Patient-specific quantification of cardiorespiratory motion for cardiac stereotactic radioablation treatment planning.

Background: Cardiac radioablation is a new treatment for patients with refractory ventricular tachycardia (VT). The target for cardiac radioablation is subject to cardiorespiratory motion (CRM), the heart's movement with breathing and cardiac contraction. Data regarding the magnitude of target CRM are limited but are highly important for treatment planning. Objectives: The study sought to assess CRM amplitude by using ablation catheter geometrical data. Methods: Electroanatomic mapping data of patients undergoing catheter ablation for VT at 3 academic centers were exported. The spatial position of the ablation catheter as a function of time while in contact with endocardium was analyzed and used to quantify CRM. Results: Forty-four patients with ischemic and nonischemic cardiomyopathy and VT contributed 1364 ablation lesions to the analysis. Average cardiac and respiratory excursion were 1.62 ± 1.21 mm and 12.12 ± 4.10 mm, respectively. The average ratio of respiratory to cardiac motion was approximately 11:1. CRM was greatest along the craniocaudal axis (9.66 ± 4.00 mm). Regional variations with respect to respiratory and cardiac motion were observed: basal segments had smaller displacements vs midventricular and apical segments. Patient characteristics (previous cardiac surgery, height, weight, body mass index, and left ventricular ejection fraction) had a statistically significant, albeit clinically moderate, impact on CRM. Conclusion: CRM is primarily determined by respiratory displacement and is modulated by the location of the target and the patient's biometric characteristics. The patient-specific quantification of CRM may allow to decrease treatment volume and reduce radiation exposure of surrounding organs at risk while delivering the therapeutic dose to the target.

A worldwide survey on incidence, management, and prognosis of oesophageal fistula formation following atrial fibrillation catheter ablation: the POTTER-AF study.

AIMS: Oesophageal fistula represents a rare but dreadful complication of atrial fibrillation catheter ablation. Data on its incidence, management, and outcome are sparse. METHODS AND RESULTS: This international multicentre registry investigates the characteristics of oesophageal fistulae after treatment of atrial fibrillation by catheter ablation. A total of 553 729 catheter ablation procedures (radiofrequency: 62.9%, cryoballoon: 36.2%, other modalities: 0.9%) were performed, at 214 centres in 35 countries. In 78 centres 138 patients [0.025%, radiofrequency: 0.038%, cryoballoon: 0.0015% (P < 0.0001)] were diagnosed with an oesophageal fistula. Peri-procedural data were available for 118 patients (85.5%). Following catheter ablation, the median time to symptoms and the median time to diagnosis were 18 (7.75, 25; range: 0-60) days and 21 (15, 29.5; range: 2-63) days, respectively. The median time from symptom onset to oesophageal fistula diagnosis was 3 (1, 9; range: 0-42) days. The most common initial symptom was fever (59.3%). The diagnosis was established by chest computed tomography in 80.2% of patients. Oesophageal surgery was performed in 47.4% and direct endoscopic treatment in 19.8% and conservative treatment in 32.8% of patients. The overall mortality was 65.8%. Mortality following surgical (51.9%) or endoscopic treatment (56.5%) was significantly lower as compared to conservative management (89.5%) [odds ratio 7.463 (2.414, 23.072) P < 0.001]. CONCLUSION: Oesophageal fistula after catheter ablation of atrial fibrillation is rare and occurs mostly with the use of radiofrequency energy rather than cryoenergy. Mortality without surgical or endoscopic intervention is exceedingly high.

Paroxysmal Atrial Fibrillation Ablation Using a Novel Variable-Loop Biphasic Pulsed Field Ablation Catheter Integrated With a 3-Dimensional Mapping System: 1-Year Outcomes of the Multicenter inspIRE Study.

BACKGROUND: The inspIRE study (Study for Treatment of Paroxysmal Atrial Fibrillation [PAF] by Pulsed Field Ablation [PFA] System With Irreversible Electroporation [IRE]) evaluated safety and effectiveness of a fully integrated biphasic pulsed field ablation (PFA) system with a variable-loop circular catheter for the treatment of drug-refractory paroxysmal atrial fibrillation. METHODS: Subjects underwent pulmonary vein (PV) isolation with the PFA system, using at least 12 applications per vein; adenosine/isoproterenol was administered to confirm entrance block. Wave I assessed initial safety, including for esophageal lesions, silent cerebral lesions, and PV stenosis. Wave II (pivotal phase) tested (1) primary safety, incidence of early-onset primary adverse events, and (2) primary effectiveness, confirmed PV isolation with freedom from documented atrial arrhythmia at 12 months. The study design specified an interim analysis to determine early success once 30 subjects reached the 12-month follow-up and all subjects reached 3-month follow-up. RESULTS: Across 13 centers in Europe/Canada, 226 subjects were enrolled, met criteria for safety and effectiveness evaluations, and received PFA (Wave I, 40; Wave II, 186). Wave I demonstrated no esophageal thermal lesions or PV stenosis. Among 39 subjects with cerebral magnetic resonance imaging, silent cerebral lesions were detected in 4 of the first 6 subjects, after which workflow enhancements, including a 10-second pause between PFA applications, were implemented; subsequently, only 4 of 33 subjects had silent cerebral lesions. In the Wave II phase, no primary adverse events were reported. Upon declaring early success, 83 subjects reached 12-month follow-up. With 100% entrance block, PV isolation without acute reconnection was achieved in 97.1% of targeted veins. For Wave II, the primary effectiveness end point per Kaplan-Meier at the time of interim analysis was 70.9%; 12-month freedom from symptomatic atrial fibrillation/atrial flutter/atrial tachycardia recurrence and repeat ablation was 78.9% and 92.3%, respectively. Total procedure and transpired PFA times were 70.1±27.7 and 26.7±14.0 minutes, respectively. CONCLUSIONS: The inspIRE trial confirmed the safety and effectiveness of the novel mapping-integrated PFA system. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; unique identifier: NCT04524364.

Adjunctive Left Atrial Posterior Wall Isolation in Treating Atrial Fibrillation: Insight From a Large Secondary Analysis.

OBJECTIVES: This study evaluated the role of adjunctive left atrium posterior wall isolation (PWI) in preventing atrial fibrillation (AF) recurrence. BACKGROUND: The left atrium posterior wall is an arrhythmogenic substrate that contributes to the development of AF. METHODS: This was an updated pooled analysis that included clinical data regarding PWI plus pulmonary vein isolation (PVI) in treating AF. The primary outcome was recurrence of atrial tachyarrhythmias. RESULTS: A total of 26 studies with 3,287 patients with AF (age 61.7 ± 10.8 years) were included. Mean follow-up was 15.2 ± 8.4 months. Procedural success to achieve PWI was 92.8%. In paroxysmal AF, adjunctive PWI did not reduce the recurrence of all atrial arrhythmias (P = 0.21) or AF (P = 0.37); however, in persistent AF, adjunctive PWI was associated with substantially lower recurrence of all atrial arrhythmias (risk ratio: 0.74; P < 0.001) and AF (risk ratio: 0.67; P = 0.01), particularly when randomized data were included. Subgroup analyses based on meta-regression demonstrated that patients with older age, a larger left atrial diameter, and persistent AF benefited more significantly from the adjunctive PWI. Adjunctive PWI using either radiofrequency or a cryoballoon reduced AF recurrence, whereas using radiofrequency seemed to be associated with higher recurrence rate of atrial tachycardias and/or atrial flutter. Non-BOX adjunctive PWI rather than BOX PWI was associated with significantly lower recurrence of AF. The incidence of procedural adverse events between the PVI+PWI (3.2%) and PVI (2.8%) groups was low and similar. PVI+PWI needed longer ablation and/or procedural time but had similar fluoroscopy time. CONCLUSIONS: Adjunctive PWI can be achieved in most patients without compromising safety. Patients with persistent AF appear to benefit from this approach. The ablation technology and/or approach may affect the clinical outcome of PWI.

Pulmonary Vein Isolation With Very High Power, Short Duration, Temperature-Controlled Lesions: The QDOT-FAST Trial.

OBJECTIVES: This study sought to evaluate the safety and short-term performance of a novel catheter for very high power-short duration (vHPSD) ablation in the treatment of paroxysmal atrial fibrillation. BACKGROUND: The vHPSD catheter is a novel contact force-sensing catheter optimized for temperature-controlled radiofrequency ablation with microelectrodes and 6 thermocouples for real-time temperature monitoring; the associated vHPSD algorithm modulates power to maintain target temperature during 90 W, 4 s lesions. METHODS: QDOT-FAST (Clinical Study for Safety and Acute Performance Evaluation of the THERMOCOOL SMARTTOUCH SF-5D System Used With Fast Ablation Mode in Treatment of Patients With Paroxysmal Atrial Fibrillation) is a prospective, multicenter, single-arm study enrolling patients with symptomatic paroxysmal atrial fibrillation indicated for catheter-based pulmonary vein isolation. Primary endpoints were short-term effectiveness (confirmation of entrance block in all targeted pulmonary veins after adenosine/isoproterenol challenge) and short-term safety (primary adverse events). Participants were screened for silent cerebral lesions by magnetic resonance imaging. Patients were followed for 3 months post-ablation. RESULTS: A total of 52 patients underwent ablation and completed follow-up. Pulmonary vein isolation was achieved in all patients using the study catheter alone, with total procedure and fluoroscopy times of 105.2 ± 24.7 min and 6.6 ± 8.2 min, respectively. Most patients (n = 49; 94.2%) were in sinus rhythm at 3 months. Two primary adverse events were reported: 1 pseudoaneurysm; and 1 asymptomatic thromboembolism. There were no deaths, stroke, atrioesophageal fistula, pulmonary vein stenosis, or unanticipated adverse device effects. Six patients had identified silent cerebral lesions-all classified as asymptomatic without clinical or neurologic deficits. CONCLUSIONS: This first-in-human study of a novel catheter with optimized temperature control demonstrated the clinical feasibility and safety of vHPSD ablation. Procedure and fluoroscopy times were substantially lower than historical standard ablation with point-by-point catheters. (Clinical Study for Safety and Acute Performance Evaluation of the THERMOCOOL SMARTTOUCH SF-5D System Used With Fast Ablation Mode in Treatment of Patients With Paroxysmal Atrial Fibrillation [QDOT-FAST]; NCT03459196).

Association of Preoperative Renin-Angiotensin System Inhibitors With Prevention of Postoperative Atrial Fibrillation and Adverse Events: A Systematic Review and Meta-analysis.

Importance: Postoperative atrial fibrillation (POAF) is a well-known complication after cardiac surgery. Renin-angiotensin system inhibitors (RASIs) have been suggested as an upstream therapy for selected patients with AF; however, evidence in the surgical setting is limited. Objective: To evaluate the role of preoperative RASIs in prevention of POAF and adverse events for patients undergoing cardiac surgery. Data Sources: The PubMed database and the Cochrane Library from inception until December 31, 2018, were searched by using the keywords renin-angiotensin system inhibitors OR angiotensin-converting enzyme inhibitors OR angiotensin receptor blocker OR aldosterone antagonist AND cardiac surgery. ClinicalTrials.gov was searched from inception until December 31, 2018, by using the keywords postoperative atrial fibrillation. Study Selection: Randomized clinical trials (RCTs) and observational studies comparing the association between preoperative RASI treatment vs no preoperative RASI treatment (control group) and the incidence of POAF were identified. Eleven unique studies met the selection criteria. Data Extraction and Synthesis: Pooled analysis was performed using a random-effects model. Sensitivity and subgroup analyses of RCTs were performed to test the stability of the overall effect. Metaregression was conducted to explore potential risk of bias. Main Outcomes and Measures: The primary outcome was POAF, and the secondary outcomes included rates of stroke and mortality and duration of hospitalization. Results: Eleven unique studies involving 27 885 unique patients (74.4% male; median age, 65 years [range, 58.5-74.5 years]) were included. Compared with the control group, the RASI group did not have a significantly reduced risk of POAF (odds ratio [OR], 1.04; 95% CI, 0.91-1.19; P = .55; z = 0.60), stroke (OR, 0.86; 95% CI, 0.62-1.19; P = .37; z = 0.90; without significant heterogeneity, P = .11), death (OR, 1.07; 95% CI, 0.85-1.35; P = .56; z = 0.59; without significant heterogeneity, P = .12), composite adverse cardiac events (OR, 1.04; 95% CI, 0.91-1.18; P = .58; z = 0.56), or a reduced hospital stay (weighted mean difference, -0.04; 95% CI, -1.05 to 0.98; P = .94; z = 0.07) using a random-effects model. Pooled analysis focusing on RCTs showed consistent results. The primary overall effect was maintained in sensitivity and subgroup analyses. Metaregression showed that male sex was significantly associated with POAF (τ2 = 0.0065; z = 3.47; Q = 12.047; P < .001) and that use of ß-blockers was associated with a significantly reduced risk in developing POAF (τ2 = 0.018; z = -2.24; Q = 5.0091; P = .03). Conclusions and Relevance: The findings from this study suggest that preoperative RASI treatment does not offer additional benefit in reducing the risk of POAF, stroke, death, and hospitalization in the setting of cardiac surgery. The results provide no support for conventional use of RASIs for the possible prevention of POAF and adverse events in patients undergoing cardiac surgery; further randomized data, particularly among those patients with heart failure, are needed.

Renal sympathetic denervation guided by renal nerve stimulation to treat ventricular arrhythmia in CKD patients with ICD.

Chronic kidney disease (CKD) patients on stage 4 present greater risk rates for malignant ventricular arrhythmia events. This study examined patients with CKD in stages 1, 2, 3 and 4, left ventricular dysfunction and automatic implantable cardioverter-defibrillator (ICD). Our goal was to record the appropriate therapies, "Anti-tachycardia Therapy Pacing" (ATP) and shock events during the 18 months of follow-up and compare the incidence and severity of these at different stages of CKD, mainly in patients with CKD stage 4 underwent renal sympathetic denervation (RSD) guided by renal nerve stimulation (RNS). One hundred and fifteen patients were evaluated once every three months till 18 months of follow-up. The arrhythmic events were assessed at each follow-up visit. Comparing the groups, we can see the number of ATP and shock events recorded by ICD during 18 months of follow-up, and differences in the number of therapeutic events between the various stages of CKD. The hazard ratio (HR), 95% confidence interval (CI) and P value for ATP and shock events between all the CKD stages were evaluated by the log-rank/Mantel-Haenszel test. At the 18th month of follow-up, 75% of patients with CKD stage 4 received ATP, and 70% were treated with shock while only 20% of the subjects with CKD stage 4 that were submitted to RSD received ATP and 20% were treated with shock, P<0.0001 and P=0.0002, respectively. In our study, a decline occurred in the incidence of arrhythmias, and therefore, appropriate ICD therapies in advanced stages of CKD, reducing the risk rates for these events in patients with CKD on stage 4 after RSD guided by RNS in comparison to the other CKD stages. Our results suggest that RSD can control the higher incidence of malignant arrhythmias in advanced CKD stages.

MediGuide in supraventricular tachycardia: initial experience from a multicentre registry.

AIMS: Currently, fluoroscopy-based catheter visualization is the standard modality in invasive electrophysiological procedures. Recently a new technology for non-fluoroscopic visualization of diagnostic (since 2010) and ablation catheters (since May 2012) has been introduced. The MediGuide™-Technology (MediGuide) projects catheter tips on prerecorded cine loops in a high time resolution. METHODS AND RESULTS: We report on MediGuide-based supraventricular tachycardia (SVT) cases [atrioventricular nodal reentry tachycardia (AVNRT), atrioventricular reentry tachycardia (AVRT), Wolff-Parkinson-White syndrome (WPW), ectopic atrial tachycardia (EAT) and typical atrial flutter) from two European centres. In all patients, diagnostic and/or ablation catheters with a special sensor were used to perform the ablation procedures. All procedural data such as acute success, duration of the procedure, fluoroscopy time, and dose and patients' characteristics were analyzed and compared with conventionally ablated patients (n = 1865). Procedure-related complications during the hospital stay were recorded. A total of 24 consecutive patients were analyzed: no significant difference to the control group was seen in the baseline characteristics. The MediGuide patients were predominantly male (66%), aged 58 ± 14 years and were ablated for 6 AVNRT (25%), 4 AVRT/WPW (17%), 1 EAT (4%), and 13 typical atrial flutter (54%). The acute success rate was 100% (98% in the control group, n.s.). The median fluoroscopy time was 0.5 ± 1.4 min (10.2 ± 9.6 in the control group, P < 0.001), the median fluoroscopy dose was 187 ± 554 cGy cm(2) (996 ± 2593 cGy cm(2), P < 0.05). Mean procedure time was 70 ± 25 min (60 ± 36 min, n.s.). No complications during the hospital stay were recorded. CONCLUSION: In several different forms of supraventricular tachycardias the MediGuide-Technology contributed to a dramatic reduction in irradiation exposure. With a median fluoroscopy time of 30 s all SVT cases were effectively performed with no complications; the fluoroscopy burden can be significantly reduced not only for the patient but also for the nurses and the physicians performing the case. The overall procedure times are not prolonged due to the use of MediGuide Technology compared with a control group of >1800 patients undergoing conventional ablation procedures.

Predicting neurally mediated syncope based on pulse arrival time: algorithm development and preliminary results.

BACKGROUND: Neurally mediated syncope (NMS) is a common disorder that is triggered by orthostatic stress. The circulatory adjustments to orthostatic stress occur just prior to a sudden loss of consciousness. NMS prediction would protect patients from falls or accidents. METHODS AND RESULTS: Based on simultaneously recorded heart rate (HR) and pulse wave during 70° head-up tilt (HUT) table testing we investigated a syncope warning system. In 14 patients with a history of suspected NMS we tested 2 algorithms based on HR and/or pulse arrival time (PAT). When the cumulative risk exceeded the threshold, which was calculated during the first 2 minutes following the posture change to upright position, a syncope prediction alarm was triggered. All syncopes (n = 7) were detected more than 16 seconds before the onset of dizziness or unconsciousness by using a prediction alarm based on HR and PAT (syncope prediction algorithm 2). No false alarm was generated in patients with negative HUT (n = 7). Syncope prediction was improved by detecting the slope of HR changes as compared with monitoring PAT changes alone (syncope prediction algorithm 1). The duration between the prediction alarm and the occurrence of syncope was 99 ± 108 seconds. CONCLUSION: Predicting NMS is feasible by monitoring HR and the onset of the pulse wave at the periphery. This approach might improve NMS management.

Identification of a high-risk population for esophageal injury during radiofrequency catheter ablation of atrial fibrillation: procedural and anatomical considerations.

BACKGROUND: Atrioesophageal fistula is an uncommon but life-threatening complication of atrial fibrillation (AF) ablation. Esophageal ulcerations (ESUL) have been proposed to be potential precursor lesions. OBJECTIVE: The purpose of our study was to prospectively investigate the incidence of ESUL in a large patient population undergoing radiofrequency catheter ablation (RFA). Additionally, we aimed to link demographic data and lesion sets with anatomical information given by multislice computed tomography imaging and to correlate these data with the development of ESUL. METHODS: This study included 267 patients and consecutively screened all individuals for evidence of ESUL 24 h after RFA of AF by endoscopy of the esophagus. A standardized ablation approach using a 25-W energy maximum at the posterior left atrial (LA) wall without esophagus visualization, temperature monitoring, or intracardiac ultrasound was performed. RESULTS: In total, we found 2.2% of patients (6 of 267) presenting with ESUL. Parameters exposing a specific patient to risk of developing ESUL in univariate analysis were persistent AF (5 of 95, P = .023), additional lines performed (roofline: 6 of 114, P = .006; LA isthmus: 4 of 49, P = .011; coronary sinus: 5 of 66, P = .004), and LA enlargement (P = .001) leading to sandwiching of the esophagus between the LA and thoracic spine. Multivariate analysis revealed LA-to-esophagus distance as the only significant risk factor. CONCLUSION: This study is the first to link anatomical information and procedural considerations to the development of ESUL in radiofrequency ablation for AF. Furthermore, it reveals the correlation and individual impact of these factors. Not a single patient with pulmonary vein isolation alone developed ESUL.

Acute development of gastroesophageal reflux after radiofrequency catheter ablation of atrial fibrillation.

BACKGROUND: Induction of gastroesophageal reflux after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) may have an impact on the progression of esophageal injury. OBJECTIVE: The purpose of this study was to assess the acute effect of RFCA on distal esophageal acidity using leadless pH-metry capsules. METHODS: A total of 31 patients (27 male and 4 female; 25 with paroxysmal AF) who underwent RFCA and esophagoscopy 24 hours before and after ablation were assessed for reflux and esophageal lesions. A leadless pH-metry capsule was inserted into the lower esophagus to screen for pH changes, number and duration of refluxes, and the DeMeester score (a standardized measure of acidity and reflux). No patient had a history of reflux or was taking proton pump inhibitors within 4 weeks before and 24 hours after ablation. RESULTS: Five patients (16.1%) who presented with asymptomatic reflux prior to ablation were excluded from further examination. Of the remaining 26 patients, 5 (19.2%) demonstrated a significant pathologic increase in DeMeester score after ablation. No statistical differences in baseline parameters, method of sedation, ablation approach, and total energy delivered on the posterior wall were observed between patients with and those without a pathologic DeMeester score. One patient with asymptomatic reflux prior to ablation developed esophageal ulceration. CONCLUSION: A significant number of patients undergoing RFCA of AF develop pathologic acid reflux after ablation. In addition, a subgroup of patients has a preexisting condition of asymptomatic reflux prior to ablation. This finding may explain a potential mechanism for progression of esophageal injury to atrio-esophageal fistulas in patients undergoing RFCA.