Etiology is a predictor of recurrence after catheter ablation of ventricular arrhythmias in pediatric patients.

BACKGROUND: Ventricular arrhythmias (VAs) are rare in pediatric patients, especially in absence of structural heart disease (SHD). Few data are available regarding the invasive VAs treatment with catheter ablation (CA) in pediatric patients and predictors of outcomes have not been fully investigated. OBJECTIVE: To describe the clinical presentation, procedural characteristics, and outcomes in pediatric patients undergoing CA for VAs. METHODS: Eighty-one consecutive pediatric patients (58 male [72%], 15.5 ± 2.2 years) treated by CA for ventricular tachycardia (VT) or premature ventricular beats (PVBs) were retrospectively evaluated. Study endpoints were VAs recurrence and mortality for any cause. RESULTS: Ninety-five procedures were performed in 81 patients, 52 (55%) PVBs and 43 (45%) VT ablations. During a follow-up of 35.0 months (interquartile range = 13.0-71.0), 14 patients (14.7%) had a VA recurrence: 11 (33.3%) patients treated with CA for VT and 3 (6.2%) patients treated for PVBs (p < .001). One patient (1%) died 26 months after the procedure during an electrical storm. Patients with SHD had higher VAs recurrence rate, as compared with idiopathic VAs (pairwise log-rank p < .001). Patients treated with CA for VT had higher VA recurrence rate, as compared with PVB patients (pairwise log-rank p = .002). At Cox multivariate analysis only SHD was an independent predictor of VAs recurrence (hazard ratio = 5.56, 95% confidence interval = 2.68-11.54, p < .001). CONCLUSION: CA of VAs is effective and safe in a pediatric population. CA of idiopathic and fascicular VAs are associated with lower recurrence rate, than VAs in the setting of SHD.

Usefulness of Electroanatomical Mapping with Contact Force Monitoring for Accessory Pathways Ablation in Pediatric Population.

The current approach for catheter ablation (CA) of accessory pathways (AP) includes the use of standard catheters under fluoroscopic visualization. We hypothesize that use of contact force (CF) irrigated tip catheters might increase procedural safety in pediatric patients compared to standard irrigated tip catheters, by decreasing the number of radiofrequency (RF) pulses required to obtain AP elimination. Seventy-one pediatric patients (13.7 ± 2.5 years, 45 male) with ventricular pre-excitation were enrolled in the study. CA was performed with a standard irrigated tip catheter up to June 2013 in 41 patients (Group S) and with a CF sensing irrigated tip catheter later on in 30 patients (Group CF). In the Group CF, RF was applied with a minimal CF of 5 g; CF > 35 g was avoided. Group CF procedures required less fluoroscopy (6.8 ± 4.8 min), compared to Group S (12.2 ± 10.8 min, p = 0.007). The number of RF pulses was smaller in Group CF compared to Group S (2.5 ± 2.0 vs 5.5 ± 1.9, p < 0.01). The mean CF during the effective RF pulse was 18 ± 7.7 g, force-time integral was 1040.7 ± 955.9 gs, Ablation Index was 513.0 ± 214.2. The procedure was acutely successful in 70 patients; at 12 months follow-up 2 patients had AP recurrence, one for each group. No major complications were reported. The use of CF irrigated tip catheters was associated with a smaller number of RF pulses and less fluoroscopy, as compared to mapping and ablation with standard irrigated tip catheters.

Late potentials abolition reduces ventricular tachycardia recurrence after ablation especially in higher-risk patients with a chronic total occlusion in an infarct-related artery.

INTRODUCTION: Late potentials (LP) abolition is recognized as an effective strategy for substrate ablation of ventricular tachycardia (VT). The presence of a chronic total occlusion in a coronary artery responsible for a previous myocardial infarction (infarct related artery CTO, IRA-CTO) is emerging as a predictor of ventricular arrhythmias and VT recurrence after ablation. We sought to analyze the effects of LP abolition, focusing on the high-risk subgroup of patients with IRA-CTO. METHODS AND RESULTS: This was a single-center, observational study that screened all patients with prior myocardial infarction and clinical VT, referred for VT ablation at San Raffaele Hospital between 2010 and June 2013. Patients were then included in the study if they had a coronary diagnostic angiography (without revascularization) performed during the index hospitalization. The main endpoint was VT recurrence after ablation. Eighty-four patients formed the population of the study. An IRA-CTO was present in 47 patients (56%) and the presence of an IRA-CTO was a predictor of VT recurrence (HR 3.7, P = 0.005). LP were observed in 51 patients and successfully abolished in 38 cases. LP abolition was associated with lower VT recurrence especially among patients with IRA-CTO (24% vs. 65%, P = 0.005). The presence of an IRA-CTO, in combination with no LP abolition, was the strongest predictor of VT recurrence (HR 4.4, P < 0.001). CONCLUSIONS: Late potentials abolition is an effective strategy for substrate ablation of ventricular tachycardia. The additional reduction of VT recurrence achieved with LP abolition on top of noninducibility is especially significant among high-risk patients with IRA-CTO.

Catheter Ablation of Ventricular Tachycardia in Patients With MitraClip Device: Preliminary Findings.

INTRODUCTION: Patients with mitral regurgitation are increasingly treated by percutaneous implantation of a MitraClip device (Abbott Park, IL, USA). We investigate the feasibility and safety of the transmitral catheter route for catheter ablation of ventricular tachycardia (VT) in these patients. METHODS: The mitral valve with the MitraClip in situ was crossed under transesophageal 3-dimensional echocardiographic and fluoroscopic guidance using a steerable sheath for ablation of the left ventricle. RESULTS: Five patients (all males, median age 74.0 ± 16.0 years) who had previously a MitraClip implanted were referred for catheter ablation of VT. The left ventricular ejection fraction was 29.0% ± 24.0%. One patient had both an atrial septal defect and a left atrial appendage occluder device in addition to a MitraClip. The duration between MitraClip implantation and ablation was 1019.0 ± 783.0 days. After transseptal puncture, ablation catheter was successfully steered through the mitral valve with the use of fluoroscopy. A complete high-density map of the substrate in sinus rhythm could be obtained in all patients using multipolar mapping catheters. In 1 patient, mapping was carried out using a mini-basket catheter. Procedural endpoints, noninducibility of all VTs, and abolition of all late potentials were achieved in all patients. Procedure time was 255.0 ± 52.5 minute, fluoroscopy time was 23.0 ± 7.3, and the radiation dose was 61.0 ± 37.5 Gycm2 . No mitral insufficiency or worsening of regurgitation was documented after the procedure. CONCLUSIONS: This is the first report demonstrating the feasibility and safety of VT ablation in patients with a MitraClip device using the anterograde transmitral catheter route.

Left atrial appendage closure: A single center experience and comparison of two contemporary devices.

OBJECTIVES: To compare indications and clinical outcomes of two contemporary left atrial appendage (LAA) percutaneous closure systems in a "real-world" population. BACKGROUND: Percutaneous LAA occlusion is an emerging therapeutic option for stroke prevention in atrial fibrillation. Some questions however remain unanswered, such as the applicability of results of randomized trials to current clinical practice. Moreover, currently available devices have never been directly compared. METHODS: We retrospectively analyzed consecutive patients who underwent LAA closure at San Raffaele Hospital, Milan, Italy between 2009 and 2015. Clinical indications and device selection were left to operators' decision; routine clinical and transesophageal echocardiography (TEE) follow-up was performed. RESULTS: One-hundred and sixty-five patients were included in the study, of which 99 were treated with the Amplatzer Cardiac Plug (ACP) and 66 with the Watchman system. During the follow-up period (median 15 months, interquartile range 6-26 months) five patients died. The incidence of ischemic events was low, with one patient suffering a transient ischemic attack and no episodes recorded of definitive strokes. Twenty-six leaks ≥1 mm were detected (23%); leaks were less common with the ACP and with periprocedural three-dimensional TEE evaluation, but were not found to correlate with clinical events. Clinical outcomes were comparable between the two devices. CONCLUSIONS: Our data show excellent safety and efficacy of LAA closure, irrespectively of the device utilized, in a population at high ischemic and hemorrhagic risk. The use of ACP and 3D-TEE minimized the incidence of residual leaks; however, the clinical relevance of small peri-device flow warrants further investigation. © 2016 Wiley Periodicals, Inc.

Characterization of the arrhythmogenic substrate in patients with arrhythmogenic right ventricular cardiomyopathy undergoing ventricular tachycardia ablation.

AIMS: Arrhythmogenic right ventricular (RV) cardiomyopathy (ARVC) is associated with ventricular arrhythmias, even without RV structural disease. We aimed to characterize the RV substrate using electroanatomical mapping and to define outcomes following ventricular tachycardia (VT) ablation in patients with and without RV structural abnormalities. METHODS AND RESULTS: Twenty-nine patients with definite or suspected ARVC undergoing VT ablation were classified as 'electrical' and 'structural' cardiomyopathy based on the absence or presence of major structural criteria. Right ventricular (RV) endocardial and epicardial mapping with assessment of bipolar and unipolar voltages, distribution of late potentials (LPs), and inducible VT morphologies were performed. The endpoints for VT ablation were VT non-inducibility and LP abolition. Fourteen patients were categorized as electrical RV cardiomyopathy and 15 were categorized as structural RV cardiomyopathy. In patients with electrical cardiomyopathy, scar was limited to the epicardial surface (epicardium 13 cm2vs. endocardium 1 cm2, P < 0.05), primarily in the outflow tract, whereas patients with structural disease had greater involvement of the endocardium. During a mean follow-up of 22 ± 11 months, the VT recurrence rate was 27%, with LP abolition being a predictor of VT-free survival (HR 0.075 (0.008-0.661), P = 0.020). There was a trend towards higher recurrence rates in structural RV cardiomyopathy (40%) compared with the electrical cardiomyopathy (15%, P = 0.17). CONCLUSION: The development of RV structural disease in patients with ARVC is associated with extensive epicardial and endocardial scar. Conversely those patients without RV structural disease have identifiable epicardial scar limited to the RV outflow tract. Ventricular tachycardia (VT) ablation in both groups targeting LP abolition is effective in preventing VT recurrence.

The value of the 12-lead electrocardiogram in localizing the scar in non-ischaemic cardiomyopathy.

AIMS: Patients with non-ischaemic cardiomyopathy (NICM) and ventricular tachycardia can be categorized as anteroseptal (AS) or inferolateral (IL) scar sub-types based on imaging and voltage mapping studies. The aim of this study was to correlate the baseline electrocardiogram (ECG) with endo-epicardial voltage maps created during ablation procedures and identify the ECG characteristics that may help to distinguish the scar as AS or IL. METHODS AND RESULTS: We assessed 108 baseline ECGs; 72 patients fulfilled criteria for dilated cardiomyopathy whereas 36 showed minimal structural abnormalities. Based on the unipolar low-voltage distribution, the scar pattern was classified as predominantly AS (n = 59) or IL (n = 49). Three ECG criteria (PR interval < 170 ms or QRS voltage in inferior leads <0.6 mV or a lateral q wave) resulted in 92% sensitivity and 90% specificity for predicting an IL pattern in patients with preserved ejection fraction (EF). The four-step algorithm for dilated cardiomyopathy included a paced ventricular rhythm or PR > 230 ms or QRS > 170 ms or an r ≤ 0.3 mV in V3 having 92 and 81% of sensitivity and specificity, respectively, in predicting AS scar pattern. A significant negative correlation was found between the extension of the endocardial unipolar low voltage area and left ventricular EF (rs = -0.719, P < 0.001). The extent of endocardial AS unipolar low voltage was correlated with PR interval and QRS duration (rs = 0.583 and rs = 0.680, P < 0.001, respectively) and the IL epicardial unipolar low voltage with the mean voltage of the limb leads (rs = -0.639, P < 0.001). CONCLUSION: Baseline ECG features are well correlated with the distribution of unipolar voltage abnormalities in NICM and may help to predict the location of scar in this population.

Impact of a chronic total occlusion in an infarct-related artery on the long-term outcome of ventricular tachycardia ablation.

INTRODUCTION: In patients with a prior myocardial infarction (MI), angiographic predictors of ventricular tachycardia (VT) recurrence after ablation are lacking. Recently, a proarrhythmic effect of a chronic total occlusion (CTO) in a coronary artery has been suggested. METHODS AND RESULTS: A total of 191 patients with prior MI were referred to our Hospital between 2010 and June 2013 for a first ablation of VT. Of these, 84 patients (44%) with stable coronary artery disease that underwent a coronary angiography during the index hospitalization were included in this study. A CTO in an infarct-related artery (IRA-CTO) was present in 47 patients (56%). Patients with and without IRA-CTO did not differ in terms of comorbidities, severity of heart failure, presentation of VT or acute outcome of ablation, that was completely successful in 93% of cases. At electroanatomic mapping, IRA-CTO was associated with greater scar and especially with greater area of border zone (34 cm(2) vs. 19 cm(2) , P = 0.001). Median follow-up was 19 months (IQR 18). At follow-up, patients with IRA-CTO had a significantly higher rate of VT recurrence (47% vs. 16%, P = 0.003). At multivariate analysis, IRA-CTO resulted to be an independent predictor of VT recurrence after ablation (HR 4.05, P = 0.004). CONCLUSIONS: IRA-CTO is an independent predictor of VT recurrence after ablation and identifies a subgroup of patients with high recurrence rate despite a successful procedure. IRA-CTO is associated with greater scars and border zone area; however, this association does not completely justify its proarrhythmic effect.

New diagnostic criteria for identifying left-sided ventricular ectopy using non-contact mapping and virtual unipolar electrogram analysis.

AIMS: To assess the efficacy of non-contact mapping for outflow tract premature ventricular contraction (PVC) and ventricular tachycardia (VT) ablation in patients without structural heart disease and a precordial transition at V3 or later and to determine the diagnostic accuracy of new virtual unipolar electrogram criteria for distinguishing left from right-sided foci using a multi-electrode array positioned within the right ventricular outflow tract. METHODS AND RESULTS: Virtual unipolar electrograms at early activation (EA) and break out (BO) sites in 100 patients (36 left-sided foci) who underwent acutely successful outflow tract ablation were analysed and voltage and timing-based criteria measured. The best performing parameters were then re-assessed in 41 patients (14 left-sided) prospectively. Of the candidate criteria for determining a left from right-sided focus, the voltage at 20 ms after EA (EA-V20) and the time from BO to QRS onset (BO-QRS) were the best discriminators with area under the curve (AUC) values based on receiver operator characteristics (ROCs) of 0.947 (0.905-0.989), P < 0.001, and 0.951 (0.907-0.995), P < 0.001, respectively. These two parameters were subsequently assessed prospectively in a further 41 patients (14 left-sided) using the pre-specified cut-off values of -2 mV for EA-V20 and 10 ms for BO-QRS which demonstrated excellent diagnostic accuracy and sufficient inter-beat and inter-observer reproducibility. CONCLUSIONS: This large single-centre experience demonstrates that a strategy for outflow tract PVC/VT ablation using non-contact mapping allows for excellent success rates. Furthermore, detailed analysis of virtual unipolar electrograms allows accurate and reproducible determination of left from right-sided foci that may be used to guide mapping and ablation.

Management of ventricular tachycardia in the setting of a dedicated unit for the treatment of complex ventricular arrhythmias: long-term outcome after ablation.

BACKGROUND: We investigated the impact of catheter ablation on ventricular tachycardia (VT) recurrence and survival in a large number of patients with structural heart disease treated in the setting of a dedicated multiskilled unit. METHODS AND RESULTS: Since January 2007, we have implemented a multidisciplinary model, aiming for a comprehensive management of VT patients. Programmed ventricular stimulation was used to assess acute outcome. Primary end points were VT recurrence and the occurrence of cardiac and sudden cardiac death. Overall, 528 patients were treated by ablation (634 procedures; 1-4 procedures per patient). Among 482 tested with programmed ventricular stimulation after the last procedure, a class A result (noninducibility of any VT) was obtained in 371 patients (77%), class B (inducibility of nondocumented VT) in 12.4%, and class C (inducibility of index VT) in 10.6%. After a median follow-up time of 26 months, VT recurred in 164 (34.1%) of 472 patients. VT recurrence was documented in 28.6% of patients with a class A result versus 39.6% of patients with class B and 66.7% with class C result (log-rank P<0.001). The incidence of cardiac mortality was lower in class A patients than in those with class B and class C (8.4% versus 18.5% versus 22%, respectively; log-rank P=0.002). On the basis of multivariate analysis, postprocedural inducibility of index VT was independently associated both with VT recurrence (hazard ratio, 4.030; P<0.001) and with cardiac mortality (hazard ratio, 2.099; P=0.04). CONCLUSIONS: Within a dedicated VT unit, catheter ablation prevents long-term VT recurrences, which may favorably affect survival in a large number of patients who have VT.

Imaging and epicardial substrate ablation of ventricular tachycardia in patients late after myocarditis.

AIMS: We present clinical, electroanatomical mapping (EAM), imaging, and catheter ablation (CA) strategies in patients with myocarditis-related ventricular tachycardia (VT). METHODS AND RESULTS: Between January 2010 and July 2012, 26 consecutive patients underwent imaging-guided CA of myocarditis-related ventricular arrhythmias, 23 of 26 using a combined endo-epicardial approach. Segment per segment correspondence of late enhanced (LE) scar localization with EAM scar was assessed in all patients with available uni/bipolar maps (n = 19). Induced VTs were targeted prior to substrate modification. Late potentials (LPs) abolition constituted a procedural endpoint independently from VT inducibility. Clinical monomorphic VT was induced in 15 of 26 patients (57.7%) and was associated with epicardial LPs in 10 of 15, completely abolished in 7 of 10 patients. Of the 10 patients rendered non-inducible VTs were ablated epicardially in 7. Late potentials were also detected in 7 of 11 initially non-inducible patients and completely abolished in 4. After a median follow-up of 23 (15-31) months, 20 of 26 patients (76.9%) remained free from VT recurrence. Bipolar mapping revealed low-voltage scar (<1.5 mV) in 1 patient endocardially and in 14 of 19 epicardially. Unipolar mapping revealed low-voltage scar (<8 mV) in 12 of 19 patients endocardially and in 18 of 19 epicardially. Correspondence of LE scar localization with endocardial bipolar scar was 1%, with endocardial unipolar scar 23.7%, with epicardial bipolar scar 39.8%, and with epicardial unipolar scar 66.2%. CONCLUSION: Pre-procedural scar imaging and EAM findings support the necessity of an epicardial approach in patients with prior myocarditis. Epicardial unipolar mapping (<8 mV) is superior in scar identification and CA based on substrate modification is safe and effective in this setting.

Contact force monitoring for cardiac mapping in patients with ventricular tachycardia.

BACKGROUND: Although the importance of contact force monitoring during mapping and ablation procedures is widely recognized, only indirect measurements have been validated. METHODS: Real-time force values were measured using the force-sensing catheter and electroanatomical mapping system from 27 chambers (13 LVs, 6 RVs, and 8 epicardial space) in 17 patients affected by ventricular tachycardia. Left ventricular mapping was performed by the transaortic approach in all patients and in 5 patients also by a transseptal approach with the aid of a deflectable sheath. All points were divided into 2 groups according to the presence of positive contact force during diastole: good and poor contact. The frequency of good contact and its impact on electrophysiological parameters such as signal amplitude, local impedance, and frequency of late potentials was evaluated. The best cut-off value to discriminate the 2 groups was calculated by a generalized linear mixed-effects model. RESULTS: Among all 5,926 points, 1,566 (26%) points were taken with poor contact. In healthy tissue, categorical increase of contact force caused the increase of unipolar and bipolar signal potential amplitude followed by plateau. The frequency of late potentials in the poor contact group was significantly lower when compared to the good contact group (11.9 vs 23.2%; P < 0.0001). The best cut-off force value to predict good contact during left ventricular endocardial and epicardial mappings was 9 g. CONCLUSIONS: A combined transaortic and transseptal approach allows better endocardial contact during left ventricular mapping. Ventricular mapping with sufficient contact force produces better substrate characterization within pathological areas.

Safety and efficacy of open irrigated-tip catheter ablation of Wolff-Parkinson-White syndrome in children and adolescents.

BACKGROUND: Irrigated-tip catheter technology has been used for the elimination of resistant accessory pathways (AP) in adults with Wolff-Parkinson-White (WPW) syndrome. However, there are persistent concerns regarding the safety of irrigated catheters in the pediatric population. In this report we present our experience, in terms of effectiveness and safety, of irrigated catheter technology in children and adolescents who underwent ablation of WPW. METHODS: We prospectively followed up all patients less than 18 years old (n = 41, mean age of 12.8 years old) who were referred to our center for radiofrequency (RF) catheter ablation of WPW between January 2010 and July 2011. Catheter ablation was performed in all patients using an open irrigated-tip catheter (Celsius Thermocool 3.5 mm, 7F, B-type, Biosense Webster, Diamond Bar, CA, USA). Power was started from 15 W up to 30 W in right-sided AP; RF pulses in left-sided APs were delivered at 40 W while 20 W was delivered inside the coronary sinus. RESULTS: Mean procedure time was 26.4 minutes and mean fluoroscopy time was 12.2 minutes. Overall procedural success was obtained in 39/41 (95.1%) patients after the first procedure. No complications were observed after the procedure. All patients attended their scheduled follow-up visit at 3, 6, and 12 months and no recurrences were observed based on 12-lead electrocardiogram and 24-hour Holter monitoring. CONCLUSIONS: RF ablation of APs using open irrigated-tip catheters can be performed in children and adolescents with a high acute and long-term success rate, very short procedure times, and acceptable fluoroscopy times.

Late potentials abolition as an additional technique for reduction of arrhythmia recurrence in scar related ventricular tachycardia ablation.

RATIONALE: To evaluate the efficacy of radiofrequency ventricular tachycardia (VT) ablation targeting complete late potential (LP) activity. METHODS AND RESULTS: Sixty-four consecutive patients (pts) with recurrent VTs and coronary artery disease or idiopathic dilated cardiomyopathy were evaluated. Fifty patients (47 male; 66.2 ± 10.1 years) had LPs at electroanatomical mapping; 35 patients had at least 1 VT inducible at basal programmed stimulation. After substrate mapping, radiofrequency ablation was performed with the endpoint of all LPs abolition. LPs could not be abolished in 5 patients despite extensive ablation, in 1 patient because of localization near an apical thrombus, and in 2 patients because of possible phrenic nerve injury. At the end of procedure, prevention of VT inducibility was achieved in 25 of 35 patients (71.4%) with previously inducible VT; VT was still inducible in 5 of 8 patients with incomplete LP abolition; and in 5 of 42 patients (16.1%) with complete LP abolition (P < 0.01). After a follow-up of 13.4 ± 4.0 months, 10 patients (20.0%) had VT recurrences and one of them died after surgical VT ablation; VT recurrence was 9.5% in patients with LPs abolition (4/42 pts) and 75.0% (6/8 pts) in those with incomplete abolition [positive predictive value (PPV): 75%, negative predictive value (NPV): 90.4%, sensibility: 60.0%, and specificity: 95.0%, P < 0.0001); although it was 12.5% (5/40 pts) in patients without inducibility VT after the ablation, and 50% (5/10 pts) in those with inducible VT (PPV: 50%, NPV: 87.5%, sensitivity: 50.0%, and specificity: 87.5%, P = 0.008). CONCLUSIONS: LP abolition is an effective endpoint of VT ablation and its prognostic value compares favorably to that achieved by programmed electrical stimulation.

Changes in the propagation pattern within the conduction channel during sinus rhythm and ventricular tachycardia demonstrated by non-contact mapping: role of late potential activity.

Sustained monomorphic ventricular tachycardia (VT) in patients with a previous myocardial infarction is due to re-entry mechanism in areas of slow conduction. The recognition of the pathogenic mechanism and the characterization of the activation pathway are usually obtained by indirect measures with entrainment mapping and pacing manoeuvres. We studied a 61-years-old patient with a history of previous inferior myocardial infarction and we provided the in vivo direct visualization of the critical components of re-entry circuit by non-contact mapping. VT circuit entrance, central pathway, and exit were characterized during the same beat by virtual electrodes and visualized on a three-dimensional map both during sinus rhythm, ongoing VT, and pacemapping. The analysis demonstrated an activation of the conductive channel in opposite directions during the sinus rhythm and ventricular tachycardia. Late potentials during sinus rhythm turned into mid-diastolic activity during VT; non-contact mapping allowed the ablation procedure to be performed in sinus rhythm, targeting the central pathway of the conducting channel and the abolition of VT inducibility.

Long-Term Outcome After Ventricular Tachycardia Ablation in Nonischemic Cardiomyopathy: Late Potential Abolition and VT Noninducibility.

BACKGROUND: In patients with an ischemic cardiomyopathy (ICM), the combination of late potential (LP) abolition and postprocedural ventricular tachycardia (VT) noninducibility is known to be the desirable end point for a successful long-term outcome after VT ablation. We investigated whether LP abolition and VT noninducibilty have a similar impact on the outcomes of patients with non-ICMs (NICM) undergoing VT ablation. METHODS: A total of 403 patients with NICM (523 procedures) who underwent a VT ablation from 2010 to 2016 were included. The procedure end points were the LP abolition (if the LPs were absent, other ablation strategies were undertaken) and the VT noninducibilty. RESULTS: The underlying structural heart disease consisted of dilated cardiomyopathy (DCM, 49%), arrhythmogenic right ventricular dysplasia (ARVD, 17%), postmyocarditis (14%), valvular heart disease (8%), congenital heart disease (2%), hypertrophic cardiomyopathy (2%), and others (5%). The epicardial access was performed in 57% of the patients. At baseline, the LPs were present in 60% of the patients and a VT was either inducible or sustained/incessant in 85% of the cases. At the end of the procedure, the LP abolition was achieved in 79% of the cases and VT noninducibility in 80%. After a multivariable analysis, the combination of LP abolition and VT noninducibilty was independently associated with free survival from VT (hazard ratio, 0.45 [95% CI, 0.29-0.69], P=0.0002) and cardiac death (hazard ratio, 0.38 [95% CI, 0.18-0.74], P=0.005). The benefit of the LP abolition on preventing the VT recurrence in patients with ARVD and postmyocarditis appeared superior to that observed for those with DCM. CONCLUSIONS: In patients with NICM undergoing VT ablation, the strategy of LP abolition and VT noninducibilty were associated with better outcomes in terms of long-term VT recurrences and cardiac survival. Graphic Abstract: A graphic abstract is available for this article.

Catheter ablation for the treatment of electrical storm in patients with implantable cardioverter-defibrillators: short- and long-term outcomes in a prospective single-center study.

BACKGROUND: Electrical storm (ES) caused by recurrent episodes of ventricular tachycardia (VT) can cause sudden death in patients with implantable cardioverter-defibrillators and adversely affects prognosis in survivors. Catheter ablation has been proposed for treating ES, but its long-term effect in a large population has never been verified. METHODS AND RESULTS: Ninety-five consecutive patients with coronary artery disease (72 patients), idiopathic dilated cardiomyopathy (10 patients), and arrhythmogenic right ventricular dysplasia/cardiomyopathy (13 patients) undergoing catheter ablation for drug-refractory ES were prospectively evaluated. Short-term efficacy was defined by a complete protocol of programmed electric stimulation and by in-hospital outcome; long-term analysis addressed ES recurrence, cardiac mortality, and VT recurrence. Pleomorphic/nontolerated VTs required electroanatomic and noncontact mapping in 48 and 22 patients, respectively, and percutaneous cardiopulmonary support in 10 patients. An epicardial approach was used in 10 patients. After 1 to 3 procedures, induction of any clinical VT(s) by programmed electrical stimulation was prevented in 85 patients (89%). ES was acutely suppressed in all patients; a minimum period of 7 days with stable rhythm was required before hospital discharge. At a median follow-up of 22 months (range, 1 to 43 months), 87 patients (92%) were free of ES and 63 patients (66%) were free of VT recurrence. Eight of 10 patients with persistent inducibility of clinical VT(s) had ES recurrence; 4 of them died suddenly despite appropriate implantable cardioverter-defibrillator intervention. All together, 11 of 95 patients (12%) died of cardiac-related reasons. In the group of patients presenting with all clinical VTs acutely abolished, no ES recurrence was documented, and cardiac mortality was significantly lower compared with the group of patients showing > or = 1 clinical VT still inducible after catheter ablation. CONCLUSIONS: Advanced strategies of catheter ablation applied to a large population of patients are effective in the short-term treatment of ES. By preventing ES recurrence, catheter ablation may play a protective role over the long term and, together with long-term pharmacological therapy, may favorably affect cardiac mortality.

Image integration-guided catheter ablation of atrial fibrillation: a prospective randomized study.

BACKGROUND: Several studies have provided details of left atrial anatomy by means of the image integration techniques, particularly focusing on the atypical patterns of the pulmonary veins. OBJECTIVE: To compare, in a prospective, randomized fashion, the conventional method of pulmonary vein disconnection and the image integration-guided approach. METHODS: Two hundred and ninety consecutive patients (290 patients, mean age 55 +/- 11 years) with drug-refractory paroxysmal or persistent atrial fibrillation were enrolled in the study and were divided into two treatment groups: group 1 (145 patients) undergoing an imaging integration-guided (CartoMerge TM) ablation; group 2 (145 patients) treated by a conventional radiofrequency catheter ablation procedure. The arrhythmia was refractory to at least two antiarrhythmic drugs (IC, amiodarone). RESULTS: Electrical disconnection of all identified pulmonary veins was obtained in all patients of both groups. Bidirectional block of the cavotricuspid isthmus was achieved in 34 group 1 patients and in 40 group 2 patients. Left mitral isthmus ablation was attempted in 52 group 1 patients and in 56 group 2 patients. At a mean follow-up of 14 +/- 12 months, the atrial fibrillation-free survival rate was significantly higher in group 1 patients compared with group 2 patients (88% vs 69%, P = 0.017). The analysis for the subset of patients with previously ineffective ablation (98 patients: 52 group 1 patients and 46 group 2 patients) showed a significantly lower recurrence rate in group 1 versus group 2 (19% vs 48%, P < 0.01). CONCLUSIONS: Our data indicate a superior efficacy of the image-integration guided catheter ablation of atrial fibrillation over the long term.

Percutaneous cardiopulmonary support for catheter ablation of unstable ventricular arrhythmias in high-risk patients.

BACKGROUND AND PURPOSE: In patients with severe cardiomyopathy, recurrent episodes of nontolerated ventricular tachycardia (VT) or electrical storm (ES) frequently cause acute heart failure and cardiac death; the suppression of the arrhythmia is therefore lifesaving, but feasibility of catheter ablation (CA) is precluded by the adverse hemodynamic conditions together with the characteristics of the arrhythmia that interdicts efficacious mapping. The use of the percutaneous cardiopulmonary support (CPS) for circulatory assistance may allow patient's stabilization and enhance efficacy and safety of CA in this emergency setting. PATIENTS AND METHODS: 19 patients (19 males; mean age 61 +/- 6 years; chronic ischemic cardiomyopathy, eleven patients; primary dilated cardiomyopathy, six patients; arrhythmogenic right ventricular dysplasia/ cardiomyopathy, two patients) with recurrent nontolerated VT episodes undergoing CPS-assisted CA were retrospectively evaluated. Twelve patients had acute hemodynamic failure refractory to inotropic agents and ventilatory assistance, seven patients had undergone a failing nonconventional CA procedure. 14 patients presented with ES, and in twelve the procedure was undertaken under emergency conditions within 24 h from admission. Patients were ventilated under general anesthesia and assisted by a multidisciplinary team. The CPS system consisted in a Medtronic Bio-Medicus centrifugal pump and in a Maxima Plus oxygenator, a 15-F arterial cannula, and a 17-F venous cannula. RESULTS: Flows between 2 and 3 l/min were activated after induction of 56/62 forms of nontolerated VT, achieving hemodynamic stabilization in all patients. CA was mainly guided by conventional activation mapping and was effective in abolishing 45/56 supported VTs; in 10/19 patients all clinical VTs were suppressed by CA. Mean procedural time was 4 h and 20 min. Complete stabilization was achieved in 13 patients (68%) without VT recurrence during a 7-day in-hospital monitoring. A significant clinical improvement was observed in two patients (11%); one patient (5%) with persistent VT episodes acutely died after heart transplant. At a mean follow-up of 42 months (range 15-60 months), 5/18 patients (28%) were free from VT recurrence, 7/18 (39%) had a clear clinical improvement with reduced implantable cardioverter defibrillator interventions. 5/14 patients (36%) had ES recurrence; among them, three died because of acute heart failure. No serious CPS-related complications were observed. CONCLUSION: The CPS warrants acceptable hemodynamic stabilization and efficacious mapping in high-risk patients undergoing CA for unstable VT in the emergency setting. Safety and efficacy of this technique translate into significant clinical improvement in the majority of patients. Even if only relatively invasive, CPS should be reserved to patients with ES or intractable arrhythmia causing acute heart failure; moreover, the need for an experienced team of multidisciplinary operators implies that its use is restricted to selected high-competency institutions.

Fast and safe mapping of ventricular tachycardia in patient with left ventricular assist device.

The characterization of the pathological substrate and/or mapping of the clinical ventricular tachycardia in patients with left ventricular assist device may represent a challenge, due to the risk of entrapment of the intracardiac catheter into the inflow cannula. Hereby, we present the technique of a fast and safe mapping using a 20-poles catheter which allowed the identification of the critical isthmus during ventricular tachycardia.