Recurrent Ventricular Tachycardia Research Articles

Propranolol triggered recurrent ventricular tachycardia and electrical storm in an infant with long QT syndrome type 2

Propranolol triggered recurrent ventricular tachycardia and electrical storm in an infant with long QT syndrome type 2

Effect of Ischemia Testing and Coronary Revascularization on Mortality and Ventricular Tachycardia Recurrence in Patients With Monomorphic Ventricular Tachycardia Without Acute Coronary Syndrome: A Meta-Analysis and Systematic Review.

Studies show mixed results regarding the effect of coronary revascularization on mortality benefit and ventricular tachycardia (VT) recurrence in patients with monomorphic VT without acute coronary syndrome (ACS). This meta-analysis aimed to assess the effect of ischemia testing and/or coronary revascularization on mortality and VT recurrence in a pooled data set. Databases including PubMed, Google Scholar, and the Cochrane Library were searched from January 2000 to December 2023 for studies reporting event data on mortality and VT recurrence in patients without ACS who presented with monomorphic VT. Data were pooled and analyzed using random effects meta-analysis. The pooled sample consisted of a total of five studies, with 1062 patients, of whom 433 underwent ischemia testing and/or coronary revascularization and 629 did not. There was no statistically significant difference in the mortality and VT recurrence in the patients who underwent ischemia testing and/or revascularization versus those who did not (mortality odds ratio [OR]: 0.98; [95% confidence interval (CI): 0.62 to 1.53]; p = 0.92; VT recurrence OR: 1.07; [95% CI: 0.51 to 2.26]; p = 0.86). No publication bias was detected by examination of the funnel plot, Begg-Mazumdar's test (p = 0.80), and Egger's test (p = 0.91). In conclusion, in patients with sustained monomorphic VT in the absence of ACS, ischemia testing and/or revascularization does not lead to improved mortality or a decrease in the incidence of VT recurrence.

Abstract 4113336: Characteristics and Outcomes of Ventricular Tachycardia Ablation in Patients with the HeartMate 3 Left Ventricular Assist Devices: Results From a Large Single-Center Registry

HeartMate 3 (HM3) is a fully magnetically levitated continuous flow left ventricular assist device (LVAD). In patients with HM3 and recurrent ventricular tachycardia (VT), data on the outcomes of catheter ablation (CA) are insufficient. We report our institutional experience with CA of VT in patients with the HM3.Consecutive patients with HM3 and recurrent drug-refractory VT undergoing CA were included. Ablation sites were identified using activation/entrainment mapping (stable VTs) and/or late/fractionated potential ablation and pace-mapping (unstable VTs). Between 2016-2023 a total of 431 patients (age 58±13, INTERMACS 3±0.98, 44% ischemic cardiomyopathy) received an HM3 LVAD at our institution. Of these, 15 (3.4%) underwent CA for recurrent VT despite therapy with 1.3±0.8 antiarrhythmic drugs a median of 700 days from the LVAD surgery (2 patients <1 month from the surgery). The LV access was transseptal in 12 (80%) cases, retrograde aortic in 2 (13%) and both in 1 (7%). A total of 23 distinct VTs were targeted. Of these, 21 (91%) were mapped with activation/entrainment mapping, always utilizing an intracardiac RV reference due to excessive surface ECG noise, and 2 (9%) were hemodynamically unstable with reduced LVAD flows and targeted with substrate-based ablation. A total of 3 (13%) VTs were targeted adjacent to the HM3 inflow cannula, and 20 (87%) from substrate remote from the HM3 cannula. At post-procedural programmed ventricular stimulation, non-inducibility of all targeted VTs was achieved in 13 (87%) patients, 1 patient had residual inducible clinical VT, and in 1 patient no post-procedural programmed stimulation was performed. Periprocedural complications occurred in 1 (7%) case (small pericardial effusion not requiring intervention). At 12 months follow-up following the index procedure, no death occurred and one patient received heart transplantation. Of the remaining 14 patients, 6 (42%) remained free from VT (2 with VT ablation <1 month post-LVAD and 12 with VT ablation >=1 month post-LVAD). In this large single-center HM3 registry, a minority of patients underwent CA for recurrent drug-refractory VT (3.4% over a 7-year period). CA of VT in HM3 recipients is feasible and appears safe also when performed soon after LVAD surgery. Myocardial scar from the underlying cardiomyopathic process rather than the apical cannula is the dominant substrate responsible for VT in these patients.

Abstract 4148095: The Impact of Body-Mass Index on Ventricular Tachycardia Outcomes Post-Catheter Ablation

Background: In recent years, catheter ablation has emerged as a sustainable, first-line therapy for the management of ventricular tachycardia (VT). Given the rise of the “obesity paradox” theory in atrial ablation outcomes, we sought to study the effect of BMI on patients undergoing structural VT ablation. Purpose: To assess the outcomes of VT ablation, specifically VT recurrence, in patients with elevated vs. normal BMI. Methods: Clinical characteristics and demographic data were collected for VT patients who underwent ablation at Mayo Clinic Rochester from 2012-2022. Patient BMI was classified as non-obese (<30 kg/m2), obese (30-40 kg/m2), and morbidly obese (≥40 kg/m2). The endpoint was a composite of initial monomorphic VT recurrence and repeat ablation after adjusting for age, sex, and comorbidities. Results: A total of 399 patients underwent 508 ablations. 51.4% of ablations had a BMI <30, 39.2% were between 30-40, and 9.4% were ≥40. There was a greater prevalence of hypertension and type 2 diabetes mellitus in morbidly obese patients (p <0.01). Morbidly obese individuals also had a significantly increased rate of general anesthesia during ablation and long VT cycle lengths. The Kaplan-Meier curve demonstrates no statistically significant differences in time to VT recurrence among the three BMI groups (p = 0.324). Neither morbid-obesity (aHR= 1.20; CI = 0.94-1.56, p = 0.14) nor nonmorbid-obesity (aHR = 0.92; CI = 0.76-1.10, p = 0.4), compared to non-obesity was a significant independent predictor of VT recurrence or repeat ablation on multivariate regression after adjusting for age, sex and comorbidities. Conclusion: There was no significant association between BMI groups and VT recurrence or repeat ablation, and no difference in complications. We did not find the obesity paradox to be relevant for VT ablation in our patient population. Further study would be needed with larger samples to corroborate these findings.

Abstract 4132217: Comorbidities Associated with One Year Mortality and Hospital Readmission After Ventricular Tachycardia Ablation

Introduction: Many studies have evaluated outcomes after ventricular tachycardia (VT) ablation though few studies have evaluated outcomes past thirty days. This study aimed to determine which comorbidities are associated with one-year readmissions and mortality after VT ablation, including socioeconomic disadvantage (SED) via the Area Deprivation Index (ADI). Methods: Patients ages ≥18 were identified in the Healthcare Cost and Utilization Project State Inpatient Databases in New York and Florida from 2016-2019 with follow-up into 2020. These states were chosen due to availability for linkage of the 2020 ADI (1-100, higher scores representing more disadvantage). International Classification of Diseases 10 codes for VT and VT ablation were used. Patients undergoing pacemaker placement or with other arrhythmias were excluded. The risk of readmission and mortality was assessed using Cox proportional hazards first in an unadjusted fashion for each comorbidity in the Charlson Comorbidity Index. In addition to demographic variables, only significant variables from the unadjusted analysis were included in the final adjusted multivariable models. Results: 1,798 patients met inclusion criteria. The readmission and mortality rates at one, three, and twelve months were 18.5%, 27.4%, 41.4% and 3.5%, 4.1%, 6.5%, respectively. Common diagnoses for readmission were VT (24.8%) and dyspnea/chest pain (10.7%). After adjustment, African American race, federal insurance, heart failure (CHF), vascular disease, renal disease (CKD), severe liver disease (SLD), and higher ADI were associated with increased risk for twelve-month readmissions. Federal insurance, CHF, cerebrovascular disease, dementia, peptic ulcer disease, CKD, and SLD were associated with increased risk for twelve-month mortality. Conclusion: CHF and CKD increased the risk of readmission and mortality. Recurrent VT was the most common cause of readmission. Patients of SED are at increased risk of readmissions within one year.

Abstract 4137919: Electrical Storm Caused by Chagasic Cardiomyopathy Successfully Treated with Ventricular Aneurysmectomy

Introduction: Chronic Chagasic cardiomyopathy (CCC) is a serious complication of Chagas disease that can manifest as LV dysfunction, ventricular aneurysms, and ventricular arrhythmias. Management of the electrical storm in CCC is challenging, especially when it is refractory to catheter ablation. Case Presentation: A 59-year-old woman from southern Peru presented to the ED with palpitations and dyspnea for 1 week. Physical exam was normal. ECG showed Q waves in III and AVF leads. TTE revealed an LVEF of 45% with an inferolateral LV aneurysm. Coronary angiography showed no lesions. CCC was suspected and serology was ordered, which was positive for T. cruzi . Cardiac MRI confirmed the presence of a 32x22mm basal inferolateral LV aneurysm. During hospitalization, she experienced 4 episodes of unstable monomorphic ventricular tachycardia (VT) within 24 hours, requiring defibrillation with 200J, vasopressor support, and invasive mechanical ventilation. The diagnosis of electrical storm secondary to CCC was proposed, for which amiodarone infusion was started until complete impregnation was achieved. Additionally, support was provided with IABP and specific antiparasitic treatment with benznidazole. Electrophysiology determined that the probable focus of the VT was situated at the level of the LV aneurysm. Therefore, ablation with endocardial-epicardial mapping was performed. However, the patient continued to experience recurrent episodes of VT. Consequently, in a multidisciplinary discussion, it was decided to perform a ventricular aneurysmectomy, which was successful. The patient's clinical progress was favorable, with initiation of GDMT and placement of a single-chamber ICD for secondary prevention. After one year of outpatient follow-up, the patient remains free of VT recurrences. Conclusion: Ventricular aneurysmectomy is a successful management approach for patients with CCC who present with electrical storm refractory to antiarrhythmic drugs and catheter ablation, and whose VT is believed to originate from the aneurysm. The diagnosis of CCC is highly arrhythmogenic and should be suspected at an early stage, given the patient's demographics and the presence of LV aneurysm in the absence of coronary artery disease.

Catheter Ablation for Ventricular Tachycardias: Current Status and Future Perspectives.

Catheter ablation for ventricular tachycardia (VT) in patients with systolic heart failure remains a critical yet challenging area of non-pharmacological therapy. Despite positive outcomes in atrial fibrillation, evidence for the efficacy of VT ablation in reducing cardiac mortality is inconclusive due to the absence of standardized ablation strategies. The primary challenges include difficulties in identifying suitable ablation targets and their deep locations within myocardial tissue. Current techniques, such as voltage mapping, provide valuable insights; however, they are limited by the presence of numerous bystander areas and the occurrence of incomplete transmural scarring. Recent advancements in functional substrate mapping have focused on identifying critical isthmuses without requiring hemodynamic stabilization during VT, thereby shifting the emphasis to the analysis of potentials during baseline rhythm. While methods like isochronal late activation mapping have improved target identification, they primarily address conduction abnormalities without adequately considering repolarization heterogeneity. This review highlights emerging technologies that utilize unipolar potentials to assess repolarization heterogeneities and identify VT isthmuses. Furthermore, novel ablation sources such as pulsed-field ablation, bipolar ablation, and ultra-low temperature cryoablation are being explored to create deeper and more durable lesions, addressing the limitations of traditional radiofrequency ablation. These advancements aim to reduce VT recurrence and improve overall treatment efficacy. Ultimately, understanding these innovative strategies is expected to optimize procedural outcomes and significantly enhance the management of patients with scar-related VT.

Abstract 4124604: Finding the Right Course: Unknown Source of Hemorrhage Following Endocardial-Epicardial Ablation for Ventricular Tachycardia

Background: Epicardial radiofrequency ablation via percutaneous access is a common technique for ventricular tachycardia (VT) ablation. Rapid identification of and response to complications can reduce morbidity and mortality. Objective: We present a case of epicardial VT ablation complicated by a distal left internal mammary artery (LIMA) transection secondary to subxiphoid sheath insertion. Report: A 66-year-old man with hypertrophic cardiomyopathy was referred for endo-epicardial ablation of recurrent VT. Pericardial access was obtained using coronary vein exit and carbon dioxide insufflation technique. An 8.5F sheath was advanced over an indwelling pericardial wire, and ablation was performed. Following ablation, 400cc of blood was aspirated from the pericardial space after replacing the 8.5F sheath with a standard pericardial drain. Urgent angiography revealed intact coronary arteries, coronary sinus (CS) and LIMA. The 8.5F sheath was re-introduced and bleeding ceased. CT scan revealed no myocardial or great vessel damage. Mild pericardial drainage continued overnight. The next day, IR angiography demonstrated transection of the distal LIMA from the indwelling sheath. The patient underwent placement of a back-up pericardial drain, followed by coil embolization of the injured artery without complication (Fig). Conclusion: This case highlights the importance of maintaining a broad differential during apparent complications of epicardial access and the importance of staying close to midline for epicardial puncture given anatomic variability. The differential for acute blood loss and pericardial effusion following epicardial ablation includes 1) coronary artery damage, 2) CS damage, 3) extracardiac vascular injury, and 4) right ventricular injury. When extracardiac vascular injury is suspected, multidisciplinary collaboration is essential.

Yield of Coronary Assessment in Sustained Monomorphic Ventricular Tachycardia

Coronary assessment is frequently conducted in patients with sustained monomorphic ventricular tachycardia (SMVT); however, its yield and subsequent treatment implications remain unclear. This study aimed to determine the prevalence of coronary artery disease (CAD) in patients presenting with SMVT, factors influencing clinician referral for coronary assessment, and clinical outcomes based on revascularisation or medical management of CAD. Consecutive patients presenting with acute SMVT requiring inpatient admission between 2017 and 2022 were identified. A total of 249 individual patients with SMVT were identified, with 140 undergoing coronary assessment. Referral for coronary assessment was driven by chest pain (p<0.001) and increased troponin kinetics (p<0.001). No patient with SMVT had an acute coronary occlusion. Significant CAD was found in 48 (34%) patients, and traditional ischaemic features did not predict significant CAD. Nineteen (40%) patients with significant CAD underwent revascularisation (n=15 percutaneous coronary intervention, n=4 coronary artery bypass grafting). There was no significant difference in time to ventricular tachycardia (VT) recurrence between revascularised and medically managed CAD (hazard ratio 1.670; 95% confidence interval 0.756-3.687; p=0.199). A total of five of six patients who underwent a revascularisation-only strategy (no upfront antiarrhythmic therapy or ablation) had VT recurrence (median time to recurrence 8.9 months). Despite being frequently performed, coronary assessment in SMVT has only modest yield, with no patients having an acute coronary occlusion. Traditional clinical factors of ischaemia did not improve this yield. Revascularisation alone did not improve freedom from VT.

Cardiac stereotactic body radiation therapy in advanced heart failure patients with recurrent ventricular tachycardia – a case series

Cardiac stereotactic body radiation therapy in advanced heart failure patients with recurrent ventricular tachycardia – a case series

Predictors of long‐term success after high‐density mapping‐guided substrate ablation procedures for ventricular tachycardia in patients with ischemic cardiomyopathy

AbstractIntroductionHigh‐density (HD) substrate mapping may increase success of catheter ablation targeting ventricular tachycardia (VT). However, despite its use, recurrent VT is not uncommon. We aim to investigate factors that are associated with outcomes after HD mapping‐guided substrate ablation procedures for VT in patients with ischemic cardiomyopathy.MethodsObservational cohort study includes patients with ischemic heart disease who underwent HD mapping‐guided substrate ablation of VT. Baseline and procedural characteristics were associated with outcomes after VT ablation.ResultsVT ablation employing HD mapping was performed in 80 patients. Median follow‐up was 2.3 years. VT‐free survival at one, two, and five years were 65%, 49%, and 40%. One‐, two‐, and five‐year implantable cardioverter defibrillator (ICD) shock‐free survival rates were 90%, 81%, and 70%. Complications occurred in 3 patients (3.8%, 1 vascular, 2 tamponades). Left ventricular ejection fraction (LVEF) and 45 W (vs. 35 W) ablation power were associated with VT‐free survival. High ablation power was also associated with shock‐free survival. All‐cause mortality during follow‐up was associated with higher age, the presence of chronic obstructive pulmonary disease (COPD), LVEF, and urgent ablation.ConclusionsIn patients with ischemic cardiomyopathy that had HD substrate mapping‐guided VT ablation, ablation power was associated with both VT‐free and shock‐free survival, underlining the importance of effective target elimination. All‐cause mortality during follow‐up was associated with several factors (age, COPD, LVEF, and urgent vs. elective ablation), which could be used to guide patient selection for VT ablation.

Drug therapy and catheter ablation for management of arrhythmias in continuous flow left ventricular assist device's patients: a Clinical Consensus Statement of the European Heart Rhythm Association and the Heart Failure Association of the ESC.

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure. Although these devices effectively improve survival, atrial and ventricular arrhythmias are common with a prevalence of 20-50% at one year after LVAD implantation. Arrhythmias predispose these patients to additional risk and are associated with considerable morbidity from recurrent implantable cardioverter-defibrillator shocks, progressive failure of the unsupported right ventricle, and herald an increased risk of mortality. Management of patients with arrhythmias and LVAD differs in many aspects from the general population heart failure patients. These include ruling out the reversible causes of arrhythmias that in LVAD patients may include mechanical irritation from the inflow cannula and suction events. For patients with symptomatic arrhythmias refractory to medical treatment, catheter ablation might be relevant. There are specific technical and procedural challenges perceived to be unique to LVAD-related ventricular tachycardia (VT) ablation such as vascular and LV access, signal filtering, catheter manoeuvrability within decompressed chambers, and electroanatomic mapping system interference. In some patients, the arrhythmogenic substrate might not be readily accessible by catheter ablation after LVAD implantation. In this regard, the peri-implantation period offers a unique opportunity to surgically address arrhythmogenic substrate and suppress future VT recurrences. This document aims to address specific aspects of the management of arrhythmias in LVAD patients focusing on anti-arrhythmic drug therapy and ablations.

Contemporary outcomes of catheter ablation of the structural ventricular tachycardias in severe ischemic and non‐ischemic cardiomyopathies in Turkish population

AbstractIntroductionCurrently, there are no data regarding outcomes of the catheter ablation for structural ventricular tachycardia (VT) in Türkiye. In this observational study, we aim to investigate cardiac outcomes of patients undergoing catheter VT ablation at a tertiary center in Türkiye.MethodsThis was a retrospective observational study performed at a single university center. Patients with a confirmed ischemic or non‐ischemic cardiomyopathy, undergoing structural VT ablation were included. Procedural and mid‐term outcomes were analyzed.ResultsA total of 124 patients were enrolled in the study. 54(43.5%) patients presented with an electrical storm. During the mean follow‐up of 351 ± 232 days 10(8.1%) patients experienced a recurrence. There was only one peri‐procedural death and cardiac tamponade occurred in two patients.14(11.3%) patients died during the follow‐up, most commonly due to a cardiovascular death. In the multivariate analysis only age &gt;70 was found to be correlated with death during follow‐up, with p =.008, HR = 4.923.ConclusionA good acute success with low complications was observed in patients undergoing VT ablation for structural heart disease in a tertiary center in Türkiye. Mid‐term outcomes are comparable with international studies with no difference in VT recurrence in ischemic and non‐ischemic patients. Similar to international studies, significant mid‐term mortality was observed.

Mineralocorticoid receptor antagonist therapy in patients with ischemic heart failure and ventricular tachycardia: a comparative analysis of spironolactone vs. eplerenone

Abstract Background Mineralocorticoid receptor antagonists (MRAs) are a cornerstone of heart failure therapy and have been shown to reduce the incidence of sudden cardiac death. However, a direct comparison between spironolactone and eplerenone in patients who present ventricular tachycardia (VT) is lacking. Purpose This study aimed to compare the effect of spironolactone and eplerenone on VT recurrence in patients with ischemic heart disease (IHD) hospitalized for VT episodes. Methods Our data utilized a registry of 405 patients with IHD and HF, who were hospitalized for an episode of sustained VT and received MRA therapy. We performed propensity score matching based on age, hypertension, diabetes, history of acute myocardial infarction, left ventricular ejection fraction (LVEF) and presentation with incessant VT. The matched population included 200 patients, stratified into two equivalent groups. Cox regression analysis was performed to identify predictors of VT recurrence, with Kaplan-Meier curves facilitating time-to-event analyses. Results The median age was 69 years and the majority (91%) were male. One-third had an ICD, and 41 patients (20%) had CRT. The median LVEF was 30%, 23 patients (12%) presented with an electrical storm, while 18 (9%) had incessant VT. VT led to hemodynamic instability in 91 cases (46%). Ablation was performed in 47 patients (24%), while 1 required mechanical circulatory support. Ablation was performed in 47 patients (24%), while 1 required mechanical circulatory support. Patients were followed for at least a year and median follow-up time was 414 days. A total of 78 patients had VT recurrence and 117 patients died. Eplerenone use significantly reduced the risk of VT recurrence compared to spironolactone (HR: 0.59 [0.37-0.93], p=0.023). This effect was consistent in the multivariate model as well (p=0.007). Conclusions Eplerenone use may confer a greater protective effect against VT recurrence in patients with IHD and sustained VT. Further studies are required to confirm these preliminary findings.

Role of ventricular tachycardia cycle length in the outcomes after catheter ablation or antiarrhythmic drugs in the SURVIVE-VT trial

Abstract Background It has been suggested that antiarrhythmic drugs (AAD) are less effective and safe in slow ventricular tachycardia (VT) due to their effect on conduction velocity, which could stabilize reentry. Conversely, catheter ablation aims to disrupt the VT circuit. Because of the distinct mechanisms of action of AAD and catheter ablation on the VT circuit, VT cycle length (VT-CL) may play a crucial role in determining their therapeutic efficacy. Therefore, VT-CL could be important in selecting VT treatment. Purpose The aim of this study was to assess the impact of VT-CL on outcomes following catheter ablation or antiarrhythmic drugs in AAD-naïve patients with ischemic cardiomyopathy presenting with VT. Methods This is a post hoc analysis of the previously published Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia (SURVIVE-VT) trial. In summary, 144 patients with ischemic cardiomyopathy and symptomatic VT were randomized to receive either catheter ablation (N=71) or AAD (N=73) as first-line therapy. We analyzed VT recurrence, implantable cardioverter-defibrillator (ICD) therapies, and the incidence of slow/incessant VT/VT storm using Cox proportional hazard models, with treatment and VT-CL interaction terms, adjusted for age. Missing VT-CL data for five patients were imputed using the median value. Results In patients with chronic ischemic heart disease and VT treated with either AAD or catheter ablation, a significant interaction was observed between clinical VT-CL and treatment effect on VT recurrence (p=0.016 for the interaction). Specifically, slower VT cycle lengths were associated with higher rates of VT recurrence (hazard ratio per 10 ms [HR] 1.094, 95% confidence interval [CI] 1.015, 1.179; p=0.037) in patients treated with AAD, while no significant effect was observed in those undergoing catheter ablation (see Figure 1). Survival freedom from VT recurrence in patients with VT-CL ≥300ms was significantly higher in patients treated with catheter ablation (78.8% vs 58.1%, log-rank p=0.044, see Figure 2). As expected, VT-CL was significantly associated with a higher risk of slow/incessant VT/VT storm (HR per 10 ms 1.115, 95% CI 1.017-1.222, p=0.047) but was not associated with ICD therapies (HR per 10 ms 1.082, 95% CI 0.994-1.178, p=0.102). Conclusion VT-CL significantly influences treatment outcomes, with slower VT cycles associated with an increased risk of VT recurrence in patients treated with AAD, but not in those undergoing catheter ablation. Therefore, VT-CL should be taken into consideration when selecting the optimal therapy for patients with ischemic cardiomyopathy and VT.Figure 1Figure 2

Machine-learning models to predict the risk of recurrent VT following catheter ablation in patients with structural heart disease

Abstract Background Ventricular tachycardia (VT) is a life-threatening arrhythmia that can complicate structural heart disease. While catheter ablation is effective in treating this condition, the recurrence of VT after the procedure continues to be a concern. Consequently, there is a need for a reliable system to evaluate the likelihood of arrhythmia recurrence following an ablation. Objective To predict recurrence or repeat ablation after a VT catheter ablation procedure using machine learning (ML) models. Methods We conducted a single-center, retrospective study of all patients undergoing catheter ablation for scar-related VT between 2012 and 2022. Data collected included demographics, comorbidities, medications, relevant laboratory abnormalities, electrocardiograms, echocardiograms, detailed procedural characteristics, and outcomes. Python version 3.8.5 for exploratory data analysis (EDA) and visualization. Using six different ML models from the training set (90:10 split), we used 34 variables to predict the primary outcome, including VT recurrence or repeat catheter ablation. The accuracy of these models was compared using ROC curves based on their performance on the test set. Results Out of 508 VT ablation procedures, 261 experienced a recurrence. Support Vector Classifier (SVM) performed the best, having an AUC of 0.73, followed by logistic regression at 0.69 (Figure A). SVM yielded sensitivity, specificity, positive and negative predictive values of 0.73, 0.73, 0.79, and 0.67, respectively. The F1 score was 0.70. Among the factors with the highest feature importance in the model, the most influential variable was the proceduralist’s experience level, followed by QRS width at baseline, LVEF, and patient’s age (Figure B). Conclusion Our model can predict recurrent VT after ablation with reasonable accuracy, outperforming the existing clinical risk scores significantly. Larger training sample sizes will help achieve more robust ML models and improve predictive accuracy further.Figure A: ROC curve depicting the AUROCB. Feature importance graph

Speckle tracking echocardiography as a predictor of location of ablation sites in candidates to catheter ablation for recurrent ventricular tachycardia

Abstract Background Preoperative imaging is essential before a ventricular tachycardia (VT) ablation procedure, to improve operative outcomes and reduce procedural times. Although MRI is the gold standard, it has several limitations, including patient compliance, possible presence of non-MRI-compatible devices, and long acquisition time. Speckle tracking echocardiography (STE) is a reliable and appealing technique that quantifies regional and global myocardial deformation, as well as layer-specific (endo-, mid- and epicardial) longitudinal strain, without MRI limitations. Purpose This study aimed to evaluate the efficacy of STE in predicting VT ablation sites. Methods In this study, we compared the bull’s eye segmentation of the left ventricle, global and layer-specific, obtained with STE (TomTec Arena), to investigate whether echocardiography can predict the areas of scar and late potential, as identified by electroanatomic mapping (EnSite X mapping, HD Grid mapping catheter, Abbott). Strain analysis and electroanatomic mapping data were matched segment-by-segment to obtain pairs of endocardial strain and bipolar substrate maps, as well as pairs of midmyocardial/epicardial strain and unipolar substrate maps. Results Twenty-three consecutive patients with an indication for catheter ablation for recurrent VT were enrolled. All patients were being treated with beta-blockers, 52% were taking amiodarone, and only 2 patients were on mexiletine. A total of 1170 pairs of bull’s eye segments were available for analysis. A binary logistic mixed-effects model was used to predict the presence of electroanatomical scar based on strain echocardiography data, to account for interpatient variability. The study findings highlighted a close correlation between the bipolar map and endocardial strain values, and between the unipolar map and midmyocardial strain values. Progressively higher (less negative) values of endocardial strain proved predictive of bipolar electroanatomical scar, with an increase in the odds ratio of bipolar electroanatomical scar equal to 6.2% (95% confidence interval 2.5%-10%) for each unit increase in strain values. Similarly, progressively higher values of midmyocardial strain were predictive of unipolar electroanatomical scar, with an increase in the odds ratio of unipolar electroanatomical scar equal to 6.2% (95% confidence interval 1.2%-11.4%) for each unit increase in strain values. Conclusions The data from our study showed an anatomical correspondence between the areas of low potential identified by electroanatomical mapping and the areas of anomalous longitudinal strain. In particular, the endocardial strain correlates with the bipolar map, and the meso-epicardial strain correlates with the unipolar map. These data may prove useful in the appropriate planning of the procedure in patients with an indication for catheter ablation in the context of recurrent VT.

Clinical presentation, risk factors and six-month outcomes in Ugandan women with peripartum cardiomyopathy: prospective case-control study

Abstract Background Peripartum Cardiomyopathy (PPCM) frequently affects women of African descent. There is scarcity of data pertaining to the clinical presentation and outcomes of PPCM patients in Uganda, particularly when employing modern diagnostic tools and adhering to guideline-directed medical therapy (GDMT). Purpose We aimed to delineate the clinical characteristics, echocardiographic findings, and 6-month outcomes among women in Uganda diagnosed with PPCM. Methods Prospective case-control design conducted from June 2022 to August 2023. We enrolled 80 PPCM cases and 80 matched controls. Inclusion criteria comprised: (i) peripartum state, (ii) signs and symptoms of HF, (iii) left ventricular (LV) ejection fraction ≤ 45%, and (iv) exclusion of alternative causes of HF. Controls were healthy women matched for age and parity. Over a 6-month period, enrolled PPCM cases were diligently monitored while on GDMT. All participants underwent a physical examination, 12-lead electrocardiography, and a detailed echocardiography incorporating global longitudinal strain measurements at both baseline and the 6-month follow-up. Results At baseline, amongst the cases, the mean age was 33.6 ± 6.6 years, mean parity was 3±2.1 pregnancies. HF onset occurred within 9.5±6.5 weeks post-delivery. A total of 20 (25.0%) cases presented in NYHA Class 4 with dyspnea as the predominant symptom in 79.95% of cases. Atrial fibrillation (AF) was observed in 2(2.5%) patients. In comparison with healthy controls, high gravidity (0.2±1.0; p&amp;lt;0.001) was identified as the only predictor of PPCM in this study. (Table 1) At 6-months follow up, the mean LV ejection fraction (LVEF) showed improvement from 35.7±-11.0% to 45.9 ± 15.7% (p&amp;lt;0.001) accompanied by a reduction in left ventricular diameter (LVD) from 6.1±0.7 cm to 5.5±1cm(p&amp;lt;0.001). At the 6-month follow-up, recovery (LVEF ≥ 50%) occurred in 37 cases (55%), and 52 (65%)patients were asymptomatic (NYHA Class 1) at the 6-month follow-up. Six-month mortality data were available for 5(6.3%) women, and one patient successfully underwent the insertion of an Implantable Cardioverter-defibrillator for recurrent Ventricular Tachycardia. Regarding GDMT, 55 participants received Bromocriptine as part of their medication. Twenty(25%) patients received anticoagulation for AF(n=2) or intracardiac thrombus (n=6, 1.67%) (Figure 1) resulting in 2(2.5%) strokes within the 6-month follow-up. Conclusion The current study demonstrated a comparable mortality rate on GDMT, aligning with contemporary global studies at 7.5%. The observed high thrombus burden in patients may indicate suboptimal adherence to anticoagulation therapy. While the incidence of PPCM remains undefined in Uganda, the primary predisposing factor identified was high gravidity. A noteworthy proportion of patients exhibited incomplete LV recovery, suggesting the need for larger studies to comprehensively define the maternal and fetal outcomes in Uganda.Figure 1Table 1

Stereotactic arrhythmia radioablation - A systematic review and meta-analysis of the prospective clinical studies

Abstract Background Stereotactic arrhythmia radioablation (STAR) is increasingly being evaluated in prospective studies as a new promising treatment option for patients with therapy-refractory ventricular tachycardia (VT). In STAR, the VT substrate is noninvasively treated with a high dose of radiotherapy. Recently, several single-arm prospective studies evaluating the clinical outcomes of STAR were published. Considering that the evidence base consists mainly of retrospective case series, we conducted a systematic review and meta-analysis to synthesize the prospective data on outcomes of STAR. Purpose To perform a systematic review and meta-analysis of prospective studies evaluating clinical outcomes of STAR for VT. Methods This study was registered in PROSPERO and adhered to the PRISMA reporting guidelines. Full-text studies describing prospective studies evaluating the safety and efficacy of STAR for VT were included in this study. Records published until August 2023 were retrieved from OVID MEDLINE, OVID Embase, Web of Science Core Collection, the Cochrane Central Register of Controlled Trials, and Google Scholar search engine (top 200 hits), deduplicated, and screened for eligibility. Abstract screening, full-text screening, data extraction and quality assessment were performed by two reviewers independently. Endpoints were defined as treatment related CTCAE grade ≥3 adverse events within 90 days after treatment, overall survival (OS), time to VT recurrence, and recurrence-free survival. Rates of patients achieving pre-defined 50%, 75% and 95% VT burden reduction thresholds were summarised. Random-effects generalized linear mixed-effects models and inverse variance models were used for the meta-analysis. Results 1861 records were identified, 987 were screened, and 10 full-text manuscripts published between 2019 and 2023 describing the results of STAR in 82 patients were included in this study. The majority were male (n=72; 88%), between 45 and 85 years old, and suffered from ischaemic cardiomyopathy (n=51; 62%). Median left ventricular ejection fraction ranged from 21 to 38% between studies. 20 patients did not undergo a prior catheter ablation for VT. All patients were treated with a single dose of 25 Gy and median planned target volume ranged from 45 to 198 cc between studies. Pooled 12-month OS rate was 0.73, and the proportion of patients experiencing grade ≥3 adverse events within 90 days after STAR was 0.11 (Figure 1). Reduction in VT burden is shown in Table 1. Although these were not pooled because of large heterogeneity in VT reduction time frame definitions, it can be appreciated that most of the patients experienced a reduction in VT burden. Conclusion The increasing evidence from prospective studies on STAR shows acceptable 12-month OS in a population of patients with advanced heart failure and refractory VT. Moreover, there is a modest rate of high-grade adverse events and most patients experience a reduction in VT burden.

Comparison of Oral Procainamide and Mexiletine Treatment of Recurrent and Refractory Ventricular Tachyarrhythmias

Background: Antiarrhythmic therapy for recurrent ventricular arrhythmias (VAs) in patients having undergone catheter ablation and in whom amiodarone and/or beta-blockers were ineffective or contraindicated is a controversial issue. Purpose: The present study sought to compare the efficacy and tolerability of oral procainamide and mexiletine in patients with recurrent ventricular arrhythmias when the standard therapy strategy failed. Methods: All patients with an implantable cardioverter defibrillator (ICD) treated with oral procainamide or mexiletine for recurrent ventricular tachycardia (VT) or ventricular fibrillation (VF) in two cardiology divisions between January 2010 and January 2020 were enrolled. Patients were divided into group A (oral procainamide) and group B (mexiletine) and the two groups were compared to each other. The primary endpoint was the efficacy of therapy; the secondary endpoint was the discontinuation of therapy. All events that occurred during procainamide or mexiletine treatment were compared with a matched duration period before the initiation of the therapy. Antiarrhythmic therapy was considered effective when a ≥80% reduction of the sustained ventricular arrhythmias burden recorded by the ICD was achieved. Results: A total of 68 consecutive patients (61 males, 89.7%; mean age 74 ± 10 years) were included in this retrospective analysis. After a median follow-up of 19 months, 38 (56%) patients had a significant reduction in the VA burden. After multivariable adjustment, therapy with procainamide was independently associated with an almost 3-fold higher efficacy on VA suppression compared to mexiletine (HR 2.54, 95% CI 1.06–6.14, p = 0.03). Only three patients (9%) treated with procainamide presented severe side effects (dyspnea or hypotension) requiring discontinuation of therapy compared with six patients (18%) treated with mexiletine who interrupted therapy because of severe side effects (p = 0.47). Conclusions: Compared to mexiletine, oral procainamide had a higher efficacy for the treatment of recurrent and refractory VAs, and showed a good profile of tolerability.