Cryocure-VT: the safety and effectiveness of ultra-low-temperature cryoablation of monomorphic ventricular tachycardia in patients with ischaemic and non-ischaemic cardiomyopathies.

AIMS: The ultra-low-temperature cryoablation (ULTC) ablation system using -196°C N2 cryogen has been reported to create lesions with freeze duration-dependent depth titratable to over 10 mm with minimum attenuation by scar. Cryocure-VT (NCT04893317) was a first-in-human clinical trial evaluating the safety and efficacy of a novel, purpose-built ULTC catheter in endocardial ablation of scar-dependent ventricular tachycardias (VTs). METHODS AND RESULTS: This prospective, multi-centre study enrolled patients referred for de novo or second ablations of recurrent monomorphic VT of both ischaemic and non-ischaemic aetiologies. Primary safety and efficacy endpoints of the study were freedom from device- or procedure-related major adverse events (MAEs) up to 30 days post-ablation, acute non-inducibility of clinical VTs at the end of the procedure, and freedom from sustained VT or implantable defibrillator intervention at 6 months. Ultra-low-temperature cryoablation was performed in 64 patients (age 67 ± 11 years, 78% ischaemic, ejection fraction = 35 ± 10%) at 9 centres. The primary acute effectiveness endpoint was achieved in 94% (51/54) of patients in whom post-ablation induction was attempted. There were no protocol-defined MAEs; four procedure-related serious adverse events resolved without clinical sequelae. At 6-month follow-up, 38 patients (60.3%) remained VT-free, and freedom from defibrillator shock was 81.0%, with no significant difference between ischaemic and non-ischaemic cohorts. In 47 patients with defibrillator for at least 6 months prior to the ablation, the VT burden was reduced from median of 4, inter-quartile range (IQR, 1-9) to 0, IQR (0-2). CONCLUSION: In this first-in-human multi-centre experience, endocardial ULTC ablation of monomorphic VT appears safe and effective in patients with both ischaemic-cardiomyopathy and non-ischaemic-cardiomyopathy. CLINICAL TRIAL REGISTRATION: NCT04893317.

Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project.

AIMS: Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers. METHODS AND RESULTS: International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA- cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA-; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA-; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100-0.681), P = 0.006]. CONCLUSION: In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up. CLINICALTRIALS.GOV IDENTIFIER: NCT0473876.

Management of patients with an electrical storm or clustered ventricular arrhythmias: a clinical consensus statement of the European Heart Rhythm Association of the ESC-endorsed by the Asia-Pacific Heart Rhythm Society, Heart Rhythm Society, and Latin-American Heart Rhythm Society.

Electrical storm (ES) is a state of electrical instability, manifesting as recurrent ventricular arrhythmias (VAs) over a short period of time (three or more episodes of sustained VA within 24 h, separated by at least 5 min, requiring termination by an intervention). The clinical presentation can vary, but ES is usually a cardiac emergency. Electrical storm mainly affects patients with structural or primary electrical heart disease, often with an implantable cardioverter-defibrillator (ICD). Management of ES requires a multi-faceted approach and the involvement of multi-disciplinary teams, but despite advanced treatment and often invasive procedures, it is associated with high morbidity and mortality. With an ageing population, longer survival of heart failure patients, and an increasing number of patients with ICD, the incidence of ES is expected to increase. This European Heart Rhythm Association clinical consensus statement focuses on pathophysiology, clinical presentation, diagnostic evaluation, and acute and long-term management of patients presenting with ES or clustered VA.

Polymorphic ventricular tachycardia and cardiac arrest from abiraterone-induced hypokalemia: a case report.

BACKGROUND: Polymorphic ventricular tachycardia (PMVT) is an unstable and often fatal cardiac tachyarrhythmia. While there are many causes of this rhythm, including electrolyte imbalances, ischemia, and genetic disorders, iatrogenic etiologies are important to recognize. Abiraterone is an androgen synthesis antagonist effective in treating prostate cancer, but here we describe a case of severe hypokalemia secondary to abiraterone resulting in polymorphic ventricular tachycardia and cardiac arrest. While this is a potential adverse effect of the medication, severe hypokalemia causing polymorphic ventricular tachycardia and cardiac arrest, as seen in our patient's case, has not been described. CASE PRESENTATION: A 78-year-old African-American man with history of prostate cancer presents with polymorphic ventricular tachycardia and cardiac arrest. After resuscitation, he was found to be severely hypokalemic and refractory to large doses of repletion. Evaluation of secondary causes of hypokalemia identified the likely culprit to be adverse effects from prostate cancer treatment. CONCLUSION: A broad differential diagnosis for polymorphic ventricular tachycardia is essential in identifying and treating patients presenting in this rhythm. Here we present a case of iatrogenic polymorphic ventricular tachycardia secondary to oncologic treatment.

Acute myocardial infarction revealed by recurrent ventricular tachyarrhythmias detected by remote monitoring.

Remote monitoring (RM) of cardiac implantable electronic devices (CIED) represented a major improvement in clinical practice and has been used with multiple indications. Many parameters monitored on a daily basis by current CIED can indeed assist in clinical practice (eg, decompensated heart failure) by providing the patient with optimal timing for anticipated outpatient visit or urgent medical care. Recognition of acute myocardial infarction (AMI) is not usually considered among the capabilities of RM. We present the case of an AMI occurring without any ischaemic symptoms but associated with recurrent ventricular tachyarrhythmias effectively treated by multiple interventions of the implantable cardioverter defibrillator and promptly detected by RM personnel, who recommended the patient to quickly access to the emergency department where diagnosis and revascularization of an otherwise untreated myocardial infarction was performed.

RV1+RV3 Index to Differentiate Idiopathic Ventricular Arrhythmias Arising From Right Ventricular Outflow Tract and Aortic Sinus of Valsalva: A Multicenter Study.

BACKGROUND: This study aimed to investigate the predictive value of parameters of every precordial lead and their combinations in differentiating between idiopathic ventricular arrhythmias (IVAs) from the right ventricular outflow tract and aortic sinus of Valsalva (ASV). METHODS AND RESULTS: Between March 1, 2018, and December 1, 2021, consecutive patients receiving successful ablation of right ventricular outflow tract or ASV IVAs were enrolled. The amplitude and duration of the R wave and S wave were measured in every precordial lead during IVAs. These parameters were either summed, subtracted, multiplied, or divided to create different indexes. The index with the highest area under the curve to predict ASV IVAs was developed, compared with established indexes, and validated in an independent prospective multicenter cohort. A total of 150 patients (60 men; mean age, 45.3±16.4 years) were included in the derivation cohort. The RV1+RV3 index (summed R-wave amplitude in leads V1 and V3) had the highest area under the curve (0.942) among the established indexes. An RV1+RV3 index >1.3 mV could predict ASV IVAs with a sensitivity of 95% and a specificity of 83%. Its predictive performance was maintained in the validation cohort (N=109). In patients with V3 R/S transition, an RV1+RV3 index >1.3 mV could predict ASV IVAs, with an area under the curve of 0.892, 93% sensitivity, and 75% specificity. CONCLUSIONS: The RV1+RV3 index is a simple and novel criterion that accurately differentiates between right ventricular outflow tract and ASV IVAs. Its performance outperformed established indexes, making it a valuable tool in clinical practice.

Discrimination between ventricular tachycardia and wide-QRS preexcited tachycardia.

BACKGROUND: To develop a new algorithm to differentiate ventricular tachycardia (VT) from preexcited tachycardia (pre-ET) according to left bundle branch block (LBBB) and right bundle branch block (RBBB) patterns. METHODS: This study included 67 electrocardiograms (ECGs) with VT and 63 ECGs with pre-ET, collected from our hospital and through PubMed. Of those, 64 were allocated to the derivation cohort and the rest to the validation cohort. The diagnoses of the ECGs were confirmed using an electrophysiological study. Parameters and classifiers from prior algorithms along with the propagation speeds in the early portion of the QRS complex (initial deflection index) in leads V1, V6, aVR, II, and III were manually measured. The performance of the new algorithm was compared with that of prior algorithms. RESULTS: The initial deflection index in lead III was the strongest predictor of pre-ET in LBBB-pattern wide-QRS tachycardia (p = 0.003, AUC 0.805). The initial deflection index in lead V1 was the most powerful predictor of pre-ET in RBBB-pattern wide-QRS tachycardia (p = 0.001, AUC 0.848). Compared to earlier algorithms, those using the initial deflection indexes: lead III in LBBB patterns (cutoff value >0.3) and lead V1 in RBBB patterns (cutoff value ≤0.48), demonstrated superior performance in screening VT, with AUC values of 0.828. The initial deflection indexes proved effective as discriminators between VT and pre-ET in the validation cohort. CONCLUSIONS: In LBBB-pattern wide-QRS tachycardia, the early propagation speed of pre-ET was faster than that in VT. Conversely, in RBBB-pattern wide-QRS tachycardia, it was slower.

Diagnosis and Management of Paroxysmal Supraventricular Tachycardia.

Importance: Paroxysmal supraventricular tachycardia (PSVT), defined as tachyarrhythmias that originate from or conduct through the atria or atrioventricular node with abrupt onset, affects 168 to 332 per 100 000 individuals. Untreated PSVT is associated with adverse outcomes including high symptom burden and tachycardia-mediated cardiomyopathy. Observations: Approximately 50% of patients with PSVT are aged 45 to 64 years and 67.5% are female. Most common symptoms include palpitations (86%), chest discomfort (47%), and dyspnea (38%). Patients may rarely develop tachycardia-mediated cardiomyopathy (1%) due to PSVT. Diagnosis is made on electrocardiogram during an arrhythmic event or using ambulatory monitoring. First-line acute therapy for hemodynamically stable patients includes vagal maneuvers such as the modified Valsalva maneuver (43% effective) and intravenous adenosine (91% effective). Emergent cardioversion is recommended for patients who are hemodynamically unstable. Catheter ablation is safe, highly effective, and recommended as first-line therapy to prevent recurrence of PSVT. Meta-analysis of observational studies shows single catheter ablation procedure success rates of 94.3% to 98.5%. Evidence is limited for the effectiveness of long-term pharmacotherapy to prevent PSVT. Nonetheless, guidelines recommend therapies including calcium channel blockers, ß-blockers, and antiarrhythmic agents as management options. Conclusion and Relevance: Paroxysmal SVT affects both adult and pediatric populations and is generally a benign condition. Catheter ablation is the most effective therapy to prevent recurrent PSVT. Pharmacotherapy is an important component of acute and long-term management of PSVT.

Intramural needle ablation or repeated standard ablation in patients referred for repeat ablation of scar-related ventricular tachycardia.

INTRODUCTION: When ventricular tachycardia (VT) recurs after standard RF ablation (sRFA) some patients benefit from repeat sRFA, whereas others warrant advanced methods such as intramural needle ablation (INA). Our objectives are to assess the utility of repeat sRFA and to clarify the benefit of INA when repeat sRFA fails in patients with VT due to structural heart disease. METHODS: In consecutive patients who were prospectively enrolled in a study for INA for recurrent sustained monomorphic VT despite sRFA, repeat sRFA was considered first. INA was performed during the same procedure if repeat sRFA failed or no targets for sRFA were identified. RESULTS: Of 85 patients enrolled, acute success with repeat sRFA was achieved in 30 patients (35%), and during the 6-month follow-up, 87% (20/23) were free of VT hospitalization, 78% were free of any VT, and 7 were lost to follow-up. INA was performed in 55 patients (65%) after sRFA failed, or no endocardial targets were found abolished or modified inducible VT in 35/55 patients (64%). During follow-up, 72% (39/54) were free of VT hospitalization, 41% were free of any VT, and 1 was lost to follow-up. Overall, 59 out of 77 (77%) patients were free of hospitalization and 52% were free of any VT. Septal-origin VTs were more likely to need INA, whereas RV and papillary muscle VTs were less likely to require INA. CONCLUSIONS: Repeat sRFA was beneficial in 23% (18/77) of patients with recurrent sustained VT who were referred for INA. The availability of INA increased favorable outcomes to 52%.

Clinical Decision Support Requirements for Ventricular Tachycardia Diagnosis Within the Frameworks of Knowledge and Practice: Survey Study.

BACKGROUND: Ventricular tachycardia (VT) diagnosis is challenging due to the similarity between VT and some forms of supraventricular tachycardia, complexity of clinical manifestations, heterogeneity of underlying diseases, and potential for life-threatening hemodynamic instability. Clinical decision support systems (CDSSs) have emerged as promising tools to augment the diagnostic capabilities of cardiologists. However, a requirements analysis is acknowledged to be vital for the success of a CDSS, especially for complex clinical tasks such as VT diagnosis. OBJECTIVE: The aims of this study were to analyze the requirements for a VT diagnosis CDSS within the frameworks of knowledge and practice and to determine the clinical decision support (CDS) needs. METHODS: Our multidisciplinary team first conducted semistructured interviews with seven cardiologists related to the clinical challenges of VT and expected decision support. A questionnaire was designed by the multidisciplinary team based on the results of interviews. The questionnaire was divided into four sections: demographic information, knowledge assessment, practice assessment, and CDS needs. The practice section consisted of two simulated cases for a total score of 10 marks. Online questionnaires were disseminated to registered cardiologists across China from December 2022 to February 2023. The scores for the practice section were summarized as continuous variables, using the mean, median, and range. The knowledge and CDS needs sections were assessed using a 4-point Likert scale without a neutral option. Kruskal-Wallis tests were performed to investigate the relationship between scores and practice years or specialty. RESULTS: Of the 687 cardiologists who completed the questionnaire, 567 responses were eligible for further analysis. The results of the knowledge assessment showed that 383 cardiologists (68%) lacked knowledge in diagnostic evaluation. The overall average score of the practice assessment was 6.11 (SD 0.55); the etiological diagnosis section had the highest overall scores (mean 6.74, SD 1.75), whereas the diagnostic evaluation section had the lowest scores (mean 5.78, SD 1.19). A majority of cardiologists (344/567, 60.7%) reported the need for a CDSS. There was a significant difference in practice competency scores between general cardiologists and arrhythmia specialists (P=.02). CONCLUSIONS: There was a notable deficiency in the knowledge and practice of VT among Chinese cardiologists. Specific knowledge and practice support requirements were identified, which provide a foundation for further development and optimization of a CDSS. Moreover, it is important to consider clinicians' specialization levels and years of practice for effective and personalized support.

Comparison of novel intrinsic versus conventional antitachycardia pacing for ventricular tachycardia among implantable cardioverter-defibrillator recipients.

INTRODUCTION: Intrinsic antitachycardia pacing (iATP) is a novel automated antitachycardia pacing (ATP) that provides individual treatment to terminate ventricular tachycardia (VT). However, the clinical efficacy of iATP in comparison with conventional ATP is unknown. We aim to compare the termination rate of VT between iATP and conventional ATP in patients with implantable cardioverter-defibrillators using a unique setting of different sequential orders of both ATP algorisms. METHODS: Patients with the iATP algorithm were assigned to iATP-first and conventional ATP-first groups sequentially. In the iATP-first group, a maximum of seven iATP sequences were delivered, followed by conventional burst and ramp pacing. In contrast, in the conventional ATP-first group, two bursts and ramp pacing were initially programmed, followed by iATP sequences. We compared the success rates of VT termination in the first and secondary programmed ATP zones between the two groups. RESULTS: Fifty-eight and 56 patients were enrolled in the iATP-first and conventional ATP-first groups, and 67 and 44 VTs were analyzed in each group, respectively. At the first single ATP therapy, success rates were 64% and 70% in the iATP and conventional groups, respectively. At the end of the first iATP treatment zone, the success rate increased from 64% to 85%. Moreover, secondary iATP therapy following the failure of conventional ATPs increased the success rate from 80% to 93%. There was a significant benefit of alternative iATP for VT termination compared to secondary conventional ATP (100% vs. 33%, p = .028). CONCLUSIONS: iATP may be beneficial as a secondary therapy after failure of conventional ATP to terminate VT.

[Whether to implant a defibrillator or not? The Possibility of Using the MADIT-ICD Benefit Score Calculator in Real Practice].

AIM: To study the predictive capabilities of the MADIT-ICD Benefit Score calculator in assessing the benefit of implantable cardioverter defibrillator (ICD) placement for the primary prevention of sudden cardiac death (SCD). MATERIAL AND METHODS: This study included 388 patients with NYHA II-IV functional class chronic heart failure (CHF) with a left ventricular ejection fraction (LVEF) ≤35 % who underwent ICD placement for the primary prevention of SCD. Patients were followed up for two years to record the endpoints of first-time paroxysmal sustained ventricular tachyarrhythmia (VT) or non-arrhythmic death. RESULTS: According to the results of calculation with the MADIT-ICD Benefit Score calculator, 276 (71 %) patients had a high risk of VT (score ≥7) and 150 (39 %) had a high risk of non-arrhythmic death (score ≥3). 336 (94%) patients would benefit from an ICD: 148 (38 %) with a high level of probability and 218 (56 %) with a medium level of probability. According to the incidence of endpoints, VT episodes predominated in the low-ICD benefit group (36%), while the high-ICD benefit group had a relatively high incidence of non-arrhythmic death (12%). CONCLUSION: The results obtained for a cohort of Russian patients with CHF and reduced LVEF indicated that the use of the MADIT-ICD Benefit Score in routine clinical practice does not improve the stratification of SCD risk compared to the traditional approach to selecting patients with CHF for ICD based on the LVEF value.

A rare case of upper septal fascicular ventricular tachycardia presented in a case report.

CASE SUMMARY: A 71-year-old presented at the outpatient clinic with palpitations and NYHA II functional class. 12-lead ECG exhibited Upper septal idiopathic left ventricular tachycardia (US-ILVT). Ventricular tachycardia (VT) was interrupted with Verapamil administration, no further recurrences were documented after beta-blockers therapy was started. No coronary artery stenosis were detected. The US-ILVT was successfully treated by ablating the proximal site of the left anterior fascicle (LAF), where diastolic potential (P1) and pre-systolic potential (P2) with inverted sequence were detected during the electrophysiology study (EP) study. Cardiac magnetic resonance imaging (CMR) was performed with demonstration of intramyocardial late gadolinium enhancement (LGE) at the level of middle-basal portions of interventricular septum and basal portion of infero-lateral wall and no edema detection. A single catheter implantable cardioverter defibrillator (ICD) was implanted as secondary prevention. VT has never recurred during 3 months of follow-up with remote control of ICD. DISCUSSION: To the best of our knowledge, this is the first report in which US-ILVT was associated with ventricular septal LGE, suggestive of previous myocarditis, as substrate of re-entrant circuit. Scar-related ventricular tachycardia circuit is also suggested by the evidence of a premature ventricular complex (PVC) as trigger of recurrent VT in our case.

Cardiac arrhythmias classification using photoplethysmography database.

Worldwide, Cardiovascular Diseases (CVDs) are the leading cause of death. Patients at high cardiovascular risk require long-term follow-up for early CVDs detection. Generally, cardiac arrhythmia detection through the electrocardiogram (ECG) signal has been the basis of many studies. This technique does not provide sufficient information in addition to a high false alarm potential. In addition, the electrodes used to record the ECG signal are not suitable for long-term monitoring. Recently, the photoplethysmogram (PPG) signal has attracted great interest among scientists as it provides a non-invasive, inexpensive, and convenient source of information related to cardiac activity. In this paper, the PPG signal (online database Physio Net Challenge 2015) is used to classify different cardiac arrhythmias, namely, tachycardia, bradycardia, ventricular tachycardia, and ventricular flutter/fibrillation. The PPG signals are pre-processed and analyzed utilizing various signal-processing techniques to eliminate noise and artifacts, which forms a stage of signal preparation prior to the feature extraction process. A set of 41 PPG features is used for cardiac arrhythmias' classification through the application of four machine-learning techniques, namely, Decision Trees (DT), Support Vector Machines (SVM), K-Nearest Neighbors (KNNs), and Ensembles. Principal Component Analysis (PCA) technique is used for dimensionality reduction and feature extraction while preserving the most important information in the data. The results show a high-throughput evaluation with an accuracy of 98.4% for the KNN technique with a sensitivity of 98.3%, 95%, 96.8%, and 99.7% for bradycardia, tachycardia, ventricular flutter/fibrillation, and ventricular tachycardia, respectively. The outcomes of this work provide a tool to correlate the properties of the PPG signal with cardiac arrhythmias and thus the early diagnosis and treatment of CVDs.

Scar architecture affects the electrophysiological characteristics of induced ventricular arrhythmias in hypertrophic cardiomyopathy.

AIMS: Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) detects myocardial scarring, a risk factor for ventricular arrhythmias (VAs) in hypertrophic cardiomyopathy (HCM). The LGE-CMR distinguishes core, borderzone (BZ) fibrosis, and BZ channels, crucial components of re-entry circuits. We studied how scar architecture affects inducibility and electrophysiological traits of VA in HCM. METHODS AND RESULTS: We correlated scar composition with programmed ventricular stimulation-inducible VA features using LGE intensity maps. Thirty consecutive patients were enrolled. Thirteen (43%) were non-inducible, 6 (20%) had inducible non-sustained, and 11 (37%) had inducible sustained mono (MMVT)- or polymorphic VT/VF (PVT/VF). Of 17 induced VA, 13 (76%) were MMVT that either ended spontaneously, persisted as sustained monomorphic, or degenerated into PVT/VF. Twenty-seven patients (90%) had LGE. Of these, 17 (57%) had non-sustained or sustained inducible VA. Scar mass significantly increased (P = 0.002) from non-inducible to inducible non-sustained and sustained VA patients in both the BZ and core components. Borderzone channels were found in 23%, 67%, and 91% of non-inducible, inducible non-sustained, and inducible sustained VA patients (P = 0.003). All 13 patients induced with MMVT or monomorphic-initiated PVT/VF had LGE. The origin of 10/13 of these VTs matched scar location, with 8/10 of these LGE regions showing BZ channels. During follow-up (20 months, interquartile range: 7-37), one patient with BZ channels and inducible PVT had an ICD shock for VF. CONCLUSION: Scar architecture determines inducibility and electrophysiological traits of VA in HCM. Larger studies should explore the role of complex LGE patterns in refining risk assessment in HCM patients.

Catheter ablation of ventricular tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy and biventricular involvement.

AIMS: Catheter ablation of ventricular tachycardia (VT) improves VT-free survival in 'classic' arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to investigate electrophysiological features and ablation outcomes in patients with ARVC and biventricular (BiV) involvement. METHODS AND RESULTS: We assembled a retrospective cohort of definite ARVC cases with sustained VTs. Patients were divided into the BiV (BiV involvement) group and the right ventricular (RV) (isolated RV involvement) group based on the left ventricular systolic function detected by cardiac magnetic resonance. All patients underwent electrophysiological mapping and VT ablation. Acute complete success was non-inducibility of any sustained VT, and the primary endpoint was VT recurrence. Ninety-eight patients (36 ± 14 years; 87% male) were enrolled, including 50 in the BiV group and 48 in the RV group. Biventricular involvement was associated with faster clinical VTs, a higher VT inducibility, and more extensive arrhythmogenic substrates (all P < 0.05). Left-sided VTs were observed in 20% of the BiV group cases and correlated with significantly reduced left ventricular systolic function. Catheter ablation achieved similar acute efficacy between these two groups, whereas the presence of left-sided VTs increased acute ablation failure (40 vs. 5%, P = 0.012). Over 51 ± 34 months [median, 48 (22-83) months] of follow-up, cumulative VT-free survival was 52% in the BiV group and 58% in the RV group (P = 0.353). A multivariate analysis showed that younger age, lower RV ejection fraction (RVEF), and non-acute complete ablation success were associated with VT recurrence in the BiV group. CONCLUSION: Biventricular involvement implied a worse arrhythmic phenotype and increased the risk of left-sided VTs, while catheter ablation maintained its efficacy for VT control in this population. Younger age, lower RVEF, and non-acute complete success predicted VT recurrence after ablation.

Impact on clinical outcome of ventricular arrhythmias in patients undergoing transcatheter aortic valve implantation.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) has become a largely used treatment for severe aortic stenosis. There are limited data, however, about predictors of long-term prognosis in this population. In this study, we assessed whether ventricular arrhythmias may predict clinical outcomes in patients undergoing TAVI. METHODS AND RESULTS: We performed a 24 h ECG Holter monitoring in 267 patients who underwent TAVI for severe aortic stenosis within 30 days from a successful procedure. The occurrence of frequent premature ventricular complexes (PVCs; ≥30/h), polymorphic PVCs and nonsustained ventricular tachycardia (NSVT) was obtained for each patient. Clinical outcome was obtained for 228 patients (85%), for an average follow-up of 3.5 years (range 1.0-8.6). Cardiovascular events (CVEs; cardiovascular death or resuscitated cardiac arrest) occurred in 26 patients (11.4%) and 63 patients died (27.6%). Frequent PVCs but not polymorphic PVCs and NSVT were found to be associated with CVEs at univariate analysis. Frequent PVCs were indeed found in 12 patients with (46.2%) and 35 without (17.3%) CVEs [hazard ratio 2.30; 95% confidence interval (CI) 1.03-5.09; P  = 0.04], whereas polymorphic PVCs were found in 11 (42.3%) and 54 (26.7%) patients of the two groups, respectively (hazard ratio 1.44; 95% CI 0.64-3.25; P  = 0.38), and NSVT in 9 (34.6%) and 43 patients of the two groups, respectively (hazard ratio 1.18; 95% CI 0.48-2.87; P  = 0.72). Frequent PVCs, however, were not significantly associated with CVEs at multivariate Cox regression analysis (hazard ratio 1.53; 95% CI 0.37-6.30; P  = 0.56). Both frequent PVCs, polymorphic PVCs and NSVT showed no significant association with mortality. CONCLUSION: In our study, the detection of frequent PVCs at Holter monitoring after TAVI was a predictor of CVEs (cardiovascular death/cardiac arrest), but this association was lost in multivariable analysis.

Evaluation of patients with implantable cardioverter-defibrillator in a Latin American tertiary center.

INTRODUCTION: Despite advancements in implantable cardioverter-defibrillator (ICD) technology, sudden cardiac death (SCD) remains a persistent public health concern. Chagas disease (ChD), prevalent in Brazil, is associated with increased ventricular tachycardia (VT) and ventricular fibrillation (VF) events and SCD compared to other cardiomyopathies. METHODS: This retrospective observational study included patients who received ICDs between October 2007 and December 2018. The study aims to assess whether mortality and VT/VF events decreased in patients who received ICDs during different time periods (2007-2010, 2011-2014, and 2015-2018). Additionally, it seeks to compare the prognosis of ChD patients with non-ChD patients. Time periods were chosen based on the establishment of the Arrhythmia Service in 2011. The primary outcome was overall mortality, assessed across the entire sample and the three periods. Secondary outcomes included VT/VF events and the combined outcome of death or VT/VF. RESULTS: Of the 885 patients included, 31% had ChD. Among them, 28% died, 14% had VT/VF events, and 37% experienced death and/or VT/VF. Analysis revealed that period 3 (2015-2018) was associated with better death-free survival (p = .007). ChD was the only variable associated with a higher rate of VT/VF events (p < .001) and the combined outcome (p = .009). CONCLUSION: Mortality and combined outcome rates decreased gradually for ICD patients during the periods 2011-2014 and 2015-2018 compared to the initial period (2007-2010). ChD was associated with higher VT/VF events in ICD patients, only in the first two periods.