Identification of Human Ventricular Tachycardia Demarcated by Fixed Lines of Conduction Block in a 3-Dimensional Hyperboloid Circuit.

BACKGROUND: The circuit boundaries for reentrant ventricular tachycardia (VT) have been historically conceptualized within a 2-dimensional (2D) construct, with their fixed or functional nature unresolved. This study aimed to examine the correlation between localized lines of conduction block (LOB) evident during baseline rhythm with lateral isthmus boundaries that 3-dimensionally constrain the VT isthmus as a hyperboloid structure. METHODS: A total of 175 VT activation maps were correlated with isochronal late activation maps during baseline rhythm in 106 patients who underwent catheter ablation for scar-related VT from 3 centers (42% nonischemic cardiomyopathy). An overt LOB was defined by a deceleration zone with split potentials (≥20 ms isoelectric segment) during baseline rhythm. A novel application of pacing within deceleration zone (≥600 ms) was implemented to unmask a concealed LOB not evident during baseline rhythm. LOB identified during baseline rhythm or pacing were correlated with isthmus boundaries during VT. RESULTS: Among 202 deceleration zones analyzed during baseline rhythm, an overt LOB was evident in 47%. When differential pacing was performed in 38 deceleration zones without overt LOB, an underlying concealed LOB was exposed in 84%. In 152 VT activation maps (2D=53, 3-dimensional [3D]=99), 69% of lateral boundaries colocalized with an LOB in 2D activation patterns, and the depth boundary during 3D VT colocalized with an LOB in 79%. In VT circuits with isthmus regions that colocalized with a U-shaped LOB (n=28), the boundary invariably served as both lateral boundaries in 2D and 3D. Overall, 74% of isthmus boundaries were identifiable as fixed LOB during baseline rhythm or differential pacing. CONCLUSIONS: The majority of VT circuit boundaries can be identified as fixed LOB from intrinsic or paced activation during sinus rhythm. Analysis of activation while pacing within the scar substrate is a novel technique that may unmask concealed LOB, previously interpreted to be functional in nature. An LOB from the perspective of a myocardial surface is frequently associated with intramural conduction, supporting the existence of a 3D hyperboloid VT circuit structure. Catheter ablation may be simplified to targeting both sides around an identified LOB during sinus rhythm.

Initial clinical experience of atrial fibrillation ablation guided by a cryoballoon-compatible, magnetic-based circular catheter.

INTRODUCTION: The circular catheter compatible with current cryoballoon system for atrial fibrillation (AF) ablation is exclusively sensed by impedance-based electro-anatomical mapping (EAM) system, limiting the accuracy of maps. We aim to investigate the feasibility and safety of a magnetic-based circular mapping catheter for AF ablation with cryoballoon. METHODS: Nineteen consecutive patients who underwent pulmonary vein isolation (PVI) with cryoballoon for paroxysmal or persistent AF were included. EAMs of left atrium (LA) created by the LASSOSTAR™NAV catheter (Lassostar map) before and after PVI were compared to that generated by a high-density mapping catheter (Pentaray map) from different aspects including structural similarity, PV angle, LA posterior wall (LAPW) and low voltage areas (LVAs), and the amplitude of far field electrograms (FFEs) recorded by catheters. RESULTS: All patients had successful PVI without major complications. With similar mapping time and density, the LA volume calculated from the Pentaray map and Lassostar map were comparable. There were no significant differences in PV angle of all PVs and PW area (16.8 ± 3.2 vs. 17.1 ± 2.8, p = .516) between Pentaray map and Lassostar map. High structural similarity score was observed between two maps (0.783 in RAO/LAO view and 0.791 in PA view). Lassostar map detected lesser but not statistically significant extension of LVA (13.9% vs. 18.3%, p = .07). Amplitude of FFE was larger at the right superior PV on Lassostar map (0.21 ± 0.16 vs. 0.14 ± 0.11 mV, p = .041) compared to that on the Pentaray map. CONCLUSION: In our initial experience, PVI with cryoballoon and magnetic-based circular LASSOSTAR™NAV catheter was safe and effective based on the accurate LA geometry it created.

Incidence of cryoballoon expansion dislodgement during pulmonary vein isolation-An underappreciated frequent cause of incomplete isolation.

BACKGROUND: Cryoballoon ablation for atrial fibrillation (AF) requires adequate contact between the pulmonary vein (PV) antrum and cryoballoon. The surge of intraballoon pressure during the initial phase of ablation may change the balloon's shape and compliance, resulting in balloon dislodgement and loss of PV occlusion. Without continuous monitoring, this phenomenon is often undetected but can be associated with incomplete PV isolation (PVI). METHODS: Primary cryoablation of AF was performed in 15 patients. PV occlusion status pre- and post-freezing were analyzed with intracardiac echocardiography (ICE) and dielectric imaging-based occlusion tool (DIOT) to calculate the incidence of expansion dislodgement of cryoballoon. RESULTS: A total of 105 cryoablation applications were performed on 57 veins, including three common ostiums of left pulmonary veins. In the evaluation of PV occlusion, both modalities reported consistent results in 86.7% of the assessments. Despite complete PV occlusion before ablation, peri-balloon leak after initiation of freezing was detected by ICE in 5/22 (22.7%) applications and by DIOT in 8/25 (32%) applications. CONCLUSION: Incidence of expansion dislodgement of the cryoballoon was detected in one-fourth to one-third of cryoablation applications depending on the imaging modality used, which was clinically frequent and significant.

Early feasibility studies in the United States: Focus on electrophysiology.

The care of patients with heart rhythm disorders is often dependent on technologies developed to address their unique clinical needs. Although much innovation occurs in the United States, recent decades have seen a significant proportion of early clinical studies performed outside the United States, driven largely by costly and time-inefficient processes seemingly inherent to the United States research ecosystem. As a result, the goals of early patient access to novel devices to address unmet needs and efficient technology development in the United States remain incompletely realized. This review will introduce key aspects of this discussion, organized by the Medical Device Innovation Consortium, in an effort to broaden awareness and encourage engagement by stakeholders in an effort to address central issues and therefore further a growing effort to shift Early Feasibility Studies to the United States for the benefit of all involved.

Design and characteristics of the prophylactic intra-operative ventricular arrhythmia ablation in high-risk LVAD candidates (PIVATAL) trial.

BACKGROUND: The use of a Left Ventricular Assist Device (LVAD) in patients with advanced heart failure refractory to optimal medical management has progressed steadily over the past two decades. Data have demonstrated reduced LVAD efficacy, worse clinical outcome, and higher mortality for patients who experience significant ventricular tachyarrhythmia (VTA). We hypothesize that a novel prophylactic intra-operative VTA ablation protocol at the time of LVAD implantation may reduce the recurrent VTA and adverse events postimplant. METHODS: We designed a prospective, multicenter, open-label, randomized-controlled clinical trial enrolling 100 patients who are LVAD candidates with a history of VTA in the previous 5 years. Enrolled patients will be randomized in a 1:1 fashion to intra-operative VTA ablation (n = 50) versus conventional medical management (n = 50) with LVAD implant. Arrhythmia outcomes data will be captured by an implantable cardioverter defibrillator (ICD) to monitor VTA events, with a uniform ICD programming protocol. Patients will be followed prospectively over a mean of 18 months (with a minimum of 9 months) after LVAD implantation to evaluate recurrent VTA, adverse events, and procedural outcomes. Secondary endpoints include right heart function/hemodynamics, healthcare utilization, and quality of life. CONCLUSION: The primary aim of this first-ever randomized trial is to assess the efficacy of intra-operative ablation during LVAD surgery in reducing VTA recurrence and improving clinical outcomes for patients with a history of VTA.

Catheter ablation of ventricular tachycardia in patients with prior cardiac surgery: An analysis from the International VT Ablation Center Collaborative Group.

INTRODUCTION: Patients with prior cardiac surgery may represent a subgroup of patients with ventricular tachycardia (VT) that may be more difficult to control with catheter ablation. METHODS: We evaluated 1901 patients with ischemic and nonischemic cardiomyopathy who underwent VT ablation at 12 centers. Clinical characteristics and VT radiofrequency ablation procedural outcomes were assessed and compared between those with and without prior cardiac surgery. Kaplan-Meier analysis was used to estimate freedom from recurrent VT and survival. RESULTS: There were 578 subjects (30.4%) with prior cardiac surgery identified in the cohort. Those with prior cardiac surgery were older (66.4 ± 11.0 years vs. 60.5 ± 13.9 years, p < .01), with lower left ventricular ejection fraction (30.2 ± 11.5% vs. 34.8 ± 13.6%, p < .01) and more ischemic heart disease (82.5% vs. 39.3%, p < .01) but less likely to undergo epicardial mapping or ablation (9.0% vs. 38.1%, p<.01) compared to those without prior surgery. When epicardial mapping was performed, a significantly greater proportion required surgical intervention for access (19/52 [36.5%] vs. 14/504 [2.8%]; p < .01). Procedural complications, including epicardial access-related complications, were lower (5.7% vs. 7.0%, p < .01) in patients with versus without prior cardiac surgery. VT-free survival (75.1% vs. 74.1%, p = .805) and survival (86.5% vs. 87.9%, p = .397) were not different between those with and without prior heart surgery, regardless of etiology of cardiomyopathy. VT recurrence was associated with increased mortality in patients with and without prior cardiac surgery. CONCLUSION: Despite different clinical characteristics and fewer epicardial procedures, the safety and efficacy of VT ablation in patients with prior cardiac surgery is similar to others in this cohort. The incremental yield of epicardial mapping in predominant ischemic cardiomyopathy population prior heart surgery may be low but appears safe in experienced centers.

Telemedicine in cardiac procedures: considerations for a remote future.

PURPOSE OF REVIEW: Present a review of relevant literature and suggest a framework for discussion of the considerations affecting the evolution and adoption of Telerobotic Support and Telerobotic Collaboration in the practice of cardiac procedural medicine. RECENT FINDINGS: Recent medical practice has undergone remarkable transformation in the adoption of telemedicine. This evolution has been accelerated by the COVID-19 (SARS-CoV-2) pandemic and has largely been focused on outpatient medicine. Clinical studies and opinion articles have highlighted benefits including reduced costs, increased patient engagement, and saved time, while also raising concerns regarding privacy, care quality and data security. Early and current efforts implementing remote procedural medicine have not only demonstrated technical success but also highlighted the many issues that must be resolved before acceptance as a major aspect of everyday patient care. SUMMARY: It is inevitable that remote technologies will play an increasing role in procedural medicine as they have in outpatient clinical medicine. Thoughtful participation by physicians in the evolution of these technologies and their modes of use will be necessary to maximize the benefits to our patients and healthcare systems.

Partnering with robotic technology in electrophysiology: have we arrived at a tipping point?

PURPOSE OF REVIEW: Bring readers up to date on the rationale for, current state of, and promising innovations in remote and robotic technology in electrophysiology. RECENT FINDINGS: There is a growing peer-reviewed literature regarding existing nontraditional technology for mapping and ablation. There also is accelerated innovation under early evaluation that promises significant impact. SUMMARY: The development and adoption of remote technologies in electrophysiology has faced considerable challenges yet holds tremendous promise for our patients. First principles must include benefit for patients in both safety and effectiveness, optimization of the process for providers, and sound economic and clinical justification for integration into healthcare systems. The limitations of traditional methods and tools that dominate current practice are discussed as a rationale for considering remote robotic systems. The growing library of published outcomes as well as the emergence of promising new technology merits fresh consideration.

Five-year impact of catheter ablation for atrial fibrillation in patients with a prior history of stroke.

BACKGROUND: Catheter ablation of atrial fibrillation (AF) is an established therapeutic rhythm approach. Patients with a prior history of a stroke (CVA) represent a unique high-risk population for recurrent thromboembolic events. The role of antiarrhythmic treatment on the natural history of stroke recurrence in these patients is not fully understood. METHODS: Three patient groups with a prior CVA and 5 years of follow-up were matched 1:3:3 by propensity score (±0.01): AF ablation patients receiving their first ablation (n  =  139), AF patients that did not receive an ablation (n  =  416), and CVA patients without clinical AF (n  =  416). Prior CVA was determined by medical chart review. Patients were followed for outcomes of recurrent CVA, heart failure, and death. RESULTS: The average age of the population was 69 ± 11 years and 51% male. AF ablation patients had higher rates of hypertension and heart failure (P < 0.0001), but diabetes prevalence was similar between the groups (P  =  0.5). Note that 5-year risk of CVA (HR  =  2.26, P < 0.0001) and death (HR  =  2.43, P < 0.0001) were higher in the AF, no ablation group compared those that were ablated. When comparing AF, ablation to no AF patients, there was not a significant difference in 5-year risk of for CVA (HR  =  0.82, P  =  0.39) and death (HR  =  0.92, P  =  0.70); however, heart failure risk was increased (HR  =  3.08, P  =  0.001). CONCLUSION: In patients with AF and a prior CVA, patients undergoing ablation have lower rates of recurrent stroke compared to AF patients not ablated. Although the full mechanisms of benefit are unknown, as CVA rates are similar to patients without AF these data are suggestive of a potential altering of the natural history of disease progression.

Vagus nerve injury symptoms after catheter ablation for atrial fibrillation.

BACKGROUND: Vagus nerve injury during catheter ablation for atrial fibrillation can significantly impact quality of life and result in lingering gastrointestinal symptoms. This study was designed to define risk factors of vagus nerve injury, symptoms, prevalence, and temporal resolution. METHODS: A total of 100 patients undergoing radiofrequency catheter ablation (RFCA) were enrolled and consented to participate in the study. Patients completed a 22-item questionnaire that included questions specific to vagus nerve injury symptomatology during their baseline visit and at 1 and 3 months post-RFCA. RESULTS: The average age of the population was 63 ± 10.6 years and 68% were male. A total of 100 patients completed their baseline questionnaire (90 patients completed the 1-month questionnaires and 85 patients completed the 3-month questionnaires). Symptoms rated as moderate were prevalent at baseline (trouble swallowing 13%, bloating 26%, feeling full 20%), and increased in all categories analyzed at 1 month and with the exception of trouble swallowing returned to the preablation percentages at 3 months (heartburn 22.4%, trouble swallowing 18.8%, bloating 16.5%, nausea 8.2%, vomiting 3.5%, constipation 18.8%, diarrhea 16.4%, feeling full 15.3%). Severe rated symptoms of trouble swallowing (2-5.5%), bloating (5-7.6%), and early satiety (5-9.8%) increased at 1 month and bloating and early satiety percentages remained approximately two times higher at 3 months (trouble swallowing 2.4%, bloating 8.2%, early satiety 7.1%). CONCLUSION: The majority of symptoms were resolved by 3 months, although those patients who rate bloating and early satiety at a severe rating may have persistent symptoms.

Long-term aspirin does not lower risk of stroke and increases bleeding risk in low-risk atrial fibrillation ablation patients.

BACKGROUND: Stroke risk is a significant concern in patients with atrial fibrillation (AF). Low stroke risk patients (CHADS2 VASc 0-2) are often treated long-term with aspirin after catheter ablation. Defining the long-term risks versus benefits of aspirin therapy, after an ablation, is essential to validate this common clinical approach. METHODS: A total of 4,124 AF ablation patients undergoing their index ablation were included in this retrospective observational study. We compared 1- and 3-year outcomes for cerebrovascular accident (CVA), transient ischemic attack (TIA), gastrointestinal (GI) bleeding, genitourinary (GU) bleeding, any bleeding, and AF recurrence among patients receiving: none, aspirin, or warfarin as long-term therapies. RESULTS: Patient distribution by CHADS2 VASc scores was as follows: 0: 1,143 (28%), 1: 1,588 (39%), and 2: 1,393 (34%). Significantly higher incidents of: female gender, hypertension, diabetes mellitus, heart failure, and vascular disease were seen with higher CHADS2 VASc scores (P < 0.0001 for all). At 3 years, 238 (5.9%) patients were on warfarin, 743 (18.6) on aspirin, and 3,013 (75.5%) on no therapy; with occurrences of CVA/TIA (1.4%, 3.0%, 3.9%, P < 0.0001, respectively), GI bleeding (0.8%, 1.9%, 1.1%, P = 0.06, respectively), and GU bleeding (1.7%, 2.8%, 2.1%, P = 0.008, respectively) that increased with advancing CHA2 DS2 VASc score. There was a significantly increased risk for both CVA/TIA with aspirin therapy, when compared to no therapy or warfarin therapy in general, and across all CHA2 DS2 VASc scores. CONCLUSIONS: After catheter ablation, low risk patients do not benefit from long-term aspirin therapy, but are at risk for higher rates of bleeding when compared to no therapy or warfarin.

A Comparison of Remote Magnetic Irrigated Tip Ablation versus Manual Catheter Irrigated Tip Catheter Ablation With and Without Force Sensing Feedback.

BACKGROUND: Remote magnetic navigation (RMN) and contact force (CF) sensing technologies have been utilized in an effort to improve safety and efficacy of catheter ablation. A comparative analysis of the relative short- and long-term outcomes of AF patients has not been performed. As such, we comparatively evaluated the safety and efficacy of these technologies. METHODS: A total of 627 patients who underwent catheter ablation with either a manual irrigated tip catheter: (312, 49.8%) or by RMN: (315, 50.2%) were included in this single-center cohort study. Patients treated with CF (59) were analyzed separately as well. One- and 3-year endpoints included death, HF hospitalization, stroke, TIA, and atrial flutter or AF recurrence. RESULTS: Age averaged 65.1 ± 10.7 years and 64.1% male. One- and 3-year endpoints of death, HF hospitalization, stroke, TIA, and atrial flutter or AF recurrence were statistically similar between manual and RMN treated groups. Fluoroscopy times were significantly lower in the RMN group compared to the manual ablation group (8.47 ± 0.45 vs. 9.63 ± 4.06 minutes, P < 0.0001). CF guided patients had 1-year recurrence rate of AF/atrial flutter statistically identical to patients treated with RMN (36.8% vs. 38.6%; P = 1.00). CONCLUSION: RMN results in outcomes similar to manual navigation. The addition of CF sensing catheters did not improve relative procedural outcome or safety profile in comparison to RMN guided ablation in this large observational study of AF ablation.

The Impact of Age on 5-Year Outcomes After Atrial Fibrillation Catheter Ablation.

BACKGROUND: Catheter ablation of atrial fibrillation (AF) is an established therapeutic rhythm approach in symptomatic patients. Many studies have shown that age has little to no impact on outcomes during the first year after ablation. However, AF is a disease of aging and age-based substrate for arrhythmia is likely to progress. To this regard, we examined patients with 5-year outcome data following an index AF ablation procedure to define the impact of age on long-term outcomes. METHODS: A total of 923 patients that underwent their index AF ablation and had 5 years of follow-up were studied. Patients were followed up for atrial flutter/AF recurrence, heart failure, stroke, death, and cardiac function. Patients were separated and compared in 5 age-based groups (<50, 51-60, 61-70, 71-80, >80). RESULTS: The average age of the population was 66 ± 11 years and 59% were male. The AF was paroxysmal in 55%, persistent in 27%, and longstanding persistent in 18%. Older patients were more likely female and had higher rates of cardiovascular diseases. For every 10-year increase in age there was a higher multivariate-adjusted risk of atrial flutter/AF recurrence (HR: 1.13, P = 0.01), death (HR:1.91, P < 0.0001), and major adverse cardiac events (HR: 1.09, P = 0.07). Although atrial flutter/AF recurrence rates by age were similar at 1 year, at 5 years, younger patients had significantly lower rates of recurrences. CONCLUSION: Age significantly impacts outcomes after AF ablation when analyzed with long-term follow-up. These data highlight the progressive nature of AF and the need to consider interventions early.

Percent Time With a Supratherapeutic INR in Atrial Fibrillation Patients Also Using an Antiplatelet Agent Is Associated With Long-Term Risk of Dementia.

BACKGROUND: Patients with atrial fibrillation (AF) are at higher risk of developing dementia. AF patients treated with warfarin with poor time in therapeutic ranges are significantly more likely to develop dementia. AF patients are also frequently treated with antiplatelet agents due to coexistent vascular disease. We hypothesize that AF patients with anticoagulation and antiplatelet therapies will be at higher risk of dementia, particularly with chronic exposure to over-anticoagulation. METHODS: Chronically anticoagulated patients receiving warfarin (target INR 2-3) for AF and managed by the Intermountain Healthcare Clinical Pharmacist Anticoagulation Service (CPAS) on concurrent antiplatelet agents with no history of dementia or stroke/TIA were included. The primary outcome was the presence of dementia defined by neurologist determined ICD-9 codes. Percent time with an INR>3.0 was determined and then compared by 3 strata <10% (n = 340), 10-24% (n = 417), ≥25% (n = 235). Multivariable Cox hazard regression was utilized to determine dementia incidence by percent time. RESULTS: A total of 992 patients were studied. Patients with an INR>3 more than 25% of the time were 2.40 times more likely to develop dementia (P = 0.04). A comparison between < 10% group and 10-24.9% group with INR>3 indicated no difference in risk for the development of dementia (P = 0.74). The risk was significantly increased in patients using triple antithrombotic therapy, although the number of patients within this group was small. CONCLUSION: In AF patients receiving antiplatelet and anticoagulant therapies, the percent of time exposed to over-anticoagulation increased dementia risk. These data support the possibility of chronic cerebral injury from microbleeds as a mechanism underlying the association of AF and dementia.

Five-year outcomes of catheter ablation in patients with atrial fibrillation and left ventricular systolic dysfunction.

BACKGROUND: Catheter ablation of atrial fibrillation (AF) is an established therapy for symptomatic patients. The long-term efficacy and impact of catheter ablation among patients with severe systolic heart failure (SHF) requires additional study to understand if outcomes achieved at 1 year are maintained and mechanisms of AF recurrence. METHODS: Three groups with SHF and 5 years of follow-up were matched 1:4:4 by age (±5 years) and sex: AF ablation patients receiving their first ablation (n = 267), AF patients that did not receive an ablation (n = 1,068), and SHF patient without AF (n = 1,068). SHF was based upon clinical diagnosis and an ejection fraction (EF) ≤35%. Patients were followed for 5-year primary outcomes of AF recurrence, heart failure, stroke, death, and cardiac function. RESULTS: At 5 years, 60.7% of patients had clinical recurrence of AF. Diabetes and a prior heart attack were significant predictors of long-term risk of AF recurrence. Long-term mortality rates were 27%, 55%, 50%, in the AF ablation, AF, and no AF groups, respectively (P < 0.0001), with the lower rates attributed to lower cardiovascular mortality. At 5 years, there was no difference in EF, yet HF hospitalizations were lower following AF ablation compared to patients with AF and no ablation. Stroke rates at 5 years trended to be lower in the AF ablation group, but the difference was not statistically significant. CONCLUSION: Recurrence rates of AF in patients with SHF after ablation are common at 5 years with an anticipated ongoing increase. Long-term AF-related comorbidities tended to be less in the AF ablation group.

MRI in Patients with Cardiovascular Implantable Electronic Devices and Fractured or Abandoned Leads.

Purpose To examine the clinical effect of lead length and lead orientation in patients with cardiac implantable electronic devices (CIEDs) and lead fragments or abandoned leads undergoing 1.5-T MRI. Materials and Methods This Health Insurance Portability and Accountability Act-compliant retrospective study included patients with CIEDs and abandoned leads or lead fragments undergoing 1.5-T MRI from March 2014 through July 2020. CIED settings before and after MRI were reviewed, with clinically significant variations defined as a composite of the change in capture threshold of at least 50%, in sensing of at least 40%, or in lead impedance of at least 30% between before MRI and after MRI interrogation. Adverse clinical events were assessed at MRI and up to 30 days after. Univariable and multivariable analysis was performed. Results Eighty patients with 126 abandoned CIED leads or lead fragments underwent 107 1.5-T MRI examinations. Sixty-seven patients (median age, 74 years; IQR, 66-78 years; 44 male patients, 23 female patients) had abandoned leads, and 13 (median age, 66 years; IQR, 52-74 years; nine male patients, four female patients) had lead fragments. There were no reported deaths, clinically significant arrhythmias, or adverse clinical events within 30 days of MRI. Three patients with abandoned leads had a significant change in the composite of capture threshold, sensing, or lead impedance. In a multivariable generalized estimating equation analysis, lead orientation, lead length, MRI type, and MRI duration were not associated with a significant change in the composite outcome. Conclusion Use of 1.5-T MRI in patients with abandoned CIED leads or lead fragments of varying length and orientation was not associated with adverse clinical events. Keywords: Cardiac Assist Devices, MRI, Cardiac Implantable Electronic Device Supplemental material is available for this article. © RSNA, 2024.

Intracardiac ultrasound for esophageal anatomic assessment and localization during left atrial ablation for atrial fibrillation.

BACKGROUND: Esophageal injury during left atrial ablation is associated with a significant risk of mortality and morbidity. There are no validated approaches to reduce injury outside of avoidance, a strategy critically dependent on a precise understanding of the esophageal anatomy and location. Intracardiac ultrasound (ICE) can provide a real-time assessment of the esophagus during ablation. We hypothesized that ICE can accurately define esophageal anatomy and location to enhance avoidance strategies during ablation. METHODS: Fifty patients underwent atrial fibrillation (AF) ablation. The left atrium and pulmonary vein anatomies were rendered by traditional electroanatomic mapping (CARTO). A Navistar catheter within the esophagus was used to create a traditional electroanatomic esophageal anatomy. ICE imaging was used to create a second geometry of the esophagus. The traditional and ICE anatomies of the esophagus were compared and the greatest border dimensions used to avoid injury. RESULTS: The average age was 66 ± 10 years, 45% had persistent/longstanding persistent AF, and 18% had a prior AF ablation. The esophagus location was leftward in 17 (34%), midline in 22 (44%), and rightward in 11 (22%). Traditional esophagus and ICE imaging correlated within 1 cm in the greatest distance in 26 (52%) patients. Traditional imaging underestimated the esophageal location by >1-1.5 cm in 9 (18%) and >1.5 cm in 15 (30%). In those with poor correlation (>1.5 cm), the most common cause was the presence of a hiatal hernia. Ablation energy delivery was performed outside the greatest esophagus anatomy borders. Of those with 12-month follow-up, 75% were AF/atrial flutter free without antiarrhythmic drugs. No esophageal injuries were observed. One patient experienced a TIA greater than 6 months postablation. CONCLUSION: These data demonstrate that traditional means of mapping the esophagus using a catheter within the esophagus are insufficient and often grossly underestimate the actual anatomy. Imaging techniques that define the complete esophageal lumen should be considered to truly minimize esophageal injury risk.

Vasovagal Responses to Human Monomorphic Ventricular Tachycardia: Hemodynamic Implications From Sinus Rate Analysis.

BACKGROUND: Factors determining hemodynamic stability during human ventricular tachycardia (VT) are incompletely understood. OBJECTIVES: The purposes of this study were to characterize sinus rate (SR) responses during monomorphic VT in association with hemodynamic stability and to prospectively assess the effects of vagolytic therapy on VT tolerance. METHODS: This is a retrospective analysis of patients undergoing scar-related VT ablation. Vasovagal responses were evaluated by analyzing sinus cycle length before VT induction and during VT. SR responses were classified into 3 groups: increasing (≥5 beats/min, sympathetic), decreasing (≥5 beats/min, vagal), and unchanged, with the latter 2 categorized as inappropriate SR. In a prospective cohort (n = 30) that exhibited a failure to increase SR, atropine was administered to improve hemodynamic tolerance to VT. RESULTS: In 150 patients, 261 VT episodes were analyzed (29% untolerated, 71% tolerated) with median VT duration 1.6 minutes. A total of 52% of VT episodes were associated with a sympathetic response, 31% had unchanged SR, and 17% of VTs exhibited a vagal response. A significantly higher prevalence of inappropriate SR responses was observed during untolerated VT (sustained VT requiring cardioversion within 150 seconds) compared with tolerated VT (84% vs 34%; P < 0.001). Untolerated VT was significantly different between groups: 9% (sympathetic), 82% (vagal), and 32% (unchanged) (P < 0.001). Atropine administration improved hemodynamic tolerance to VT in 70%. CONCLUSIONS: Nearly one-half of VT episodes are associated with failure to augment SR, indicative of an under-recognized pathophysiological vasovagal response to VT. Inappropriate SR responses were more predictive of hemodynamic instability than VT rate and ejection fraction. Vagolytic therapy may be a novel method to augment blood pressure during VT.

Efficacy and safety of ventricular tachycardia ablation with mechanical circulatory support compared with substrate-based ablation techniques.

AIMS: Catheter ablation of ventricular tachycardia (VT) can be limited by haemodynamic instability. In these cases, substrate-based ablation is typically performed. An alternative is to perform activation and entrainment mapping during VT supported by a percutaneous left ventricular assist device (pVAD). We sought to compare the complication and success rates of pVAD-assisted VT ablation with scar-based techniques. METHODS AND RESULTS: Thirteen consecutive patients with haemodynamically unstable VT underwent pVAD-assisted ablation (pVAD group) and were retrospectively compared with 18-matched patients undergoing a substrate-based VT ablation (non-pVAD group). There was no significant difference in age or ejection fraction between the groups although pVAD patients tended to have more shocks in the preceding months. Procedure times were longer for the pVAD group. The number of monomorphic VTs induced was greater in the pVAD group (3.2 vs. 1.6, P= 0.04); however, after ablation, there was no difference in inducibility between the pVAD and non-pVAD group (10 of 13 vs. 12 of 18; 77 vs. 67%, P = 0.69). There was no difference in acute complications including stroke or death. At 9 ± 3 months, 1-year freedom from implantable cardioverter-defibrillator (ICD) shocks/therapies for sustained VT were similar (P= 0.96). In multivariable analysis, the absence of atrial fibrillation (hazard ratio=0.15, P= 0.04) was associated with a lower incidence of ICD shocks. CONCLUSIONS: In high-risk patients, pVAD-assisted VT ablation guided by activation and entrainment mapping is a feasible alternative to substrate mapping and allows outcomes comparable to substrate mapping.

A strategy of rapid cardioversion minimizes the significance of early recurrent atrial tachyarrhythmias after ablation for atrial fibrillation.

BACKGROUND: The significance of early recurrent atrial tachyarrhythmias after atrial fibrillation (AF) ablation is unclear. Atrial remodeling driven by these tachyarrhythmias can result in electrical, contractile, and structural changes that may impair long-term therapy success. Aggressive attempts to restore sinus rhythm in the temporal period of healing after ablation might improve outcomes. METHODS: A total of 1,759 AF ablations were performed at Intermountain Medical Center or LDS Hospital. A total of 455 of those were among patients requiring repeat ablations. Patients were instructed to take their pulse daily and, if greater than 100 bpm or irregular, present the following business day fasting to the clinic for evaluation and cardioversion if AF or atrial flutter (AFL) were present. RESULTS: Of the ablations performed, a total of 515 (29%, age: 65.6 ± 11.2 years, male: 57.9%) developed AF/AFL that required cardioverison. The majority of these arrhythmias first occurred in the initial 90 days (63.7%) postablation. During this period, 62.8% were on an antiarrhythmic drug (AAD). Only 25.1% were using an AAD at 3 months. The majority of ablations (75.6%) who experienced AF/AFL within the first 90 days after ablation were in sinus rhythm with no AAD at 1 year. Further, 48% of those with the first recurrence from 90 to 180 days were in sinus rhythm with no AAD at 1 year. CONCLUSIONS: The time at which the first recurrence of AF/AFL occurs impacts long-term outcomes. An aggressive strategy of rapid cardioversion postablation reduces the significance of recurrent AF/AFL during the first 6 months.