure (single-procedure success), off antiarrhythmic drugs. Key secondary endpoints include AF burden, freedom from AF/AT after repeat procedures and quality of life.

CONCLUSIONS

The VENUS-AF and MARS-AF will determine the safety and potential rhythm control benefit of VOM ethanol infusion when added to PVI in patients with persistent AF undergoing de novo or repeat ablation, respectively.

Ethanol infusion for Marshall bundle epicardial connections in Marshall bundle-related atrial tachycardias following atrial fibrillation ablation: The accessibility and success rate of ethanol infusion by using a femoral approach

BACKGROUND

Ethanol infusion of the vein of Marshall (VOM) may be effective to treat Marshall bundle-related atrial tachycardia (MB-AT). However, methods and clinical results of ethanol infusion for MB-AT have been not established.

OBJECTIVE

To assess the accessibility of the VOM and the success rate of ethanol infusion using a femoral approach for MB-AT.

METHODS

A single-center observational study included consecutive patients who had MB-AT and in whom we attempted to treat MB-AT during AT by ethanol infusion. When the VOM was able to be cannulated following VOM venogram using a femoral approach, we systematically performed ethanol infusion with selective balloon occlusion of the VOM. We analyzed in detail the efficacy of ethanol infusion of VOM in patients who were in MB-AT during ethanol infusion.

RESULTS

We enrolled 54 consecutive patients in whom we attempted to treat MB-AT by ethanol infusion. Of those, the VOM was accessible in 92.5% of patients (50 of 54). Of the 50 patients treated by ethanol infusion during MB-AT, AT was successfully terminated in 56% percent of the patients (28 of 50) by solo treatment of ethanol infusion without RF ablation. The remainder required additional RF application to terminate the MB-AT. A mean of 6.2 ± 2.8 mL of ethanol was infused resulting in the low-voltage area significantly larger than that before ethanol infusion (12.7 ± 8.3 vs 6.6 ± 5.3 cm² , P < .001).

CONCLUSION

The present study demonstrated that the VOM was highly accessible and MB-AT was amenable to treatment by ethanol infusion by using a femoral approach.

The role of Marshall bundle epicardial connections in atrial tachycardias after atrial fibrillation ablation

BACKGROUND

Atrial tachycardias (ATs) are often seen in the context of atrial fibrillation (AF) ablation.

OBJECTIVES

To evaluate the role of the Marshall bundle (MB) network in left atrial (LA) ATs using high-density 3-dimensional mapping.

METHODS

A total of 199 ATs were mapped in 140 patients (112 male, mean age: 61.8 years); 133 (66.8%) were macroreentrant and 66 (33.2%) were scar-related reentry circuits. MB-dependent ATs were suggested by activation mapping analysis and confirmed with entrainment along the circuit.

RESULTS

The MB network participated in 60 (30.2%) reentrant ATs: 31 perimitral ATs (PMATs) and 29 localized reentry circuits. Of 60 MB-related ATs, 49 (81.6%) terminated with radiofrequency (RF) ablation: 44 (73.3%) at the MB-LA junction and 5 (8.3%) at the MB-coronary sinus (CS) junction, while 9 (15%) terminated after 2.5-5 cc of ethanol infusion inside the vein of Marshall (VOM). Of the 31 PMATs, 17 (54.8%) terminated at the MB-LA junction, 5 (16.1%) at the MB-CS junction, and 7 (22.6%) with ethanol infusion. Of the 29 localized reentry circuits using the MB, 27 (93.1%) terminated at the MB-LA junction, none at the MB-CS junction, and 2 (6.9%) after ethanol infusion. Recurrences were mostly observed after RF ablation (18 of 37 patients, 49%) compared to ethanol infusion (1 of 9 patients, 11%) (P = .06).

CONCLUSIONS

MB reentrant ATs accounted for up to 30.2% of the left ATs after AF ablation. Ablation of the MB-LA or CS-MB connections or ethanol infusion inside the VOM is required to treat these arrhythmias.

Importance of the vein of Marshall involvement in mitral isthmus ablation

BACKGROUND

Epicardiac conduction via the vein of Marshall (VOM) can bypass the mitral isthmus (MI) line, making MI ablation difficult. This study aimed to assess the contribution of the VOM in achieving MI conduction block.

METHODS

This study included 143 consecutive patients with nonparoxysmal atrial fibrillation who underwent initial MI ablation. They were retrospectively classified into two groups, a VOM-guided group (n = 28) and a conventional group (n = 115), according to the use of a 2-Fr electrode catheter inserted in the VOM. The acute success rate of achieving MI block and the ablation data were assessed. When the bidirectional block was verified exclusively in the VOM or coronary sinus (CS) electrodes, we defined it as a pseudo MI block. In the VOM-guided group, we ascertained the complete MI block, verified both in the VOM and CS electrodes.

RESULTS

In the VOM-guided group, the pseudoblock was observed in 33.3% of the patients during MI ablation. With significantly less radiofrequency energy (19 322.6 ± 11 352.8 vs 25 389.3 ± 19 951.9, P = 0.04), we achieved a similar level of success rate in MI ablation in the VOM-guided group (96.4% vs 91.3%, P = 0.36). Notably, after achieving complete MI block, atrial burst pacing induced two perimitral flutters in the VOM-guided group, which were successfully terminated by the additional radiofrequency application.

CONCLUSIONS

Assessment of electrical conduction through the VOM could clarify the existence of a pseudo MI conduction block. However, the existence of a slow conduction through the MI could be detected only after induction of perimitral atrial tachycardia with atrial programmed stimulation.

MARSHALL bundles elimination, Pulmonary veins isolation and Lines completion for ANatomical ablation of persistent atrial fibrillation: MARSHALL-PLAN case series

INTRODUCTION

Beyond pulmonary veins (PV) isolation, the ablation strategy for persistent atrial fibrillation (AF) remains controversial. Substrate ablation may provide a high termination rate but at the cost of impaired atrial physiology and recurrent complex re-entries. To overcome these pitfalls, we investigated a new lesion set based on important anatomical considerations.

METHODS AND RESULTS

The case series included 10 consecutive patients with persistent AF. Three atrial structures were successively targeted: (1) coronary sinus and vein of Marshall (CS-VOM) musculature elimination; (2) PVs isolation; and (3) anatomical isthmuses block. The lesion set completion was the procedural endpoint. Step 1: VOM ethanol infusion was feasible in all cases (mean time of 33.4 ± 9.4 minutes), mean radiofrequency (RF) time for CS-VOM bundles was 14.4 ± 6.9 minutes. Step 2: mean RF time for PV isolation was 27.7 ± 9.3 minutes. Step 3: mean RF time for mitral, roof, and cavotricuspid lines was 5.7 ± 2.3, 8.1 ± 4.3, and 5.9 ± 1.9 minutes, respectively. The lesion set was achieved in all patients. Mean procedure time was 270 ± 29.9 minutes. AF termination and noninducibility were, respectively, obtained in 50% and 90% of the patients. After a 6-month follow-up, all patients were free from arrhythmia recurrence.

CONCLUSION

The present case series reports a new ablation strategy systematically targeting anatomical structures previously identified as possibly involved in the fibrillatory process and the recurrent tachycardias. The resulting lesion set provides good short-term outcomes. Although promising, these preliminary results need to be confirmed in the larger prospective study.

Ethanol injection into the Marshall vein provoking a pericardial effusion resulting in a fatal complication in a patient with persistent atrial fibrillation

An EIM (ethanol infusion into the vein of Marshall [VOM]) provoked a fatal complication in a chronic hemodialysis patient. Autopsy revealed a lacerated VOM covered with thrombi as the only potential cause. The EIM caused vascular damage and clots resulting in myocardial necrosis and interstitial bleeding around the lacerated VOM.

Vagal denervation in atrial fibrillation ablation: A comprehensive review

Although pulmonary vein isolation is accepted as an established interventional treatment in paroxysmal atrial fibrillation (AF), alternative modalities are being investigated because of the high recurrence rates of nonparoxysmal forms. One of the alternative ablation approaches is ablation or modification of vagal ganglionated plexi (VGP). The technique has not only been used in vagally mediated AF but also investigated in paroxysmal and nonparoxysmal AF. Clinical studies demonstrate significant discrepancy related with detection of VGP sites or ablation targets and definition of procedurel end-points, so far. In this review, we aimed to discuss the current data on the role of VGP in the pathogenesis of AF and potential therapeutic implications of ablation of these ganglia.

The Human Left Atrial Venous Circulation as a Vascular Route for Atrial Pharmacological Therapies: Effects of Ethanol Infusion

OBJECTIVES

This study catalogued the human venous left atrium (LA) circulation system and the ablative effects of ethanol in different branches.

BACKGROUND

Vascular routes to target the LA could have significant therapeutic potential. Beyond the vein of Marshall (VOM), the fluoroscopic LA venous anatomy has not been described.

METHODS

Patients undergoing ethanol infusion in the VOM as adjunctive therapy to atrial fibrillation (AF) catheter ablation were included in this study. Balloon occlusion venograms of the VOM and other LA veins were obtained in 218 patients.

RESULTS

Sequentially from the coronary sinus (CS) ostium, LA veins included: 1) proximal septal vein draining the inferior septum; 2) inferior LA vein in the annular inferior LA; 3) VOM; 4) LA appendage vein; and 4) anterior LA vein. Additionally, venous sinuses not connected to the CS included roof veins and posterior wall veins, which drained into the right and left atria, respectively. Venous connections between LA veins through capillaries and with pulmonary veins were abundant. Extracardiac collateral vessels were present in 38 patients (17.4%). Ethanol infusion in LA veins led to tissue ablation in their corresponding regions.

CONCLUSIONS

The atrial venous anatomy is amenable to selective cannulation. Consistent anatomical patterns are present. Targeting atrial tissues through atrial veins can be used for therapeutic purposes.

Techniques for the provocation, localization, and ablation of non-pulmonary vein triggers for atrial fibrillation

The end point of current catheter-based ablation approaches for the treatment of atrial fibrillation (AF) is the elimination of all the possible triggers with the least amount of ablation necessary. Once all the triggers have been eliminated, the incremental value of any additional lesion sets remains to be proven. Pulmonary vein (PV) isolation is the cornerstone of catheter ablation approaches for eliminating AF triggers. However, up to 11% of patients demonstrate reproducible sustained AF initiation from non-PV foci. In these patients, triggers can typically be elicited using standardized induction protocols, which include cardioversion of spontaneous and/or induced AF and infusion of high-dose isoproterenol. Non-PV triggers typically arise from discrete anatomical structures that include the mitral and tricuspid periannular regions, the crista terminalis and Eustachian ridge, the interatrial septum, the left atrial (LA) posterior wall, the left atrial appendage (LAA), and other thoracic veins such as the superior vena cava, the coronary sinus, and the ligament of Marshall. Localization of non-PV foci involves a detailed analysis of specific intra-atrial activation sequences using multipolar catheters in standard atrial locations coupled with information from the surface electrocardiogram P wave when possible. Multipolar catheters positioned along the coronary sinus and crista terminalis/superior vena cava region together with direct recordings from the right and left PVs allow a quick localization of non-PV foci. Elimination of non-PV triggers by means of focal ablation at the site of origin or isolation of arrhythmogenic structures (eg, LA posterior wall or superior vena cava) has been associated with improved arrhythmia-free survival.

Prevalence and distribution of focal triggers in persistent and long-standing persistent atrial fibrillation

BACKGROUND

The relevance of focal triggers in persistent atrial fibrillation (PerAF) and long-standing persistent atrial fibrillation (LSPAF) has not been previously investigated.

OBJECTIVE

We prospectively evaluated the prevalence and distribution of AF triggers in patients referred for catheter ablation of PerAF and LSPAF.

METHODS

We analyzed consecutive patients undergoing first time AF ablation who underwent a standardized trigger protocol including cardioversion of induced or spontaneous AF and infusion of up to 20 μg of isoproterenol for 15-20 minutes either before or after pulmonary vein (PV) isolation accomplished. Triggers were defined as AF/sustained atrial tachyarrhythmia or repetitive atrial premature depolarizations.

RESULTS

A total of 2168 patients were included (mean age 57 ± 11 years; 1636 [75%] men), with 1531 patients having paroxysmal AF (PAF) (71%), 496 having PerAF (23%), and 141 having LSPAF (7%). PV triggers were found in 1398 patients with PAF (91%), 449 patients with PerAF (91%), and 129 patients with LSPAF (91%) (P = .856 for comparison across groups). Non-PV triggers were elicited in a total of 234 patients (11%), and the prevalence was similar across the different types of AF (PAF, 165 [11%]; PerAF, 54 [11%]; LSPAF, 15 [11%]; P = .996 for comparison across groups).

CONCLUSION

PVs are the main AF trigger site in patients with PerAF and LSPAF, with an overall prevalence similar to that found in patients with PAF. These results support the current recommendations for PV isolation as the cornerstone of catheter ablation to eliminate AF triggers in PerAF and LSPAF.

Ethanol Infusion in the Vein of Marshall in a Patient with Persistent Atrial Fibrillation

We report the case of a 64-year-old male with persistent atrial fibrillation (AF) terminated by ethanol infusion into vein of Marshall as add-on therapy. Three-dimensional automated complex fractionated atrial electrogram (CFAE) during AF revealed clustering of CFAE at perimitral isthmus (PMI) and its unipolar mapping showed rotor-like activation, which was suggested to be critical in the perpetuation of AF. AF was organized to atrial tachycardia (AT) by 100% ethanol infusion in the vein of Marshall. Adjunctive radiofrequency ablation at PMI successfully terminated AT and led to bidirectional block of PMI.

Ethanol for the treatment of cardiac arrhythmias

INTRODUCTION

Ethanol infusion was an early mode of ablative treatment for cardiac arrhythmias. Its initial descriptions involved coronary intra-arterial delivery, targeting arrhythmogenic substrates in drug-refractory ventricular tachycardia or the atrioventricular node. Largely superseded by radiofrequency ablation (RFA) and other contact-based technologies as a routine ablation strategy, intracoronary arterial ethanol infusion remains as an alternative option in the treatment of ventricular tachycardia when conventional ablation fails. Arrhythmic foci that are deep-seated in the myocardium may not be amenable to catheter ablation from either the endocardium or the epicardium by RFA, but they can be targeted by an ethanol infusion.

RECENT FINDINGS

Recently, we have explored ethanol injection through cardiac venous systems, in order to avoid the risks of complications and limitations of coronary arterial instrumentation. Vein of Marshall ethanol infusion is being studied as an adjunctive procedure in ablation of atrial fibrillation, and coronary venous ethanol infusion for ventricular tachycardia.

CONCLUSION

Ethanol ablation remains useful as a bail-out technique for refractory cases to RFA, or as an adjunctive therapy that may improve the efficacy of catheter ablation procedures.

Adjunct ablation strategies for persistent atrial fibrillation-beyond pulmonary vein isolation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Recent guidelines recommend pulmonary vein isolation (PVI) as the main procedural endpoint to control recurrent AF in symptomatic patients resistant to antiarrhythmic drugs. The efficacy of such procedure is higher in paroxysmal AF while is still unsatisfactory in persistent and long-standing persistent AF. This review will summarize the state-of-the-art of AF ablation techniques in patients with persistent AF, discussing the evidence underlying different approaches with a particular focus on adjunctive ablation strategies beyond PVI including linear ablation, ablation of complex fractionated atrial electrograms (CFAE), ablation of ganglionated plexi, dominant frequency, rotors and other anatomical sites frequently involved in AF triggers.

Ethanol infusion in the vein of Marshall leads to parasympathetic denervation of the human left atrium: implications for atrial fibrillation

OBJECTIVES

This study sought to determine whether ethanol infusion in the vein of Marshall (VOM) can ablate intrinsic cardiac nerves (ICN).

BACKGROUND

ICN cluster around the left atrial epicardium and are implicated in the genesis of atrial fibrillation (AF).

METHODS

Patients undergoing catheter AF ablation underwent adjunctive ethanol injection in the VOM. A multipolar catheter was introduced in the VOM and used for high-frequency stimulation (HFS), either as HFS with P-wave synchronized (SynchHFS), 30 pulses, 100 Hz (n = 8) or as HFS with 3 to 10 s bursts (BurstHFS), 33 Hz (n = 72) at 25 mA for 1-ms duration. Atrioventricular (AV) nodal conduction slowing (asystole >2 s or R-R interval prolongation >50%) and AF inducibility were assessed before and after VOM ethanol infusion. Up to 4 1-ml infusions of 98% ethanol were delivered via an angioplasty balloon in the VOM.

RESULTS

SynchHFS induced AF in 8 of 8 patients. In 4 of 8 AF initiated spontaneously without VOM capture. No parasympathetic responses were elicited by SynchHFS. BurstHFS was performed in 32 patients undergoing de novo AF ablation (Group 1) and 40 patients undergoing repeat ablation (Group 2). Parasympathetic responses were found in all 32 Group 1 patients and in 75% of Group 2 patients. After VOM ethanol infusion, parasympathetic responses were abolished in all patients (both groups). There were no acute complications related to VOM ethanol infusion.

CONCLUSIONS

The VOM contains ICN that connect with the AV node and can trigger AF. Retrograde ethanol infusion in the VOM reliably eliminates local ICN responses. The VOM is a vascular route for ICN-targeting therapies.

Effect of Age on Outcomes of Catheter Ablation of Atrial Fibrillation

Age has a great impact in the development of atrial fibrillation, which is the most common arrhythmia found in the elderly. The higher risk of stroke, heart failure and mortality associated with atrial fibrillation highlights the need for successful therapeutic interventions that can translate in better outcomes in this population. The introduction of catheter ablation has revolutionized the management of atrial fibrillation over the past decades with an undeniable impact in morbidity, mortality and quality of life. This benefit has not been fully extended to the older patients due to the lack of definitive data from randomized control trials assessing the impact ofrhythm control strategies such as catheter ablation in this population, in whom a rate-control strategy has been suggested as a better therapeutic option. In this review, we summarize the pathogenesis of atrial fibrillation in the elderly, the benefits and complications of catheter ablation reported in the literature and the impact of age in the outcomes of ablation compared to younger populations.

A review of mitral isthmus ablation

Mitral isthmus ablation forms part of the electrophysiologist’s armoury in the catheter ablation treatment of atrial fibrillation. It is well recognised however, that mitral isthmus ablation is technically challenging and incomplete ablation may be pro-arrhythmic, leading some to question its role. This article first reviews the evidence for the use of adjunctive mitral isthmus ablation and its association with the development of macroreentrant perimitral flutter. It then describes the practical techniques of mitral isthmus ablation, with particular emphasis on the assessment of bi-directional mitral isthmus block. The anatomy of the mitral isthmus is also discussed in order to understand the possible obstacles to successful ablation. Finally, novel techniques which may facilitate mitral isthmus ablation are reviewed.

Role of the vein of Marshall in atrial fibrillation recurrences after catheter ablation: therapeutic effect of ethanol infusion

Vein of Marshall Ethanol in Recurrent AF.

INTRODUCTION

Atrial fibrillation (AF) or flutter can recur after pulmonary vein (PV) antral isolation (PVAI). The vein of Marshall (VOM) has been linked to the genesis of AF. We hypothesized that the VOM may play a role in AF recurrences and that VOM ethanol infusion may have therapeutic value in this setting.

METHODS AND RESULTS

Sixty-one patients with recurrent AF or flutter after PVAI were studied. The VOM was successfully cannulated in 54; VOM and PV electrograms were recorded, and differential PV-VOM pacing was performed. VOM signals were present in all patients; however, VOM triggers of AF could not be demonstrated. VOM tachycardia was present in 1 patient. Left inferior (LIPV) and left superior (LSPV) reconnection was present in 32 and 30 patients, respectively. Differential pacing in VOM and LIPV showed VOM-mediated LIPV reconnection in 5/32 patients. In others, VOM and PV connected indirectly via left atrial tissues. Up to four 1 cc infusions of 98% ethanol were delivered in the VOM. Regardless of the reconnection pattern, ethanol infusion eliminated LIPV and LSPV reconnection in 23/32 and 13/30 patients, respectively. Ethanol terminated VOM and LIPV tachycardias in 2 patients. There were no acute procedural complications.

CONCLUSIONS

VOM signals are consistently present in recurrent AF. VOM may rarely play a role in PV reconnection. However, VOM ethanol infusion can be useful in patients with recurrent AF after PVAI, assisting in achieving redisconnection of reconnected left PVs.

Ethanol infusion in the vein of Marshall facilitates mitral isthmus ablation

BACKGROUND

Treatment of perimitral flutter (PMF) requires bidirectional mitral isthmus (MI) block, which can be difficult with radiofrequency ablation (RFA). The vein of Marshall (VOM) is located within the MI.

OBJECTIVE

To test whether VOM ethanol infusion could help achieve MI block.

METHODS

Perimitral conduction was studied in patients undergoing ablation of atrial fibrillation. Group 1 included 50 patients with a previous atrial fibrillation ablation undergoing repeat ablation, 30 of whom had had MI ablation. Spontaneous (8 of 50) or inducible PMF (21 of 50) was confirmed by activation mapping. Group 2 included 21 patients undergoing de novo VOM ethanol infusion. The VOM was cannulated with a quadripolar catheter for pacing and with an angioplasty balloon to deliver up to four 1-mL infusions of 98% ethanol. Voltage maps were created before and after VOM ethanol infusion. Bidirectional MI block was verified by differential pacing. RFA times required to achieve it were assessed.

RESULTS

In group 1, VOM ethanol infusion acutely terminated PMF in 5 of 29 patients. RFA needed to achieve bidirectional MI block was 2.2 ± 1.6 minutes. Presence of PMF or previous MI ablation did not affect RFA times. In group 2, RFA needed to achieve bidirectional MI block was 2.0 ± 1.6 minutes (P = NS). Five patients had bidirectional MI block achieved solely by VOM ethanol infusion without RFA. In both groups, ablation after VOM ethanol infusion was required in the annular aspect of the MI. There were no acute complications.

CONCLUSION

VOM ethanol infusion is useful in the treatment of PMF and assists in reliably achieving bidirectional MI block.

Atrial Coronary Arteries: Anatomy And Atrial Perfusion Territories

Coronary anatomy has traditionally focused on ventricular circulation. This is largely due to the extent to which coronary artery disease contributes to ischemic heart disease through ventricular myocardial damage. Atrial fibrillation and other tachyarrhythmias that involve the atria, however, remain a major cause of morbidity and mortality. In order to increase mechanistic research and therapeutic interventional procedures for diseases of the atria, an optimal knowledge of atrial anatomy is necessary. While substantial clarity exists regarding the distribution of nerve terminals and the organization of muscle bundles, the anatomy of coronary atrial circulation remains understudied. Historically, the high anatomical variability of atrial coronary branches led to unstandardized nomenclature in the literature. In this review, we delineate the anatomic courses of key atrial coronary branches and their perfusion territories, clarify their nomenclature, and propose unifying anatomical concepts of atrial circulation that we believe to be critical to the success of modern electrophysiologic and surgical procedures.

Left atrial coronary perfusion territories in isolated sheep hearts: implications for atrial fibrillation maintenance

BACKGROUND

The role of coronary perfusion in the maintenance of atrial fibrillation (AF) electrical sources that anchor to the posterior (wall of the) left atrium (PLA) has been incompletely investigated. We hypothesized that the PLA-pulmonary vein region is perfused by branches originating from both the right and left coronary arteries.

OBJECTIVE

The purpose of this study was to evaluate whether branches originating from the right and left coronary arteries could serve as conduits to chemically ablate restricted PLA regions.

METHODS

In Langendorff-perfused sheep hearts, the right anterior and left anterior atrial arteries (RAAA and LAAA) and the branches of the left circumflex artery (LCX) were identified as main coronary artery branches perfusing the atria. During sustained AF, 20-mL boluses of cold Tyrode's solution (4°C) was injected into each artery to determine changes in dominant frequency. The injection that yielded the largest dominant frequency decrease indicated the coronary branch to be subsequently perfused with ethanol. Ethanol was selectively injected into the LAAA (n = 4), LCX (n = 4), or RAAA (n = 1).

RESULTS

Six of nine AF cases rapidly terminated upon ethanol perfusion. In those hearts and in eight additional preparations (n = 17), Congo red and Evans blue was subsequently perfused into the remaining atrial branches. The perfusion territories were classified as triple-vessel PLA perfusion (n = 4), LAAA-dominant PLA perfusion (n = 5), balanced double-vessel PLA perfusion (n = 5), and LCX or RAAA dominant (n = 3).

CONCLUSION

PLA coronary perfusion relies on a variable contribution of right and left coronary branches. Regional irrigation of ethanol in well-delineated PLA perfusion territories enabled ablation of high-frequency sites during AF.