Evaluating temperature gradients across the posterior left atrium with radiofrequency ablation.

INTRODUCTION: Esophageal injury is a well-known complication associated with catheter ablation. Though novel methods to mitigate esophageal injury have been developed, few studies have evaluated temperature gradients with catheter ablation across the posterior wall of the left atrium, interstitium, and esophagus. METHODS: To investigate temperature gradients across the tissue, we developed a porcine heart-esophageal model to perform ex vivo catheter ablation on the posterior wall of the left atrium (LA), with juxtaposed interstitial tissue and esophagus. Circulating saline (5 L/min) was used to mimic blood flow along the LA and alteration of ionic content to modulate impedance. Thermistors along the region of interest were used to analyze temperature gradients. Varying time and power, radiofrequency (RF) ablation lesions were applied with an externally irrigated ablation catheter. Ablation strategies were divided into standard approaches (SAs, 10-15 g, 25-35 W, 30 s) or high-power short duration (HPSD, 10-15 g, 40-50 W, 10 s). Temperature gradients, time to the maximum measured temperature, and the relationship between measured temperature as a function of distance from the site of ablation was analyzed. RESULTS: In total, five experiments were conducted each utilizing new porcine posterior LA wall-esophageal specimens for RF ablation (n = 60 lesions each for SA and HPSD). For both SA and HPSD, maximum temperature rise from baseline was markedly higher at the anterior wall (AW) of the esophagus compared to the esophageal lumen (SA: 4.29°C vs. 0.41°C, p < .0001 and HPSD: 3.13°C vs. 0.28°C, p < .0001). Across ablation strategies, the average temperature rise at the AW of the esophagus was significantly higher with SA relative to HPSD ablation (4.29°C vs. 3.13°C, p = .01). From the start of ablation, the average time to reach a maximum temperature as measured at the AW of the esophagus with SA was 36.49 ± 12.12 s, compared to 16.57 ± 4.54 s with HPSD ablation, p < .0001. Fit to a linear scale, a 0.37°C drop in temperature was seen for every 1 cm increase in distance from the site of ablation and thermistor location at the AW of the esophagus. CONCLUSION: Both SA and HPSD ablation strategies resulted in markedly higher temperatures measured at the AW of the esophagus compared to the esophageal lumen, raising concern about the value of clinical intraluminal temperature monitoring. The temperature rise at the AW was lower with HPSD. A significant time delay was seen to reach the maximum measured temperature and a modest increase in distance between the site of ablation and thermistor location impacted the accuracy of monitored temperatures.

PRIME score for prediction of permanent pacemaker implantation after transcatheter aortic valve replacement.

OBJECTIVES: We sought to produce a simple scoring system that can be applied at clinical visits before transcatheter aortic valve replacement (TAVR) to stratify the risk of permanent pacemaker (PPM) after the procedure. BACKGROUND: Atrioventricular block is a known complication of TAVR. Current models for predicting the risk of PPM after TAVR are not designed to be applied clinically to assist with preprocedural planning. METHODS: Patients undergoing TAVR at the University of Colorado were split into a training cohort for the development of a predictive model, and a testing cohort for model validation. Stepwise and binary logistic regressions were performed on the training cohort to produce a predictive model. Beta coefficients from the binary logistic regression were used to create a simple scoring system for predicting the need for PPM implantation. Scores were then applied to the validation cohort to assess predictive accuracy. RESULTS: Patients undergoing TAVR from 2013 to 2019 were analyzed: with 483 included in the training cohort and 123 included in the validation cohort. The need for a pacemaker was associated with five preprocedure variables in the training cohort: PR interval > 200 ms, Right bundle branch block, valve-In-valve procedure, prior Myocardial infarction, and self-Expandable valve. The PRIME score was developed using these clinical features, and was highly accurate for predicting PPM in both the training and model validation cohorts (area under the curve 0.804 and 0.830 in the model training and validation cohorts, respectively). CONCLUSIONS: The PRIME score is a simple and accurate preprocedural tool for predicting the need for PPM implantation after TAVR.

Electrophysiologic testing for diagnostic evaluation and risk stratification in patients with suspected cardiac sarcoidosis with preserved left and right ventricular systolic function.

INTRODUCTION: While cardiac sarcoidosis (CS) carries a risk of ventricular arrhythmias (VAs) and sudden cardiac death (SCD), risk stratification of patients with CS and preserved left ventricular/right ventricular (LV/RV) systolic function remains challenging. We sought to evaluate the role of electrophysiologic testing and programmed electrical stimulation of the ventricle (EPS) in patients with suspected CS with preserved ventricular function. METHODS: One hundred twenty consecutive patients with biopsy-proven extracardiac sarcoidosis and preserved LV/RV systolic function underwent EPS. All patients had either probable CS defined by an abnormal cardiac positron emission tomography or cardiac magnetic resonance imaging, or possible CS with normal advanced imaging but abnormal echocardiogram (ECG), SAECG, Holter, or clinical factors. Patients were followed for 4.5 ± 2.6 years for SCD and VAs. RESULTS: Seven of 120 patients (6%) had inducible ventricular tachycardia (VT) with EPS and received an implantable cardioverter defibrillator (ICD). Three patients (43%) with positive EPS later had ICD therapies for VAs. Kaplan-Meier analysis stratified by EPS demonstrated a significant difference in freedom from VAs and SCD (P = 0.009), though this finding was driven entirely by patients within the cohort with probable CS (P = 0.018, n = 69). One patient with possible CS and negative EPS had unrecognized progression of the disease and unexplained death with evidence of CS at autopsy. CONCLUSIONS: EPS is useful in the risk stratification of patients with probable CS with preserved LV and RV function. A positive EPS was associated with VAs. While a negative EPS appeared to confer low risk, close follow-up is needed as EPS cannot predict fatal VAs related to new cardiac involvement or disease progression.

Esophageal position, measured luminal temperatures, and risk of atrioesophageal fistula with atrial fibrillation ablation.

BACKGROUND: Despite improvement in catheter ablation for atrial fibrillation (AF), ability to recognize and prevent esophageal injury remains challenging. We hypothesized that esophageal course may impact esophageal heating, as measured through ablation, and thereby, risk of injury. METHODS: We evaluated all patients undergoing first-time AF ablation with preprocedural computed tomography (CT) imaging from 2014 to 2016 at our institution, focusing on esophageal position at the left atrial (LA)/pulmonary vein junction. Esophageal luminal temperatures (ELTs) were analyzed by esophageal course. In exploratory work by investigation of published reports of atrioesophageal fistula (AEF), we evaluated for a relationship between esophageal course and risk of AEF. RESULTS: Of 68 patients, 48.5% had midline, 36.8% leftward, and 14.7% rightward esophageal positions. Of 20 patients (29% of cohort) with esophageal confinement-defined as a midline or leftward position relative to the LA, vertebrae, and aorta, with luminal distortion-14 had leftward position. No significant differences in patient or procedure characteristics were noted between confinement and nonconfinement cohorts. The average peak ELT was significantly higher in those with confinement (36.9°C vs 36.2°C, P < 0.05) and confinement with a left-sided esophagus (37.1°C vs 36.2°C, P < 0.05). There was a significant correlation between esophageal confinement and risk of AEF (odds ratio [OR]: 2.7, 95% confidence interval [CI]: 1.2-6.2, P < 0.01). CONCLUSION: Approximately one-third of patients undergoing AF ablation display leftward esophageal course along the ablation zone on preprocedure CT imaging, with a significant portion exhibiting esophageal confinement. In those with confinement, higher peak ELTs are noted with ablation. Esophageal confinement may be a risk factor for development of AEF.

A genotype-directed comparative effectiveness trial of Bucindolol and metoprolol succinate for prevention of symptomatic atrial fibrillation/atrial flutter in patients with heart failure: Rationale and design of the GENETIC-AF trial.

BACKGROUND: Few therapies are available for the safe and effective treatment of atrial fibrillation (AF) in patients with heart failure. Bucindolol is a non-selective beta-blocker with mild vasodilator activity previously found to have accentuated antiarrhythmic effects and increased efficacy for preventing heart failure events in patients homozygous for the major allele of the ADRB1 Arg389Gly polymorphism (ADRB1 Arg389Arg genotype). The safety and efficacy of bucindolol for the prevention of AF or atrial flutter (AFL) in these patients has not been proven in randomized trials. METHODS/DESIGN: The Genotype-Directed Comparative Effectiveness Trial of Bucindolol and Metoprolol Succinate for Prevention of Symptomatic Atrial Fibrillation/Atrial Flutter in Patients with Heart Failure (GENETIC-AF) trial is a multicenter, randomized, double-blinded "seamless" phase 2B/3 trial of bucindolol hydrochloride versus metoprolol succinate, for the prevention of symptomatic AF/AFL in patients with reduced ejection fraction heart failure (HFrEF). Patients with pre-existing HFrEF and recent history of symptomatic AF are eligible for enrollment and genotype screening, and if they are ADRB1 Arg389Arg, eligible for randomization. A total of approximately 200 patients will comprise the phase 2B component and if pre-trial assumptions are met, 620 patients will be randomized at approximately 135 sites to form the Phase 3 population. The primary endpoint is the time to recurrence of symptomatic AF/AFL or mortality over a 24-week follow-up period, and the trial will continue until 330 primary endpoints have occurred. CONCLUSIONS: GENETIC-AF is the first randomized trial of pharmacogenetic guided rhythm control, and will test the safety and efficacy of bucindolol compared with metoprolol succinate for the prevention of recurrent symptomatic AF/AFL in patients with HFrEF and an ADRB1 Arg389Arg genotype. (ClinicalTrials.govNCT01970501).

Repeat ablation of refractory ventricular arrhythmias in patients with nonischemic cardiomyopathy: Impact of midmyocardial substrate and role of adjunctive ablation techniques.

INTRODUCTION: Multiple ablations are often necessary to manage ventricular arrhythmias (VAs) in nonischemic cardiomyopathy (NICM) patients. We assessed characteristics and outcomes and role of adjunctive, nonstandard ablation in repeat VA ablation (RAbl) in NICM. METHODS AND RESULTS: Consecutive NICM patients undergoing RAbl were analyzed, with characteristics of the last VA ablations compared between those undergoing 1 versus multiple-repeat ablations (1-RAbl vs. >1RAbl), and between those with or without midmyocardial substrate (MMS). VA-free survival was compared. Eighty-eight patients underwent 124 RAbl, 26 with > 1RAbl, and 26 with MMS. 1-RAbl and > 1-RAbl groups were similar in age (57 ± 16 vs. 57 ± 17 years; P = 0.92), males (76% vs. 69%; P = 0.60), LVEF (40 ± 17% vs. 40 ± 18%; P = 0.96), and amiodarone use (31% vs. 46%, P = 0.22). One-year VA freedom between 1-RAbl vs. > 1RAbl was similar (82% vs. 80%; P = 0.81); adjunctive ablation was utilized more in >1RAbl (31% vs. 11%, P = 0.02), and complication rates were higher (27% vs. 7%, P = 0.01), most due to septal substrate and anticipated heart block. >1-RAbl patients had more MMS (62% vs. 16%, P < 0.01). Although MMS was associated with worse VA-free survival after 1-RAbl (43% vs. 69%, P = 0.01), when >1RAbl was performed, more often with nonstandard ablation, VA-free survival was comparable to non-MMS patients (85% vs. 81%; P = 0.69). More RAbls were required in MMS versus non-MMS patients (2.00 ± 0.98 vs. 1.16 ± 0.37; P < 0.001). CONCLUSION: For NICM patients with recurrent, refractory VAs despite previous ablation, effective arrhythmia control can safely be achieved with subsequent ablation, although >1 repeat procedure with adjunctive ablation is often required, especially with MMS.

Acute and Long-Term Outcomes of Catheter Ablation of Atrial Fibrillation Using the Second-Generation Cryoballoon versus Open-Irrigated Radiofrequency: A Multicenter Experience.

INTRODUCTION: There are limited comparative data on catheter ablation of atrial fibrillation (CAAF) using the second-generation cryoballoon (CB-2) versus point-by-point radiofrequency (RF). This study examines the acute/long-term CAAF outcomes using these 2 strategies. METHODS AND RESULTS: In this multicenter, retrospective, nonrandomized analysis, procedural and clinical outcomes of 1,196 patients (76% with paroxysmal AF) undergoing CAAF using CB-2 (n = 773) and open-irrigated, non-force sensing RF (n = 423) were evaluated. Pulmonary vein isolation was achieved in 98% with CB-2 and 99% with RF (P = 0.168). CB-2 was associated with shorter ablation time (40 ± 14 min vs. 66 ± 26 min; P < 0.001) and procedure time (145 ± 49 minutes vs. 188 ± 42 minutes; P < 0.001), but greater fluoroscopic utilization (29 ± 13 minutes vs. 23 ± 14 minutes; P < 0.001). While transient (7.6% vs. 0%; P < 0.001) and persistent (1.2% vs. 0%; P = 0.026) phrenic nerve palsy occurred exclusively with CB-2, other adverse event rates were similar between CB-2 (1.6%) and RF (2.6%); P = 0.207. However, freedom from AF/atrial flutter/tachycardia at 12 months following a single procedure without antiarrhythmic therapy was greater with CB-2 (76.6%) versus RF (60.4%); P < 0.001. While this difference was evident in patients with paroxysmal AF (P < 0.001), it did not reach significance in those with persistent AF (P = 0.089). Additionally, CB-2 was associated with reduced long-term need for antiarrhythmic therapy (16.7% vs. 22.0%; P = 0.024) and repeat ablations (14.6% vs. 24.1%; P < 0.001). CONCLUSION: In this multicenter, retrospective, nonrandomized study, CAAF using CB-2 coupled with RF as occasionally required was associated with greater freedom from atrial arrhythmias at 12 months following a single procedure without antiarrhythmic therapy when compared to open-irrigated, non-force sensing RF, alone.

A polygenic risk score for the QT interval is an independent predictor of drug-induced QT prolongation.

Drug-induced QT prolongation (diLQTS), and subsequent risk of torsade de pointes, is a major concern with use of many medications, including for non-cardiac conditions. The possibility that genetic risk, in the form of polygenic risk scores (PGS), could be integrated into prediction of risk of diLQTS has great potential, although it is unknown how genetic risk is related to clinical risk factors as might be applied in clinical decision-making. In this study, we examined the PGS for QT interval in 2500 subjects exposed to a known QT-prolonging drug on prolongation of the QT interval over 500ms on subsequent ECG using electronic health record data. We found that the normalized QT PGS was higher in cases than controls (0.212±0.954 vs. -0.0270±1.003, P = 0.0002), with an unadjusted odds ratio of 1.34 (95%CI 1.17-1.53, P<0.001) for association with diLQTS. When included with age and clinical predictors of QT prolongation, we found that the PGS for QT interval provided independent risk prediction for diLQTS, in which the interaction for high-risk diagnosis or with certain high-risk medications (amiodarone, sotalol, and dofetilide) was not significant, indicating that genetic risk did not modify the effect of other risk factors on risk of diLQTS. We found that a high-risk cutoff (QT PGS ≥ 2 standard deviations above mean), but not a low-risk cutoff, was associated with risk of diLQTS after adjustment for clinical factors, and provided one method of integration based on the decision-tree framework. In conclusion, we found that PGS for QT interval is an independent predictor of diLQTS, but that in contrast to existing theories about repolarization reserve as a mechanism of increasing risk, the effect is independent of other clinical risk factors. More work is needed for external validation in clinical decision-making, as well as defining the mechanism through which genes that increase QT interval are associated with risk of diLQTS.

Development and validation of the Atri-Risk Conduction Index risk score to predict risk of atrial fibrillation after typical atrial flutter ablation.

BACKGROUND: Identification of patients at risk for atrial fibrillation (AF) after typical atrial flutter (tAFL) ablation is important to guide monitoring and treatment. OBJECTIVE: The purpose of this study was to create and validate a risk score to predict AF after tAFL ablation METHODS: We identified patients who underwent tAFL ablation with no AF history between 2017 and 2022 and randomly allocated to derivation and validation cohorts. We collected clinical variables and measured conduction parameters in sinus rhythm on an electrophysiology recording system (CardioLab, GE Healthcare). Univariate and multivariate logistic regressions (LogR) were used to evaluate association with AF development. RESULTS: A total of 242 consecutive patients (81% male; mean age 66 ± 11 years) were divided into derivation (n =142) and validation (n = 100) cohorts. Forty-two percent developed AF over median follow-up of 330 days. In multivariate LogR (derivation cohort), proximal to distal coronary sinus time (pCS-dCS) ≥70 ms (odds ratio [OR] 16.7; 95% confidence interval [CI] 5.6-49), pCS time ≥36 ms (OR 4.5; 95% CI 1.5-13), and CHADS2-VASc score ≥3 (OR 4.3; 95% CI 1.6-11.8) were independently associated with new AF during follow-up. The Atri-Risk Conduction Index (ARCI) score was created with 0 as minimal and 4 as high-risk using pCS-dCS ≥70 ms = 2 points; pCS ≥36 ms = 1 point; and CHADS2-VASc score ≥3 = 1 point. In the validation cohort, 0% of patients with ARCI score = 0 developed AF, whereas 89% of patients with ARCI score = 4 developed AF. CONCLUSION: We developed and validated a risk score using atrial conduction parameters and clinical risk factors to predict AF after tAFL ablation. It stratifies low-, moderate-, and high-risk patients and may be helpful in individualizing approaches to AF monitoring and anticoagulation.

Endocardial electrogram characteristics of epicardial ventricular arrhythmias.

INTRODUCTION: While most ventricular arrhythmias (VA) can be ablated successfully using an endocardial (endo) approach, epicardial (epi) mapping and ablation is sometimes required. There may be suggestive clues on the surface electrocardiogram; however, identification of an epi origin of VA with certainty remains problematic. METHODS AND RESULTS: All patients referred for ablation of ventricular tachycardia or frequent ventricular ectopy from June 2007 to July 2011 were evaluated. Patients with completed endo and epi electroanatomical activation maps of an epi VA were included (n = 10). Bipolar electrograms (EGMs) in the area of earliest endo activation were analyzed and compared to the area of early epi activation. An EGM component was characterized as far field if it was monophasic and there was inability to capture. We identified 3 characteristics from endo mapping that consistently indicated need for epi ablation: (1) Diffusely early activation (>2 cm(2) region of sites with equally earliest activation within 10 milliseconds). (2) Sequence of a far-field EGM followed by a near-field EGM in the region of earliest endo activation. (3) Inability to capture the far-field component of the earliest EGM (stim-QRS < egm-QRS time) or reproduce morphological features of the VA complex with stimulation at the earliest endo site of activation. CONCLUSIONS: The presence of a diffusely early area of activation and inability to capture a far-field endo EGM indicates that epi ablation may be needed to eliminate a VA.

Use of stored implanted cardiac defibrillator electrograms in catheter ablation of ventricular fibrillation.

BACKGROUND: Ventricular fibrillation (VF) can be abolished by targeting triggering ventricular ectopy, most often originating in the Purkinje network or right ventricular outflow tract (RVOT). This strategy relies upon the induction of premature ventricular complex (PVC) and/or VF. We sought to evaluate a VF ablation strategy that utilizes analysis of stored implantable cardioverter defibrillator (ICD) electrograms. METHODS: Eleven consecutive patients experiencing frequent VF episodes (≥three episodes in prior month) underwent electrophysiology study and ablation of VF triggers. PVC and VF induction was intentionally avoided or not possible in all of these patients. Pacemapping at likely sites for PVC triggers of VF using an analysis of the morphology and relative timing of the stored far- and near-field ICD electrograms of VF triggers was used to identify potential culprit locations. Radiofrequency energy was applied to these sites for ablation of the identified VF trigger. RESULTS: Areas targeted for ablation included the left posterior fascicle (six), left anterior fascicle (three), RVOT (three) and left ventricular outflow tract (one); two patients had two separate triggers. Ablation was completed successfully without any complications. With a mean follow-up of 288 days (range 45-649), 10 patients are free of VF. CONCLUSION: Ablation of VF triggers can be performed successfully with good short-term outcomes in patients with and without underlying heart disease. Use of stored ICD electrograms with a focus on likely target areas permit ablation without the need for PVC or VF induction. This can be useful when ectopy is not present for mapping and to avoid potentially dangerous initiation of multiple episodes of VF.

A Discussion of the Contemporary Prediction Models for Atrial Fibrillation.

Atrial Fibrillation is a complex disease state with many environmental and genetic risk factors. While there are environmental factors that have been shown to increase an individual's risk of atrial fibrillation, it has become clear that atrial fibrillation has a genetic component that influences why some patients are at a higher risk of developing atrial fibrillation compared to others. This review will first discuss the clinical diagnosis of atrial fibrillation and the corresponding rhythm atrial flutter. We will then discuss how a patients' risk of stroke can be assessed by using other clinical co-morbidities. We will then review the clinical risk factors that can be used to help predict an individual patient's risk of atrial fibrillation. Many of the clinical risk factors have been used to create several different risk scoring methods that will be reviewed. We will then discuss how genetics can be used to identify individuals who are at higher risk for developing atrial fibrillation. We will discuss genome-wide association studies and other sequencing high-throughput sequencing studies. Finally, we will touch on how genetic variants derived from a genome-wide association studies can be used to calculate an individual's polygenic risk score for atrial fibrillation. An atrial fibrillation polygenic risk score can be used to identify patients at higher risk of developing atrial fibrillation and may allow for a reduction in some of the complications associated with atrial fibrillation such as cerebrovascular accidents and the development of heart failure. Finally, there is a brief discussion of how artificial intelligence models can be used to predict which patients will develop atrial fibrillation.

Evaluation of Quantitative Decision-Making for Rhythm Management of Atrial Fibrillation Using Tabular Q-Learning.

Background Rhythm management is a complex decision for patients with atrial fibrillation (AF). Although clinical trials have identified subsets of patients who might benefit from a given rhythm-management strategy, for individual patients it is not always clear which strategy is expected to have the greatest mortality benefit or durability. Methods and Results In this investigation 52 547 patients with a new atrial fibrillation diagnosis between 2010 and 2020 were retrospectively identified. We applied a type of artificial intelligence called tabular Q-learning to identify the optimal initial rhythm-management strategy, based on a composite outcome of mortality, change in treatment, and sustainability of the given treatment, termed the reward function. We first applied an unsupervised learning algorithm using a variational autoencoder with K-means clustering to cluster atrial fibrillation patients into 8 distinct phenotypes. We then fit a Q-learning algorithm to predict the best outcome for each cluster. Although rate-control strategy was most frequently selected by treating providers, the outcome was superior for rhythm-control strategies across all clusters. Subjects in whom provider-selected treatment matched the Q-table recommendation had fewer total deaths (4 [8.5%] versus 473 [22.4%], odds ratio=0.32, P=0.02) and a greater reward (P=4.8×10-6). We then demonstrated application of dynamic learning by updating the Q-table prospectively using batch gradient descent, in which the optimal strategy in some clusters changed from cardioversion to ablation. Conclusions Tabular Q-learning provides a dynamic and interpretable approach to apply artificial intelligence to clinical decision-making for atrial fibrillation. Further work is needed to examine application of Q-learning prospectively in clinical patients.

Implantable cardioverter defibrillator therapy in patients with cardiac sarcoidosis.

UNLABELLED: ICD Shocks in Cardiac Sarcoidosis. BACKGROUND: An implantable cardioverter defibrillator (ICD) is indicated for some patients with cardiac sarcoidosis (CS) for prevention of sudden death. However, there are little data regarding the event rates of ICD therapies in these patients. We sought to identify the incidence and characteristics of ICD therapies in this patient population. METHODS: We performed a cohort study of patients with ICDs at 3 institutions. Cases were those patients with CS and an ICD implanted for primary or secondary prevention of sudden death. Additionally, we included a comparison with historical controls of ICD therapy rates reported in clinical trials evaluating the ICD for primary and secondary prevention of sudden death. RESULTS: Of the 112 CS subjects identified, 36 (32.1%) received appropriate therapies for ventricular tachyarrhythmias (VT) over a mean follow-up period of 29.2 months. VT storm (>3 episodes in 24 hours) occurred in 16 (14.2%) CS subjects. Inappropriate therapies occurred in 13 CS subjects (11.6%). Covariates associated with appropriate ICD therapies included left ventricular ejection fraction (LVEF) <55% (OR 6.52 [95% CI 2.43-17.5]), right ventricular dysfunction (OR 6.73 [95% CI 2.69-16.8]), and symptomatic heart failure (OR 4.33 [95% CI 1.86-10.1]). CONCLUSIONS: In our cohort of patients with CS and ICDs, almost one-third receive appropriate therapies. This may be due to a myocardial inflammatory process leading to increased triggered activity and subsequent scarring leading to reentrant tachyarrhythmias. Adjusted predictors of ICD therapies in this population include left or right ventricular dysfunction. (J Cardiovasc Electrophysiol, Vol. 23, pp. 925-929, September 2012).

Esophago-Pericardial Fistula as a Rare and Life-Threatening Complication of Epicardial Ventricular Tachycardia Ablation.

We describe a rare complication of esophago-pericardial fistula after epicardial ventricular tachycardia ablation. Echocardiogram revealed evidence of pneumopericardium and additional imaging studies confirmed esophageal leak with evidence of fistula formation requiring prompt surgical repair. (Level of Difficulty: Intermediate.).

Device-Sizing and Associated Complications With Left Atrial Appendage Occlusion: Findings From the NCDR LAAO Registry.

BACKGROUND: Left atrial appendage occlusion is an important alternative to anticoagulation in select patients with nonvalvular atrial fibrillation. Trends in real-world device sizing and associated short-term complications have not been characterized. METHODS: Using the National Cardiovascular Data Left Atrial Appendage Occlusion (NCDR LAAO) Registry, patients who underwent left atrial appendage occlusion with a Watchman 2.5 device from January 1, 2016, to June 30, 2020, were identified. Patients were stratified by device size based on left atrial appendage orifice size, and categorized as receiving a device that was undersized, oversized, or per manufacturer recommendation. Relationships between device sizing and short-term outcomes, including pericardial effusion, device embolism, and significant leak, were assessed. RESULTS: Of the 68 456 patients, 6539 (10.5%) of patients received undersized devices, 17 791 (26.0%) according to manufacturer recommendations, and 44 126 (64.4%) received an oversized device. The 27-mm device was most commonly deployed [21 736 (31.8%)], whereas the smallest and largest devices (21 and 33 mm) were least commonly deployed [7695 (11.2%) and 9077 (13.3%), respectively]. Compared with manufacturer recommended sizing, there was no difference in the odds of pericardial effusion for either undersized (1.048 [95% CI' 0.801-1.372]; P=0.733) or oversized (1.101 [95% CI' 0.933-1.298]; P=0.254) devices. Similarly, relative to manufacturer recommended sizing, the odds of a composite adverse outcome of device migration or embolization and significant peridevice leak at 45 days were similar among undersized devices (1.030 [95% CI' 0.735-1.444]; P=0.863) and favorable for oversized devices (0.701 [95% CI' 0.561-0.876]; P=0.002) devices, primarily driven by lower odds of leak. Selection of oversized devices increased significantly over the study period (from 60.3% in 2016 to 66.0% in 2020; P<0.001). CONCLUSIONS: Among patients undergoing left atrial appendage occlusion with the first-generation Watchman device, receipt of oversized devices was common and increased over time. The high prevalence of oversizing was associated with lower odds of significant leak or device embolization without increased odds of other adverse events.

Limitations of Unipolar Signals in Guiding Successful Outflow Tract Premature Ventricular Contraction Ablation.

BACKGROUND: Unipolar electrograms (UniEGMs) are commonly used to annotate earliest local activation of focal arrhythmias. However, their utility in guiding premature ventricular contractions (PVCs) ablation may be limited when the PVC source is less superficial. OBJECTIVES: The authors sought to compare bipolar electrograms (BiEGMs) vs UniEGMs in guiding successful ablation of right ventricular outflow tract (RVOT) vs intramural outflow tract (OT) PVCs. The authors hypothesized that: 1) earliest bipolar local activation time (LATBi) would better guide mapping and ablation, vs UniEGM dV/dt (LATUni) or QS morphology; and 2) LAT differences using bipolar vs unipolar EGMs (ΔLATBi-Uni) would be greater for intramural OT than RVOT PVCs. METHODS: Consecutive patients undergoing successful PVC ablation 2017 to2020 requiring only RVOT or RVOT+left ventricular OT (RVOT+LVOT) ablation were retrospectively analyzed. BiEGMs and UniEGMs at successful ablation sites were compared. RESULTS: Of 70 patients, 50 required RVOT-only, and 20 required RVOT+LVOT ablation for acute and long-term PVC suppression. Mean ΔLATBi-Uni was lower for RVOT vs RVOT+LVOT groups (9.3 ± 6.4 ms vs 17.4 ± 9.9 ms; P < 0.01). QS UniEGM was seen in 78% of RVOT, compared with 53% of RVOT+LVOT patients (P < 0.016). RVOT+LVOT sites most frequently included the posteroseptal RVOT and adjacent LVOT (73%), and 43% lacked a QS unipolar EGM. ΔLATBi-Uni ≥15 ms best distinguished sites in which RVOT-only vs RVOT+LVOT ablation achieved acute PVC suppression (area under the curve: 0.77). CONCLUSIONS: Earliest BiEGM activation guides successful ablation of OT PVCs better than UniEGM-guided analysis, especially when an intramural PVC source is present.

Dose-limiting, adverse event-associated bradycardia with ß-blocker treatment of atrial fibrillation in the GENETIC-AF trial.

BACKGROUND: Heart failure (HF) patients with atrial fibrillation (AF) often have conduction system disorders, which may be worsened by ß-blocker therapy. OBJECTIVE: In a post hoc analysis we examined the prevalence of bradycardia and its association with adverse events (AEs) and failure to achieve target dose in the GENETIC-AF trial. METHODS: Patients randomized to metoprolol (n = 125) or bucindolol (n = 131) entering 24-week efficacy follow-up and receiving study medication were evaluated. Bradycardia was defined as an electrocardiogram (ECG) heart rate (HR) <60 beats per minute (bpm) and severe bradycardia <50 bpm. RESULTS: Mean HR in sinus rhythm (SR) was 62.6 ± 12.5 bpm for metoprolol and 68.3 ± 11.1 bpm for bucindolol (P < .0001), but in AF HRs were not different (87.5 bpm vs 89.7 bpm, respectively). Episodes per patient for bucindolol vs metoprolol were 0.82 vs 2.08 (P < .001) for bradycardia and 0.24 vs 0.57 for severe bradycardia (P < .001), with 98.9% of the episodes occurring in SR. Patients experiencing bradycardia had a 4.15-fold higher prevalence of study medication dose reduction (P <.0001) compared to patients without bradycardia. Fewer patients receiving metoprolol were at target dose (61.7% vs 74.9% for bucindolol, P < .0001) at ECG recordings, and bradycardia AEs were more prevalent in the metoprolol group (13 vs 1 for bucindolol, P = .001). On multivariate analysis of 21 candidate bradycardia predictors including presence of a device with pacing capability, bucindolol treatment was associated with the greatest degree of prevention (Zodds ratio -4.24, P < .0001). CONCLUSION: In AF-prone HF patients bradycardia may limit the effectiveness of ß blockers, and this property is agent-dependent.

2022 HRS expert consensus statement on evaluation and management of arrhythmic risk in neuromuscular disorders.

This international multidisciplinary document is intended to guide electrophysiologists, cardiologists, other clinicians, and health care professionals in caring for patients with arrhythmic complications of neuromuscular disorders (NMDs). The document presents an overview of arrhythmias in NMDs followed by detailed sections on specific disorders: Duchenne muscular dystrophy, Becker muscular dystrophy, and limb-girdle muscular dystrophy type 2; myotonic dystrophy type 1 and type 2; Emery-Dreifuss muscular dystrophy and limb-girdle muscular dystrophy type 1B; facioscapulohumeral muscular dystrophy; and mitochondrial myopathies, including Friedreich ataxia and Kearns-Sayre syndrome, with an emphasis on managing arrhythmic cardiac manifestations. End-of-life management of arrhythmias in patients with NMDs is also covered. The document sections were drafted by the writing committee members according to their area of expertise. The recommendations represent the consensus opinion of the expert writing group, graded by class of recommendation and level of evidence utilizing defined criteria. The recommendations were made available for public comment; the document underwent review by the Heart Rhythm Society Scientific and Clinical Documents Committee and external review and endorsement by the partner and collaborating societies. Changes were incorporated based on these reviews. By using a breadth of accumulated available evidence, the document is designed to provide practical and actionable clinical information and recommendations for the diagnosis and management of arrhythmias and thus improve the care of patients with NMDs.

Electrocardiographic characteristics in patients with pulmonary sarcoidosis indicating cardiac involvement.

INTRODUCTION: Sarcoidosis is a multisystem granulomatous disease that can affect the heart. Early identification of cardiac sarcoidosis (CS) is critical because sudden death can be the initial presentation. We sought to evaluate the potential role of the ECG for identification of cardiac involvement in a cohort of patients with biopsy-proven pulmonary sarcoidosis. METHODS: Our cohort consisted of referred patients with biopsy-proven pulmonary sarcoidosis who demonstrated symptoms consistent with cardiac involvement. The ECG characteristics collected were PR, QRS duration, QT interval, rate, bundle branch block (BBB), fragmented QRS (fQRS). QRS fragmentation was defined as 2 anatomically contiguous leads demonstrating RSR' patterns in the absence of BBB. RESULTS: There were 112 subjects included in the cohort. Of the 52 subjects eventually diagnosed with CS, 39 had an ECG demonstrating fQRS while 21 of the 60 of non-CS patients had fQRS (75% vs 33.9%, P < 0.01). A RBBB or LBBB pattern were both more prevalent in the CS population (RBBB: 23.1% vs 6.7%, P = 0.016; LBBB: 3.8% vs 1.7%, P = 0.6). QRS duration remained significantly associated with CS after exclusion of those with BBB (93.5 +/- 10.6 vs 88 +/- 11 ms; P = 0.04). When fQRS and bundle branch block were combined, 90.4% of CS patient's ECGs contained at least one of the features, compared to 36.7% of noncardiac CS (P < 0.01). CONCLUSIONS: The presence of fQRS or BBB pattern in patients with pulmonary sarcoidosis is associated with cardiac involvement and therefore should prompt further evaluation.