Accessory pathway localization with probabilistic density maps generated by a mobile application: Assessment of a full pre-excitation net-vector method.

INTRODUCTION: Precise electrocardiographic localization of accessory pathways (AP) can be challenging. Seminal AP localization studies were limited by complexity of algorithms and sample size. We aimed to create a nonalgorithmic method for AP localization based on color-coded maps of AP distribution generated by a web-based application. METHODS: APs were categorized into 19 regions/types based on invasive electrophysiologic mapping. Preexcited QRS complexes were categorized into 6 types based on polarity and notch/slur. For each QRS type in each lead the distribution of APs was visualized on a gradient map. The principle of common set was used to combine the single lead maps to create the distribution map for AP with any combination of QRS types in several leads. For the validation phase, a separate cohort of APs was obtained. RESULTS: A total of 800 patients with overt APs were studied. The application used the exploratory data set of 553 consecutive APs and the corresponding QRS complexes to generate AP localization maps for any possible combination of QRS types in 12 leads. Optimized approach (on average 3 steps) for evaluation of preexcited electrcardiogram was developed. The area of maximum probability of AP localization was pinpointed by providing the QRS type for the subsequent leads. The exploratory data set was validated with the separate cohort of APs (n = 256); p = .23 for difference in AP distribution. CONCLUSIONS: In the largest data set of APs to-date, a novel probabilistic and semi-automatic approach to electrocardiographic localization of APs was highly predictive for anatomic localization.

Effect of SGLT-2 inhibitors on arrhythmia events: insight from an updated secondary analysis of > 80,000 patients (the SGLT2i-Arrhythmias and Sudden Cardiac Death).

OBJECTIVE: We aimed to assess the effect of SGLT2i on arrhythmias by conducting a meta-analysis using data from randomized controlled trials(RCTs). BACKGROUND: Sodium-glucose co-transporter 2 inhibitors (SGLT2i) have shown cardioprotective effects via multiple mechanisms that may also contribute to decrease arrhythmias risk. METHODS: We searched in databases (PubMed, Embase, Cochrane Library, and clinicaltrials.gov) up to April 2023. RCTs comparing SGLT2i with placebo were included. The effects of SGLT2i on atrial fibrillation(AF), atrial flutter(AFL), composite AF/AFL, ventricular fibrillation(VF), ventricular tachycardia(VT), ventricular extrasystoles(VES), sudden cardiac death(SCD) and composite VF/VT/SCD were evaluated. RESULTS: 33 placebo-controlled RCTs were included, comprising 88,098 patients (48,585 in SGLT2i vs. 39,513 in placebo). The mean age was 64.9 ± 9.4 years, 63.0% were male. The mean follow-up was 1.4 ± 1.1 years. The pooled-results showed that SGLT2i was associated with a significantly lower risk of AF [risk ratio(RR): 0.88, 95% confidence interval(CI) 0.78-1.00, P = 0.04] and composite AF/AFL (RR: 0.86, 95%CI 0.77-0.96, P = 0.01). This favorable effect appeared to be substantially pronounced in patients with HFrEF, male gender, dapagliflozin, and > 1 year follow-up. For SCD, only in heart failure patients, SGLT2i were found to be associated with a borderline lower risk of SCD (RR: 0.67, P = 0.05). No significant effects of SGLT2i on other ventricular arrhythmic outcomes were found. CONCLUSIONS: SGLT2i lowers the risks of AF and AF/AFL, and this favorable effect appeared to be particularly pronounced in patients with HFrEF, male gender, dapagliflozin, and longer follow-up (> 1 year). SGLT2i lowers the risk of SCD only in heart failure patients.

Stereotactic arrhythmia radioablation and its implications for modern cardiac electrophysiology: results of an EHRA survey.

Stereotactic arrhythmia radioablation (STAR) is a treatment option for recurrent ventricular tachycardia/fibrillation (VT/VF) in patients with structural heart disease (SHD). The current and future role of STAR as viewed by cardiologists is unknown. The study aimed to assess the current role, barriers to application, and expected future role of STAR. An online survey consisting of 20 questions on baseline demographics, awareness/access, current use, and the future role of STAR was conducted. A total of 129 international participants completed the survey [mean age 43 ± 11 years, 25 (16.4%) female]. Ninety-one (59.9%) participants were electrophysiologists. Nine participants (7%) were unaware of STAR as a therapeutic option. Sixty-four (49.6%) had access to STAR, while 62 (48.1%) had treated/referred a patient for treatment. Common primary indications for STAR were recurrent VT/VF in SHD (45%), recurrent VT/VF without SHD (7.8%), or premature ventricular contraction (3.9%). Reported main advantages of STAR were efficacy in the treatment of arrhythmias not amenable to conventional treatment (49%) and non-invasive treatment approach with overall low expected acute and short-term procedural risk (23%). Most respondents have foreseen a future clinical role of STAR in the treatment of VT/VF with or without underlying SHD (72% and 75%, respectively), although only a minority expected a first-line indication for it (7% and 5%, respectively). Stereotactic arrhythmia radioablation as a novel treatment option of recurrent VT appears to gain acceptance within the cardiology community. Further trials are critical to further define efficacy, patient populations, as well as the appropriate clinical use for the treatment of VT.

Cardioneuroablation for vasovagal syncope: insights on patients' selection, centre settings, procedural workflow and endpoints-results from an European Heart Rhythm Association survey.

AIMS: Cardioneuroablation (CNA) is a catheter-based intervention for recurrent vasovagal syncope (VVS) that consists in the modulation of the parasympathetic cardiac autonomic nervous system. This survey aims to provide a comprehensive overview of current CNA utilization in Europe. METHODS AND RESULTS: A total of 202 participants from 40 different countries replied to the survey. Half of the respondents have performed a CNA during the last 12 months, reflecting that it is considered a treatment option of a subset of patients. Seventy-one per cent of respondents adopt an approach targeting ganglionated plexuses (GPs) systematically in both the right atrium (RA) and left atrium (LA). The second most common strategy (16%) involves LA GP ablation only after no response following RA ablation. The procedural endpoint is frequently an increase in heart rate. Ganglionated plexus localization predominantly relies on an anatomical approach (90%) and electrogram analysis (59%). Less utilized methods include pre-procedural imaging (20%), high-frequency stimulation (17%), and spectral analysis (10%). Post-CNA, anticoagulation or antiplatelet therapy is prescribed, with only 11% of the respondents discharging patients without such medication. Cardioneuroablation is perceived as effective (80% of respondents) and safe (71% estimated <1% rate of procedure-related complications). Half view CNA emerging as a first-line therapy in the near future. CONCLUSION: This survey offers a snapshot of the current implementation of CNA in Europe. The results show high expectations for the future of CNA, but important heterogeneity exists regarding indications, procedural workflow, and endpoints of CNA. Ongoing efforts are essential to standardize procedural protocols and peri-procedural patient management.

Management of ventricular tachycardias: insights on centre settings, procedural workflow, endpoints, and implementation of guidelines-results from an EHRA survey.

Ventricular tachycardia (VT), and its occurrence, is still one of the main reasons for sudden cardiac death and, therefore, for increased mortality and morbidity foremost in patients with structural heart [Kahle A-K, Jungen C, Alken F-A, Scherschel K, Willems S, Pürerfellner H et al. Management of ventricular tachycardia in patients with ischaemic cardiomyopathy: contemporary armamentarium. Europace 2022;24:538-51]. Catheter ablation has become a safe and effective treatment option in patients with recurrent VT [Cronin EM, Bogun FM, Maury P, Peichl P, Chen M, Namboodiri N et al. 2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias. Heart Rhythm 2020;17:e2-154]. Previous and current guidelines provide guidance on indication for VT ablation and risk assessment and evaluation of underlying disease. However, no uniform recommendation is provided regarding procedural strategies, timing of ablation, and centre setting. Therefore, these specifics seem to differ largely, and recent data are sparse. This physician-based European Heart Rhythm Association survey aims to deliver insights on not only infrastructural settings but also procedural specifics, applied technologies, ablation strategies, and procedural endpoints. Therefore, these findings might deliver a real-world scenario of VT management and potentially are of guidance for other centres.

Bipolar ablation of ventricular arrhythmias: Step-by-step.

Radiofrequency (RF) ablation of intramural ventricular arrhythmias (VAs) may require advanced ablation techniques to achieve effective energy transfer to the targeted tissue. As an alternative to standard RF ablation, catheter ablation can also be conducted in bipolar configuration when two ablation catheters participate in the RF circuit. This strategy has proved to result in deeper lesion formation and may be effective for eliminating arrhythmias that have been refractory to standard ablation. In this article, we provide a step-by-step guide on when and how to perform bipolar ablation of VAs.

Prevention and treatment of pericardial tamponade in the electrophysiology laboratory: a European Heart Rhythm Association survey.

AIMS: Pericardial tamponade (PT) is the most frequent severe complication during electrophysiology (EP) procedures and requires immediate, co-ordinated, and effective treatment. However, multiple aspects of PT treatment are either not standardized or are under ongoing debate. METHODS AND RESULTS: An online questionnaire consisting of 26 multiple-choice questions was sent out to the European Heart Rhythm (EHRA) Research Network and also distributed via social media outputs. The EHRA survey was conducted between May and June 2023. A total of 213 replies were received from European (87%) and non-European countries. Ninety per cent of all participants perform interventions in dedicated EP labs equipped with different ablation platforms. In case of PT, most participants use X-ray as the main imaging modality guiding pericardial puncture, predominantly aiming for an anterior puncture site. Sheaths of different sizes are introduced into the pericardial space (84.3%), followed by a pigtail catheter. Application of protamine is an established but variable step in the majority (84.6%). Novel oral anticoagulants (NOAC) antidotes are not used by 73.3% of participants, while 15.2% routinely apply them. Re-transfusion of aspirated blood is performed by 72.1% [before protamine administration (18.2%), after protamine administration (13.5%), if pericardial effusion cannot be controlled (40.4%)]. A total of 72.4% re-transfuse without blood filter systems. A decision for surgical intervention is mostly taken if bleeding continues despite all interventional measures. CONCLUSION: The current survey demonstrates that the management of PT is heterogeneous among centres. The findings of this survey may help to guide operators in their treatment and decisions in the setting of PT.

Catheter ablation of intramural outflow tract premature ventricular complexes: a multicentre study.

AIMS: Ablation of outflow tract ventricular arrhythmias may be limited by a deep intramural location of the arrhythmogenic source. This study evaluates the acute and long-term outcomes of patients undergoing ablation of intramural outflow tract premature ventricular complexes (PVCs). METHODS AND RESULTS: This multicenter series included patients with structurally normal heart or nonischemic cardiomyopathy and intramural outflow tract PVCs defined by: (a) ≥ 2 of the following criteria: (1) earliest endocardial or epicardial activation < 20ms pre-QRS; (2) Similar activation in different chambers; (3) no/transient PVC suppression with ablation at earliest endocardial/epicardial site; or (b) earliest ventricular activation recorded in a septal coronary vein. Ninety-two patients were included, with a mean PVC burden of 21.5±10.9%. Twenty-six patients had had previous ablations. All PVCs had inferior axis, with LBBB pattern in 68%. In 29 patients (32%) direct mapping of the intramural septum was performed using an insulated wire or multielectrode catheter, and in 13 of these cases the earliest activation was recorded within a septal vein. Most patients required special ablation techniques (one or more), including sequential unipolar ablation in 73%, low-ionic irrigation in 26%, bipolar ablation in 15% and ethanol ablation in 1%. Acute PVC suppression was achieved in 75% of patients. Following the procedure, the PVC burden was reduced to 5.8±8.4%. The mean follow-up was 15±14 months and 16 patients underwent a repeat ablation. CONCLUSION: Ablation of intramural PVCs is challenging; acute arrhythmia elimination is achieved in 3/4 patients, and non-conventional approaches are often necessary for success.

Local impedance for the optimization of radiofrequency lesion delivery: A review of bench and clinical data.

INTRODUCTION: Radiofrequency catheter ablation is a cornerstone of treatment for many cardiac arrhythmias. Progression in three-dimensional mapping and contact-force sensing technologies have improved our capability to achieve success, but challenges still remain. METHODS: In this article, we discuss the importance of overall circuit impedance in radiofrequency lesion formation. This is followed by a review of the literature regarding recently developed "local impedance" technology and its current and future potential applications and limitations, in the context of established surrogate markers currently used to infer effective ablation. RESULTS: We discuss the role of local impedance in assessing myocardial substrate, as well as its role in clinical studies of ablation. We also discuss safety considerations, limitations and ongoing research. CONCLUSION: Local impedance is a novel tool which has the potential to tailor ablation in a manner distinct from other established metrics.

Catheter ablation vs. antiarrhythmic drugs as 'first-line' initial therapy for atrial fibrillation: a pooled analysis of randomized data.

AIMS: Catheter ablation (CA) is recommended for patients with atrial fibrillation (AF) after failure of antiarrhythmic drugs (AADs). The role of CA as 'initial therapy' for AF is to be determined. METHODS AND RESULTS: Following PRISMA guideline an up-to-date pooled analysis of randomized data comparing ablation vs. AADs as first-line therapy for symptomatic AF was performed. The primary outcome was recurrence of atrial tachyarrhythmia. The secondary outcomes were improvement in quality-of-life (QoL) and major adverse events. A total of 997 patients from five randomized trials were enrolled (mean age 57.4 years, 68.6% male patients, 98% paroxysmal AF, mean follow-up 1.4 years). The baseline characteristics were similar between the ablation and AADs group. Overall pooled analysis showed that, as compared with AADs, CA as first-line therapy was associated with significantly higher freedom from arrhythmia recurrence (69% vs. 48%, odds ratio: 0.36, 95% confidence interval: 0.27-0.48, P < 0.001). This significance was maintained in subgroup analyses of 1- and 2-year follow-up (P < 0.001). Catheter ablation was associated with significantly greater improvement in QoL regarding AFEQT score and 36-Item Short-Form Health Survey score. The incidence of serious adverse events between ablation and AADs group (5.6% vs. 4.9%, P = 0.62) was similar. CONCLUSIONS: Catheter ablation as 'initial therapy' was superior to AADs in maintenance of sinus rhythm and improving QoL for patients with symptomatic paroxysmal AF, without increasing risk of serious adverse events.

Effects of permanent cardiac pacing on ventricular repolarization when compared to cardioneuroablation.

INTRODUCTION: The impact of cardioneuroablation (CNA) on ventricular repolarization by using corrected QT interval (QTc) measurements has been recently demonstrated. The effects of cardiac pacing (CP) on ventricular repolarization have not been studied in patients with vasovagal syncope (VVS). We sought to compare ventricular repolarization effects of CNA (group 1) with CP (group 2) in patients with VVS. METHODS: We enrolled 69 patients with age 38 ± 13 years (53.6% male), n = 47 in group 1 and n = 22 in group 2. Clinical diagnosis of cardioinhibitory type was supported by cardiac monitoring or tilt testing. QTc was calculated at baseline (time-1), at 24 h after ablation (time-2), and at 9-12 months (time-3) in the follow-up. RESULTS: In the group 1, from time-1 to time-2, a significant shortening in QTcFredericia (from 403 ± 27 to 382 ± 27 ms, p < 0.0001), QTcFramingham (from 402 ± 27 to 384 ± 27 ms, p < 0.0001), and QTcHodges (from 405 ± 26 to 388 ± 24 ms, p < 0.0001) was observed which remained lower than baseline in time-3 (373 ± 29, 376 ± 27, and 378 ± 27 ms, respectively). Although the difference between measurements in time-1 and time-2 was not statistically significant for QTcBazett, a significant shortening was detected between time-1 and time-3 (from 408 ± 30 to 394 ± 33, p = 0.005). In the group 2, there was no time-based changes on QTc measurements. In the linear mixed model analysis, the longitudinal reduction tendency in the QTcFredericia and QTcFramingham was more pronounced in group 1. CONCLUSIONS: Our results demonstrate that CNA reduces QTc levels through neuromodulation effect whereas CP has no effect on ventricular repolarization in patients with VVS.

Respiratory cycle-dependent atrial tachycardia originating from the left atrial roof.

Respiratory cycle-dependent atrial tachycardia (RCAT) is rare. RCAT can be associated with severe symptoms and trigger atrial fibrillation. Focal radiofrequency ablation of RCAT can be a successful method of treatment. In the presented case RCAT originated from the roof of the left atrium - the site not previously reported in the literature. Ablation led to complete elimination of arrhythmia with no recurrence during follow up.

Bipolar ablation of refractory atrial and ventricular arrhythmias: Importance of temperature values of intracardiac return electrodes.

INTRODUCTION: Bipolar radiofrequency catheter ablation (Bi-RFCA) emerged as an option for treatment of arrhythmias resistant to the conventional approach. Data on safety issues of Bi-RFCA, including temperature values of intracardiac return electrode (IRE) are lacking. OBJECTIVE: To determine the safety profile of Bi-RFCA regarding temperature measurements obtained from nonirrigated IRE of different sizes. METHODS: The study group consisted of consecutive patients after failed conventional RFCA who underwent Bi-RFCA. RESULTS: Out of 1510 RFCA performed in our center, 19 patients underwent Bi-RFCA due to refractory to previous RFCA ventricular arrhythmias (15 patients) or typical atrial flutter (four patients). Nonirrigated small (4 mm) and large (8 mm) tip catheters were used as IRE in 14 (including three cross-overs to 8 mm IRE) and five patients, respectively. A total number of 164 bipolar applications were performed (128 for 4 mm and 36 for 8 mm IRE). Maximal temperatures of 4 mm IRE were significantly higher than those of 8 mm IRE (63°C ± 16°C vs 43°C ± 4°C; P = .027). A significant rise of temperature and steam-pops, preventing further Bi-RFCA, occurred in seven patients treated with 4 mm IRE. Bi-RFCA using 4 mm IRE operated at significantly higher impedance values (211 ± 83 vs 143 ± 38; P = .04) and lower power values (mean 20 W ± 6 W vs 32 W ± 7 W, P = .0005; max 29 W ± 9 W vs 39 W ± 10 W, P = .027). CONCLUSION: The use of 8 mm IRE for Bi-RFCA is associated with lower temperatures of the catheter used as ground and lower incidence of steam-pops which may suggest a better safety profile than 4 mm IRE. Determination of safety/efficacy balance requires further studies.

Right atrial position of a return electrode for bipolar ablation of the left posterosuperior process ventricular tachycardia.

INTRODUCTION: Radiofrequency (RF) catheter ablation (RFCA) of ventricular tachycardia (VT) is an effective method of treatment. However, when arrhythmia has ischemic etiology and originates from the posterosuperior process (PSP) of the left ventricular (LV) base, ablation performed with conventional unipolar energy sources may be challenging or impossible. METHOD AND RESULT: A 67-year-old male after six unsuccessful RFCA for highly symptomatic VT originating from PSP of LV base underwent successful RFCA using multiple bipolar RF applications delivered between two electrodes located at LV endocardium and adjacent right atrial sites. CONCLUSION: This case report shows that bipolar RFCA can be used for safe and successful treatment of VT originating from deep PSP of LV base.

Prognostic value of noninvasive programmed stimulation in patients with implantable cardioverter defibrillator.

BACKGROUND: Implantable cardioverter defibrillator (ICD) offers an opportunity to examine vulnerability to ventricular tachycardia (VT) or ventricular fibrillation (VF) by performing noninvasive programmed ventricular stimulation (NIPS). Whether NIPS can predict VT/VF recurrences has not yet been established. PURPOSE: To examine the predictive value of NIPS for identification of patients with VT/VF recurrences. METHODS: The study group consisted of consecutive 105 ICD recipients included in the prospective NIPS-ICD study (ClinicalTrials ID: NCT02373306) (88 males, age 65 ± 11 years). The patients underwent NIPS using the protocol up to three premature extrastimuli at 600-500- and 400-ms drive cycle lengths. The endpoint of NIPS was induction of sustained VT or VF or completion of the protocol. RESULTS: VT/VF was induced in 29 (27.6%) patients. During a 12-month follow-up NIPS-inducible patients had significantly more frequently appropriate ICD therapy than noninducible patients (17% vs 4%, P = 0.023). NIPS-induced VT/VF had a sensitivity of 63%, specificity of 75%, positive predictive value of 17%, and negative predictive value of 96% for identification of patients with future VT/VF. Apart from NIPS, age ≥ 65 years, QRS duration, treatment with angiotensin-converting enzyme, history of coronary artery bypass grafting, history of VT/VF prior to NIPS, and prior appropriate ICD therapy were also associated with VT/VF recurrences. Multivariate analysis showed that, together with QRS duration, NIPS result was an independent predictor of future VT/VF. Predictive value of NIPS was significantly higher in ischemic than nonischemic patients. CONCLUSIONS: NIPS result is associated with future VT/VF. Noninducibility at NIPS identifies those patients with high accuracy who will have uneventful follow-up.

Improvement in Atrioventricular Conduction Using Cardioneuroablation Performed Immediately after Pulmonary Vein Isolation.

In patients with atrial fibrillation (AF) recurrences after pulmonary vein isolation (PVI), concomitant treatment using anti arrhythmic drugs (AADs) can lead to clinical success. However, patients with atrioventricular (AV) block may not be good candidates for concomitant AAD therapy due to the risk of further worsening of conduction abnormalities. Cardioneuroablation (CNA), as an adjunct to PVI, may offer a solution to this problem. We present a case of a 74-year-old male with paroxysmal AF and first degree AV block in whom CNA following PVI led to PR normalization. The presented case describes an example of CNA utilization in patients with AF undergoing PVI who have concomitant problems with AV conduction and shows that CNA can be sometimes useful in older patients with functional AV block.

Prognostic value of noninvasive programmed stimulation in primary prevention implantable cardioverter-defibrillator recipients.

Background: Implantable cardioverter-defibrillator (ICD) offers an opportunity to study inducibility of ventricular tachycardia (VT) or ventricular fibrillation (VF) by performing noninvasive programmed ventricular stimulation (NIPS). Whether NIPS can predict future arrhythmic events or mortality in patients with primary prevention ICD, has not yet been examined. Methods: From the NIPS-ICD study (ClinicalTrials ID: NCT02373306) 41 consecutive patients (34 males, age 64 ± 11 years, 76% ischemic cardiomyopathy [ICM]) had ICD for primary prevention indication. Patients underwent NIPS using a standardized protocol of up to three premature extrastimuli at 600, 500 and 400 ms drive cycle lengths. NIPS was classified as positive if sustained VT or VF was induced. The study endpoint was occurrence of sustained VT/VF during the follow-up. Results: At baseline NIPS, VT/VF was induced in 8 (20%) ICM patients. During the 5-year follow-up, the VT/VF occurred in 7 (17%) patients, all with ICM. The difference between NIPS-inducible versus NIPS-noninducible patients regarding VT/VF occurrence did not meet statistical significance (38% vs. 12%, log rank test p = .11). After a 5-year follow-up, the mortality rate was significantly higher in patients who had VT/VF induced at NIPS versus no VT/VF at NIPS (38% vs. 12%, p = .043). The occurrence of a composite endpoint consisting of VT/VF recurrence or death in patients with ICM was also most frequent in the NIPS-inducible group (75% vs. 35%, p = .037). Conclusions: Inducibility of VT/VF during NIPS in ICM patients with primary prevention ICD is associated with higher mortality and higher incidence of composite endpoint consisting of death or VT/VF during a long-term observation.