Acute and Chronic Effects of Epicardial Radiofrequency Applications Delivered on Epicardial Coronary Arteries

Sensitivity analysis of the mechanical properties on atherosclerotic arteries rupture risk with an artificial neural network method

Considering the differences between individuals, in this paper, an uncertainty analysis model for predicting rupture risk of atherosclerotic arteries is established based on a back-propagation artificial neural network. The influence of isotropy and anisotropy on the rupture risk of atherosclerotic arteries is analyzed, and the results demonstrate the effectiveness of the artificial neural network in predicting the rupture risk. Moreover, the rupture risk of atherosclerotic arteries at different inflation sizes are simulated. This study contributes to a better understanding of the underlying mechanisms of atherosclerotic arteries rupture and promotes the advancement of artificial neural networks in atherosclerosis research.

Epicardial Ablation as a Treatment of Recurrent Ventricular Tachycardia Originating From a Left Ventricular Aneurysm: A Case Report and Review of the Literature

Catheter ablation (CA) is an important therapeutic modality for the management of ventricular tachycardia (VT). In some patients, CA may be ineffective because of the inability to reach the effective target site from the endocardial surface. Partly, this is due to the effect of the transmural extent of the myocardial scars. The operator's ability to map and ablate the epicardial surface has enhanced our understanding of scar-related VT in various substrate states. A left ventricular aneurysm (LVA) that develops after myocardial infarction may increase the risk of VT. Endocardial ablation alone of LVA may be insufficient in preventing recurrent VT. Numerous studies have demonstrated greater freedom from recurrence with adjunctive epicardial mapping and ablation via a percutaneous subxiphoid technique. Currently, epicardial ablation is performed predominantly at high-volume tertiary referral centers via the percutaneous subxiphoid approach. In this review, we first report a case of a man in his 70s with ischemic cardiomyopathy, a large apical aneurysm, and recurrent VT status post-endocardial ablation who presented with incessant VT. The patient underwent successful epicardial ablation over the apical aneurysm. Second, our case showcases the percutaneous approach and underscores its clinical indications and potential complications.

Patient Selection, Techniques, and Complication Mitigation for Epicardial Ventricular Tachycardia Ablation

Percutaneous epicardial ventricular tachycardia ablation can decrease implanted cardioverter defibrillator shocks and hospitalizations; proper patient selection and procedural technique are imperative to maximize the benefit-risk ratio. The best candidates for epicardial ventricular tachycardia will depend on history of prior ablation, type of cardiomyopathy, and specific electrocardiogram and cardiac imaging findings. Complications include hemopericardium, hemoperitoneum, coronary vessel injury, and phrenic nerve injury. Modern epicardial mapping techniques provide new understandings of the 3-dimensional nature of reentrant ventricular tachycardia circuits across cardiomyopathy etiologies. Where epicardial access is not feasible, alternative techniques to reach epicardial ventricular tachycardia sources may be necessary.

Effect of Epicardial Pulsed Field Ablation Directly on Coronary Arteries

BACKGROUND

The unique tissue selectivity of pulsed field ablation (PFA) allows for minimizing collateral damage to the nerves/esophagus. However, the safety profile of epicardial PFA on coronary arteries (CAs) has not been well defined.

OBJECTIVES

This study sought to evaluate the effect of epicardial PFA directly on CAs in a swine model.

METHODS

In 4 swine, an 8-F linear quadripolar PFA catheter (FARAPULSE Inc) was introduced into the pericardial space via a subxiphoid puncture. After coronary angiography (Angio), QRS synchronized, biphasic, bipolar PFA was delivered directly on the left anterior descending artery, left circumflex artery, or normal myocardium (control) (2.0 kV × 4 applications per site). Angio was repeated immediately after ablation and repeated every 5 minutes to quantify the degree of CA narrowing. After 4- or 8-week survival, repeat Angio was performed followed by gross and histologic lesion analyses.

RESULTS

A total of 15 lesions were delivered (8 left anterior descending arteries, 3 left circumflexes, and 4 controls). Target site Angio revealed median of 47% (IQR: 38%-69%) acute luminal narrowing immediately after PFA, which gradually resolved over 30 minutes. Epicardial PFA lesions extended into the myocardium with a median depth of 4.1 mm (IQR: 3.6-5.6 mm) passing across the CAs and adipose tissue. However, 87.5% of the CAs demonstrated minimal to mild CA stenosis associated with neointimal hyperplasia and tunica media fibrosis.

CONCLUSIONS

In a swine model, epicardial PFA directly on CAs allowed the creation of myocardial lesions but led to a CA response characterized by acute moderate spasm and chronic mild stenosis via neointimal hyperplasia.

Idiopathic Ventricular Arrhythmias Originating from Different Portions of the Coronary Venous System: Prevalence, Electrocardiographic Characteristics, Catheter Ablation, and Complications

(1) Background: To determine the prevalence, electrocardiographic characteristics, mapping, and ablation of IVAs arising from the CVS. (2) Methods: Detailed activation and pace mapping of the CVS IVAs was performed before attempted radiofrequency ablation (RFCA). (3) Results: The IVAs originating from the vicinity of the CVS represented approximately 5.27% (164/3113) of all IVAs; 94.51% (155/164) cases were accessed at the earliest identified site and 83.54% (137/164) IVAs were successfully ablated. The main coronary vein group had a relatively short procedure time, short fluoroscopy time, fewer radiofrequency lesions prior to success, and less Swartz sheath support. IVAs originating from the CVS had distinct ECG characteristics: Rs, RS or rS (with s or S) wave in lead V1 indicate the Vas arising from the proximal portion of the anterior interventricular vein (AIV) and summit-CV; Rs (with s or S) wave in leads V5−V6 indicate the Vas arising from the adjacent regions of the distal great cardiac vein 1 (DGCV1); positive wave (R, Rs or r) In lead I indicate the VAs ori”inat’ng from Summit-CV and posterior wall subgroup (including middle cardiac vein [MCV], posterior lateral vein [PLV], coronary sinus [CS]). Compared with the IVAs originating from the endocardial mitral annulus, a PdW > 45 ms, an IDT > 74 ms, and an MDI > 0.50 indicate a CVS origin of the IVAs. The common peri-procedure complications were CV dissection (6.45%, 10/155), CV rupture (1.29%, 2/155), coronary artery spasm (1.29%, 2/155), coronary artery stenosis (0.65%, 1/155), pericardial effusion (0.65%, 1/155) and tamponade (1.29%, 2/155). Stenosis of coronary arteries was not observed at the adjacent ablation site in the CVS during follow-up. (4) Conclusions: vAs arising from the CVS are not a rare phenomenon. Several ECG and procedure characteristics could help regionalize, map, and ablate the origin of IVAs from different portions of the CVS. RFCA within the CVS was relatively effective and safe.

Epicardial access complications during electrophysiology procedures

INTRODUCTION

Percutaneous epicardial access (EA) was first described more than two decades ago. Since its initial introduction, indications for its utilization in the field of electrophysiology have expanded dramatically.

DISCUSSION

Epicardial mapping and ablation in patients with ventricular tachycardia is routinely performed in tertiary electrophysiology centers around the world. Although limited by lack of randomized controlled trials, epicardial ablation for atrial fibrillation has been suggested as a conjunctive strategy in patients who have failed an initial endocardial catheter ablation attempt, and it is necessary for placement of some left atrial appendage occlusion devices as well. An accurate understanding of the cardiac anatomy is crucial to avoid complications such as inadvertent right ventricular puncture, injury to the coronary arteries, abdominal viscera, phrenic nerves, and esophagus during both EA and catheter ablation.

CONCLUSION

The aim of this review is to provide a comprehensive overview of the cardiac anatomy, technical aspects to optimize the safety of epicardial puncture, recognize and avoid potential complications.

Sensitivity analysis of non-local damage in soft biological tissues

Computational modeling can provide insight into understanding the damage mechanisms of soft biological tissues. Our gradient-enhanced damage model presented in a previous publication has shown advantages in considering the internal length scales and in satisfying mesh independence for simulating damage, growth and remodeling processes. Performing sensitivity analyses for this model is an essential step towards applications involving uncertain patient-specific data. In this paper, a numerical analysis approach is developed. For that we integrate two existing methods, that is, the gradient-enhanced damage model and the surrogate model-based probability analysis. To increase the computational efficiency of the Monte Carlo method in uncertainty propagation for the nonlinear hyperelastic damage analysis, the surrogate model based on Legendre polynomial series is employed to replace the direct FEM solutions, and the sparse grid collocation method (SGCM) is adopted for setting the collocation points to further reduce the computational cost in training the surrogate model. The effectiveness of the proposed approach is illustrated by two numerical examples, including an application of artery dilatation mimicking to the clinical problem of balloon angioplasty.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Sinoatrial nodal artery injury in thoracoscopic epicardial ablation for atrial fibrillation

OBJECTIVES

This study aimed to clarify the incidence of sinoatrial nodal artery (SANa) injury in thoracoscopic epicardial surgical ablation for atrial fibrillation (AF) and its impact on postoperative outcomes, which have not been previously elucidated.

METHODS

We enrolled 103 consecutively patients with AF who underwent thoracoscopic epicardial ablation at our institution. In these patients, we evaluated the postoperative incidence of SANa injury by using enhanced cardiac computed tomography. For patients with confirmed SANa injury, 3-day continuous electrocardiographic monitoring and exercise stress tests were performed to assess the sinus rhythm maintenance and sinus node function.

RESULTS

Thirteen patients (12.6%) had a confirmed SANa injury (left anterior type in 6 patients, left posterior type in 2 patients and double-branch type in 5 patients). After a median follow-up of 24 months, the patients with SANa injury were not found to be associated with lower sinus rhythm maintenance (hazard ratio 1.09, 95% confidential interval 0.36-3.31) as compared with those without SANa injury after adjustment for patient characteristics. Sinus node function was evaluated in 7 patients with SANa injury who remained in sinus rhythm after the procedure, and no sinus node dysfunction was confirmed in the 3-day electrocardiographic monitoring and exercise stress tests at a median follow-up of 12 months.

CONCLUSIONS

The prevalence of SANa injury in the patients who underwent thoracoscopic epicardial ablation for AF was relatively low, and the incidence of SANa injury was not associated with postoperative restoration of sinus rhythm and sinoatrial node dysfunction. More studies are required to better understand SANa injury.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Ductal closure with radiofrequency energy; outcomes of the first series

Using radiofrequency energy for closure of the patent ductus arteriosus (PDA) has been reported by us previously. In this article we report the early and late outcome of the first group in whom patent ductus arteriosus has been occluded with radiofrequency. Six children with PDA were enrolled. The procedure was successful in five cases and transient hoarseness was observed in 2 cases as the only complication.

Feasibility of near-infrared spectroscopy as a tool for anatomical mapping of the human epicardium

Epicardial ablation is necessary for the treatment of ventricular tachycardias refractory to endocardial ablation due to arrhythmic substrates involving the epicardium. The human epicardium is composed of adipose tissue and coronary vasculature embedded on the surface and within the myocardium, which can complicate electroanatomical mapping, electrogram interpretation and ablation delivery. We propose using near-infrared spectroscopy (NIRS) to decipher adipose tissue from myocardial tissue within human hearts ex vivo. Histological measurement of epicardial adipose thickness direct correlated (R = 0.884) with the adipose contrast index. These results demonstrate the potential of NIRS integrated catheters for mapping the spatial distribution of epicardial substrates and could aid in improving guidance during epicardial ablation interventions.

Development of a Shock-Wave Catheter Ablation System for Ventricular Tachyarrhythmias: Validation Study in Pigs In Vivo

Background

Although radiofrequency catheter ablation is the current state‐of‐the‐art treatment for ventricular tachyarrhythmias, it has limited success for several reasons, including insufficient lesion depth, prolonged inflammation with subsequent recurrence, and thromboembolisms due to myoendocardial thermal injury. Because shock waves can be applied to deep lesions without heat, we have been developing a shock‐wave catheter ablation (SWCA) system to overcome these fundamental limitations of radiofrequency catheter ablation. In this study, we evaluated the efficacy and safety of our SWCA system for clinical application to treat ventricular tachyarrhythmia.

Methods and Results

In 33 pigs, we examined SWCA in vivo for the following 4 protocols. First, in an epicardial substrate model (n=8), endocardial SWCA significantly decreased the sensing threshold (pre‐ versus postablation: 11.4±3.8 versus 6.8±3.6 mV; P<0.05) and increased the pacing threshold (pre‐ versus postablation: 1.6±0.8 versus 2.0±1.1 V; P<0.05), whereas endocardial radiofrequency catheter ablation failed to do so. Second, in a myocardial infarction model (n=3), epicardial SWCA of the border zone of the infarcted lesion was as effective as ablation of the normal myocardium. Third, in a coronary artery application model (n=10), direct application of shock waves to the epicardial coronary arteries caused no adverse effects in either the acute or chronic phase. Fourth, with an epicardial approach (n=8), we found that 90 shots per site provided an ideal therapeutic condition to create deep lesions with less superficial damage.

Conclusions

These results indicate that our new SWCA system is effective and safe for treatment of ventricular tachyarrhythmias with deep arrhythmogenic substrates.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Gradient-enhanced continuum models of healing in damaged soft tissues

Healing of soft biological tissue is the process of self-recovering or self-repairing the injured or damaged extracellular matrix (ECM). Healing is assumed to be stress-driven, with the objective of returning to a homeostatic stress metrics in the tissue after replacing the damaged ECM with new undamaged one. However, based on the existence of intrinsic length scales in soft tissues, it is thought that computational models of healing should be non-local. In the present study, we introduce for the first time two gradient-enhanced constitutive healing models for soft tissues including non-local variables. The first model combines a continuum damage model with a temporally homogenized growth model, where the growth direction is determined according to local principal stress directions. The second one is based on a gradient-enhanced healing model with continuously recoverable damage variable. Both models are implemented in the finite-element package Abaqus by means of a user subroutine UEL. Three two-dimensional situations simulating the healing process of soft tissues are modeled numerically with both models, and their application for simulation of balloon angioplasty is provided by illustrating the change of damage field and geometry in the media layer throughout the healing process.

Management of Arrhythmias Associated with Cardiac Sarcoidosis

Sarcoidosis is a multisystem granulomatous disorder of unknown etiology. The annual incidence of systemic sarcoidosis is estimated at 10-20 per 100,000 individuals. Owing to the recent advances in imaging modalities, cardiac sarcoidosis (CS) is diagnosed more frequently. The triad of CS includes conduction abnormality, ventricular tachycardia, and heart failure. Atrial and ventricular arrhythmias are caused by either inflammation or scar formation. Inflammation should be treated with immunosuppression and antiarrhythmic agents and scar formation should be treated with antiarrhythmics and/or ablation, in addition to implantable cardioverter defibrillator (ICD) implantation, if necessary. Ablation can provide a good outcome, but it might require bipolar ablation if the critical portion is located mid-myocardium. Late recurrence might be caused by reactivation of sarcoidosis, which would need to be evaluated by positron emission tomography-computed tomography imaging. Risk of sudden cardiac death (SCD) in patients with advanced atrioventricular block is not low, and ICD implantation could be considered instead of a pacemaker. For risk stratification for SCD, late gadolinium enhancement by cardiac magnetic resonance imaging or program stimulation is often used.

Epicardial Ablation of Ventricular Tachycardia: a Review

For over 3 decades, it has been known that reentry circuits for ventricular tachycardia (VT) are not limited to the subendocardial myocardium. Rather, intramural or subepicardial substrates may also give rise to VT, particularly in those with non-ischemic cardiomyopathy. Percutaneous epicardial mapping and ablation has been successfully introduced for the treatment of such subepicardial VT. Herein, we review the indications for epicardial ablation and the identification of epicardial VT by electrocardiographic and imaging modalities. We also discuss the optimal technique for epicardial access and the implications of epicardial fat which has the potential to mimic scar, decreasing the specificity of electrogram morphology and impeding energy delivery to the tissue. Finally, we also report on possible complications of the procedure and strategies to mitigate adverse events.

Serial examinations of right coronary artery directly injured by radiofrequency catheter ablation with optical coherence tomography and intravascular ultrasound

A 42-year-old man was referred for ablation. The origin of VT was localized close to the right coronary ostium. During ablation, the catheter tip inadvertently fell into a RCA ostium. The patient developed chest discomfort and ST-segment elevation in the inferior leads was observed. Coronary angiography confirmed severe narrowing of the ostial RCA. Stenting was deferred after satisfactory dilatation by a balloon. The patient discharged with eventless clinical course afterward. Follow-up coronary angiographic, FD-OCT, IVUS, and iMap examinations were performed at 3, 6, and 15 months after index procedure. The lesion showed progressive positive remodeling associated with intimal proliferation, medial thickening, and lumen narrowing up to 6 months. The patient underwent stenting at 15 months after the index procedure. The lesion required high-pressure post dilatation to obtain optimal stent expansion.

Better Lesion Creation And Assessment During Catheter Ablation

Permanent destruction of abnormal cardiac tissue responsible for cardiac arrhythmogenesis whilst avoiding collateral tissue injury forms the cornerstone of catheter ablation therapy. As the acceptance and performance of catheter ablation increases worldwide, limitations in current technology are becoming increasingly apparent in the treatment of complex arrhythmias such as atrial fibrillation. This review will discuss the role of new technologies aimed to improve lesion formation with the ultimate goal of improving arrhythmia-free survival of patients undergoing catheter ablation of atrial arrhythmias.

Ductal closure with radiofrequency energy: the first in-human report

BACKGROUND

Vascular obstruction is one of the complications of radiofrequency ablation. Following our previous report on the use of radiofrequency energy for vascular closure in an animal model in this journal, we herein present the first ever in-human report. Patient and method The patient was a 3-year-old boy, who received a permanent endocardial pacemaker for congenital complete heart block. He also had a conical patent ductus arteriosus. The ductus was occluded with radiofrequency energy on the arterial side with no complications.

CONCLUSION

Closure of patent ductus arteriosus and probably other problematic small vessels could be achieved with radiofrequency energy. Further experience will elucidate the future scope of this novel technique.

Arrhythmias in chagasic cardiomyopathy

Chagas disease, a chronic parasitosis caused by the protozoa Trypanosoma cruzi, is an increasing worldwide problem because of the number of cases in endemic areas and the migration of infected individuals to more developed regions. Chagas disease affects the heart through cardiac parasympathetic neuronal depopulation, immune-mediated myocardial injury, parasite persistence in cardiac tissue with secondary antigenic stimulation, and coronary microvascular abnormalities causing myocardial ischemia. A lack of knowledge exists for risk stratification, management, and prevention of ventricular arrhythmias in patients with chagasic cardiomyopathy. Catheter ablation can be effective for the management of recurrent ventricular tachycardia.

How To Identify & Treat Epicardial Origin Of Outflow Tract Tachycardias

The right ventricle outflow tract (RVOT) is the most common site of origin of idiopathic ventricular arrhythmias. The typical outflow tract arrhythmias pattern on ECG is an inferior axis deviation and left bundle branch block when originated on the RVOT and right bundle branch block morphology when originated on the left ventricular outflow tract (LVOT). There are several ECG tricks for different locations of origin. An increased Maximum Deflection Index (MDI) suggests epicardial origin of arrhythmia. In general the result of ablation is very good, but sometimes there are difficult and unsuccessful procedures. The origin in the aortic cusps and epicardium are the reason for failure in some cases. When they are epicardial, the arrhythmias can be accessed by the venous system or by subxiphoid epicardial mapping.

Accessory Atrioventricular Pathways Refractory to Catheter Ablation

Background—

Epicardial mapping and ablation of accessory pathways through a subxiphoid approach can be an alternative when endocardial or epicardial transvenous mapping has failed.

Methods and Results—

We reviewed acute and long-term follow-up of 21 patients (14 males) referred for percutaneous epicardial accessory pathway ablation. There was a median of 2 previous failed procedures. All patients were highly symptomatic, 8 had atrial fibrillation (3 with cardiac arrest) and 13 had frequent symptomatic episodes of atrioventricular reentrant tachycardia. Six patients (28.5%) had a successful epicardial ablation. Five patients (23.8%) underwent a successful repeated endocardial mapping, and ablation after epicardial mapping yielded no early activation site. Epicardial mapping was helpful in guiding endocardial ablation in 2 patients (9.5%), showing that the earliest activation was simultaneous at the epicardium and endocardium. Four patients (19%) underwent successful open-chest surgery after failing epicardial/endocardial ablation. Two patients (9.5%) remained controlled under antiarrhythmic drugs after unsuccessful endocardial/epicardial ablation. Two patients had a coronary sinus diverticulum and one a right atrium to right ventricle diverticulum. Three patients acquired postablation coronary sinus stenosis. There was no major complication related to pericardial access.

Conclusions—

Percutaneous epicardial approach is an alternative when conventional endocardial or transvenous epicardial ablation fails in the elimination of the accessory pathway. A new attempt by endocardial approach was successful in a significant number of patients. Open-chest surgery may be required in symptomatic cases refractory to endocardial–epicardial approach.

Catheter ablation of accessory pathways near the coronary sinus: value of defining coronary arterial anatomy

BACKGROUND

Accessory pathways can lie near or within the coronary sinus (CS). Radiofrequency catheter ablation of accessory pathways is a well-established treatment option, but this procedure can cause damage to adjacent coronary arteries.

OBJECTIVE

The purpose of this study was to evaluate the anatomic relationship between the coronary arteries and the CS.

METHODS

Retrospective data of patients who underwent catheter ablation of supraventricular tachycardia between June 2011 and August 2013 was reviewed. In addition, detailed analysis of coronary computed tomographic angiography (CTA) data from 50 patients was performed.

RESULTS

Between June 2011 and August 2013, 427 patients underwent catheter ablation of supraventricular tachycardia, of whom 105 (age 28 ± 17 years, 60% male) had accessory pathway-mediated tachycardia. Of these, 23 patients had accessory pathways near the CS, and 60% (N = 14) underwent concurrent coronary angiography. In 4 patients, the posterolateral (inferolateral) branch (PLA) of the right coronary artery was in close proximity to the CS, and 2 patients (18%) had stenosis of the PLA at the site of ablation. On CTA at their closest proximity, the PLA was 1.9 ± 1.3 mm and the left circumflex artery (LCx) was 2.0 ± 0.8 mm from the body of the CS, in right and left coronary artery-dominant patients, respectively. CS ostium and PLA were 3.6 ± 1.9 mm apart. In left-dominant patients, LCx and CS ostium were 3.8 ± 1.2 mm apart.

CONCLUSION

The PLA and LCx are in close proximity to the anteroinferior aspect of the CS ostium and proximal CS. The relationship of the CS and coronary arteries should be evaluated before ablation at these sites.

Numerical simulation of arterial dissection during balloon angioplasty of atherosclerotic coronary arteries

Balloon angioplasty is a standard clinical treatment for symptomatic coronary artery disease. In this procedure, controlled damage is applied intraluminally to the wall of a stenotic artery. Dissection of the coronary artery is a commonly observed clinical complication of angioplasty; however, not all dissections can be detected angioscopically. This work focuses on studying the dissection mechanisms triggered during the early stages of angioplasty in an atherosclerotic coronary artery, addressing the problem by means of a parametric study based on a simplified finite element model and cohesive interface modeling. Our results emphasize the presence of several damage mechanisms, at different locations, that are triggered near the very beginning of the process and evolve competitively, depending on both geometry and material properties of the atherosclerotic vessel. Small-scale damage was evidenced, which would not be detectable by angiography or intravascular ultrasound, but could potentially be sufficient to stimulate smooth muscle cell activation, promoting late-onset complications such as restenosis.

Characterization of Catheter–Tissue Contact Force During Epicardial Radiofrequency Ablation in an Ovine Model

Background—

Contact force (CF) during radiofrequency ablation (RFA) is an important determinant of endocardial lesion size with limited data on epicardial RFA and CF. We evaluated CF characteristics using irrigated RFA on the epicardium in an ovine model.

Methods and Results—

In 12 sheep, a 7-F irrigated RFA catheter with CF sensor was introduced via a pericardial incision onto/in parallel with ventricular epicardium. RFA (30 W per 30 second duration) was applied at 5 g , 10 g , 20 g , 40 g , and 70 g : (1) over left and right ventricular myocardium with or without fat, (2) either directly over or adjacent to a coronary artery, or directly over the phrenic nerve. Force–time integral, lesion dimensions, and coronary artery/phrenic nerve injury were recorded. Lesion size, volume, and force–time integral progressively increased with higher CF ( P <0.05). Steam pops occurred with high CF. Epicardial fat had an attenuating effect on RF penetration into myocardium ( P <0.05); however, myocardial RF lesions could be created at sites with >3.5 mm epicardial fat. At sites with epicardial fat, each 10 g increment in CF led to a 0.6 mm increase in lesion depth, whereas each 1 mm of fat reduced lesion depth into underlying myocardium by 0.7 mm. Extent of acute coronary injury with direct and indirect RFA and phrenic nerve palsy occurrence was proportional to CF.

Conclusions—

CF is a determinant of epicardial RF lesion size, steam pops, acute coronary artery injury, and phrenic nerve injury. Although epicardial fat limits lesion size, RFA with high CF can produce small myocardial RF lesions at sites of thick epicardial fat.

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.