Recurrent monomorphic ventricular tachycardia in a patient with myocarditis-Importance of understanding and targeting midmyocardial anatomic substrate.

INTRODUCTION: Patients with viral myocarditis can present with challenging life-threatening arrhythmias. Catheter ablation can be a life-saving procedure in some patients with recurrent drug-refractory ventricular arrhythmias. METHODS AND RESULTS: A patient with three prior ablations targeting two different monomorphic ventricular tachycardias (MMVTs) presented with recurrent ventricular tachycardia (VT). Consequently, he underwent epicardial mapping with adjuvant AI-enabled CT images with the creation of a three-dimensional model, which demonstrated a midmyocardial scar. Fractionated potentials were noted during mapping in this region, and entrainment suggested an inner loop. Interestingly, pacing showed two different QRS morphologies identical to his previously ablated VTs with a long stim-QRS at this region. Epicardial ablation carried on during the VT successfully terminated it, but the VT remained inducible and required endocardial ablation to make it noninducible. CONCLUSION: This case emphasizes the importance of recognizing possible three-dimensional VT circuits in some patients and the need to understand and target mid-myocardial substrate from both the endocardium and epicardium to achieve the elimination of the VT circuits.

Exploring the Full Potential of Radiofrequency Technology: A Practical Guide to Advanced Radiofrequency Ablation for Complex Ventricular Arrhythmias.

PURPOSE OF REVIEW: Percutaneous radiofrequency (RF) catheter ablation is an established strategy to prevent ventricular tachycardia (VT) recurrence and ICD shocks. Yet delivery of durable lesion sets by means of traditional unipolar radiofrequency ablation remains challenging, and left ventricular transmurality is rarely achieved. Failure to ablate and eliminate functionally relevant areas is particularly common in deep intramyocardial substrates, e.g. septal VT and cardiomyopathies. Here, we aim to give a practical-orientated overview of advanced and emerging RF ablation technologies to target these complex VT substrates. We summarize recent evidence in support of these technologies and share experiences from a tertiary VT centre to highlight important "hands-on" considerations for operators new to advanced RF ablation strategies. RECENT FINDINGS: A number of innovative and modified radiofrequency ablation approaches have been proposed to increase energy delivery to the myocardium and maximize RF lesion dimensions and depth. These include measures of impedance modulation, combinations of simultaneous unipolar ablations or true bipolar ablation, intramyocardial RF delivery via wires or extendable RF needles and investigational linear or spherical catheter designs. Recent new clinical evidence for the efficacy and safety of these investigational technologies and strategies merits a re-evaluation of their role and clinic application for percutaneous VT ablations. Complexity of substrates targeted with percutaneous VT ablation is increasing and requires detailed preprocedural imaging to characterize the substrate to inform the procedural approach and selection of ablation technology. Depending on local experience, options for additional and/or complementary interventional treatments should be considered upfront in challenging substrates to improve the success rates of index procedures. Advanced RF technologies available for clinical VT ablations include impedance modulation via hypotonic irrigation or additional dispersive patches and simultaneous unipolar as well as true bipolar ablation. Promising investigational RF technologies involve an extendable needle RF catheter, intramyocardial RF delivery over intentionally perforated wires as well as a variety of innovative ablation catheter designs including multipolar linear, spherical and partially insulated ablation catheters.

Crazy accessory pathway- going round the bend!

A 15-year-old boy with manifest preexcitation and recurrent palpitations had undergone an unsuccessful ablation procedure elsewhere and was subsequently referred to us. The ECG suggested a left free wall pathway but there was a pattern break in lead V2. This helped localise the accessory pathway to the summit region and achieve success.

Radiofrequency catheter ablation of ventricular arrhythmias in patients with hypertrophic cardiomyopathy.

BACKGROUND: Compared to other non-ischemic substrates, there is limited data on the role and outcome of catheter ablation in HCM. The objective of this study is to assess the safety and efficacy of catheter ablation for the treatment of VT in patients with HCM. METHODS: Fourteen patients with HCM and drug refractory VT who underwent catheter ablation at a single center were included in this study. The data was evaluated retrospectively. Acute success, procedure-related complications, and long-term outcomes were documented during follow up. RESULTS: Among the 14 patients (mean age 48.2 ± 8.2 years, 85.7% males, mean LVEF 42.6 ± 6.5%), 4 had an apical aneurysm. Eleven patients had evidence of scar-related VT and three patients had a bundle-branch re-entry VT. The most common sites for scar-related VT were the border-zones of the apical aneurysms, basal septum, and LV lateral wall. Patient either underwent an endocardial ablation or a combined endocardial and epicardial ablation. Acute success was achieved in all patients. In 6 patients VT was terminated during ablation. In two patients, non-clinical VTs were inducible at the end of the procedure. No major or minor complications were observed during and after the procedure in all patients. During long-term follow up, elimination of VTs reached 78%. CONCLUSION: Catheter ablation of VT in patients with HCM is safe and successful in eliminating VT. Combining endocardial and epicardial ablation techniques can potentially lead to better outcomes in these patients. Bundle branch re-entry should be considered as a potential mechanism of VT in patients with HCM.

Epicardial mapping and ablation of biatrial macroreentrant tachycardia via Bachmann's bundle.

INTRODUCTION: Recent reports highlighted the role of epicardial connections in the development of biatrial tachycardia circuits. METHODS: We reported a case of 60-year-old female patient who was admitted with recurrent atrial tachycardia (AT) after endocardial pulmonary vein isolation and anterior mitral line formation. RESULTS: Epicardial activation map demonstrated fragmented continuous potentials at the Bachmann's bundle region with good entrainment response. Epicardial radiofrequency ablation terminated AT with complete block in the anterior mitral line. CONCLUSIONS: This case corroborates the data relevant to the role of interatrial connections-specifically Bachmann's bundle-in biatrial macroreentrant ATs and demonstrates that epicardial mapping is an effective method to identify the entire reentrant circuit.

Dry suction water seal system for management of pericardial fluid during epicardial ablation.

INTRODUCTION: Epicardial ablation is an important approach in the management of patients with complex ventricular arrhythmias. Irrigated ablation catheters present a challenge in this potential space due to fluid accumulation that can cause hemodynamic compromise, requiring frequent manual fluid aspiration. In this series, we report our initial experience with the use of a dry suction water seal system for pericardial fluid management during epicardial ablation. METHODS: Consecutive patients undergoing epicardial ventricular tachycardia (VT) ablation at a single center were included. All patients underwent epicardial access via a subxiphoid approach with a single operator. A deflectable sheath was advanced into the pericardial space, and the side port was attached to a dry suction water seal system attached to wall suction at -20 mmHg. Procedural information including patient characteristics, outcomes, and adverse events. After a period of initial experience, pericardial fluid infusion and aspiration volumes were recorded. RESULTS: Eleven patients were included in this series. All patients underwent epicardial ablation with complete success achieved in 8 of the 11 patients and partial success in the remaining patients. Pericardial fluid intake ranging from 485 to 3050 mL with aspiration of 350-3050 mL using the dry suction water seal system. No adverse events occurred. CONCLUSION: Dry suction water seal drainage systems can provide a safe strategy for efficient pericardial fluid management during epicardial VT ablation, potentially shortening procedure duration.

Successful Epicardial Radiofrequency Ablation of Ventricular Tachycardia That Shared a Pathway with Bi-Directional Conduction in a Patient with Human Immunodeficiency Virus-Associated Cardiomyopathy.

A 59-year-old man who had been diagnosed with human immunodeficiency virus-associated cardiomyopathy was referred for catheter ablation of ventricular tachycardia (VT). An electrocardiogram (ECG) waveform revealed that the clinical VT originated from the epicardium. A deceleration zone (DZ) was identified on an isochronal late activation map. Moreover, 2 forms of monomorphic VT were induced by different cycle length burst pacings from near the DZ. The morphologies of the 2 VTs with an identical cycle length were very likely to use a shared common pathway with bi-directional conduction around the slow conduction area in the left ventricle posterolateral small epicardial surface area. After ablation of the DZ, the VT was uninducible.

Left atrial macroreentrant tachycardia via Bachmann bundle revealed by epicardial mapping.

Although it is common for bi-atrial tachycardia (AT) circuits to include the Bachmann bundle, there are few reports of its role in left AT circuits. A 77-year-old man was admitted for recurrent AT with a cycle length of 425 ms. The endocardial and epicardial activation map revealed an AT circuit located in the left atrial anterior wall and transverse pericardial sinus, showing a centrifugal pattern stemming from the left atrial appendage. After radiofrequency ablation, AT was no longer induced. This case suggests that the Bachmann bundle may be part of the left AT circuit.

A case of cardiac sarcoidosis mimicking Brugada syndrome.

A 17-year-old boy was admitted for management of ventricular fibrillation (VF) with intermittent Brugada pattern on ECG. On evaluation, cardiac MRI revealed myocardial scar and mediastinal lymphadenopathy. 18-Fluorodeoxyglucose positron emission tomography scan showed inflammation in the heart, lungs, and lymph nodes. He was diagnosed as a case of cardiac sarcoidosis (CS) and treated with steroids. However, there was a reactivation of cardiac inflammation and the development of a second VF storm. Following catheter ablation, the patient's arrhythmia improved. This report highlights the inflammation due to CS mimicking channelopathic features.

Stepwise endo-/epicardial catheter ablation for atrial fibrillation: The Mediterranea approach.

BACKGROUND: Outcomes of catheter ablation (CA) among patients with nonparoxysmal atrial fibrillation (AF) are largely disappointing. OBJECTIVE: We sought to evaluate the feasibility, effectiveness, and safety of a single-stage stepwise endo-/epicardial approach in patients with persistent/longstanding-persistent AF. METHODS: We enrolled 25 consecutive patients with symptomatic persistent (n = 4) or longstanding-persistent (n = 21) AF and at least one prior endocardial procedure, who underwent CA using an endo-/epicardial approach. Our anatomical stepwise protocol included multiple endocardial as well as epicardial (Bachmann's bundle [BB] and ligament of Marshall ablations) components, and entailed ablation of atrial tachycardias emerging during the procedure. The primary outcome was freedom from any AF/atrial tachycardia episode after a 3-month blanking period. The secondary outcome was patients' symptom status during follow-up. RESULTS: The stepwise endo-/epicardial approach allowed sinus rhythm restoration in 72% of patients, either directly (n = 6, 24%) or after AF organization into atrial tachycardia (n = 12, 48%). BB's ablation was commonly implicated in arrhythmia termination. After a median follow-up of 266 days (interquartile range, 96 days), survival free from AF/atrial tachycardia was 88%. Antiarrhythmic drugs could be discontinued in 22 patients (88%). As compared to baseline, more patients were asymptomatic at 9-month follow-up (0% vs. 56%, p = .02). Five patients (20%) developed mild medical complications, whereas one subject (4%) had severe kidney injury requiring dialysis. CONCLUSION: A single-stage endo-/epicardial CA resulted in favorable rhythm and symptom outcomes in a cohort of patients with symptomatic persistent/longstanding-persistent AF and one or more prior endocardial procedures. Epicardial ablation of BB was commonly implicated in procedural success.

The surgical technique of the convergent procedure.

The convergent procedure is a newly developed hybrid ablation procedure that involves extensive epicardial ablation of the posterior left atrial wall followed by endocardial mapping and addition of pulmonary vein isolation. It is a team-based approach that provides a promising option for patients with persistent and permanent atrial fibrillation. In this manuscript, we present a detailed description of the surgical component of this procedure and include potential pitfalls based on our experience in performing it.

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.

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.

Outcomes after catheter ablation of ventricular tachycardia without implantable cardioverter-defibrillator in selected patients with arrhythmogenic right ventricular cardiomyopathy.

AIMS: The roles of implantable cardioverter-defibrillators (ICDs) and radiofrequency catheter ablation (RCA) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and well-tolerated monomorphic ventricular tachycardia (MVT) are debated. In this multicentre retrospective study, we aimed at reporting the outcome of selected patients with ARVC after RCA without a back-up ICD. METHODS AND RESULTS: Patients with ARVC who underwent RCA of well-tolerated MVT at 10 tertiary centres across 5 countries, without an ICD before and 3 months after RCA, without syncope or electrical storm, and with left ventricular ejection fraction ≥50% were included. In total, 65 ARVC patients [mean age 44.5 ± 13.2 years, 78% males] underwent RCA of MVT between 2003 and 2016. Clinical presentation was palpitations in 51 (80%) patients. One (2%) patient had >1 clinical MVT. At the ablative procedure, clinical MVTs (mean rate 185 ± 32 b.p.m.) were inducible in 50 (81%) patients. Epicardial ablation was performed in 19 (29%) patients. Complete acute success was achieved in 47 (72%) patients. After a median follow-up of 52.4 months (range 12.3-171.4), there was no death or aborted cardiac arrest, and VT recurred in 19 (29%) patients. Survival without VT recurrence was estimated at 88%, 80%, and 68%, 12, 36, and 60 months after RCA, respectively, and was significantly associated with the approach and the procedural outcome. CONCLUSION: In patients with ARVC, well-tolerated MVT without a back-up ICD did not lead to fatal arrhythmic event after RCA despite VT recurrences in some. Our data suggest that RCA may be an alternative to ICD in selected ARVC patients.

A hybrid approach to complex arrhythmias.

Despite many years of research, the different aspects of the mechanism of atrial fibrillation (AF) are still incompletely understood. And although the latest guidelines recommend catheter ablation with pulmonary vein isolation as a rhythm control strategy, long-term results in persistent and long-standing persistent AF are suboptimal. Historically, a mechanistic-based patient-tailored approach for the treatment of AF was impossible because of the lack real-time mapping techniques and advanced ablation tools. Therefore, surgeons created lesion sets based upon the anatomy of both atria and the safety of the incisions made by the knife. These complex open-heart procedures had to be performed through a sternotomy on the arrested heart and where therefore not generally adopted. The use of controlled energy sources such as cryothermy and radiofrequency where the first step to make the creation of these lesions less complex. With the development and improvement of electrophysiology techniques and catheters, this invasive and solely anatomical approach could again be partially redesigned. Now less invasive, it prepared the way for collaboration between electrophysiologists working on the endocardial side of the heart and cardiac surgeons providing epicardial access. The introduction of video-assisted technology and hybrid procedures has further increased the possibilities of new successful therapies. Now more than 40 years since the beginning of this exciting maze of AF procedures and still working towards a less aggressive and more comprehensive approach we give an overview of the history of the different minimally invasive surgical solutions and of the hybrid approach.

Successful Ablation of an Epicardial Accessory Pathway via the Subxiphoid Approach in a Child.

Data is scarce regarding epicardial ablation in children. I herewith present a case of successful epicardial ablation in a child with previous unsuccessful attempts at endocardial ablation. This report could be used to guide further such attempts.

Novel Doppler-guided subxyphoid approach to avoid coronary artery damage during left ventricular epicardial lead placement or ablation.

BACKGROUND: Subxyphoid active left ventricular epicardial (LVE) lead implants or VT ablation are attractive but remain a challenge due to concerns of coronary artery damage. We aimed to see if Doppler-guided positioning could permit safe LVE lead placement without coronary angiography. We evaluated the feasibility of a Doppler flow-guided subxyphoid epicardial screw-in lead fixation in a swine model. METHODS: Acute subxyphoid access to the pericardial space was performed in an anesthetized swine model using a deflectable sheath and a modified needle-derived Doppler flow meter. The audio signal and visual display from the Doppler flow meter were recorded. Coronary angiography was performed to verify the catheter location. A SelectSecure Model 3830 lead (Medtronic) was used to assess pacing in the procedure. RESULTS: In both of two swine, the deflectable catheter was inserted into pericardial space via subxyphoid access. The tip of the deflectable catheter with the Doppler was directed to several locations, from quiet (no nearby coronary artery expected) to typical rhythmic pulsatile sound locations which were maximal when superimposed on a coronary artery. Repeated coronary angiograms confirmed the expected findings. A 3830 active lead was fixed into a quiet location for LVE pacing, and confirmed by angiography as distant from a coronary artery. CONCLUSIONS: Doppler-guided subxyphoid epicardial screw-in lead placement is feasible once the catheter tip is directed and stabilized in a desired LVE location. This obviates the need for repeated (or any) coronary angiography. The Doppler-guided subxyphoid epicardial procedure may also be applicable for epicardial ventricular arrhythmia ablation procedures.

Endo-epicardial ablation vs endocardial ablation for the management of ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy: A systematic review and meta-analysis.

BACKGROUND: The pathologic process of ARVC (arrhythmogenic right ventricular cardiomyopathy) typically originates in the epicardium or subepicardial layers with progression toward endocardium. However, in the most recent ARVC international task force consensus statement, epicardial ventricular tachycardia (VT) ablation is recommended as a Class I indication only in patients with at least one failed endocardial VT ablation attempt. OBJECTIVE: The aim of this meta-analysis is to assess the outcomes of ARVC patients undergoing combined endo-epicardial VT ablation, as compared to endocardial ablation alone. METHODS: A systematic review of PubMed, Embase, and Cochrane was performed for studies reporting clinical outcomes of endo-epicardial VT ablation vs endocardial-only VT ablation in patients with ARVC. Fixed-Effect model was used if I2 < 25 and the Random-Effects Model was used if I2 ≥ 25%. RESULTS: Nine studies consisting of 452 patients were included (mean age 42.3 ± 5.7 years; 70% male). After a mean follow-up of 48.1 ± 21.5 months, endo-epicardial ablation was associated with 42% relative risk reduction in VA recurrence as opposed to endocardial ablation alone (risk ratio [RR], 0.58; 95% confidence interval [CI], 0.45-0.75; P < .0001). No significant differences were noted between endo-epicardial and endocardial VT ablation groups in terms of all-cause mortality (RR, 1.19; 95% CI, 0.03-47.08; P = .93) and acute procedural complications (RR, 5.39; 95% CI, 0.60-48.74; P = .13). CONCLUSIONS: Our findings suggest that in patients with ARVC, endo-epicardial VT ablation is associated with a significant reduction in VA recurrence as opposed to endocardial ablation alone, without a significant difference in all-cause mortality or acute procedural complications.

Convergent epicardial-endocardial ablation for treatment of long-standing persistent atrial fibrillation: A review of literature.

BACKGROUND AND AIM OF STUDY: The convergent procedure (CVP) is a hybrid ablation technique via a subxiphoid incision that has recently emerged as a treatment option for non-paroxysmal atrial fibrillation (npAF). By combining endocardial and epicardial ablation into a simultaneous or staged procedure, the pulmonary vein and posterior left atrium can be isolated with transmural lesion sets while minimizing the risk of proarrhythmic gaps that are a known limitation with endocardial linear lesion sets. We reviewed the 12-month outcomes in patients who underwent CVP compared to those who underwent endocardial catheter ablation (CA) and surgical ablation (SA). METHODS: A literature search was conducted using the PubMed database for publications related to CVP. Selected studies included detailed 12-month follow-up of patients, patient characteristics, periprocedural complications, use of antiarrhythmic drugs (AADs), and monitoring method. RESULTS: Five studies with 340 patients who underwent CVP between January 2009 and March 2017 were selected for this review. A total of 8.5% of patients had paroxysmal AF (pAF), 42.2% had persistent AF (peAF), and 49.1% had long-standing persistent AF (lspAF). At 12 months, 81.9% of patients were in sinus rhythm, while 54.1% of patients were in sinus rhythm while not taking AADs. The overall complication rate was 10%. CONCLUSION: CVP had better 1-year efficacy in eliminating AF when compared to CA. However, SA, specifically the Cox Maze IV, had lower rates of AF recurrence in the npAF patient population. Despite its promising 1-year efficacy rates, the periprocedural complication rate for CVP was significantly higher than both CA and SA.