Successful Ventricular Tachycardia Ablation Research Articles

Endomyocardial substrate of ventricular arrhythmias in patients with autoimmune rheumatic diseases.

Delayed enhancement-magnetic resonance imaging (DE-MRI) has demonstrated that nonischemic cardiomyopathy is mainly characterized by intramural or epicardial fibrosis whereas global endomyocardial fibrosis suggests cardiac involvement in autoimmune rheumatic diseases or amyloidosis. Conduction disorders and sudden cardiac death are important manifestations of autoimmune rheumatic diseases with cardiac involvement but the substrates of ventricular arrhythmias in autoimmune rheumatic diseases have not been fully elucidated. 20 patients with autoimmune rheumatic diseases presenting with ventricular tachycardia (VT) (n = 11) or frequent ventricular extrasystoles (n = 9) underwent DE-MRI and/or endocardial electroanatomical mapping of the left ventricle (LV). Ten patients with autoimmune rheumatic diseases underwent VT ablation. Global endomyocardial fibrosis without myocardial thickening and unrelated to coronary territories was detected by DE-MRI or electroanatomical voltage mapping in 9 of 20 patients with autoimmune rheumatic diseases. In the other patients with autoimmune rheumatic diseases, limited regions of predominantly epicardial (n = 4) and intramyocardial (n = 5) fibrosis or only minimal fibrosis (n = 2) were found using DE-MRI. Endocardial low-amplitude diastolic potentials and pre-systolic Purkinje or fascicular potentials, mostly within fibrotic areas, were identified as the targets of successful VT ablation in 7 of 10 patients with autoimmune rheumatic diseases. Global endomyocardial fibrosis can be a tool to diagnose severe cardiac involvement in autoimmune rheumatic diseases and may serve as the substrate of ventricular arrhythmias in a substantial part of patients.

P105: Pre-Emptive Use of Mechanical Circulatory support in sudden cardiac death- A contrasting case series

Life-threatening ventricular tachycardia(VT) and fibrillation(VF) are the most important causes of sudden cardiac death(SCD). Patients who survive are often predisposed to recurrent VT secondary to scar tissue and require definitive ablation therapies. However given the unpredictable nature of arrhythmias, patients can degenerate into VT storm even as outpatient and become hemodynamically unstable which precludes ablation therapies. Using preemptive mechanical circulatory support in such patients as a bridge to ablation can be a game changer, especially in the event of a fresh VT. We present two contrasting cases, where preemptive use of Impella showed better outcomes in neurological status post cardiac arrest. Our patient is a 16-year-old competitive basketball player who suffered an out-of-hospital VT arrest during match practice requiring bystander CPR and multiple shocks. He was stabilized in an outside hospital and brought to us intubated, paralyzed, on multiple pressors and maintained on IV amiodarone and lidocaine. ECHO demonstrated a very large right ventricle (RV) with severe left ventricle(LV) dysfunction, ejection fraction(EF) 10-15% with basal RV diameter 6.8cm. Cardiac MRI(CMRI) showed an area of late gadolinium enhancement (LGE) of the RV-free wall near the apex. Endomyocardial biopsy, Cardiac catheterization, and CT angiogram were unremarkable. With improvement in volume status, he was weaned off all inotropes and antiarrhythmics, received an AICD, and maintained only on sotalol and lisinopril. On outpatient follow-up, repeat CMRI confirmed Arrhythmogenic RV dysplasia. Unfortunately, four months later, the patient had another episode of cardiac arrest secondary to a VT storm with 20 minutes of downtime. He was deemed too unstable for VT ablation and thus emergently underwent a stellate ganglion block. The patient remained encephalopathic post-cardiac arrest with very slow neurologic recovery. He subsequently underwent cardiac transplantation The second case is that of a 63-year-old male with a past medical history of nonischemic cardiomyopathy with LVEF of 10% status post-ICD placement, and VT on amiodarone who presented with episodes of monomorphic VT followed by ICD shocks and syncope. Heart catheterization showed diffuse three-vessel disease. Due to recurrent VT patients, he received an Impella CP as a bridge to VT ablation. Interestingly during ablation, the patient goes into cardiac arrest requiring CPR for 90 minutes. He had successful VT ablation and with no neurological deficit post-procedure. Multiple trials have shown an improved 30-day survival rate without neurological sequelae with early implantation of Impella during ongoing CPR for cardiac arrest. Impella has several favorable properties by unloading the LV which limits the infarct size and maintains cerebral perfusion during the arrest. Preemptive Impella use is often used as a bridge to transplant, however using it as a bridge to ablation is yet to gain prominence.

Inducibility of Multiple Ventricular Tachycardia's during a Successful Ablation Procedure Is a Marker of Ventricular Tachycardia Recurrence.

Even after a successful ventricular tachycardia ablation (VTA), some patients have recurrent ventricular tachycardia (VT) during their follow-up. We assessed the long-term predictors of recurrent VT after having a successful VTA. The patients who underwent a successful VTA (defined as the non-inducibility of any VT at the procedure's end) in 2014-2021 at our center in Israel were retrospectively analyzed. A total of 111 successful VTAs were evaluated. Out of them, 31 (27.9%) had a recurrent event of VT after the procedure during a median follow-up time of 264 days. The mean left ventricular ejection fraction (LVEF) was significantly lower among patients with recurrent VT events (28.9 ± 12.67 vs. 23.53 ± 12.224, p = 0.048). A high number of induced VTs (>two) during the procedure was found to be a significant predictor of VT recurrence (24.69% vs. 56.67%, 20 vs. 17, p = 0.002). In a multivariate analysis, a lower LVEF (HR, 0.964; p = 0.037) and a high number of induced VTs (HR, 2.15; p = 0.039) were independent predictors of arrhythmia recurrence. The inducibility of more than two VTs during a VTA procedure remains a predictor of VT recurrence even after a successful VT ablation. This group of patients remains at high risk for VT and should be followed up with and treated more vigorously.

Catheter ablation as first line treatment in patients with ischemic cardiomyopathy, tolerated ventricular tachycardia and left ventricular ejection fraction over 35%: long term outcomes

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Patients with ischemic cardiomyopathy (ICM) and monomorphic, sustained ventricular tachycardia (VT) are considered to be at risk for arrhythmia-related sudden cardiac death (SCD). Prior studies have suggested that patients with well-tolerated VTs and preserved or moderately reduced left ventricular ejection fraction (LVEF) and successful VT ablation may not benefit from cardioverter defibrillator implantation (ICD Current guidelines indicate that in selected patients catheter ablation should be considered instead of ICD, but supporting evidence is limited. Aim This study aims to analyze arrhythmia outcomes of ICM patients referred for VT ablation without prior ICD implantation according to LVEF, hemodynamical stability during VT and ablation outcome. Methods ICM patients without prior ICD implantation undergoing VT ablation in a tertiary center between 2009 and 2022 were included. Patients who presented with a first episode of tolerated VT and w a LVEF≥35% were offered catheter ablation (CA) as first-line therapy. Patients were categorized according to (1) LVEF, (2) clinical presentation (hemodynamically tolerated/non-tolerated VT) and (3) acute ablation outcome. According to the institutional protocol, ICD was offered to all patients after ablation, but was subject to shared decision making, explaining the available evidence supporting ICDs for the different categories. Results Eighty-six ICM patients without ICD underwent ablation for VT. Mean age was 69±9 years and 72 (84%) were men, mean LVEF was 41±9% and 34 patients (28%) were using anti-arrhythmic drugs (AAD). The median VT cycle length (VTCL) at presentation was 323ms [300 – 375] and VT was tolerated in 58 (67%) patients (median tolerated VTCL 325ms [300 – 371]). In 66 (77%) patients, the LVEF was ≥35% of which 51 had well-tolerated VT. Of these 51 patients, 37 (73%) were rendered non-inducible after ablation and in 14 patients non-clinical VTs remained inducible (median remaining VTCL 238ms [203-288]). In 5/37 non-inducible and in 11/14 inducible patients, an ICD was implanted. Of the 35 patients who had LVEF<35% and/or non-tolerated VTs, 7 refused ICD implantation. (Figure 1) During a median follow-up of 35 [22 – 53] months, 10 patients (12%) had VT-recurrence and one patient with an ICD had SCD. Mortality was 22%. In the 37 patients with LVEF≥35%, tolerated VT and non-inducibility post procedure, no SCD or VT-recurrence was observed. Also, in this group no patient was using AAD for VT at last follow-up. In the 14 remaining patients with LVEF≥35% and tolerated VT who were still inducible after ablation, no SCD occurred but VT recurred in 29% (median VTCL 303ms [200-374]) with AAD-use for VT in 29%. Conclusion This study supports that ICM patients without prior ICD and LVEF≥35% who present with hemodynamically well-tolerated VT and are non-inducible after ablation have an excellent prognosis. Successful CA without ICD implantation seems to be safe in these selected patients.

PO-05-031 CATHETER ABLATION AS FIRST LINE TREATMENT IN PATIENTS WITH ISCHEMIC CARDIOMYOPATHY, TOLERATED VENTRICULAR TACHYCARDIA AND LEFT VENTRICULAR EJECTION FRACTION ≥35%: LONG TERM OUTCOMES

Patients with ischemic cardiomyopathy (ICM) and ventricular tachycardia (VT) are at risk for sudden cardiac death (SCD). Prior studies have suggested that patients with well-tolerated VTs and preserved/moderately reduced left ventricular ejection fraction (LVEF) and successful VT ablation may not benefit from cardioverter defibrillator implantation (ICD). Current guidelines indicate that in selected patients catheter ablation should be considered instead of ICD. This study aims to analyze arrythmia outcomes of ICM patients referred for VT ablation without prior ICD implantation according to LVEF, tolerance of VT and ablation outcome. ICM patients without prior ICD implantation undergoing VT ablation in a single center between 2009 and 2022 were included. Patients who presented with tolerated VT and who had a LVEF≥35% were offered catheter ablation (CA) as first-line therapy. Patients were categorized according to (1) LVEF, (2) hemodynamical tolerance of VT, and (3) acute ablation outcome. According to the institutional protocol, ICD was offered to all patients after ablation. Eighty-six patients (mean age 69±9 years, 84% male, mean LVEF 41±9%) underwent VT ablation. The median presenting VT cycle length (VTCL) was 323ms [300 – 375] and was tolerated in 67% (tolerated VTCL 325ms [300 – 371]). In 66 patients, the LVEF was ≥35%, of which 51 had well-tolerated VT. Of these 51 patients, 37 (73%) were rendered non-inducible and in 14 patients non-clinical VTs remained inducible (median VTCL 238ms [203-288]). In 5/37 non-inducible and in 11/14 inducible patients, an ICD was implanted. Of the 35 patients who had LVEF<35% and/or non-tolerated VTs, 7 refused ICD implantation. During a median follow-up of 35 [22 – 53] months, 10 patients (12%) had VT-recurrence and one patient with an ICD had SCD. Overall mortality was 22%. In the 37 patients with LVEF≥35%, tolerated VT and non-inducibility post procedure, no SCD or VT-recurrence was observed. Also, in this group no patient was using AAD for VT at last follow-up. In the 14 remaining patients with LVEF≥35% and tolerated VT who were inducible after ablation, no SCD occurred but VT recurred in 29% (median VTCL 303ms [200-374]). This study supports that ICM patients without prior ICD and LVEF≥35% with hemodynamically well-tolerated VT and are non-inducible after ablation have an excellent prognosis. Successful catheter ablation without ICD implantation seems to be safe in these selected patients.

Short-time ventricular tachycardia ablation for cardiac sarcoidosis using coherent map.

A 69‐year‐old woman with isolated cardiac sarcoidosis was hospitalized for frequent appropriate implantable converter defibrillator therapies for ventricular tachycardia (VT) despite of favorably controlled condition with oral prednisolone. The patient underwent urgent catheter ablation with CARTO 3D mapping system. Although the voltage map, activation map, and propagation map during VT could not visualize the tachycardia circuit, the coherent map clarified entrance and exit sites of the tachycardia circuit with slow or nonconducting (SNO) zones, which seemed like a figure‐of‐eight circuit. Considering the risk of VT termination or acceleration to rapid unstable VT, neither entrainment nor pacing studies were performed. The VT was terminated near the exit site of the isthmus where tiny pre‐systolic potential was detected. Any diastolic potentials could not be detected. This meant that the critical isthmus might be located at the epicardium or deep incite of the left‐ventricular myocardium where the coherent map showed as SNO zones. We should recognize coherent map as artificial that may represent VT circuit as if complete endocardial reentry even if not. The procedural time from mapping to termination of VT was only 22 minutes. The patient has been free from any cardiovascular events after the procedure. Coherent map might be feasible for revealing the critical isthmus of hemodynamically stable VTs without using electrophysiological techniques, including entrainment, pacing study, and voltage map during own beats, and would enable us to achieve successful VT ablation in a short time.

Noninvasive programmed stimulation in the setting of ventricular tachycardia catheter ablation.

In the setting of catheter ablation of ventricular tachycardia (VT), invasive programmed ventricular stimulation (PVS) is considered an important tool to assess the (residual) inducibility of ventricular arrhythmias and determine the acute success of the procedure. In patients with cardiovascular implantable electronic devices, noninvasive programmed stimulation via implantable cardioverter-defibrillator (ICD) leads can be an alternative to the invasive PVS with intracardiac catheters. The advantages of noninvasive programmed stimulation include preprocedure planning of the electrophysiology procedure to ensure optimal conditions for successful catheter ablation of VT. Following the procedure, noninvasive programmed stimulation has been shown to be used as a guide for repeat early ablation, to offer better programming of ICD, to offer prognostic value regarding the VT recurrence, and to guide antiarrhythmic drug therapy. The noninvasive nature of noninvasive programmed stimulation makes it an attractive alternative to PVS in patients with ICD who have not undergone catheter ablation of VT to obtain prognostic value regarding the occurrence of VT.

Dynamic changes in the signal-averaged electrocardiogram are associated with the long-term outcomes after ablation of ischemic ventricular tachycardia

PurposeSignal-averaged ECG (SAECG) can detect inhomogeneous myocardial conduction in patients presenting with ventricular tachycardia (VT) after myocardial infarction. Radiofrequency ablation (RFCA) aims at elimination of the endocardial late potentials and non-inducibility of VT. Previously, we demonstrated that abnormal SAECG at baseline can return to normal after a successful VT ablation. The present research investigates the post-ablation changes in SAECG after RFCA of VT and their relation to the procedural long-term outcomes.MethodsThirty-three patients (31 male; age 68 ± 9 years; EF 36 ± 12%) with ischemic VT were prospectively enrolled to receive RFCA. One VT (range 1–7) per patient was ablated using substrate-guided RFCA and complete success was achieved in 28 (85%) cases. SAECG was performed before (t1), immediately after (t2), and at least 6 months (t3) after the RFCA.ResultsAfter RFCA, the amount of patients showing abnormal SAECG decreased from 82% initially (t1) to 57.6% post-interventionally (t2); P = 0.008; and remained unchanged thereafter in 57% (t3). Patients who experienced VT recurrence (VT+) during the follow-up period had broader averaged QRS (t2): (VT+) 150 ± 26 vs. (VT−) 129 ± 21 ms; P = 0.015, as well as longer LAS40 (t2): (VT+) 60 ± 26 vs. (VT−) 43 ± 18 ms; P = 0.03. Abnormal SAECG (t2) was a strong predictor for VT recurrence: HR 5.4; 95% CI 1.5–21. SAECG detected more late potentials in patients with inferior than in those with anterior scars: 95% vs. 58%; P = 0.016.ConclusionsRFCA of VT in the left ventricle can improve an abnormal SAECG in some patients after myocardial infarction. Normal SAECG after RFCA of VT is associated with a lower risk for VT recurrence and death.

New Adjusted Cutoffs for "Normal" Endocardial Voltages in Patients With Post-Infarct LV Remodeling.

This study sought to determine new reference cutoffs for normal unipolar voltage (UV) and bipolar voltage (BV) that would be adjusted for the LV remodeling. The definition of "normal" left ventricular (LV) endocardial voltage in patients with post-infarct scar is still lacking. The reference voltage of the noninfarcted myocardium (NIM) may differ between patients depending on LV structural remodeling and the ensuing interstitial fibrosis. Electroanatomic voltage mapping was integrated with isotropic late gadolinium-enhanced cardiac magnetic resonance in 15 patients with nonremodeled LV and 12 patients with remodeled LV (end-systolic volume index >50ml/m2 with ejection fraction<47% assessed by cardiac magnetic resonance). Reference voltages (fifth percentile values) were determined from pooled NIM segments without late gadolinium enhancement. The cutoffs for normal BV and UV were≥3.0 and≥6.7mV for nonremodeled LV and≥2.1 and≥6.4mV for remodeled LV. Endocardial low-voltage area (LVA) defined by the adjusted cutoffs corresponded better to late gadolinium enhancement-detected scar than did LVA defined by uniform cutoffs. In 15 patients who underwent successful ablation of ventricular tachycardia, the LVA contained >97% of targeted evoked delayed potentials. Insights from whole-heart T1 mapping revealed more fibrotic NIM in patients with remodeled LV compared with nonremodeled LV. This study found substantial differences in endocardial voltage of NIM in post-infarct patients with remodeled versus nonremodeled LV. The new adjusted cutoffs for "normal" BV and UV enable a patient-tailored approach to electroanatomic voltage mapping of LV.

An automated fractionation mapping algorithm for mapping of scar-based ventricular tachycardia.

Mapping and ablation of fractionated electrograms is a common treatment for scar-based ventricular tachycardia (VT). An automated algorithm has been developed for rapid "fractionation mapping." Electroanatomic maps from 21 ablation procedures (14 scar-based VT and seven control idiopathic VT/premature ventricular contractions with normal voltage) were retrospectively analyzed using the Ensite Precision fractionation map (fMap; Abbott Laboratories; Abbott Park, IL, USA) algorithm. For each study, voltage maps and 30 fMaps were generated using combinations of parameters: width (5, 10, 20ms), refractory time (15, 30ms), sensitivity (0.1, 0.2mV), and fractionation threshold (2, 3, 5). Parameter sensitivity was assessed by overlap of fractionated areas (fArea) with successful VT ablation sites (defined by entrainment and/or pace mapping). Specificity was assessed by presence of fractionated areas in control patients. Of the 30 fMap parameter sets tested, seven identified >50% of scar-based VT ablation sites, and 26 contained <5cm2 fractionation on control fMaps. Three combinations of fMap width/refractory/sensitivity/threshold parameters met both of the above criteria, and 20/30/0.1/2 identified the most VT ablation sites (79%) and generated 42.3 ± 28.2 cm2 of fArea on scar-based VT maps compared with 4.9 ± 3.2 cm2 on control maps (P=.001). None of the control patients and 23% of the scar-based VT patients had VT recurrence at mean 15 month follow-up. Careful selection of signal processing parameters optimizes sensitivity and specificity of automated fractionation mapping for scar-based VT. Real-time use of fMap algorithms may reduce VT ablation procedure time and improve substrate modification, which may improve outcomes.

Successful Ablation of Ventricular Tachycardia in Repaired Tetralogy of Fallot via Transjugular and Subclavian Approach.

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Surgical repair with ventricular septal defect (VSD) patch and right ventricular outflow tract (RVOT) reconstruction is the only curative therapy. The population of adults with repaired Tetralogy of Fallot (rTOF) is growing due to the improvement of surgical technique. As a consequence, the increase burden of age-dependent ventricular arrhythmias (VAs) in patients with rTOF becomes an important reason for late morbidity and mortality. Notably, the vast majority of VAs in patients with rTOF are monomorphic ventricular tachycardias (VTs).1 Given the better understanding of the potential 4 anatomic isthmuses for VT circuits,2 catheter ablation has been implemented to be an effective and curative strategy to manage VTs in patients with rTOF, while clinical approaches are frequently achieved using femoral vein. However, clinical hurdle persisted once if patients with rTOF had limited vascular access. Here, we reported a challenging case with difficult vascular access owing to multiple occluded thrombosis and successful ablation of multiple monomorphic VT was performed using superior approach guided by merged intracardiac echocardiography (ICE) and reconstructed cardiac computed tomography (CT) image reconstruction in a case of rTOF.

Electrocardiographic criteria of epicardial ventricular tachycardia with anterior origin.

ECG criteria for identifying an epicardial origin of ventricular tachycardia (VT) have mainly been described for VTs with basal-superior and lateral origin. The aim of this study was to determine ECG criteria for epicardial VTs with anterior origin as a guide for trans-pericardial ablation. Among 22 patients undergoing successful ablation of VTs from the anterior myocardial wall, 14 patients underwent endocardial ablation and 8 patients underwent epicardial ablation. VTs with anterior origin ablated epicardially had widened QS complexes in precordial leads with staircase-shaped notching and slowing of the descent to the nadir of S. In comparison, endocardial VTs with anterior origin usually had narrower QS complexes with a smooth and fast downstroke to the nadir of S. The duration of the negative pseudodelta wave was longer in epicardial VTs (55 ± 12ms) compared to endocardial VTs (22 ± 12ms). The interval "time to the nadir of S" in patients with anterior VT origin was longer in epicardial VTs (121 ± 16ms) than in endocardial VTs (80 ± 22ms). The QRS duration was also longer in patients with epicardial origin (212 ± 19ms) than with endocardial VT origin (166 ± 30ms). Epicardial origin of VTs arising from the anterior myocardial wall produces a slowing, widening and staircase-shaped notching in the initial VT-QS complex. Thus, the morphology of the initial part of the QS complex in precordial leads can be used as a guide for trans-pericardial ablation of VTs with anterior origin.

Catheter Ablation of Ventricular Tachycardia.

Catheter ablation of ventricular tachycardia (VT) in patients with structural heart disease has been effective in reducing VT burden. Current guidelines from the American College of Cardiology, American Heart Association, and Heart Rhythm Society include considering catheter ablation in patients whose VT recurs despite antiarrhythmic drug therapy.1 Although the success rates of VT ablation in major trials have ranged from 50% to 70%,2,3 the long-term prognosis of this patient population is guarded, and it is unknown whether successful ablation alters survival outcomes.At first, approaches to VT ablation necessitated that patients undergo the induction of VT to enable mapping and ablation. However, most patients do not tolerate VT. Many centers have since adopted a more substrate-based approach, evaluating regions of slow or abnormal conduction while patients are in sinus rhythm. Indications include late potentials, fractionated electrograms, and sites with latent or multiple morphologies during pacing. Higher-density mapping has led to more extensive targets for ablation.4Investigators have evaluated survival prospects after VT ablation.3,5 Of note in a multicenter study of 1,064 patients undergoing VT ablation,5 noninducibility of VT after ablation was independently associated with better survival rates; conversely, older age, atrial fibrillation, and diabetes mellitus were associated with higher mortality rates. In a 12-center study of 2,061 patients with ischemic and nonischemic cardiomyopathy who underwent VT ablation,3 the one-year rate of freedom from recurrent VT was 70%, and it was associated with less all-cause death and better transplant-free survival rates.In terms of survival rates across New York Heart Association functional classes, all patients benefited after successful VT ablation, especially those in functional class IV—implying that the sickest patients have the most to gain.6In a prospective trial among patients whose VT recurred despite antiarrhythmic drug therapy,7 patients were randomized to ablation or to escalated drug therapy. During a mean follow-up period of 27.9 ± 17.1 months, there was a significant difference in the overall combined endpoint of death, VT, and implantable cardioverter-defibrillator (ICD) shocks. The ablation group fared significantly better with fewer incidences of VT storm and ICD shocks; however, between-group mortality rates did not differ.The multicenter observational studies3,5 suggest improved survival rates after successful VT ablation. This association warrants further clarification in prospective, randomized trials such as that described above.7 Meanwhile, it is hoped that advances in VT treatment can improve outcomes in the challenging population of patients with drug-refractory VT.

Ventricular Tachycardia Ablation in the Elderly

Successful ventricular tachycardia (VT) ablation is associated with improved survival in patients with heart failure. However, the safety and efficacy of VT ablation in the elderly, a population with higher competing nonsudden death risk and comorbidities, have not been well defined. The International Ventricular Tachycardia Center Collaborative Study Group registry of 2061 patients who underwent VT ablation at 12 international centers was analyzed. Kaplan-Meier analysis was used to estimate survival of patients ≥70 years with and without VT recurrence. Of the 2049 patients who met inclusion criteria, 681 (33%) patients were ≥70 years of age (mean age, 75±4 years). Among these, 92% were men, 71% had ischemic VT, and 42% had VT storm at presentation. Mean (±SD) left ventricular ejection fraction was 30±11%. Compared with patients <70 years, patients ≥70 years had higher in-hospital (4.4% versus 2.3%; P=0.01) and 1-year mortality (15% versus 11%; P=0.002) but a similar incidence of VT recurrence at 1 year (26% versus 25%; P=0.74) and time to VT recurrence (280 versus 289 days; P=0.20). Absence of VT recurrence during follow-up was strongly associated with improved survival in patients ≥70 years. VT ablation in the elderly is feasible and reasonably safe with a modestly higher in-hospital and 1-year mortality, with similar rates of VT recurrence at 1 year compared with younger patients. Successful VT ablation, that is, lack of VT recurrence, is strongly associated with improved survival even in this elderly subgroup.

Epicardial ablation of tachyarrhythmia in children: Experience at two academic centers.

Experience with percutaneous epicardial ablation of tachyarrhythmia in pediatrics is limited. This case series addresses the feasibility, safety, and complications of the procedure in children. A total of nine patients underwent 10 epicardial ablation procedures from 2002 to 2013 at two academic centers. Activation mapping was performed in all cases, and electroanatomic map was utilized in nine of the 10 procedures. Patients had undergone one to three failed endocardial catheter ablations in addition to medical management, and all had symptoms, a high-risk accessory pathway (AP), aborted cardiac arrest with Wolff-Parkinson-White syndrome (WPW), or ventricular dysfunction. A standard epicardial approach was used for access in all cases, using a 7- or 8- Fr sheath. Epicardial ablation modality was radiofrequency (RF) in seven, cryoablation (CRYO) in one, and CRYO plus RF in one. Median age was 14 (range 8-19) years. drug refractory ectopic atrial tachycardia (one), ventricular tachycardia (VT) (five), high-risk AP (two), and aborted cardiac arrest from WPW - (one). Epicardial ablation was not performed in one case despite access due to an inability to maneuver the catheter around a former pericardial scar. VT foci included the right ventricular outflow tract septum, high posterior left ventricle (LV), LV outflow tract, postero-basal LV, and scar from previous rhabdomyoma surgery. WPW foci were in the area of the posterior septum and coronary sinus in all three cases. Overall procedural success was 70% (7/10), with epicardial ablation success in five and endocardial ablation success after epicardial mapping in two. The VT focus was close to the left anterior descending coronary artery in one of the unsuccessful cases in which both RF and CRYO were used. There was one recurrence after a successful epicardial VT ablation, which was managed with a second successful epicardial procedure. There were no other recurrences at more than 1 year of follow-up. Complications were minimal, with one case of inadvertent pleural access requiring no specific therapy. No pericarditis or effusion was seen in any of the patients who underwent epicardial ablation. Epicardial ablation in pediatric patients can be performed with low complications and acceptable success. It can be considered for a spectrum of tachycardia mechanisms after failed endocardial ablation attempts and suspected epicardial foci. Success and recurrence may be related to foci in proximity to the epicardial coronaries, pericardial scar, or a distant location from the closest epicardial location. Repeat procedures may be necessary.

Successful ventricular tachycardia ablation in patients with electrical storm reduces recurrences and improves survival

The purpose of this study was to evaluate the characteristics and outcome of patients undergoing ablation after electrical storm (ES). Clinical and procedural characteristics, ventricular tachycardia (VT) recurrence, and mortality rates from 1940 patients undergoing VT ablation were compared between patients with and without ES. The group of 677 patients with ES (34.9%) were older, were more frequently men, and had a lower ejection fraction, more advanced heart failure, and a higher prevalence of cardiovascular comorbidities as compared with those without ES (86.1% patients with ES had ≥2 comorbidities vs 71.4%; P < .001). Patients with ES had more inducible VTs (2.5 ± 1.8 vs 1.9 ± 1.9; P < .001), required longer procedures (296.1 ± 119.1 minutes vs 265.7 ±110.3 minutes; P < .001), and had a higher in-hospital mortality (42 deaths [6.2%] vs 18 deaths [1.4%]; P < .001). At 1-year follow-up, patients with ES experienced a higher risk of VT recurrence and mortality (32.1% vs 22.6% and 20.1% vs 8.5%; long-rank, P < .001 for both). Among patients with ES, those without any inducible VT after ablation had a higher survival rate (86.3%) than did those with nonclinical VTs only (72.9%), those with clinical VTs inducible at programmed electrical stimulation (51.2%), and not-tested patients (65.0%) (long-rank, P < .001 for all). In multivariate analysis, ES remained an independent predictor of in-hospital mortality, VT recurrence, and 1-year mortality (P < .001). Patients with ES have a high risk of VT recurrence and mortality. Patient and procedure characteristics are consistent with advanced cardiac disease and longer and more complex procedures. In patients with ES, acute procedural success is associated with a significant reduction in VT recurrence and improved 1-year survival.

Amiodarone Discontinuation or Dose Reduction Following Catheter Ablation for Ventricular Tachycardia in Structural Heart Disease.

This study sought to examine long-term outcomes in patients with structural heart disease in whom amiodarone was reduced/discontinued after ventricular tachycardia (VT) ablation. VT in patients with structural heart disease increases morbidity and mortality. Amiodarone can decrease VT burden, but long-term use may result in organ toxicities and possibly increased mortality. Catheter ablation can also decrease VT burden. Whether amiodarone can be safely reduced/discontinued following ablation remains unknown. We studied consecutive patients undergoing VT ablation from 2008 to 2011, typically followed by noninvasive programmed stimulation several days later. Patients were divided into 3 groups by amiodarone use: group A-amiodarone reduced/discontinued following ablation; group B-amiodarone not reduced; group C-not on amiodarone at time of ablation. Baseline characteristics and outcomes were compared between groups. Overall, 231 patients (90% male; mean age: 63.4 ± 12.9 years; 53.7% ischemic cardiomyopathy) were included (group A: 99 patients; group B: 29 patients; group C: 103 patients). Group B patients were older with more advanced heart failure. Group A patients less frequently had inducible VT at the end of ablation or noninvasive programmed stimulation. In follow-up, 1-year VT-free survival was similar between groups (p= 0.10). Mortality was highest in group B (p< 0.001). Higher amiodarone dose after ablation (hazard ratio: 1.23; 95% confidence interval: 1.03 to 1.47; p= 0.02) was independently associated with shorter time to death. After successful VT ablation, as confirmed by noninducibility at the end of ablation and noninvasive programmed stimulation, amiodarone may be safely reduced/discontinued without an unacceptable increase in VTrecurrence. Reduction/discontinuation of amiodarone should be considered an important goal of VT ablation.

Anatomy for Ventricular Tachycardia Ablation in Structural Heart Disease.

Ablation of ventricular tachycardia (VT) in the setting of structural heart disease, previously reserved for highly experienced specialized centers, is being performed at more centers internationally as cardiac electrophysiologists gain advanced training. Interventional cardiac electrophysiologists need a high level of anatomic knowledge to guide a procedure that can carry significant risk. Understanding cardiac anatomy improves the chance of procedural success and also the likelihood of appropriate decision making if complications are encountered. This article focuses on selected anatomic regions where complex anatomy can be an impediment to successful VT ablation.

Catheter ablation of ventricular tachycardia and mortality in patients with nonischemic dilated cardiomyopathy: can noninducibility after ablation be a predictor for reduced mortality?

Data on outcomes after catheter ablation of ventricular tachycardia (VT) in patients with nonischemic dilated cardiomyopathy (NIDCM) are insufficient. We aimed to investigate the effects of successful catheter ablation of VT on cardiac mortality in patients with NIDCM. One hundred two patients with NIDCM (86 men; mean age, 58.8±15.2 years; mean ejection fraction, 33.3±11.9%) underwent VT ablation. After catheter ablation, a programmed ventricular stimulation to test for success was performed. Complete VT noninducibility was achieved in 62 (61%) patients and partial success or failure in 32 (31%) patients. During 2 years of follow-up, VT recurrence was observed in 33 patients (53%) without inducible VTs and in 24 patients (75%) with inducible VT inducible (P=0.041). VT inducibility was associated with higher VT recurrence (adjusted hazard ratio, 1.84; 95% confidence interval, 1.08-3.13; P=0.025). The primary end point of all-cause mortality was reached in 9 patients (15%) with noninducible VTs versus 11 patients (34%) with inducible sustained VTs (P=0.026). VT inducibility was associated with all-cause mortality (adjusted hazard ratio, 2.73; 95% confidence interval, 1.003-7.43; P=0.049). In patients with NIDCM and recurrent sustained VTs, a complete ablation of all inducible VTs may be achieved in 60% of the cases. The complete noninducibility may be a preferable end point of ablation because it was associated with better long-term success. Importantly, if possible to achieve through ablation, a complete VT noninducibility was associated with reduction of the likelihood for all-cause mortality in patients with NIDCM.

(576) - Detailed Endocardial Mapping Around the Left Ventricular Assist Device Inflow Cannula Facilitates Successful Ablation of Ventricular Tachycardia

Ventricular tachycardia (VT) is an important cause of morbidity after left ventricular assist device (LVAD) implantation. We sought to demonstrate feasibility and efficacy of VT ablation in this population, and to determine how often ablation is required around the LVAD inflow cannula.