Citations

Abstract Background Radiofrequency ablation (RFA) has been effective in managing premature ventricular contractions (PVCs). Despite improvement in ablation techniques, recurrence remains high for LV summit PVCs. Epicardial ablation here is often precluded due to fat and proximity to coronaries, thus, aggressive but safe endocardial options are needed. Purpose To evaluate the safety and effectiveness of ultra-long ablation (>240 seconds) duration for refractory LV summit PVCs. Methods Patients with deep intramural LV summit PVCs were identified by lack of PVC elimination or late (>60 s suppression) and recurrence post-lesion under the left aortic sinus of Valsalva. We included patients who received the longest RFA of at least 240 seconds (maximum 15 minutes). RFA power was titrated slowly from 20 to 35W, carefully ensuring that the impedance drop did not exceed 12 ohms. Acute procedure success was defined as clinical PVC suppression for ≥60 minutes after the last lesion. Short-term success was defined as symptom improvement, ejection fraction (EF) recovery, and drop in PVC burden at 3 months. Results Twenty patients (59.5 ± 16.4 years, 55% male) were included. Baseline features are shown in Table 1. All RFA were delivered endocardially. No steam pops were noted. PVC burden was significantly lower at 3-month follow-up (P< 0.01), Figure 1A. Most patients had a normal ejection fraction (EF) at baseline; thus, no significant difference change in EF was observed (Figure 1B). One complication was recorded, which was tamponade likely caused by coronary sinus dissection requiring pericardiocentesis. Acute success was achieved in 95.0% of the cases, and all cases followed at 3 months (18/18) achieved short-term success. Conclusion Ultra-long duration RFA with lesions ≥ 240 seconds at 35W per lesion for LV summit PVCs appeared to be safe and effective in achieving acute and short-term success. The lack of acute suppression should not discourage operators, as there seems to be delayed suppression in some cases. Careful monitoring of biophysics is paramount when attempting this technique.

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

Abstract Background Catheter ablation of ventricular tachycardia (VT) has emerged as the mainstay of management for these sick patients. There is a lack of long-term data studying the characteristics and outcomes of VT ablation in females and the comparison with males. Purpose The purpose of the study was to assess the impact of sex on outcomes of catheter ablation for ventricular tachycardia. Methods A single-center retrospective study of 200 procedures in 168 patients undergoing catheter ablation for scar-related VT under GA or MAC sedation was conducted. Data collected included demographics, comorbidities, medications, relevant laboratory abnormalities, electrocardiograms, structural data including echocardiograms and cardiac magnetic resonance imaging, detailed procedural characteristics, and outcomes. Results Females undergoing VT ablation were younger (49.4 ± 15.6 vs. 65.5 ± 12.2 years) [Figure 1]. Females had a lower burden of comorbidities, including congestive heart failure (30.0 % vs. 82.5%), hypertension (27.5% vs. 74.4%), atrial arrhythmias (20.0% vs. 55.6%), chronic kidney disease (25.0% vs. 43.8%), prior myocardial infarction (15.0% & 35.0%), and coronary artery bypass graft surgery (0.0% & 23.8%). Females were on fewer antiarrhythmic drugs at baseline. During the procedure, males had a greater likelihood of undergoing general anesthesia (72.5% vs. 50.0%) and associated hemodynamic instability at baseline (30.0% vs. 12.5%). It was more likely for VT to be induced in males, and females required more induction medications. There was no difference in complication rates between males and females. A greater proportion of males were discharged and maintained on antiarrhythmic drugs after the procedure. There was no significant difference in VT recurrence or long-term mortality. Using Kaplan-Meier analysis, no difference was seen in long-term VT-free survival by sex (p=0.20) [Figure 2]. In a multivariate regression model, female sex had no bearing on the VT-free survival. Conclusion Females undergoing catheter ablation for VT are younger and have fewer comorbidities. They tend to be on fewer antiarrhythmic drugs at baseline, and after ablation. Interestingly, despite a healthier baseline profile, females do not experience less VT recurrence or mortality compared to males. Further study would be needed to investigate this association.Figure 1Figure 2

Abstract Background Catheter ablation has emerged as the first-line therapy for management of ventricular tachycardia (VT) over the last decade. There is a reluctance for older patients to be referred for catheter ablation with concerns for complications and poor outcomes. Purpose The purpose of the study was to assess the safety and outcomes of catheter ablation for VT in patients more than 74 years of age in comparison to younger patients. Methods A single-center retrospective study of 200 procedures in 168 patients undergoing catheter ablation for scar-related VT was conducted. Data collected included demographics, comorbidities, medications, relevant laboratory abnormalities, electrocardiograms, Holter, device electrograms, structural data including echocardiograms and cardiac magnetic resonance imaging, detailed procedural characteristics, and outcomes. Results The mean age in the older cohort was 77.7 ± 3.7 years compared to 57.6 ± 13.1 years in the younger group (p < 0.01) [Figure 1]. The geriatric patients had more males (93.6% vs. 75.8%) and had greater proportion of comorbidities including congestive heart failure (89.4% vs. 66.7%), hypertension (91.5% & 56.9%), atrial arrhythmias (66.0% vs. 43.1%), chronic kidney disease (68.1% vs. 31.4%), prior myocardial infarction (53.2% vs. 24.2%), and stroke (21.3% vs. 8.5%). The older patients were on more antiarrhythmic drugs at baseline. During the procedure, the number of cases with VT induction and hemodynamic stability was similar in older and younger groups. In cases where VT was induced, the older patients had a greater number of VTs induced (2.7 ± 3.0 vs. 1.9 ± 1.8), with slower cycle lengths (454.9 ± 122.6 vs. 379.3 ± 108.1 milliseconds). There was no difference noted in the procedural complications between the two groups. Older patients were more likely to be discharged on antiarrhythmic medications (87.2% vs. 71.2%) and had higher long-term mortality (29.8% vs. 7.8%). The older group was less likely to have a repeat ablation procedure (8.5% vs 24.2%). There was no difference in long-term VT-free survival rates among the two groups [Figure 2]. Conclusion Patients more than 74 years of age undergoing catheter ablation for structural VT have a greater comorbidity burden but demonstrate similar procedural complications and VT-free survival rates, when compared to the younger cohort.Figure 1Figure 2

Abstract Background Atrial fibrillation (AF) is common in hypertrophic cardiomyopathy (HCM). There is limited data regarding the outcomes of AF catheter ablation in HCM patients. In this study, we aimed to synthesize all available evidence on the effectiveness of ablation of AF in patients with HCM compared to those without HCM. Methods and results We systematically reviewed bibliographic databases to identify studies published through February 2023. We included cohort studies with available quantitative information on rates of recurrent atrial arrhythmias, anti-arrhythmic drug (AAD) therapy, and repeat ablation procedures after initial AF ablation in patients with vs without HCM. Estimates were combined using random-effects meta-analysis models and reported as risk ratios (RR) and 95% confidence intervals (CI). Eight studies were included in quantitative synthesis (262 HCM and 642 non-HCM patients). During median follow-up 13–54 months across studies, AF recurrence rates ranged from 13.3% to 92.9% in HCM and 7.6% to 58.8% in non-HCM patients. The pooled RR for recurrent atrial arrhythmia after the first AF ablation in HCM patients compared to non-HCM controls was 1.498 (95% CI = 1.305–1.720; P < 0.001). During follow-up, HCM patients more often required AAD therapy (RR = 2.844; 95% CI = 1.713–4.856; P < 0.001) and repeat AF ablation (RR = 1.544; 95% CI = 1.070–2.228; P = 0.02). The pooled RR for recurrent atrial arrhythmias after the last AF ablation was higher in patients with HCM than those without HCM (RR = 1.607; 95% CI = 1.235–2.090; P < 0.001). Conclusions Compared to non-HCM patients, those with HCM had higher rates of recurrent atrial arrhythmias, AAD use, and need for repeat AF ablation after initial ablation of AF.

AbstractWe present a novel description of Bezold–Jarisch Reflex (BJR) during cardiopulmonary exercise testing (CPET) in three young female patients with Group 1 pulmonary arterial hypertension (PAH). These three cases presented within 26 months, representing only 0.8% of 11,387 tests on patients with PAH undergoing CPET during this time frame.

AbstractIntroductionCardiac sarcoidosis (CS) is a nonischemic cardiomyopathy (NICM) characterized by infiltration of noncaseating granulomas involving the heart with highly variable clinical manifestations that can include conduction abnormalities and systolic heart failure. Cardiac resynchronization therapy (CRT) has shown significant promise in NICM, though little is known about its efficacy in patients with CS.ObjectiveTo determine if CRT improved cardiac remodeling in patients with CS.MethodsWe retrospectively reviewed all patients with a clinical or histological diagnosis of CS who underwent CRT implantation at the Mayo Clinic enterprise from 2000 to 2021. Baseline characteristics, imaging parameters, heart failure hospitalizations and need for advanced therapies, and major adverse cardiac events (MACE) were assessed.ResultsOur cohort was comprised of 55 patients with 61.8% male and a mean age of 58.7 ± 10.9 years. Eighteen (32.7%) patients had definite CS, 21 (38.2%) had probable CS, while 16 (29.1%) had presumed CS, and 26 (47.3%) with extracardiac sarcoidosis. The majority underwent CRT‐D implantation (n = 52, 94.5%) and 3 (5.5%) underwent CRT‐P implantation with 67.3% of implanted devices being upgrades from prior pacemakers or implantable cardioverter defibrillators. At 6 months postimplantation there was no significant improvement in ejection fraction (34.8 ± 10.9% vs. 37.7 ± 14.2%, p = .331) or left ventricular end‐diastolic diameter (58.5 ± 10.2 vs. 57.5 ± 8.1 mm, p = .236), though mild improvement in left ventricular end systolic diameter (49.1 ± 9.9 vs. 45.7± 9.9 mm, p < .0001). Within the first 6 months postimplantation, 5 (9.1%) patients sustained a heart failure hospitalization. At a mean follow‐up of 4.1± 3.7 years, 14 (25.5%) patients experienced a heart failure hospitalization, 11 (20.0%) underwent cardiac transplantation, 1 (1.8%) underwent left ventricular assist device implantation and 7 (12.7%) patients died.ConclusionsOur findings suggest variable response to CRT in patients with CS with no overall improvement in ventricular function within 6 months and a substantial proportion of patients progressing to advanced heart failure therapies.

Abstract Background: Atrial fibrillation (AF) is relatively less frequent in younger patients (age<50). Recently, studies have suggested that early restoration of sinus rhythm may lead to improved outcomes compared with rate control. Methods: We included all hospitalized patients between 18 and 50 years with a diagnosis of AF from the Nationwide Readmission Database 2016-2017 from the Healthcare Cost and Utilization Project. Demographic and comorbidity data were collected and analyzed. Outcomes assessed included one-year AF readmission rates, all-cause readmission, ischemic stroke, and all-cause mortality. Subgroup analyses were performed for all demographic and comorbidity variables.Results: Overall, 52,598 patients (medium age 44, interquartile range 38-48, female 25.7%) were included in the study, including 2,146 (4.0%) who underwent catheter ablation for AF. Patients who underwent catheter ablation had a significantly lower rate of readmission for AF or any cause at one year (adjusted hazard ratios (HR) of 0.52 [95% confidence interval (CI): 0.43-0.63] and HR of 0.81 [95% CI: 0.72 - 0.89], respectively). There was no difference in 1-year readmission for stroke or all-cause mortality between the two groups. Subgroup analyses showed a consistent reduction in the risk of AF readmission among major demographic and comorbidity subgroups.Conclusion: Catheter ablation in young patients with AF was associated with a reduction in 1-year AF related and all-cause readmissions. These data merit further prospective investigation for validation.

AbstractAimsThe MicraTM transcatheter pacing system (TPS) (Medtronic) is the only leadless pacemaker that promotes atrioventricular (AV) synchrony via accelerometer‐based atrial sensing. Data regarding the real‐world experience with this novel system are scarce. We sought to characterize patients undergoing MicraTM‐AV implants, describe percentage AV synchrony achieved, and analyze the causes for suboptimal AV synchrony.MethodsIn this retrospective cohort study, electronic medical records from 56 consecutive patients undergoing MicraTM‐AV implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona with a minimum follow‐up of 3 months were reviewed. Demographic data, comorbidities, echocardiographic data, and clinical outcomes were compared among patients with and without atrial synchronous ventricular pacing (AsVP) ≥ 70%.ResultsSixty‐five percent of patients achieved AsVP ≥ 70%. Patients with adequate AsVP had smaller body mass indices, a lower proportion of congestive heart failure, and prior cardiac surgery. Echocardiographic parameters and procedural characteristics were similar across the two groups. Active device troubleshooting was associated with higher AsVP. The likely reasons for low AsVP were small A4‐wave amplitude, high ventricular pacing burden, and inadequate device reprogramming. Importantly, in patients with low AsVP, subjective clinical worsening was not noted during follow‐up.ConclusionWith the increasing popularity of leadless pacemakers, it is paramount for device implanting teams to be familiar with common predictors of AV synchrony and troubleshooting with MicraTM‐AV devices.