Citations

Introduction: Cardiac veins serve as substrate for arrhythmogenesis, and are especially involved as foci in atrial fibrillation. Understanding cardiac vein anatomy along with myocardial extension into these structures can improve electrophysiological mapping and electrical isolation of arrhythmogenic substrate. Accurately defining cardiac vein anatomy is critical in improving success of ablation therapy for atrial fibrillation. Methods: We performed measurements on 620 formalin-fixed autopsy hearts explanted from October 1998 to July 2003. The integrity of the thoracic veins and their cardiac connections were examined and systematic measurements of the superior and inferior vena cavae, azygous vein, vein of Marshall, coronary sinus, and pulmonary veins were performed and data were analyzed using univariate statistics. Results: We found that muscular extensions into the pulmonary veins were visible in 99% of the examined hearts, and were circumferential around the vein ostia (99.6%). Muscle extension into the SVC was found in 78% of examined hearts. These extensions were largely circumferential around the ostium (39%), but were also found to be asymmetric in a majority of hearts. Asymmetry was found in hearts with longer muscle extensions; no symmetry was observed in extensions greater than 0.8cm. Muscle extensions into the IVC were not seen. Occasionally, macroscopic muscle extensions into the azygous vein were visible (6%). The vein of Marshall was found to be patent to probing in the majority of hearts examined (72%) and was almost always overlying the lateral left atrial endocardial ridge. Conclusions: Our data suggest that all pulmonary veins need to be electrically isolated during atrial fibrillation ablation because of the almost universal presence of myocardial tissue extending into the veins. Mapping of the SVC should be done circumferentially and if potentials are noted isolation should also be performed. The IVC did not have muscle extensions and is unlikely to be a site of arrhythmogenesis. The azygous vein occasionally had muscle extensions and thus requires mapping and possible isolation. The vein of Marshall can be a substrate for arrhythmogenesis and is accessible for ablation by targeting the lateral left atrial endocardial ridge.

AbstractIntroductionVentricular tachycardia storm or electrical storm (ES) is a common complication following left ventricular assist device (LVAD) implantation. The factors contributing to ES and outcomes are less studied. The study aimed to determine the factors associated with ES and the probability of survival in patients undergoing LVAD in three tertiary centers over a span of 15 years.MethodsWe performed a retrospective cohort study on all patients who underwent LVAD implantation at the Mayo Clinic (Rochester, Phoenix, and Jacksonville) from January 1, 2006 to December 31, 2020. ES was defined as ≥3 episodes of sustained ventricular tachycardia over a period of 24 h with no identifiable reversible cause. Detailed chart reviews of the electronic health records within the Mayo Clinic and outside medical records were performed.ResultsA total of 883 patients who underwent LVAD implantation were included in our study. ES occurred in 7% (n = 61) of patients with a median of 13 days (interquartile range [IQR]: 5–297 days) following surgery. We found 57% of patients (n = 35) developed ES within 30 days, while 43% (n = 26) patients developed ES at a median of 545 (IQR 152–1032) days after surgery. Following ES, 26% of patients died within 1 year. Patients with ES had a significant association with a history of ventricular arrhythmias and implantable cardioverter defibrillator (ICD) shocks before the procedure. ES was significantly associated with reduced survival compared to patients without ES (hazards ratio [HR]: 1.92, 95% CI: 1.39–2.64, p < .001).ConclusionFollowing LVAD implantation, the rate of ES was 7% with majority of ES occurring within 30 days of LVAD. Risk factors for ES included pre‐implant history of ventricular arrhythmias and ICD shock. ES was significantly associated with reduced survival compared to patients without ES.

Background: Inflammation is integral in the pathogenesis and propagation of atrial fibrillation (AF). Peri-ablation administration of steroids has been shown to significantly reduce AF recurrence at 3 months. We sought to determine the effect of intraoperative dexamethasone on early recurrence at both 3 months and 12 months post-ablation. Methods: A cohort of 94 adult patients (>18 years) underwent catheter ablation at Mayo Clinic Rochester from January to March 2019. Only first-time ablation patients were included, with all re-do ablations excluded to minimize heterogeneity. Administration of intraoperative dexamethasone 4 mg or 8 mg was determined by chart review from the procedure. At our institution, intraoperative intravenous steroids are administered for postoperative nausea and vomiting (PONV) prophylaxis at the discretion of the anesthesiologist. AF recurrence was determined by ECG or cardiac monitoring at less than 3 months or between 3 months and 1 year with an in-person follow-up visit. Results: A total of 36.2% of patients received intravenous dexamethasone compared to 63.8% who did not (providing a 2:1 comparison group). The incidence of documented AF or flutter lasting greater than 30 seconds was 20.6% in the dexamethasone group versus 21.7% in the non-dexamethasone group, p value 1.00. AF or atrial flutter recurrence from 3 months to 1 year was 20.6% in the dexamethasone group compared to 21.7% in the non-dexamethasone group, p value 1.00. Conclusion: These data suggest that intraoperative intravenous dexamethasone administered during AF ablation for postoperative nausea and vomiting prophylaxis does not have a significant effect on AF recurrence rates.

Background: Catheter ablation is an effective tool to reduce ventricular tachycardia (VT) burden. There is a lack of robust data studying the characteristics and outcomes of VT ablation in patients with ischemic (ICM) versus non-ischemic cardiomyopathy (NICM). Aims: The aim of this study was to assess the impact of ICM vs NICM on outcomes of VT ablation. Methods: A single-center, retrospective study of patients undergoing catheter ablation for VT was conducted. Results: A total of 168 patients, undergoing 200 VT ablation procedures, were included in this study. NICM group (112 procedures) was compared to ICM group (88 procedures). Patients in the ICM group were older (66.6 ± 13.4 vs 58.9 ± 14.4 years) and had higher rates of prior myocardial infarction (65.9% vs 3.6) and coronary artery bypass graft surgery (40.9% vs 1.8%). Overall, ICM group had more comorbidities like hypertension (80.7% vs 52.7%), diabetes mellitus (23.9% vs 12.5%), chronic kidney disease (45.5% vs 35.7%), stroke (17% vs 7.1%), and lower left ventricular ejection fraction (36.8 ± 13.2% vs 43.1 ± 14.7%). The ICM group had lower incidence of prior cardiac valvular surgery (9.1% vs 29.5%). The inducibility of VT (93% vs 93.5%; p= 1.0) and the number of different VT morphologies induced during the case (1.9 ± 1.5 vs 2.3 ± 2.5; p=0.19) was similar between the two groups. There was no acute mortality in either group. There was a non-significant trend towards greater VT recurrence in the NICM group (43.2% vs 33.3%, p= 0.19). However, patients with NICM had a lower VT-free survival as determined by Kaplan-Meier analysis (p=0.05) [Figure]. Long term mortality was higher in ICM group when compared to NICM group (18.2% vs 8.9%, p<0.01). Conclusion: Patients undergoing VT ablation in the NICM group when compared to the ICM group were noted to be younger, had fewer comorbidities, and lower long-term mortality. However, they had significantly less VT-free survival, likely owing to more challenging substrate responsible for VT.

Introduction: Accurate pre-procedure localization of the premature ventricular contractions (PVCs) is critical in preparing for the ablation. So far, no tools exist for artificial intelligence guided PVC-localization. Hypothesis: Trained deep learning model will be able to predict the site of origin (SOO) of PVCs using 12 lead electrocardiogram (ECG). Methods: We analyzed 707 ECG-ablation pairs from 2403 patients who had at least one ECG flagged for PVCs in the 6 months prior to their procedure. First, we used a cohort of 100,000 ECGs without PVCs and 10,000 ECGs with PVCs to train a convolutional neural network (CNN) to isolate the ECG segments with PVCs in them from a 12-lead ECG (Figure 1). We then trained two models, one utilizing a 10-second 12-lead ECG, and the other with just the isolated PVC beats as input. The models were trained using the Keras framework with TensorFlow (Google). Results: The mean age of the patients in the cohort was 61.2 ± 15.0 years. 66.3 percent of patients underwent left ventricle ablation, 54.6 percent had outflow ablation, and 55.3 percent had ablation of sites with leftward axis (septal location for midline and left ventricle PVCs). The model trained on 10-second ECGs yielded validation and test AUCs of 0.941 and 0.931 for outflow, 0.898 and 0.891 for ventricle, and 0.863 and 0.846 for leftward axis (Figure 1A). The model trained on isolated segments containing PVC beats yielded validation and test AUCs of 0.966 and 0.957 for outflow, 0.879 and 0.907 for ventricle, and 0.846 and 0.829 for SOO for leftward axis (Figure 1B). Conclusions: We have trained an accurate convolutional neural network that can predict SOO using the surface ECG. Further fine-tuning would be needed to refine the model and develop prediction of specific sites.

Introduction: Atrial fibrillation (AF) is a common arrhythmia that can impair quality of life and increase cardiovascular mortality. Previous studies have shown potentially better outcomes with rate-control agents in patients with coronary artery disease (CAD). Yet, optimal treatment of AF is not yet known. Methods: Leveraging data from the AFFIRM trial, we performed a post-hoc analysis examining outcome differences in patients on rate vs. rhythm-control agents, based on CAD status. The primary outcome was defined as death from any cause; secondary outcomes included ischemic stroke, major bleeding, and hospitalization after baseline. Univariate and multivariate modeling were used to determine risk factors associated with designated outcomes. Results: Of 4060 patients enrolled, 1551 patients had CAD at baseline. There were no differences in treatment randomization based on CAD status; however, more patients with CAD had worse heart function and comorbid CHF. More patients with CAD ultimately used some form of rate-control compared to those without. Overall, CAD patients were more likely to experience death (HR 2.08 [1.79-2.42], P<0.001), specifically those on rhythm-control (HR 1.24 [1.01-1.52], P=0.04, Figure). CAD patients were also more likely to have ischemic stroke (HR 1.24 [1.00-1.53], P=0.05). When comparing CVD vs. non-CVD death, only CAD patients on rhythm-control exhibited a significantly higher rate of CVD death (HR 1.39 [1.03-1.89], P=0.03), while no differences in primary outcomes were noted for all other groups (P>0.05, Figure). In multivariate modeling, the effect of treatment arm on risk of CVD death in CAD patients diminished upon accounting for age, smoking, rhythm at randomization, first episode of AF, CHF, and LVEF<50% (HR 1.18 [0.93-1.50], P=0.17). Conclusions: AF patients with CAD on rhythm-control agents exhibited worse CVD outcomes, which may be more reflective of heart disease severity rather than treatment effects.

Introduction: There is a lack of data on the impact of sex on the outcomes of patients with heart failure (HF) undergoing atrial fibrillation (AF) ablation. Hypothesis: We hypothesized that outcomes of patients with HF undergoing AF ablation differ between males and females and tested this hypothesis using data from a nationally representative sample of the US population. Methods: The National Readmissions Database (NRD) was analyzed from 2016-2019 to identify patients ≥ 18 years old undergoing AF ablation. Patients were then divided into two cohorts based on their sex. A multivariable logistic regression model was used to adjust for confounders. Results: A total of 21,439 patients with HF underwent AF ablation between 2016-2019, of which 8,103 had heart failure with preserved ejection fraction (HFpEF) [64.8% were females], and 13,336 had heart failure with reduced ejection fraction (HFrEF) [38.4% were females]. Crude outcomes are shown in Figure 1. After multivariate adjustment, among patients with HFrEF, females had a longer length of stay (adjusted mean difference (aMD): 0.55 (0.16-0.93) days longer, p<0.01) along with lower odds of routine home discharge (adjusted odds ratio (aOR):0.62; 95% confidence interval (CI):0.55-0.70; p<0.01). Females had similar odds of in-hospital mortality, procedural complications, and 30-day/ 180-day all-cause, heart failure, and arrhythmia-related readmissions as compared to males. Among patients with HFpEF, females had higher odds of 30-day (aOR: 1.91; 95% CI: 1.24-2.93; p<0.01) and 180-day heart failure readmissions (aOR: 1.53; 95% CI: 1.04-2.28; p=0.03) along with lower odds of routine home discharge (aOR:0.67; 95% CI: 0.57-0.78; p<0.01), as compared to males. Conclusion: In conclusion, our results show that females with HFrEF undergoing AF ablation have similar odds of in-hospital/30-day/180-day outcomes whereas females with HFpEF have higher odds of 30-day/180-day HF readmissions, as compared to males.

Introduction: There is a lack of data on procedural safety and outcomes in patients with rheumatic mitral valve disease (RMVD) undergoing atrial fibrillation (AF) ablation. Hypothesis: We hypothesized that the presence of RMVD may affect the outcomes of patients undergoing AF ablation and tested this hypothesis using data from a large, nationally representative sample of the US population. Methods: The National Readmissions Database (NRD) was analyzed from 2016-2019 to identify patients ≥ 18 years old undergoing AF ablation. Patients with RMVD were then identified by using ICD-10 CM codes. A multivariable logistic regression model was used to adjust for confounders. Results: Our cohort included 50,728 weighted AF ablation procedures, of which 3,500 (6.9%) patients had RMVD. Patients with RMVD were older at the time of catheter ablation, with a significantly higher percentage of females, less likely to have paroxysmal AF, and had a higher burden of comorbidities including congestive heart failure, renal failure, and hypertension. On multivariable analysis, the presence of RMVD was associated with higher odds of cardiovascular complications (adjusted odds ratio [aOR] 1.28; 95% confidence interval [CI]: 1.12-1.47; p<0.01) with no difference in the odds of in-hospital mortality or other periprocedural outcomes. Also, RMVD was associated with longer length of stay (adjusted mean difference: +1.06; 95% CI: +0.67 - +1.45; p<0.01) days and lower odds of routine home discharge (aOR:0.77; 95% CI: 0.69-0.87; p<0.01). There was no difference in the odds of 30-day or 180-day all-cause, AF-related, or atrial flutter-related readmissions in patients with RMVD vs. no RMVD (Figure 1). Conclusion: In conclusion, patients with RMVD undergoing AF ablation have higher odds of periprocedural cardiovascular complications with similar odds of 30-day and 180-day all-cause and AF-related readmissions

Introduction: There is limited data on how psychosocial risk factors (PSRFs) affect the outcomes of patients undergoing atrial fibrillation (AF) ablation. Hypothesis: We hypothesized that the presence of PSRFs affects the outcomes of AF ablation and tested this hypothesis using a nationally representative sample of the US population. Methods: The National Readmissions Database (NRD) was analyzed from 2016-2019 to identify patients ≥ 18 years old undergoing AF ablation. Patients were divided into two cohorts based on the presence or absence of ≥1 PSRF. PSRFs were divided into 5 domains including limited cognitive understanding, substance use, psychiatric disease, low socioeconomic status, and uninsured status. A multivariable logistic regression model was utilized to adjust for confounders. Results: Our cohort included 50,623 AF ablation procedures, of which 21,363 (42.2%) had ≥ 1 PSRF. On multivariable analysis, the presence of ≥ 1 PSRF was associated with higher odds of cardiovascular complications (adjusted odds ratio [aOR] 1.11; 95% confidence interval [CI]: 1.02-1.22; p=0.02), peripheral vascular complications (aOR:1.18; 95% CI: 1.01-1.38; p=0.04), pulmonary complications (aOR:1.16; 95% CI: 1.05-1.29; p<0.01) and neurological complications (aOR:1.42; 95% CI: 1.12-1.78; p<0.01), along with higher odds of 30-day all-cause readmissions (aOR:1.30; 95% CI: 1.19-1.43; p<0.01) and atrial fibrillation/flutter related readmissions (aOR:1.27; 95% CI: 1.08-1.50; p<0.01), 90-day all-cause readmissions (aOR:1.30; 95% CI: 1.20-1.40; p<0.01) and atrial fibrillation/flutter related readmissions (aOR:1.22; 95% CI: 1.06-1.41; p<0.01), and 180-day all-cause readmissions (aOR:1.35; 95% CI: 1.24-1.45; p<0.01) (Figure 1). Conclusion: In conclusion, our data suggest an association between PSRFs and worse in-hospital outcomes along with increased all-cause and arrhythmia-related readmissions in patients undergoing AF ablation.