Percutaneous pericardial instrumentation for endo-epicardial mapping of previously failed ablations

Catheter Ablation of Left Ventricular Summit Arrhythmias from Adjacent Anatomic Vantage Points

Idiopathic ventricular arrhythmias (VA), particularly left ventricular outflow tract (LVOT) VA accounts for up to 10% of all VAs referred for ablative therapy. In addition to being infrequent, its intricate anatomy and its pathophysiology make catheter ablation (CA) of these arrhythmias a challenge even for experts. In this scenario, detailed right ventricular outflow tract as well as LVOT electroanatomic mapping including epicardial mapping are essential. In this article, we will emphasize our approach toward the CA technique used for LVOT VA, particularly IVS and/or LVS VA originating from intramural foci, along with its acute and long-term efficacy and safety.

Dexmedetomidine for sedation during epicardial ablation for ventricular tachycardia: a single-center experience

BACKGROUND

Epicardial approach to ventricular tachycardia (VT) ablation is mainly performed under general anesthesia (GA). Although catheter manipulation and ablation in the epicardial space could be painful, GA lowers blood pressure and may interfere with arrhythmia induction and mapping, and the use of muscle relaxants precludes identification of the phrenic nerve (PN). Moreover, an anesthesiologist's presence is required during GA for the whole procedure, which may not always be possible. Therefore, we evaluated the feasibility and safety of epicardial VT ablations performed under conscious sedation using dexmedetomidine in our center.

METHODS

Between January 2018 and January 2022, all patients who underwent epicardial VT ablation under continuous dexmedetomidine infusion were prospectively included in the study. All patients received premedication 30 min before the epicardial puncture with paracetamol (acetaminophen 10 mg/ml) 1000 mg and ketorolac 30 mg. Sedation protocol included an intravenous bolus of midazolam hydrochloride (0.03-0.05 mg/kg) followed by continuous infusion of dexmedetomidine (0.2-0.7 mcg/kg/h). In addition, an intravenous fentanyl citrate bolus (0.7-1.4 mcg/kg) was given for short-term analgesia, followed by a second dose repeated after 30 to 45 min. Sedation-related complications were defined in case of respiratory failure, severe hypotension, and bradycardia requiring treatment.

RESULTS

Sixty-nine patients underwent epicardial or endo-epi VT ablation under conscious sedation and were included in the analysis. The mean age was 65.4 ± 12.1 years; forty-six patients were males (66.6%). All patients had drug-refractory recurrent VT. Forty-seven patients (68.1%) had non-ischemic cardiomyopathy (NICM), 13 patients (18.9%) had ischemic-cardiomyopathy (ICM), and 9 patients (13%) had myocarditis. Standard percutaneous sub-xiphoid access was attempted in all patients. Non-inducibility of any VT was achieved in 82.6% (9/9 myocarditis, 10/13 ICM, 38/47 NICM, n = 57/69 patients), inducibility of non-clinical VT in 13% (3/13 ICM, 6/38 NICM, n = 9/69 patients), and failure in 4.3% (3/38 NICM, n = 3/69 patients). Although we observed procedural-related complications in five patients (7.2%), one transient PN palsy, two pericarditis, and two vascular complications, those were not related to the conscious sedation protocol. No respiratory failure, severe hypotension, or bradycardia requiring treatment has been observed among the patients.

CONCLUSIONS

Prompt availability of anesthesiology support remains crucial for complex procedures such as epicardial VT ablation. Continuous infusion of dexmedetomidine and administration of midazolam and fentanyl seem to be a safe and effective sedation protocol in patients undergoing epicardial VT ablation.

Impact of sex on clinical, procedural characteristics and outcomes of catheter ablation for ventricular arrhythmias according to underlying heart disease

BACKGROUND

Women are under-represented in many key studies and trials examining outcomes of catheter ablation (CA) for ventricular arrhythmias (VA). We compared characteristics between men and women undergoing their first catheter ablation for VA at a single centre over 10 years.

METHODS

The clinical, procedural characteristics and outcomes of 287 consecutive patients (male = 182, female = 105), undergoing their first CA at our centre over 10 years were compared according to sex and underlying heart disease.

RESULTS

In the ablation population, women were younger, had fewer co-morbidities, were less likely to have ischemic cardiomyopathy (ICM) and VA storm and were more likely to have idiopathic VA and premature ventricular complexes as the indication for ablation (P < 0.05 for all). Amongst idiopathic and non-ischemic cardiomyopathy (NICM) subgroups, baseline characteristics were similar; amongst ICM, women were younger and had higher numbers of drug failure pre-ablation (P = 0.05). Women were similar to men in all procedural characteristics, acute procedural success and complications, regardless of underlying heart disease. At median follow-up of 666 days, VA-free survival, overall mortality and survival free of death or transplant were comparable in both groups. Sex was not a predictor of these outcomes, after accounting for clinical and procedural characteristics.

CONCLUSION

Women represented 36% of the real-world population at our centre referred for CA of VA. There are key differences in clinical features of women versus men referred for VA ablation. Despite these differences, VA ablation in women can be accomplished with similar success and complication rates to men, regardless of underlying heart disease.

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.

Successful ventricular tachycardia radioablation in a patient with previous chemical pleurodesis: A case report

Introduction

Stereotactic arrhythmia radioablation (STAR) is a novel technique for the ablation of ventricular tachycardia in patients with contraindications to standard procedures, i.e., radiofrequency ablation.

Case presentation

We report the case of a 73-year-old man with non-ischemic dilated cardiomyopathy and recurrent VT episodes. Electroanatomic mapping showed VT prevalently of epicardial origin, but direct epicardial access through subxyphoid puncture could not be performed due to pleuropericardial adhesions from a past history of chemical pleurodesis. STAR was performed, with no VT recurrence at 6 months follow-up.

Conclusions

Previous experiences with STAR have demonstrated its importance in the management of patients with refractory VT in whom other ablation strategies were not successful. Our case report highlights the use of STAR as a second choice in a patient with an unfavorable VT anatomical location and technical limitations to an optimal radiofrequency ablation. Moreover, it confirms STAR's effectiveness in the ablation of complex transmural lesions, which are more often associated with non-ischemic structural heart disease.

Catheter Ablation for Ventricular Tachycardia in Ischaemic Versus Non-Ischaemic Cardiomyopathy: A Systematic Review and Meta-Analysis

BACKGROUND

There are differences in substrate and ablation approaches for ventricular tachycardia (VT) in ischaemic (ICM) and non-ischaemic cardiomyopathy (NICM).

OBJECTIVE

To perform a systematic review and meta-analysis comparing clinical and procedural characteristics/outcomes of VT ablation in ICM versus NICM.

METHODS

Electronic databases were searched for comparative studies reporting outcomes of VT ablation in patients with ICM and NICM. Primary outcomes were acute procedural success, VT recurrence and long-term mortality. Meta-analyses were performed using random-effects modelling.

RESULTS

Thirty-one (31) studies (7,473 patients; 4,418 ICM and 3,055 NICM) were included. Patients with ICM were significantly older (67.0 vs 55.3 yrs), more commonly male (89% vs 79%), had lower left ventricular ejection fraction (29% vs 38%) were less likely to undergo epicardial access (11% vs 36%) and were more likely to require haemodynamic support during ablation (relative risk [RR] 1.30; 95% CI 1.01-1.69). Acute procedural success (i.e. non-inducibility of VT) was higher in the ICM cohort (RR 1.10, 95% CI 1.05-1.15). Recurrence of VT at follow-up was significantly lower in the ICM cohort (RR 0.77; 95% CI 0.70-0.84). Peri-procedural mortality, incidence of procedural complications and long-term mortality were not significantly different between the cohorts.

CONCLUSIONS

NICM and ICM patients undergoing VT ablation are fundamentally different in their clinical characteristics, ablation approaches, acute procedural outcomes and likelihood of VA recurrence. VT ablation in NICM has a lower likelihood of procedural success with increased risk of VA recurrence, consistent with known challenging arrhythmia substrate.

Epicardial ablation of ventricular tachycardia in patients with structural heart disease: a single-centre experience over 12 years

AIMS

Epicardial ablation has risen to an essential part of the treatment of ventricular tachycardias (VTs). In this study, we report the efficacy, risks, and current trends of epicardial ablation in structural heart disease as reported in a tertiary single centre over a 12-year period.

METHODS AND RESULTS

Two hundred and thirty-six patients referred for VT ablation underwent a successful epicardial access and were included in the analysis (89% non-ischaemic cardiomyopathy, 90% males, mean age 60 years, mean left ventricular ejection fraction 38.4%). After performing epicardial ablation the clinical VTs were eliminated in 87% of the patients and 71% of the cohort achieved freedom from VT during 22-month follow-up. Twelve patients (5%) suffered major procedure-related complications. Until the end of follow-up 47 (20%) patients died, 9 (4%) underwent a left ventricular assist device implantation and 10 (4%) patients received a heart transplantation. Antiarrhythmic drugs at baseline and during follow-up were independent predictors of VT recurrence. Atrial fibrillation, renal dysfunction, worse New York Heart Association class, and antiarrhythmic drugs at follow-up were associated with worse survival in our cohort.

CONCLUSION

In this large tertiary single-centre experience, percutaneous epicardial access was feasible in the large majority of the cohort with acceptably low complications rates. A combined endo-/epicardial approach resulted in 87% acute and 71% long-term success. Further studies are needed to clarify the role of routine combined endo-/epicardial ablation in these complex cardiomyopathies.

Ablation of Accessory Pathways with Challenging Anatomy

Although catheter ablation of accessory pathways is deemed highly safe and effective, peculiar location of these pathways might lead to complex and potentially hazardous procedures requiring ablation in anatomic regions such as para-Hisian area, coronary sinus, and epicardial surface. The electrophysiologist should know these possible scenarios to plan the best strategy for safe and effective ablation of these uncommon accessory pathways.

Epicardial Ablation of Supraventricular Tachycardias

Supraventricular arrhythmias are the most common cardiac arrhythmias encountered; however, it is uncommon that supraventricular tachycardias require percutaneous epicardial access for successful mapping and ablation. There are particular scenarios where epicardial access and ablation should be considered. Certain accessory pathways particularly in the posteroseptal region may require epicardial access for successful ablation. These pathways may also be approached from within the coronary sinus system. In addition, tachycardias near the phrenic nerve in the right atrium or left atrium may require epicardial access for successful ablation or to allow displacement of the phrenic nerve facilitating safe catheter ablation.

Applicability of computed tomography preoperative assessment of the LAA in LV summit ablations

Purpose

Ventricular arrhythmias originating from the left ventricular summit (LVS) may present with challenges for catheter ablation. Recently, the left atrial appendage (LAA) became a new vantage point for mapping and ablating arrhythmias from that region, but data of possible usefulness is limited.

Methods

From September to December 2019, we retrospectively analyzed 48 consecutive patient hearts (20 male; mean age 57.9y ± 11.56) undergoing diagnostic coronary vessel imaging in 64 dual-source computer tomography angiography (CTA). Distances from the LAA to the LVS, LAA shape type, and coronary arteries in the LVS region were measured. Also, we compared the true LVS area from CTA with a calculated formula derived from LVS definition.

Results

The mean LVS area calculated from the formula was 291.58 mm² (± 115.5) while the true area calculated from CT was 263.33 mm² (± 99.49) (p = 0.44). The mean inaccessible area was 133.42 mm² (± 72.89), accessible 95.67 mm² (± 72.77). The mean LAA coverage over LVS was 196.08 mm²—which is approximately 75% of LVS size in general. The most common LAA shape was chicken wing (50%); windsock has the highest accessible area coverage on average (80.23%), followed by chicken wing (59.88%), broccoli (47.72%), and cactus (46.98%). The mean distance from LAA to the surface was 5.14 mm (1.5 to 10 mm) and was not correlated with BMI. LAA has a 98% coverage over the point of transition between the great cardiac vein and anterior interventricular vein.

Conclusion

Angio-CT assessment of the LAA over the LVS structures may be helpful in decision making before an ablation procedure. LAA appears to be a promising mapping approach in LVS arrhythmias.

Patient Selection for Epicardial Ablation-Part I: The Role of Epicardial Ablation in Various Cardiac Disease States

Epicardial catheter ablation is most commonly performed following unsuccessful endocardial ablation. Given the frequency of epicardial substrates in certain cardiomyopathic disease states, however, a combined endocardial–epicardial approach should be considered as a primary treatment strategy. Although epicardial ablation is primarily deployed in patients with ventricular arrhythmias, the role of epicardial approaches in supraventricular tachycardias (eg, atrial fibrillation, inappropriate sinus tachycardia, and—rarely—accessory pathways) is growing, with continued advances being made.

Percutaneous Epicardial Approach to Catheter Ablation of Cardiac Arrhythmias

Since their introduction >2 decades ago, percutaneous catheter-based epicardial mapping and ablation have become widely adopted by cardiac electrophysiologists around the world. Although epicardial mapping has been used for catheter ablation of a wide variety of cardiac arrhythmias, its most common use is for ablation of intramural and subepicardial substrates that give rise to ventricular tachycardia, particularly in patients with nonischemic cardiomyopathy. As such, the subxiphoid percutaneous epicardial approach has emerged as an important adjunct, and, in some cases, is the preferred strategy in this regard. This review discusses the rationale and indications for epicardial catheter mapping and/or ablation. This paper also reviews the prevalence of epicardial arrhythmias and their electrocardiographic criteria. In addition, it examines the anatomy of the pericardium and commonly used epicardial access techniques, as well as the optimal methodologies for epicardial mapping and ablation and the impact of epicardial fat. Finally, this review discusses the potential of the various complications associated with the percutaneous epicardial approach, in addition to patient-specific risk factors, and potential strategies to mitigate the risk of complications.

Ventricular Arrhythmias

Ventricular tachycardia is commonly seen in medical practice. It may be completely benign or portend high risk for sudden cardiac death. Therefore, it is important that clinicians be familiar with and able to promptly recognize and manage ventricular tachycardia when confronted with it clinically. In many cases, curative therapy for a given ventricular arrhythmia may be provided after a thorough understanding of the underlying substrate and mechanism. In this article, the authors broadly review the current classification of the different ventricular arrhythmias encountered in medical practice, provide brief background regarding the different mechanisms, and discuss practical diagnosis and management scenarios.

Repeat ablation of refractory ventricular arrhythmias in patients with nonischemic cardiomyopathy: Impact of midmyocardial substrate and role of adjunctive ablation techniques

INTRODUCTION

Multiple ablations are often necessary to manage ventricular arrhythmias (VAs) in nonischemic cardiomyopathy (NICM) patients. We assessed characteristics and outcomes and role of adjunctive, nonstandard ablation in repeat VA ablation (RAbl) in NICM.

METHODS AND RESULTS

Consecutive NICM patients undergoing RAbl were analyzed, with characteristics of the last VA ablations compared between those undergoing 1 versus multiple-repeat ablations (1-RAbl vs. >1RAbl), and between those with or without midmyocardial substrate (MMS). VA-free survival was compared. Eighty-eight patients underwent 124 RAbl, 26 with > 1RAbl, and 26 with MMS. 1-RAbl and > 1-RAbl groups were similar in age (57 ± 16 vs. 57 ± 17 years; P = 0.92), males (76% vs. 69%; P = 0.60), LVEF (40 ± 17% vs. 40 ± 18%; P = 0.96), and amiodarone use (31% vs. 46%, P = 0.22). One-year VA freedom between 1-RAbl vs. > 1RAbl was similar (82% vs. 80%; P = 0.81); adjunctive ablation was utilized more in >1RAbl (31% vs. 11%, P = 0.02), and complication rates were higher (27% vs. 7%, P = 0.01), most due to septal substrate and anticipated heart block. >1-RAbl patients had more MMS (62% vs. 16%, P < 0.01). Although MMS was associated with worse VA-free survival after 1-RAbl (43% vs. 69%, P = 0.01), when >1RAbl was performed, more often with nonstandard ablation, VA-free survival was comparable to non-MMS patients (85% vs. 81%; P = 0.69). More RAbls were required in MMS versus non-MMS patients (2.00 ± 0.98 vs. 1.16 ± 0.37; P < 0.001).

CONCLUSION

For NICM patients with recurrent, refractory VAs despite previous ablation, effective arrhythmia control can safely be achieved with subsequent ablation, although >1 repeat procedure with adjunctive ablation is often required, especially with MMS.

An alternative under-valve approach to ablate right-sided accessory pathways

BACKGROUND

Right-sided accessory pathway (RAP) ablation is sometimes challenging.

OBJECTIVE

Our study aimed to demonstrate an alternative ablation approach to RAPs under the tricuspid valve, especially when the conventional ablation attempts at the atrial side failed.

METHODS

Twelve patients with RAPs were enrolled, 8 of whom had previously failed ablation. With the help of a long sheath, the under-valve approach was attempted in 3 patients during tachycardia, in 2 patients during ventricular pacing, and in 7 patients during sinus rhythm. Three-dimensional electroanatomic mapping was performed in 3 patients during their repeat procedures.

RESULTS

The acute outcomes of the procedures in all patients were successful. Patients were free of tachycardia or recurrence of accessory pathway conduction during a median follow-up of 12.5 months (range 7-45 months). No complications were found during the procedure or follow-up period.

CONCLUSION

Radiofrequency ablation under the tricuspid valve to eliminate RAPs is feasible because of its stable contact and the accurate ablation of the ventricular insertion site. It provides an alternative approach to tough RAP ablation.

Ventricular Arrhythmias

Ventricular tachycardia (VT) is the most common form of wide complex tachycardia and is associated with a high mortality rate. Electrocardiographic analysis remains paramount in diagnosis and helps to direct therapy. Antiarrhythmic agents, although effective in reducing arrhythmia burden, have never demonstrated a mortality benefit. The implantable cardioverter-defibrillator aids not only in the acute termination of ventricular arrhythmia, but provides a wealth of information for the long-term management of patients with VT. Contemporary treatment options such as catheter ablation are increasingly used and effective, but often remain imperfect, with recurrent VT being not uncommon.

Anterior pericardial access to facilitate electrophysiology study and catheter ablation of ventricular arrhythmias: A single tertiary center experience

INTRODUCTION

Epicardial ablation is becoming an important part of management in patients with ventricular tachycardia (VT). Posterior epicardial access via the Sosa or needle-in-needle (NIN) approach for epicardial VT ablation is considered to be the method of choice for most electrophysiologists. Anterior epicardial access as an alternative technique has recently been proposed, but there are limited data about its safety, efficacy, and the rate of immediate complications. In this study, we report our experience with anterior epicardial access between 2009 and 2016.

METHODS

Between 2009 and June 2016, 100 consecutive patients underwent epicardial VT ablation using an anterior approach. The success rate, epicardial bleeding, and other complications related to the epicardial access in these patients were compared to the previously reported rate of complications in patients whom epicardial access was performed using the NIN or Sosa techniques.

RESULTS

Anterior epicardial access was obtained successfully in 100% of patients in the first attempt. The success rate of the anterior approach was comparable with the reported success rate of the NIN technique (100% vs. 100%, P value not significant) but better than the Sosa technique (100% vs. 94%, P = 0.012). None of the patients in the anterior approach series suffered from significant pericardial bleeding (defined as greater than 80 mL of blood loss), RV puncture/damage, or need for an emergent cardiac surgery.

CONCLUSION

An anterior epicardial approach is feasible and appears to have an acceptable safety profile in comparison with other epicardial approaches.

Safety and efficacy of epicardial approach to catheter ablation of ventricular tachycardia - An institutional experience

BACKGROUND AND AIM

Epicardial approach to VT ablation increases the success rate of ablation but is not without complications. We studied the safety and efficacy of epicardial VT ablations performed at our institute.

METHODS

All patients who underwent epicardial VT ablation at our institute were studied retrospectively. The outcome of VT ablation was among three groups: ischaemic cardiomyopathy (ICM), non-ischaemic cardiomyopathy (NICM) and granulomatous myocarditis (GM). Safety outcomes assessed included all complications considered to be due to pericardial access or epicardial mapping/ablation.

RESULTS

A total of 54 patients (total 119 VTs, mean 2.2 (0.9)) were taken up for ablation procedure through epicardial access. Mean age: 47 (10) years, males: 83%. All patients had drug resistant recurrent VTs. The epicardial procedure was abandoned in three patients due to access issues; percutaneous sub-xiphoid access was employed in 48 and surgical approach in four patients. Complete success was achieved in 59% and partial success in 76%. The outcomes were poor in ICM patients as compared to those with GM and NICM. Overall success rates for all clinical VTs were 89% in GM, 90% in NICM and 67% in ICM. Success rates for epicardial VT ablation were 94%, 85% and 78% respectively for GM, NICM and ICM. Procedure related complications occurred in six patients.

CONCLUSION

Epicardial ablation for VT offers good immediate outcomes with acceptable safety profile.

Percutaneous epicardial ablation of incessant atrial tachycardia originating from the left atrial appendage

A 38-year-old woman presented with antiarrhythmic drug-refractory atrial tachycardia (AT). Holter recording demonstrated incessant episodes of AT followed by a long sinus pause. Electrophysiologic study revealed that the earliest endocardial activation was observed at the neck of the left atrial appendage (LAA). After unsuccessful endocardial ablation, epicardial access via a percutaneous subxiphoid approach demonstrated that the earliest epicardial atrial activation was observed on the opposite site to the endocardial LAA neck suggestive of ligament of Marshall (LOM) muscle sleeve as regarding the epicardial sharp potentials under guidance of a circular mapping catheter. Application of radiofrequency (RF) energy at this site terminated the tachycardia. After tachycardia ablation, the sinus pause also resolved.

Percutaneous Catheter Ablation of Epicardial Accessory Pathways

Radiofrequency (RF) catheter ablation is the treatment of choice in patients with accessory pathways (APs) and Wolff-Parkinson-White syndrome. Endocardial catheter ablation has limitations, including the inability to map and ablate intramural or subepicardial APs. Some of these difficulties can be overcome using an epicardial approach performed through the epicardial venous system or by percutaneous catheterisation of the pericardial space. When a suspected left inferior or infero-paraseptal AP is refractory to ablation or no early activation is found at the endocardium, a transvenous approach via the coronary sinus is warranted because such epicardial pathways can be in close proximity to the coronary venous system. Associated congenital abnormalities, such as right atrial appendage, right ventricle diverticulum, coronary sinus diverticulum and absence of coronary sinus ostium, may also hamper a successful outcome. Percutaneous epicardial subxiphoid approach should be considered when endocardial or transvenous mapping and ablation fails. Epicardial mapping may be successful. It can guide and enhance the effectiveness of endocardial ablation. The finding of no epicardial early activation leads to a more persistent new endocardial attempt. When both endocardial and epicardial ablation are unsuccessful, open-chest surgery is the only option to eliminate the AP.

Epicardial Ventricular Tachycardia Ablation for Which Patients?

With the widespread use of implantable cardioverter-defibrillators, an increasing number of patients present with ventricular tachycardia (VT). Large multicentre studies have shown that ablation of VT successfully reduces recurrent VT and this procedure is being performed by an increasing number of centres. However, for a number of reasons, many patients experience VT recurrence after ablation. One important reason for VT recurrence is the presence of an epicardial substrate involved in the VT circuit which is not affected by endocardial ablation. Epicardial access and ablation is now frequently performed either after failed endocardial VT ablation or as first-line treatment in selected patients. This review will focus on the available evidence for identifying VT of epicardial origin, and discuss in which patients an epicardial approach would be benefitial.

[Localization of the origin of idiopathic ventricular extrasystoles and tachycardia from the outflow tract]

Premature ventricular contractions (PVC) are a common cause for complaints. As a rule PVCs are not life-threatening if no structural heart disease is present; however, due to the symptoms treatment is often required using either antiarrhythmic drugs or more commonly catheter ablation. The surface electrocardiogram (ECG) is very helpful in localizing the origin of the arrhythmia, in particular for differentiating right from left ventricular sources.

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.

Electrophysiological Characteristics and Radiofrequency Catheter Ablation of Accessory Pathway Connecting the Right Atrial Appendage and the Right Ventricle

BACKGROUND

The accessory pathway (AP) connecting the right atrial appendage (RAA) and the right ventricle (RV) is rare.

OBJECTIVE

We sought to investigate the feature of the AP connecting the RAA and the RV and the efficacy of radiofrequency catheter ablation via the endocardial access.

METHODS

We retrospectively analyzed 14 consecutive patients with 14 APs connecting the RAA and the RV managed by 15 procedures between January 2003 and December 2014.

RESULTS

Ten patients presented as preexcitation during sinus rhythm. All APs had retrograde conduction. None had either antegrade or retrograde decremental conduction property. Ablation targeting the sites at the tricuspid annulus failed in all patients. They were successfully managed by ablating the atrial insertion sites with a median of 10.5 (range 5-28) radiofrequency applications. Electrograms at the successful target showed high amplitude atrial electrogram and low amplitude or no ventricular electrogram. The atrial insertion sites were at the floor of the RAA in 10 patients and inside the lower lobe of the RAA in the remaining 4 patients. The shortest distance between the successful target and the tricuspid annulus in the right anterior oblique projection was 19.7 ± 4.0 mm. There were no complications or recurrences during a median follow-up period of 4.3 (range 0.2-11.8) years.

CONCLUSION

The APs connecting the RAA and the RV had typical conduction properties. The atrial insertion site favored the floor and the lower lobe of the RAA. Ablation targeting the atrial insertion sites was effective and safe, albeit multiple radiofrequency applications were needed.

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.

Epicardial ablation of focal atrial tachycardia arising from left atrial appendage in children

Focal left atrial tachycardia (FLAT) although a common cause of supraventricular tachycardia(SVT) among children, the one's arising from left atrial appendage (LAA) present a unique challenge for successful ablation because of anatomical location. We present two children with FLAT arising from the epicardial LAA, successfully mapped and ablated through percutaneuous epicardial approach.

How to recognize epicardial origin of ventricular tachycardias?

Percutaneous pericardial access for epicardial mapping and ablation of ventricular arrhythmias has expanded considerably in recent years. After its description in patients with Chagas disease, the technique has provided relevant in-formation on the arrhythmia substrate in other cardiomyopathies and has improved the results of ablation procedures in various clinical settings. Electrocardiographic criteria proposed for the recognition of the epicardial origin of ventricular tachycardias are mainly based on analysis of the first QRS components. Ventricular activation at the epicardium has a slow initial component reflecting the transmural activation and influenced by the absence of Purkinje system in the epicardium. Various parameters (pseudodelta wave, intrinsicoid deflection and shortest RS interval) of these initial intervals predict an epicardial origin in patients with scar-related ventricular tachycardias with right bundle branch block morphology. Using the same concept, the maximum deflection index was defined for the location of idiopathic epicardial tachycardias remote from the aortic root. Electrocardiogram criteria based on the morphology of the first component of the QRS (q wave in lead I) have been proposed in patients with nonischemic cardiomyopathy. All these criteria seem to be substrate-specific and have several limitations. Other information, including type of underlying heart disease, previous failed endocardial ablation, and evidence of epicardial scar on magnetic resonance imaging, can help to plan the ablation procedure and decide on an epicardial approach.

Pericardial Access for LARIAT Left Atrial Appendage Closure

Anterior pericardial puncture requires intimate knowledge of the mediastinal anatomy and careful review of the individual anatomic characteristics of each patient. Familiarity with the procedure's anatomic foundations and with the basic principles of each procedural step are critical, but once this is achieved, the procedure is safe and, in most cases, preferable to a standard inferior puncture. An uncomplicated and properly placed pericardial puncture is the basis of a successful of LARIAT suture delivery device procedure. Operators must master the intricacies of the anterior pericardial puncture before embarking on LARIAT left atrial appendage ligation.

Catheter ablation for ventricular tachycardia: indications and techniques

Ventricular tachycardia (VT) may be secondary to many different underlying pathophysiologies. The nature of the underlying disorder determines amenability to catheter ablation, thus, dictating the circumstances under which it should be undertaken. The differing substrates also influence the choice of techniques that are used. The most intensively studied clinical subgroup of VT is re-entrant VT in the setting of ischemic heart disease. The approach to ablation in such patients is discussed in detail. Subsequent discussion focuses on other clinically encountered varieties of VT and the ablation methods used in each individual disease state.

Epicardial ablation for ventricular tachycardia

Epicardial ablation has lately become a necessary tool to approach some ventricular tachycardias in different types of cardiomyopathy. Its diffusion is now limited to a few high volume centers not because of the difficulty of the pericardial puncture but since it requires high competence not only in the VT ablation field but also in knowing and recognizing the possible complications each of which require a careful treatment.

This article will review the state of the art of epicardial ablation with special attention to the procedural aspects and to the possible selection criteria of the patients

The Emerging Role of Epicardial Ablation

Sosa and colleagues first described a percutaneous approach (via the subxiphoid area) to access the pericardial space in 1996. Epicardial mapping and ablation is increasingly used for the treatment of supraventricular and ventricular arrhythmias and represents an adjunctive approach for challenging arrhythmias to improve procedural success rates. Epicardial ablation should be considered not only after the failure of an endocardial ablation but often as a first-line approach. Complications may occur during percutaneous access and epicardial ablation, and these might be reduced or avoided by improved operator skills and experience. New tools to access the epicardial space are being evaluated.

Three dimensional epicardial mapping and ablation of recurrent non-ischaemic ventricular tachycardia

Radiofrequency ablation is a therapeutic option for recurrent ventricular tachycardia (VT) in both ischaemic and non-ischaemic subsets. Usually this is attempted by mapping endocardially; however, in some situations epicardial approach may be needed to access the VT circuit. We report two cases in which epicardial approach was used to successfully ablate the VT, when endocardial ablation was ineffective.