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 ablation (tAFl) is important to guide monitoring and treatment. OBJECTIVE: 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 2017-2022 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: 242 consecutive patients (81% males, mean age 66+/-11) were divided into derivation and validation cohorts, (n=142 and n=100). 42% developed AF over a median follow up of 330 days. In multivariate LogR (derivation cohort) , proximal to distal coronary sinus time (pCS-dCS) ≥70ms (OR 16.7 CI 5.6-49), pCS time≥36ms (OR 4.5 CI 1.5-13), and CHADS2VASc≥3 (OR 4.3 CI 1.6-11.8) were independently associated with new AF in follow-up. The Atri-Risk Conduction Index (ARCI) score was created with 0 as minimal and 4 as high-risk using pCS-dCS ≥70ms =2 points, pCS≥36ms=1 point, and CHADS2VASC≥3=1point. In the validation cohort, 0% of patients with ARCI score of 0 developed AF while 89% of patients with ARCI score of 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.

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.

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.

Open surgical ablation of ventricular tachycardia: Utility and feasibility of contemporary mapping and ablation tools.

BACKGROUND: Ventricular tachycardia (VT) catheter ablation success may be limited when transcutaneous epicardial access is contraindicated. Surgical ablation (SurgAbl) is an option, but ablation guidance is limited without simultaneously acquired electrophysiological data. OBJECTIVE: We describe our SurgAbl experience utilizing contemporary electroanatomic mapping (EAM) among patients with refractory VT storm. METHODS: Consecutive patients with recurrent VT despite antiarrhythmic drugs (AADs) and prior ablation, for whom percutaneous epicardial access was contraindicated, underwent open SurgAbl using intraoperative EAM guidance. RESULTS: Eight patients were included, among whom mean age was 63 ± 5 years, all were male, mean left ventricular ejection fraction was 39% ± 12%, and 2 (25%) had ischemic cardiomyopathy. Reasons for surgical epicardial access included dense adhesions owing to prior cardiac surgery, hemopericardium, or pericarditis (n = 6); or planned left ventricular assist device (LVAD) implantation at time of SurgAbl (n = 2). Cryoablation guided by real-time EAM was performed in all. Goals of clinical VT noninducibility or core isolation were achieved in 100%. VT burden was significantly reduced, from median 15 to 0 events in the month pre- and post-SurgAbl (P = .01). One patient underwent orthotopic heart transplantation for recurrent VT storm 2 weeks post-SurgAbl. Over mean follow-up of 3.4 ± 1.7 years, VT storm-free survival was achieved in 6 (75%); all continued AADs, although at lower dose. CONCLUSION: Surgical mapping and ablation of refractory VT with use of contemporary EAM is feasible and effective, particularly among patients with contraindication to percutaneous epicardial access or with another indication for cardiac surgery.

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.

Ambulatory Rhythm Monitoring to Detect Late High-Grade Atrioventricular Block Following Transcatheter Aortic Valve Replacement.

BACKGROUND: High-grade atrioventricular block (H-AVB) is a well-described in-hospital complication of transcatheter aortic valve replacement (TAVR). Delayed high-grade atrioventricular block (DH-AVB) has not been systematically studied among outpatients post-TAVR, using latest-generation TAVR technology and in the early post-TAVR discharge era. OBJECTIVES: The purpose of this study was to assess utility of ambulatory event monitoring (AEM) in identifying post-TAVR DH-AVB and associated risk factors. METHODS: Patients without pre-existing pacing device undergoing TAVR at the University of Colorado Hospital from October 2016 to March 2018, and who did not require permanent pacemaker implantation pre-discharge, were discharged with 30-day AEM to assess for DH-AVB (≥2 days post-TAVR). Clinical and follow-up data were collected and compared among those without incident H-AVB. RESULTS: Among 150 consecutive TAVR patients without a prior pacing device, 18 (12%) developed H-AVB necessitating permanent pacemaker <2 days post-TAVR, 1 died pre-discharge, and 13 declined AEM; 118 had 30-day AEM data. DH-AVB occurred in 12 (10% of AEM patients, 8% of total cohort) a median of 6 days (range 3 to 24 days) post-TAVR. DH-AVB versus non-AVB patients were more likely to have hypertension and right bundle branch block (RBBB). Sensitivity and specificity of RBBB in predicting DH-AVB was 27% and 94%, respectively. CONCLUSIONS: DH-AVB is an underappreciated complication of TAVR among patients without pre-procedure pacing devices, occurring at rates similar to in-hospital, acute post-TAVR H-AVB. RBBB is a risk factor for DH-AVB but has poor sensitivity, and other predictors remain unclear. In this single-center analysis, AEM was helpful in expeditious identification and treatment of 10% of post-TAVR outpatients. Prospective study is needed to clarify incidence, risk factors, and patient selection for outpatient monitoring.

Use of half-normal saline irrigant with cooled radiofrequency ablation within the great cardiac vein to ablate premature ventricular contractions arising from the left ventricular summit.

A 62-year-old man was referred to our institution for high-density, symptomatic premature ventricular contractions (PVCs) with resultant decrease in left ventricular (LV) function having failed prior ablation attempts. Successful, durable ablation of the patient's mid-myocardial PVC arising from the LV summit region was achieved through the proximal great cardiac vein with ablation depth augmented by use of half-normal saline irrigant. Though standard ablation of ventricular arrhythmias using normal saline irrigation from the coronary venous system has been well-reported, this may be of limited value in addressing mid-myocardial sites of origin. This novel case describes the safe use of cooled radiofrequency ablation with use of half-normal saline irrigant from the distal coronary sinus as an option to address complex sites of PVC origin such as the LV summit.

Spectrum of Cardiac Arrhythmias in Isolated Ventricular Non-Compaction.

A wide spectrum of cardiac arrhythmias has been observed in patients with isolated ventricular non-compaction, which is defined by hypertrabeculated ventricular myocardium with deep intertrabecular recesses, in the absence of concomitant congenital heart disease. In this genetically diverse phenotype, the development of fibrosis contributes to an arrhythmogenic substrate underlying atrioventricular conduction diseases, supraventricular tachycardias and ventricular tachycardias. Within this spectrum, monomorphic ventricular tachycardia is the most frequently observed arrhythmia, and this prevalence has important implications for sudden cardiac death risk.

Relationship between use of electronic health record features and health care quality: results of a statewide survey.

BACKGROUND: Electronic health records (EHRs) are widely viewed as useful tools for supporting the provision of high quality healthcare. However, evidence regarding their effectiveness for this purpose is mixed, and existing studies have generally considered EHR usage a binary factor and have not considered the availability and use of specific EHR features. OBJECTIVE: To assess the relationship between the use of an EHR and the use of specific EHR features with quality of care. RESEARCH DESIGN: A statewide mail survey of physicians in Massachusetts conducted in 2005. The results of the survey were linked with Healthcare Effectiveness Data and Information Set (HEDIS) quality measures, and generalized linear regression models were estimated to examine the associations between the use of EHRs and specific EHR features with quality measures, adjusting for physician practice characteristics. SUBJECTS: A stratified random sample of 1884 licensed physicians in Massachusetts, 1345 of whom responded. Of these, 507 had HEDIS measures available and were included in the analysis (measures are only available for primary care providers). MEASURE: Performance on HEDIS quality measures. RESULTS: The survey had a response rate of 71%. There was no statistically significant association between use of an EHR as a binary factor and performance on any of the HEDIS measure groups. However, there were statistically significant associations between the use of many, but not all, specific EHR features and HEDIS measure group scores. The associations were strongest for the problem list, visit note and radiology test result EHR features and for quality measures relating to women's health, colon cancer screening, and cancer prevention. For example, users of problem list functionality performed better on women's health, depression, colon cancer screening, and cancer prevention measures, with problem list users outperforming nonusers by 3.3% to 9.6% points on HEDIS measure group scores (all significant at the P < 0.05 level). However, these associations were not universal. CONCLUSIONS: Consistent with past studies, there was no significant relationship between use of EHR as a binary factor and performance on quality measures. However, availability and use of specific EHR features by primary care physicians was associated with higher performance on certain quality measures. These results suggest that, to maximize health care quality, developers, implementers and certifiers of EHRs should focus on increasing the adoption of robust EHR systems and increasing the use of specific features rather than simply aiming to deploy an EHR regardless of functionality.

Readiness for electronic health records: comparison of characteristics of practices in a collaborative with the remainder of Massachusetts.

OBJECTIVE: The Massachusetts e-Health Collaborative (MAeHC) is implementing electronic health records (EHRs) in physicians' offices throughout three diverse communities. This study's objective was to assess the degree to which these practices are representative of physicians' practices statewide. DESIGN: We surveyed all MAeHC physicians (n=464) and compared their responses to those of a contemporaneously surveyed statewide random sample (n=1884). MEASUREMENTS: The survey questionnaire assessed practice characteristics related to EHR adoption, prevailing office culture related to quality and safety, attitudes toward health information technology (HIT) and perceptions of medical practice. RESULTS: A total of 355 MAeHC physicians (77%) and 1345 physicians from the statewide sample (71%) completed the survey. MAeHC practices resembled practices throughout Massachusetts in terms of practice size, physician age and gender, prevailing financial incentives for quality performance and HIT adoption and available resources for practice expansion. MAeHC practices were more likely to be located in rural areas (9.5% vs 4.4%, P=0.004). Physicians in both samples responded similarly to six of seven self-assessments of the office practice environment for quality and safety. Internet connections were more prevalent among MAeHC practices than across the state (96% vs 83%, P<0.001), but similar proportions of MAeHC physicians (83%) and statewide physicians (86%) used the internet daily (P=0.19). CONCLUSION: MAeHC is implementing EHRs and health information exchange among communities with physicians and practices that appear generally representative of Massachusetts. The lessons learned from this pilot project should be applicable statewide and to other states with large numbers of physicians in small office practices.