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Background: Stereotactic arrhythmia radioablation (STAR) is delivered with a planning target volume (PTV) prescription dose of 25 Gy, mostly to the surrounding 75–85% isodose line. This means that the average and maximum dose received by the target is less than 35 Gy, which is the minimum threshold required to create a homogenous transmural fibrosis. Similar to catheter ablation, the primary objective of STAR should be transmural fibrosis to prevent heterogenous intracardiac conduction velocities and the occurrence of sustained ventricular arrhythmias (sVA) caused by reentry. We hypothesize that the current dose prescription used in STAR is inadequate for the long-term prevention of sVA and that a significant increase in dose is necessary to induce transmural scar formation. Objective: A single arm, multi-center, phase II, dose escalation prospective clinical trial employing the i3 + 3 design is being conducted to examine the safety of a radiation dose-escalation strategy aimed at inducing transmural scar formation. The ultimate objective of this trial is to decrease the likelihood of sVA recurrence in patients at risk. Methods: Patients with ischemic or non-ischemic cardiomyopathy and recurrent sVA, with an ICD and history of ≥ 1 catheter ablation for sVA will be included. This is a prospective, multicenter, one-arm, dose-escalation trial utilizing the i3 + 3 design, a modified 3 + 3 specifically created to overcome limitations in traditional dose-finding studies. A total of 15 patients will be recruited. The trial aims to escalate the ITV dose from 27.0 Gy to an ITV prescription dose-equivalent level of maximum 35.1 Gy by keeping the PTV prescription dose constant at 25 Gy while increasing the dose to the target (i.e. the VT substrate without PTV margin) by step-wise reduction of the prescribing isodose line (85% down to 65%). The primary outcome of this trial is safety measured by registered radiation associated adverse events (AE) up to 90 days after study intervention including radiation associated serious adverse events graded as at least 4 or 5 according to CTCAE v5, radiation pneumonitis or pericarditis requiring hospitalization and decrease in LVEF ≥ 10% as assessed by echocardiography or cardiac MRI at 90 days after STAR. The sample size was determined assuming an acceptable primary outcome event rate of 20%. Secondary outcomes include sVA burden at 6 months after STAR, time to first sVA recurrence, reduction in appropriate ICD therapies, the need for escalation of antiarrhythmic drugs, non-radiation associated safety and patient reported outcome measures such as SF-36 and EQ5D. Discussion: DEFT-STAR is an innovative prospective phase II trial that aims to evaluate the optimal radiation dose for STAR in patients with therapy-refractory sVA. The trial has obtained IRB approval and focuses on determining the safe and effective radiation dose to be employed in the STAR procedure. Trial registration: NCT05594368. [ABSTRACT FROM AUTHOR]

Conduction disorders such as left bundle branch block (LBBB) are common after transcatheter aortic valve implantation (TAVI). Consensus regarding a reasonable strategy to manage conduction disturbances after TAVI has been elusive. The European Heart Rhythm Association (EHRA) conducted a survey to capture contemporary clinical practice for conduction disorders after TAVI. A 25-item online questionnaire was developed and distributed among the EHRA electrophysiology (EP) research network centres. Of 117 respondents, 44% were affiliated with university hospitals. A standardized management protocol for advanced conduction disorders such as LBBB or atrioventricular block (AVB) after TAVI was available in 63% of participating centres. Telemetry after TAVI was chosen as the most frequent management strategy for patients with new-onset or pre-existing LBBB (79% and 70%, respectively). Duration of telemetry in patients with new-onset LBBB varied, with a 48-h period being the most frequently chosen, but almost half monitoring continued for at least 72 h. Similarly, in patients undergoing EP study due to new-onset LBBB, the HV interval cut-off point leading to pacemaker implantation was heterogeneous among European centres, although an HV >75 ms threshold was the most common. Conduction system pacing was chosen as a preferred approach by 3.7% of respondents for patients with LBBB and normal left ventricular ejection fraction (LVEF), and by 5.6% for patients with LBBB and reduced LVEF. This survey suggests some heterogenity in the management of conduction disorders after TAVI across European centres. The risk stratification strategies vary substantially. Conduction system pacing in patients with LBBB after TAVI is still underused. [ABSTRACT FROM AUTHOR]

Fragmented QRS (fQRS) is an electrocardiographic (ECG) marker of myocardial conduction abnormality, characterized by additional notches in the QRS complex. The presence of fQRS has been associated with an increased risk of all-cause mortality and arrhythmia in patients with cardiovascular disease. However, current binary visual analysis is prone to intra- and inter-observer variability and different definitions are problematic in clinical practice. Therefore, objective quantification of fQRS is needed and could further improve risk stratification of these patients. We present an automated method for fQRS detection and quantification. First, a novel robust QRS complex segmentation strategy is proposed, which combines multi-lead information and excludes abnormal heartbeats automatically. Afterwards extracted features, based on variational mode decomposition (VMD), phase-rectified signal averaging (PRSA) and the number of baseline-crossings of the ECG, were used to train a machine learning classifier (Support Vector Machine) to discriminate fragmented from non-fragmented ECG-traces using multi-center data and combining different fQRS criteria used in clinical settings. The best model was trained on the combination of two independent previously annotated datasets and, compared to these visual fQRS annotations, achieved Kappa scores of 0.68 and 0.44, respectively. We also show that the algorithm might be used in both regular sinus rhythm and irregular beats during atrial fibrillation. These results demonstrate that the proposed approach could be relevant for clinical practice by objectively assessing and quantifying fQRS. The study sets the path for further clinical application of the developed automated fQRS algorithm. [ABSTRACT FROM AUTHOR]

Background: Patients with atrial fibrillation (AF) have an increased risk for the development of heart failure (HF). In this study, we aimed to detect predictors of HF hospitalizations in an unselected AF population. Methods: The Basel Atrial Fibrillation Cohort Study is an ongoing observational multicenter cohort study in Switzerland. For this analysis, 1193 patients with documented AF underwent clinical examination, venous blood sampling and resting 12-lead ECG at baseline. Questionnaires about lifestyle and medical history were obtained in person at baseline and during yearly follow-up phone calls. HF hospitalizations were validated by two independent physicians. Cox regression analyses were performed using a forward selection strategy. Results: Overall, 29.8% of all patients were female and mean age was 69 ±12 years. Mean follow-up time was 3.7 ±1.5 years. Hospitalization for HF occurred in 110 patients, corresponding to an incidence of 2.5 events per 100 person years of follow-up. Independent predictors for HF were body mass index (HR 1.40 [95%CI 1.17; 1.66], p = 0.0002), chronic kidney disease (2.27 [1.49; 3.45], p = 0.0001), diabetes mellitus (2.13 [1.41; 3.24], p = 0.0004), QTc interval (1.25 [1.04; 1.49], p = 0.02), brain natriuretic peptide (2.19 [1.73; 2.77], p<0.0001), diastolic blood pressure (0.79 [0.65; 0.96], p = 0.02), history of pulmonary vein isolation or electrical cardioversion (0.54 [0.36; 0.80], p = 0.003) and serum chloride (0.82 [0.70; 0.96], p = 0.02). Conclusions: In this unselected AF population, several traditional cardiovascular risk factors and arrhythmia interventions predicted HF hospitalizations, providing potential opportunities for the implementation of strategies to reduce HF among AF patients. [ABSTRACT FROM AUTHOR]

Background: Population based studies showed an association of early repolarization in the electrocardiogram (ECG) and a higher rate of sudden cardiac death presumably due to ventricular fibrillation. The triggers for ventricular fibrillation in patients with early repolarization are not fully understood.Case Presentation: We describe the case of a young patient with a survived ventricular fibrillation arrest while asleep followed by multiple episodes of recurrent ventricular fibrillation. The admission ECG showed an early repolarization pattern with substantial J-point elevation in most of the ECG-leads. After initiation of a hypothermia protocol, the patient developed an electrical storm with multiple ventricular fibrillation episodes requiring multiple cardioversions. Intravenous isoproterenol infusion successfully suppressed the malignant arrhythmia.Conclusion: Hypothermia appears proarrhythmic in patients with early repolarization and may trigger ventricular fibrillation. This knowledge is particularly important when initiating temperature management protocols in patients after a survived cardiac arrest. During the acute phase of an early repolarization associated electrical storm, isoproterenol is the most effective treatment suppressing the ventricular fibrillation-inducing premature ventricular complexes at higher heart rates. [ABSTRACT FROM AUTHOR]

Introduction: Left atrial (LA) enlargement is an important risk factor for incident stroke and a key determinant for the success of rhythm control strategies in patients with atrial fibrillation (AF). However, factors associated with LA volume in AF patients remain poorly understood. Methods: Patients with paroxysmal or persistent AF were enrolled in this study. Real time 3-D echocardiography was performed in all participants and analyzed offline in a standardized manner. We performed stepwise backward linear regression analyses using a broad set of clinical parameters to determine independent correlates for 3-D LA volume. Results: We included 210 patients (70.9% male, mean age 61±11years). Paroxysmal and persistent AF were present in 95 (45%) and 115 (55%) patients, respectively. Overall, 115 (55%) had hypertension, 11 (5%) had diabetes, and 18 (9%) had ischemic heart disease. Mean indexed LA volume was 36±12ml/m2. In multivariable models, significant associations were found for female sex (β coefficient -10.51 (95% confidence interval (CI) -17.85;-3.16), p = 0.0053), undergoing cardioversion (β 11.95 (CI 5.15; 18.74), p = 0.0006), diabetes (β 14.23 (CI 2.36; 26.10), p = 0.019), body surface area (BSA) (β 34.21 (CI 19.30; 49.12), p<0.0001), glomerular filtration rate (β -0.21 (CI -0.36; -0.06), p = 0.0064) and plasma levels of NT-pro brain natriuretic peptide (NT-proBNP) (β 6.79 (CI 4.05; 9.52), p<0.0001), but not age (p = 0.59) or hypertension (p = 0.42). Our final model explained 52% of the LA volume variability. Conclusions: In patients with AF, the most important correlates with LA volume are sex, BSA, diabetes, renal function and NT-proBNP, but not age or hypertension. These results may help to refine rhythm control strategies in AF patients. [ABSTRACT FROM AUTHOR]

Introduction: The advent of electroanatomical mapping (EAM) systems for pulmonary vein isolation (PVI) has dramatically decreased radiation exposure. However, the need for some fluoroscopy remains for obtaining left atrial (LA) access. The aim was to test the feasibility of fluoroscopy-free PVI in patients with atrial fibrillation (AF) and a patent foramen ovale (PFO) guided solely by an EAM system. Methods: Consecutive patients with AF undergoing PVI and documented PFO were studied. An EAM-guided approach without fluoroscopy and ultrasound was used. After completing the map of the right atrium, the superior vena cava and the coronary sinus, a catheter pull-down to the PFO was performed allowing LA access. The map of the LA and subsequent PVI was also performed without fluoroscopy. Results: 30 patients [age 61±12 years, 73% male, ejection fraction 0.64 (0.53–0.65), LA size in parasternal long axis 38±7 mm] undergoing PVI were included. The time required for right atrial mapping including transseptal crossing was 9±4 minutes. Total procedure time was 127±37 minutes. Fluoroscopy-free PVI was feasible in 26/30 (87%) patients. In four patients, fluoroscopy was needed to access (n = 3) or to re-access (n = 1) the LA. In these four patients, total fluoroscopy time was 5±3 min and the DAP was 14.9±13.4 Gy*cm2. Single-procedure success rate was 80% (24/30) after a median follow-up of 12 months. Conclusion: In patients with a documented PFO, completely fluoroscopy-free PVI is feasible in the vast majority of cases. [ABSTRACT FROM AUTHOR]

Aims The aim of this study was to determine the relationship between improved ejection fraction (EF) and occurrence of arrhythmias in patients with cardiac resynchronization therapy devices with defibrillator function (CRT-D). The hypothesis was that patients who experienced a marked improvement in EF also had fewer appropriate defibrillator interventions. Methods and results We analysed data of 270 patients from2 prospective registries with follow-up of ≥12 months and echocardiography performed ≥8 months after CRT-D implantation. The discriminator was whether left ventricular ejection fraction (LVEF) improved to >35% [cut-off for primary prevention implantable cardioverter-defibrillator (ICD) implantation]. Mean age was 61 ± 11 years, LVEF 22 ± 5%, and follow-up 40 ± 22 months. Ischaemic cardiomyopathy was present in 48%, and secondary prevention indication was present in 25%. Implantable cardioverter-defibrillator interventions were delivered to 35% of patients. Echocardiography (20 ± 15 months after implantation) showed an improvement in LVEF from 22% (SD 5.4%) to 30% (SD 9.8%). Improvement to >35% was seen in 21% of patients. Those who improved to >35% had fewer ICD interventions than those who did not (23 vs.38%; P-value 0.03). Analysing only patients with a primary prevention indication and stratifying again in patients with and without improvement of LVEF to >35%, the latter had highly significant more ICD-therapies (6 vs. 31%; P-value 0.0008). Conclusion Patients with CRT-D for primary prevention, whose LVEF improved to >35% during mid-term follow-up, are at low risk of first ICD therapies beyond year 1. If similar findings are reported in other patient cohorts, this might impact on decision-making at the time of battery depletion. [ABSTRACT FROM AUTHOR]

Background: The wearable cardioverter defibrillator (WCD) uses surface electrodes to detect arrhythmia before initiating a treatment sequence. However, it is also prone to inappropriate detection due to artefacts. Objective: The aim of this study is to assess the alarm burden in patients and its impact on clinical outcomes. Methods: Patients from the nationwide Swiss WCD Registry were included. Clinical characteristics and data were obtained from the WCDs. Arrhythmia recordings ≥30 s in length were analysed and categorized as VT/VF, atrial fibrillation (AF), supraventricular tachycardia (SVT) or artefact. Results: A total of 10653 device alarms were documented in 324 of 456 patients (71.1%) over a mean WCD wear-time of 2.0 ± 1.6 months. Episode duration was 30 s or more in 2996 alarms (28.2%). One hundred and eleven (3.7%) were VT/VF episodes. The remaining recordings were inappropriate detections (2736 (91%) due to artefacts; 117 (3.7%) AF; 48 (1.6%) SVT). Two-hundred and seven patients (45%) had three or more alarms per month. Obesity was significantly associated with three or more alarms per month (p = 0.01, 27.7% vs. 15.9%). High alarm burden was not associated with a lower average daily wear time (20.8 h vs. 20.7 h, p = 0.785) or a decreased implantable cardioverter defibrillator implantation rate after stopping WCD use (48% vs. 47.3%, p = 0.156). Conclusions: In patients using WCDs, alarms emitted by the device and impending inappropriate shocks were frequent and most commonly caused by artefacts. A high alarm burden was associated with obesity but did not lead to a decreased adherence. [ABSTRACT FROM AUTHOR]

Introduction: Previous data have shown that about 25% of pts receiving CRT have atrial fibrillation (AF) but AF pts have been underrepresented in randomized CRT trials. The ESC/EHRA CRT Survey II collected data on current CRT implantation practice in 42 European countries. This analysis focuses on CRT implantation practice with regard to the presence of AF. Methods and Results: Between October 2015 and January 2017, 11.088 patients (pts) with an initial implant or upgrade from a previous device were included in the Survey. We analyzed 10843 pts with available data on AF presence. Overall, 4582 pts (42.2%) had AF. Permanent AF was present in 1889 pts. (42.4% of all AF pts), persistent AF in 994 (22.3%) and paroxysmal AF in 1548 pts (34.7%). AF pts. were older, had more advanced HF stage and more co-morbidities than pts. without AF (see table). There were also differences with regard to pacemaker dependency, CRT indication and device type implanted. Perioperative bleeding occurred slightly more often in AF pts. (1.3 vs. 0.8%, p=0.002) but the overall complication rate was not increased (5.2 vs. 5.8%, p=n.s.). Adverse events until discharge were more frequent in AF pts (5.4 vs. 4.3%, p=0.01), mostly due to increases in infections, worsening renal function and arrhythmias, but did not more often necessitate re-intervention (4.0 vs. 4.1%). Conclusion: The percentage of pts currently receiving CRT with concomitant AF is higher than previously reported. AF pts are older and sicker than pts receiving CRT without AF. Assuming a worse prognosis in the AF population, there is need for more prospective data on these pts. [ABSTRACT FROM AUTHOR]