Catheter ablation of atrioventricular nodal reentrant tachycardia with an irrigated contact-force sensing radiofrequency ablation catheter.

INTRODUCTION: Radiofrequency ablation (RFA) slow pathway modification for catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT) is traditionally performed using a 4-mm nonirrigated (NI) RF ablation catheter. Slow pathway modification using irrigated, contact-force sensing (ICFS) RFA catheters has been described in case reports, but the outcomes have not been systematically evaluated. METHODS: Acute procedural outcomes of 200 consecutive patients undergoing slow pathway modification for AVNRT were analyzed. A 3.5-mm ICFS RFA catheter (ThermoCool SmartTouch STSF, Biosense Webster, Inc.) was utilized in 134 patients, and a 4-mm NI RFA catheter (EZ Steer, Biosense Webster, Inc.) was utilized in 66 patients. Electroanatomic maps were retrospectively analyzed in a blinded fashion to determine the proximity of ablation lesions to the His region. RESULTS: The baseline characteristics of patients in both groups were similar. Total RF time was significantly lower in the ICFS group compared to the NI group (5.53 ± 4.6 vs. 6.24 ± 4.9 min, p = 0.03). Median procedure time was similar in both groups (ICFS, 108.0 (87.5-131.5) min vs. NI, 100.0 (85.0-125.0) min; p = 0.2). Ablation was required in closer proximity to the His region in the NI group compared to the ICFS group (14.4 ± 5.9 vs. 16.7 ± 6.4 mm, respectively, p = 0.01). AVNRT was rendered noninducible in all patients, and there was no arrhythmia recurrence during follow-up in both groups. Catheter ablation was complicated by AV block in one patient in the NI group. CONCLUSION: Slow pathway modification for catheter ablation of AVNRT using an ICFS RFA catheter is feasible, safe, and may facilitate shorter duration ablation while avoiding ablation in close proximity to the His region.

Temporal trends in atrial fibrillation ablation procedures at an academic medical center: 2011-2021.

INTRODUCTION: Radiofrequency ablation technology for treating atrial fibrillation (AF) has evolved rapidly over the past decade. We investigated the impact of technological and procedural advances on procedure times and ablation outcomes at a major academic medical center over a 10-year period. METHODS: Clinical data was collected from patients who presented to NYU Langone Health between 2011 and 2021 for a first-time AF ablation. Time to redo AF ablation or direct current cardioversion (DCCV) for recurrent AF during a 3-year follow-up period was determined and correlated with ablation technology and practices, antiarrhythmic medications, and patient comorbid conditions. RESULTS: From 2011 to 2021, the cardiac electrophysiology lab adopted irrigated-contact force ablation catheters, high-power short duration ablation lesions, steady-pacing, jet ventilation, and eliminated stepwise linear ablation for AF ablation. During this time the number of first time AF ablations increased from 403 to 1074, the percentage of patients requiring repeat AF-related intervention within 3-years of the index procedure dropped from 22% to 14%, mean procedure time decreased from 271 ± 65 to 135 ± 36 min, and mean annual major adverse event rate remained constant at 1.1 ± 0.5%. Patient comorbid conditions increased during this time period and antiarrhythmic use was unchanged. CONCLUSION: Rates of redo-AF ablation or DCCV following an initial AF ablation at a single center decreased 36% over a 10-year period. Procedural and technological changes likely contributed to this improvement, despite increased AF related comorbidities.

Outcomes and atrial substrate analysis in patients with HIV undergoing atrial fibrillation ablation.

INTRODUCTION: Patients with HIV infection have increased risk of atrial fibrillation, but the pathophysiologic mechanisms and the utility of catheter ablation in this population are not well-studied. We aimed to characterize outcomes of atrial fibrillation ablation and left atrial substrate in patients with HIV. METHODS: The study was a retrospective propensity score-matched analysis of patients with and without HIV undergoing atrial fibrillation ablation. A search was performed in the electronic medical record for all patients with HIV who received initial atrial fibrillation ablation from 2011 to 2020. After calculating propensity scores for HIV, matching was performed with patients without HIV by using nearest-neighbor matching without replacement in a 1:2 ratio. The primary outcome was freedom from atrial arrhythmia and secondary outcomes were freedom from atrial fibrillation, freedom from atrial tachycardia, and freedom from repeat ablation, compared by log-rank analysis. The procedures of patients with HIV who underwent repeat ablation at our institution were further analyzed for etiology of recurrence. To further characterize the left atrial substrate, a subsequent case-control analysis was then performed for a set of randomly chosen 10 patients with HIV matched with 10 without HIV to compare minimum and maximum voltage at nine pre-specified regions of the left atrium. RESULTS: Twenty-seven patients with HIV were identified. All were prescribed antiretroviral therapy at time of ablation. These patients were matched with 54 patients without HIV by propensity score. 86.4% of patients with HIV and 76.9% of controls were free of atrial fibrillation or atrial tachycardia at 1 year (p = .509). Log-rank analysis showed no difference in freedom from atrial arrhythmia (p value .971), atrial fibrillation (p-value .346), atrial tachycardia (p value .306), or repeat ablation (p value .401) after initial atrial fibrillation ablation in patients with HIV compared to patients without HIV. In patients with HIV with recurrent atrial fibrillation, the majority had pulmonary vein reconnection (67%). There were no significant differences in minimum or maximum voltage at any of the nine left atrial regions between the matched patients with and without HIV. CONCLUSIONS: Ablation to treat atrial fibrillation in patients with HIV, but without overt AIDS is frequently successful therapy. The majority of patients with recurrence of atrial fibrillation had pulmonary vein reconnection, suggesting infrequent nonpulmonary vein substrate. In this population, the left atrial voltage in patients with HIV is similar to that of patients without HIV. These findings suggest that the pulmonary veins remain a critical component to the initiation and maintenance of atrial fibrillation in patients with HIV.

A systematic review of the use of 3D printing in left atrial appendage occlusion procedures.

The placement of a left atrial appendage occlusion (LAAO) device can be a technically challenging transcatheter-based procedure. Key challenges include accurate pre-procedural device sizing and proper device positioning at the LAA ostium to ensure sufficient device anchoring and avoid peri-device leaks. To address these challenges, 3D printing (3DP) of LAA models has recently emerged in the literature, first being described in 2015. We present a review of the benefits and drawbacks of employing this technology for LAAO procedures. Pre-procedurally the use of 3DP can consistently and accurately determine LAAO device size over standard of care approaches. Intra-procedurally 3DP's impact entailed a statistically significant decrease in the number of devices used per procedure, as well as in the fluoroscopic time and dose. Post-procedurally, there is some evidence that 3DP could reduce the rate of peri-device leaks, with limited data on its effect on complication rates. Based on existing evidence, we recommend the focused application of 3DP to cases of complex LAA anatomy and for the training of proceduralists. Lastly, we address the emergence of next generation LAAO devices and AR/VR systems that could limit even this narrow window of clinical benefit afforded by 3DP.

Outcomes of posterior wall isolation with pulmonary vein isolation for paroxysmal atrial fibrillation.

INTRODUCTION: Prior studies have shown that addition of posterior wall isolation (PWI) may reduce atrial fibrillation recurrence in patients with persistent atrial fibrillation. No data on PWI in paroxysmal AF (pAF) patients with normal left atrial voltage is available, to date. OBJECTIVE: This study sought to evaluate the efficacy of PWI in addition to pulmonary vein isolation (PVI) in patients presenting with pAF and normal left atrial voltage. METHODS: Consecutive patient registry analysis was performed on all patients with pAF and normal left atrial voltage undergoing initial radiofrequency ablation from November 1, 2018 to November 15, 2019. Primary endpoint was recurrence of atrial arrhythmia including AF, atrial tachycardia (AT), or atrial flutter (AFL). RESULTS: A total of 321 patients were studied, 214 in the PVI group and 107 in the PWI + PVI group. Recurrence of any atrial arrhythmia occurred in 18.2% of patients in the PVI group and 16.8% in the PVI + PWI cohort (p = 0.58). At 1 year, recurrence was 14.0% in the PVI group and 15.0% in the PWI + PVI group (p = 0.96). There was a lower AT/AFL recurrence in the PVI + PWI group, not reaching significance (3.7% in the PWI + PVI group vs. 7.9% in PVI group, p = 0.31). Need for carina lesions predicted recurrence in the PVI-only group. CONCLUSIONS: Addition of PWI to PVI in pAF patients undergoing their first ablation did not reduce the frequency of atrial arrhythmia recurrence. This warrants further study in a prospective trial.

Inability to perform 'en bloc' pulmonary vein isolation requiring ablation of the intervenous carina increases recurrence of atrial fibrillation: A meta-analysis.

INTRODUCTION: Failure to isolate ipsilateral pulmonary veins (PV) "en bloc" by wide-area circumferential ablation (WACA) may necessitate ablation at the intervenous carina. It is unknown how this scenario impacts rates of atrial fibrillation (AF) recurrence. METHODS: A standard random-effect meta-analysis of randomized or observational studies were performed, where the outcome of first-time AF ablation was reported in patients with "en bloc" isolation of PVs by WACA as compared with those in whom ablation at the intervenous carina was needed after WACA to achieve complete isolation. RESULTS: A total of five single-center, observational studies (N = 1185) and one, multi-center randomized trial (N = 234) were enrolled. PV isolation could be achieved by WACA "en bloc" in 902/1419 (63.6%) cases. The rest required additional ablation at one or both of the left and right intervenous carinas to achieve isolation. The follow-up time after ablation ranged from 1 to 2 years in the included trials. The incidence of AF recurrence proved to be significantly lower in patients with successful "en bloc" isolation compared to those requiring carina ablation(s) to achieve complete bilateral PV isolation (MH-OR 1.89, 95% CI 1.42-2.53, p < .01) CONCLUSION: This present meta-analysis demonstrates a lower arrhythmia recurrence rate in patients with bilateral "en bloc" isolation, as compared to those who needed additional carina ablation for complete PVI. Therefore, it is imperative that every effort be made to isolate ipsilateral PVs "en bloc" during PVI.

Quantitative analysis of ablation technique predicts arrhythmia recurrence following atrial fibrillation ablation.

BACKGROUND: Optimal ablation technique, including catheter-tissue contact during atrial fibrillation (AF) radiofrequency (RF) ablation, is associated with improved procedural outcomes. We used a custom developed software to analyze high-frequency catheter position data to study the interaction between catheter excursion during lesion placement, lesion-set sequentiality, and arrhythmia recurrence. METHODS: A total of 100 consecutive patients undergoing first-time RF ablation for paroxysmal AF were analyzed. Spatial positioning of the ablation catheter sampled at 60 Hz during RF application was extracted from the CARTO3 system (Biosense Webster Inc, USA) and analyzed using custom-developed MATLAB software to determine precise catheter spatial 3D excursion during RF ablation. The primary end point was freedom from atrial arrhythmia lasting longer than 30 seconds after a single ablation procedure. RESULTS: At 1 year, 86% of patients were free from recurrent arrhythmia. There was no significant difference in clinical, echocardiographic, or ablation characteristics between patients with and without recurrent arrhythmia. Analyzing 15,356,998 position data points revealed that lesion-set sequentiality and mean lesion catheter excursion were predictors of arrhythmia recurrence. Analyzing arrhythmia recurrence by mean single-lesion catheter excursion (excursion >2.81 mm) and by sequentiality (using 46% of lesions with interlesion distance >6 mm as cutoff) revealed significantly increased arrhythmia recurrence in the higher excursion group (23% vs 6%, P = .03) and in the less sequential group (24% vs 4%, P = .02). CONCLUSIONS: Ablation lesion sequentiality measured by catheter interlesion distance and catheter stability measured by catheter excursion during lesion placement are potentially modifiable factors affecting arrhythmia recurrence after RF ablation for AF.

Early ICD lead failure in defibrillator systems with multiple leads via cephalic access.

INTRODUCTION: Implantable cardioverter defibrillators (ICDs) are proven to prevent sudden death in patients at elevated risk for sustained ventricular tachycardia or fibrillation. Complications related to ICD failure can stem from lead dysfunction, manufacturing defects, patient characteristics, or implantation technique. We conducted a review of all ICD leads implanted at our center from 2011 to 2017 to determine risk factors for premature lead failure. METHODS: We conducted a retrospective review of patients of all ICD leads implanted from December 2011 to June 2017 at our institution. A total of 660 patients (Biotronik Linox S/SD, n = 281; Sprint Quatro, n = 207; Durata, n = 121; Endotak, n = 51) underwent ICD implantations. Patient and lead characteristics, procedural outcomes and complications were recorded. Lead failure was defined per Heart Rhythm Society lead-management consensus as a lack of procedural or clinical success, thus requiring an extraction of the lead. Patient and lead outcomes were recorded and variables associated with lead failure were assessed by the Kaplan-Meier method. RESULTS: Overall failure rate was similar for all leads: Linox S/SD-0.29%/year; Sprint Quattro-0.21%/year, Durata-0.39%/year and Endotak Reliance-0.0% (P = .769). No difference was found in overall survival when comparing all ICD manufacturers during the study period. Subgroup analysis revealed the risk of premature lead failure was particularly pronounced in multi-lead ICD systems implanted via cephalic access (P < .001). The estimated failure rate of Linox leads implanted via cephalic access in multi-lead systems was 19%/year. The estimated failure rate of non-Linox leads implanted via cephalic access in multi-lead systems was 11%/year. Neither age, nor gender were risk factors for lead failure in the Linox, or non-Linox cohorts. CONCLUSION: All analyzed ICD leads were found to have a similar overall risk of premature failure. ICD lead implantation via cephalic access in multilead ICD systems may be a previously unidentified risk factor for premature ICD lead failure, although these findings require further validation.

Direct autotransfusion following emergency pericardiocentesis in patients undergoing cardiac electrophysiology procedures.

INTRODUCTION: Acute hemopericardium during cardiac electrophysiology (EP) procedures may result in significant blood loss and is the most common cause of procedure-related death. Matched allogeneic blood is often not immediately available. The feasibility and safety of direct autotransfusion in cardiac electrophysiology patients requiring emergency pericardiocentesis is unknown. METHODS: We retrospectively analyzed records of patients undergoing EP procedures at a single, tertiary care medical center who had procedure-related acute hemopericardium requiring emergency pericardiocentesis during a 3-year period. Procedure details, transfusion volumes, and clinical outcomes of patients who received direct autotransfusion of aspirated pericardial blood via a femoral venous sheath were compared to those of patients who did not receive direct autotransfusion. RESULTS: During the study period, 10 patients received direct autotransfusion (group 1) and outcomes were compared with those of 14 control patients who did not receive direct autotransfusion (group 2). The volume of aspirated pericardial blood was similar in groups 1 and 2 (1.6 ± 0.7 L vs 1.3 ± 1.0 L, respectively; P = .52). Amongst patients with aspirated volumes <1 L, group 1 patients (n = 4) were less likely than group 2 patients (n = 8) to require allotransfusion (0% vs 75%, P = .02). Amongst patients with aspirated volume ≥1 L, group 1 patients (n = 6) required fewer units of red cell allotransfusion than group 2 patients (n = 6) (1.5 ± 0.8 units vs 4.3 ± 2.0 units, P = .01). No procedural complications related to direct autotransfusion occurred. CONCLUSIONS: Direct autotransfusion following emergency pericardiocentesis during electrophysiology procedures requiring systemic anticoagulation is feasible and safe. The utilization of direct autotransfusion may eliminate or reduce the need for allotransfusion.

Multiple procedure outcomes for nonparoxysmal atrial fibrillation: Left atrial posterior wall isolation versus stepwise ablation.

OBJECTIVE: To compare multiple-procedure catheter ablation outcomes of a stepwise approach versus left atrial posterior wall isolation (LA PWI) in patients undergoing nonparoxysmal atrial fibrillation (NPAF) ablation. BACKGROUND: Unfavorable outcomes for stepwise ablation of NPAF in large clinical trials may be attributable to proarrhythmic effects of incomplete ablation lines. It is unknown if a more extensive initial ablation strategy results in improved outcomes following multiple ablation procedures. METHODS: Two hundred twenty two consecutive patients with NPAF underwent first-time ablation using a contact-force sensing ablation catheter utilizing either a stepwise (Group 1, n = 111) or LA PWI (Group 2, n = 111) approach. The duration of follow-up was 36 months. The primary endpoint was freedom from atrial arrhythmia >30 s. Secondary endpoints were freedom from persistent arrhythmia, repeat ablation, and recurrent arrhythmia after repeat ablation. RESULTS: There was similar freedom from atrial arrhythmias after index ablation for both stepwise and LA PWI groups at 36 months (60% vs. 69%, p = .1). The stepwise group was more likely to present with persistent recurrent arrhythmia (29% vs. 14%, p = .005) and more likely to undergo second catheter ablation (32% vs. 12%, p < .001) compared to LA PWI patients. Recurrent arrhythmia after repeat ablation was more likely in the stepwise group compared to the LA PWI group (15% vs. 4%, p = .003). CONCLUSIONS: Compared to a stepwise approach, LA PWI for patients with NPAF resulted in a similar incidence of any atrial arrhythmia, lower incidence of persistent arrhythmia, and fewer repeat ablations. Results for repeat ablation were not improved with a more extensive initial approach.

Rapid pacing and high-frequency jet ventilation additively improve catheter stability during atrial fibrillation ablation.

INTRODUCTION: Catheter stability during atrial fibrillation ablation is associated with higher ablation success rates. Rapid cardiac pacing and high-frequency jet ventilation (HFJV) independently improve catheter stability. Simultaneous modulation of cardiac and respiratory motion has not been previously studied. The objective of this study was to determine the effect of simultaneous heart rate and respiratory rate modulation on catheter stability. METHODS: Forty patients undergoing paroxysmal atrial fibrillation ablation received ablation lesions at 15 prespecified locations (12 left atria, 3 right atria). Patients were randomly assigned to undergo rapid atrial pacing for either the first or the second half of each lesion. Within each group, half of the patients received HFJV and the other half standard ventilation. Contact force and ablation data for all lesions were compared among the study groups. Standard deviation of contact force was the primary endpoint defined to examine contact force variability. RESULTS: Lesions with no pacing and standard ventilation had the greatest contact force standard deviation (5.86 ± 3.08 g), compared to lesions with pacing and standard ventilation (5.45 ± 3.28 g; P < .01) or to lesions with no pacing and HFJV (4.92 ± 3.00 g; P < .01). Lesions with both pacing and HFJV had the greatest reduction in contact force standard deviation (4.35 ± 2.81 g; P < .01), confirming an additive benefit of each maneuver. Pacing and HFJV together was also associated with a reduction in the proportion of lesions with excessive maximum contact force (P < .001). DISCUSSION: Rapid pacing and HFJV additively improve catheter stability. Simultaneous pacing with HFJV further improves catheter stability over pacing or HFJV alone to optimize ablation lesions.

Reducing right ventricular pacing burden: algorithms, benefits, and risks.

Algorithms designed to reduce the burden of right ventricular pacing are widely available in modern implantable pacing devices. To ensure safe and optimal utilization, understanding the properties of these algorithms as well as their possible unfavourable effects is essential. In this review, we discuss in detail the technical and clinical aspects of rhythm management algorithms and update on their significant recent modifications. In addition, we highlight possible adverse phenomena that may be induced by these different pacing algorithms intended to minimize pacing.

Electric storm triggered by short-coupled premature ventricular complexes in a young patient with non-obstructive hypertrophic cardiomyopathy.

Ventricular arrhythmias are commonly associated with hypertrophic cardiomyopathy with and without midventricular obstruction. Although the overall prognosis is relatively good with an annual mortality rate <1%, the propensity to potentially fatal ventricular arrhythmias (ventricular tachycardia) is the most feared complication. Electrical storms are a severe manifestation of ventricular arrhythmias, with poor outcomes. In this report, we present a case of a young patient with non-obstructive hypertrophic cardiomyopathy who presents after a syncopal episode and is found to have an electric storm that is refractory to medical therapy.

Performance of Publicly Available Large Language Models on Internal Medicine Board-style Questions.

Ongoing research attempts to benchmark large language models (LLM) against physicians' fund of knowledge by assessing LLM performance on medical examinations. No prior study has assessed LLM performance on internal medicine (IM) board examination questions. Limited data exists on how knowledge supplied to the models, derived from medical texts improves LLM performance. The performance of GPT-3.5, GPT-4.0, LaMDA and Llama 2, with and without additional model input augmentation, was assessed on 240 randomly selected IM board-style questions. Questions were sourced from the Medical Knowledge Self-Assessment Program released by the American College of Physicians with each question serving as part of the LLM prompt. When available, LLMs were accessed both through their application programming interface (API) and their corresponding chatbot. Mode inputs were augmented with Harrison's Principles of Internal Medicine using the method of Retrieval Augmented Generation. LLM-generated explanations to 25 correctly answered questions were presented in a blinded fashion alongside the MKSAP explanation to an IM board-certified physician tasked with selecting the human generated response. GPT-4.0, accessed either through Bing Chat or its API, scored 77.5-80.7% outperforming GPT-3.5, human respondents, LaMDA and Llama 2 in that order. GPT-4.0 outperformed human MKSAP users on every tested IM subject with its highest and lowest percentile scores in Infectious Disease (80th) and Rheumatology (99.7th), respectively. There is a 3.2-5.3% decrease in performance of both GPT-3.5 and GPT-4.0 when accessing the LLM through its API instead of its online chatbot. There is 4.5-7.5% increase in performance of both GPT-3.5 and GPT-4.0 accessed through their APIs after additional input augmentation. The blinded reviewer correctly identified the human generated MKSAP response in 72% of the 25-question sample set. GPT-4.0 performed best on IM board-style questions outperforming human respondents. Augmenting with domain-specific information improved performance rendering Retrieval Augmented Generation a possible technique for improving accuracy in medical examination LLM responses.

QTNet: Predicting Drug-Induced QT Prolongation With Artificial Intelligence-Enabled Electrocardiograms.

BACKGROUND: Prediction of drug-induced long QT syndrome (diLQTS) is of critical importance given its association with torsades de pointes. There is no reliable method for the outpatient prediction of diLQTS. OBJECTIVES: This study sought to evaluate the use of a convolutional neural network (CNN) applied to electrocardiograms (ECGs) to predict diLQTS in an outpatient population. METHODS: We identified all adult outpatients newly prescribed a QT-prolonging medication between January 1, 2003, and March 31, 2022, who had a 12-lead sinus ECG in the preceding 6 months. Using risk factor data and the ECG signal as inputs, the CNN QTNet was implemented in TensorFlow to predict diLQTS. RESULTS: Models were evaluated in a held-out test dataset of 44,386 patients (57% female) with a median age of 62 years. Compared with 3 other models relying on risk factors or ECG signal or baseline QTc alone, QTNet achieved the best (P < 0.001) performance with a mean area under the curve of 0.802 (95% CI: 0.786-0.818). In a survival analysis, QTNet also had the highest inverse probability of censorship-weighted area under the receiver-operating characteristic curve at day 2 (0.875; 95% CI: 0.848-0.904) and up to 6 months. In a subgroup analysis, QTNet performed best among males and patients ≤50 years or with baseline QTc <450 ms. In an external validation cohort of solely suburban outpatient practices, QTNet similarly maintained the highest predictive performance. CONCLUSIONS: An ECG-based CNN can accurately predict diLQTS in the outpatient setting while maintaining its predictive performance over time. In the outpatient setting, our model could identify higher-risk individuals who would benefit from closer monitoring.

Conduction velocity is reduced in the posterior wall of hypertrophic cardiomyopathy patients with normal bipolar voltage undergoing ablation for paroxysmal atrial fibrillation.

OBJECTIVES: We investigated characteristics of left atrial conduction in patients with HCM, paroxysmal AF and normal bipolar voltage. BACKGROUND: Patients with hypertrophic cardiomyopathy (HCM) exhibit abnormal cardiac tissue arrangement. The incidence of atrial fibrillation (AF) is increased fourfold in patients with HCM and confers a fourfold increased risk of death. Catheter ablation is less effective in HCM, with twofold increased risk of AF recurrence. The mechanisms of AF perpetuation in HCM are poorly understood. METHODS: We analyzed 20 patients with HCM and 20 controls presenting for radiofrequency ablation of paroxysmal AF normal left atrial voltage(> 0.5 mV). Intracardiac electrograms were extracted from the CARTO mapping system and analyzed using Matlab/Python code interfacing with Core OpenEP software. Conduction velocity maps were calculated using local activation time gradients. RESULTS: There were no differences in baseline demographics, atrial size, or valvular disease between HCM and control patients. Patients with HCM had significantly reduced atrial conduction velocity compared to controls (0.44 ± 0.17 vs 0.56 ± 0.10 m/s, p = 0.01), despite no significant differences in bipolar voltage amplitude (1.23 ± 0.38 vs 1.20 ± 0.41 mV, p = 0.76). There was a statistically significant reduction in conduction velocity in the posterior left atrium in HCM patients relative to controls (0.43 ± 0.18 vs 0.58 ± 0.10 m/s, p = 0.003), but not in the anterior left atrium (0.46 ± 0.17 vs 0.55 ± 0.10 m/s, p = 0.05). There was a significant association between conduction velocity and interventricular septal thickness (slope = -0.013, R2 = 0.13, p = 0.03). CONCLUSIONS: Atrial conduction velocity is significantly reduced in patients with HCM and paroxysmal AF, possibly contributing to arrhythmia persistence after catheter ablation.

Performance of a Protein Language Model for Variant Annotation in Cardiac Disease.

BACKGROUND: Genetic testing is a cornerstone in the assessment of many cardiac diseases. However, variants are frequently classified as variants of unknown significance, limiting the utility of testing. Recently, the DeepMind group (Google) developed AlphaMissense, a unique artificial intelligence-based model, based on language model principles, for the prediction of missense variant pathogenicity. We aimed to report on the performance of AlphaMissense, accessed by VarCardio, an open web-based variant annotation engine, in a real-world cardiovascular genetics center. METHODS AND RESULTS: All genetic variants from an inherited arrhythmia program were examined using AlphaMissense via VarCard.io and compared with the ClinVar variant classification system, as well as another variant classification platform (Franklin by Genoox). The mutation reclassification rate and genotype-phenotype concordance were examined for all variants in the study. We included 266 patients with heritable cardiac diseases, harboring 339 missense variants. Of those, 230 (67.8%) were classified by ClinVar as either variants of unknown significance or nonclassified. Using VarCard.io, 198 variants of unknown significance (86.1%, 95% CI, 80.9-90.3) were reclassified to either likely pathogenic or likely benign. The reclassification rate was significantly higher for VarCard.io than for Franklin (86.1% versus 34.8%, P<0.001). Genotype-phenotype concordance was highly aligned using VarCard.io predictions, at 95.9% (95% CI, 92.8-97.9) concordance rate. For 109 variants classified as pathogenic, likely pathogenic, benign, or likely benign by ClinVar, concordance with VarCard.io was high (90.5%). CONCLUSIONS: AlphaMissense, accessed via VarCard.io, may be a highly efficient tool for cardiac genetic variant interpretation. The engine's notable performance in assessing variants that are classified as variants of unknown significance in ClinVar demonstrates its potential to enhance cardiac genetic testing.

Catheter ablation compared to medical therapy for ventricular tachycardia in sarcoidosis: nationwide outcomes and hospital readmissions.

Background: Catheter ablation (CA) for ventricular tachycardia (VT) can be a useful treatment strategy, however, few studies have compared CA to medical therapy (MT) in the sarcoidosis population. Objective: To assess in-hospital outcomes and unplanned readmissions following CA for VT compared to MT in patients with sarcoidosis. Methods: Data was obtained from the Nationwide Readmissions Database between 2010 and 2019 to identify patients with sarcoidosis admitted for VT either undergoing CA or MT during elective and non-elective admission. Primary endpoints were a composite endpoint of inpatient mortality, cardiogenic shock, cardiac arrest and 30-day hospital readmissions. Procedural complications at index admission and causes of readmission were also identified. Results: Among 1581 patients, 1217 with sarcoidosis and VT underwent MT compared to 168 with CA during non-elective admission. 63 patients admitted electively underwent CA compared with 129 managed medically. There was no difference in the composite outcome for patients undergoing catheter ablation or medical therapy during both non-elective (9.0 % vs 12.0 %, p = 0.312) and elective admission (3.2 % vs. 7.8 %, p = 0.343). The most common cause of readmission were ventricular arrhythmias (VA) in both groups, however, those undergoing elective CA were less likely to be readmitted for VA compared to non-elective CA. The most common complication in the CA group was cardiac tamponade (4.8 %). Conclusion: VT ablation is associated with similar rates of 30-day readmission compared to MT and does not confer increased risk of harm with respect to inpatient mortality, cardiogenic shock or cardiac arrest. Further research is warranted to determine if a subgroup of sarcoidosis patients admitted with VT are better served with an initial conservative management strategy followed by VT ablation.

Catheter ablation alone versus catheter ablation with combined percutaneous left atrial appendage closure for atrial fibrillation: a systematic review and meta-analysis.

BACKGROUND: Combined catheter ablation (CA) with percutaneous left atrial appendage closure (LAAC) may produce comprehensive treatment for atrial fibrillation (AF) whereby rhythm control is achieved and stroke risk is reduced without the need for chronic oral anticoagulation. However, the efficacy and safety of this strategy is still controversial. METHODS: This meta-analysis was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines. Medline, Scopus, and Cochrane Central Register of Controlled Trials were systematically searched to identify relevant studies. The risk of bias was assessed using the Modified Newcastle-Ottawa scale and Cochrane risk of bias tool. Eligible studies reported outcomes in patients with AF who underwent combined CA and LAAC vs CA alone. Studies performing CA without pulmonary vein isolation were excluded. RESULTS: Eight studies comprising 1878 patients were included (2 RCT, 6 observational). When comparing combined CA and LAAC vs CA alone, pooled results showed no difference in arrhythmia recurrence (risk ratio (RR) 1.04; 95% confidence interval (CI) 0.82-1.33), stroke or systemic embolism (RR 0.78; 95% CI 0.27-2.22), or major periprocedural complications (RR 1.28; 95% CI 0.28-5.89). Total procedure time was shorter with CA alone (mean difference 48.45 min; 95% CI 23.06-74.62). CONCLUSION: Combined CA with LAAC for AF is associated with similar rates of arrhythmia-free survival, stroke, and major periprocedural complications when compared to CA alone. A combined strategy may be as safe and efficacious for patients at moderate to high risk for bleeding events to negate the need for chronic oral anticoagulation.