István Osztheimer

Aims: Point-by-point radiofrequency catheter ablation is commonly used for pulmonary vein isolation (PVI) in atrial fibrillation (AF). Very high power short duration (vHPSD) technology offers similar efficacy to high power short duration (HPSD) with reduced procedure times. A major complication of thermal ablation is atrio-oesophageal fistula (AEF), with oesophageal lesions and gastroparesis indicating increased risk. A direct comparison of HPSD and vHPSD regarding thermal safety is lacking. This randomized, single-centre study aimed to compare the thermal safety of vHPSD to HPSD and identify anatomical and biophysical predictors of thermal injury (ClinicalTrials.gov ID: NCT06617442). Methods and results: Patients undergoing first-time PVI for AF were randomized to either HPSD (50 W) or vHPSD (90 W). The study followed a non-inferiority design, with the primary endpoint being a composite of oesophageal mucosal lesion and gastroparesis, assessed via endoscopy within 15 days post-procedure. Pre-procedural computed tomography scans were analysed for anatomical risk factors. Among 100 patients (50 per group), the primary endpoint occurred in 7 (14%) of the vHPSD group and 6 (12%) of the HPSD group (estimated mean difference −2%, lower bound of one-sided 95% CI −0.13), confirming non-inferiority. A smaller inter-lesion distance on the posterior wall was associated with increased risk (3.76 mm vs. 4.16 mm, P = 0.042). Conclusion: Pulmonary vein isolation using 90 W (vHPSD) applications was non-inferior to the 50 W (HPSD) power setting in terms of oesophageal safety. A smaller inter-lesion distance on the posterior wall was predictive of oesophageal injury.

Aims: We hypothesize that sinus rhythm (SR) maintenance in persistent atrial fibrillation (AF) patients taking anti-arrhythmic drugs (AADs) after pre-procedural electrical cardioversion (ECV) could predict outcomes after catheter ablation procedures. Methods and results: 219 persistent AF patients on AADs underwent ECV 1–6 months before ablation. Patients were categorized into two groups according to their response to ECV: patients in whom SR was restored and maintained until the ablation procedure (ECV-SR group), and patients with AF recurrence before the procedure (ECV-AF group). Then, 1:1 propensity score matching was used to create study groups (94–94 patients). The efficacy outcomes of the present study were freedom from atrial tachyarrhythmia on/off AADs following a single ablation procedure and recurrence of persistent AF. The median follow-up duration was 42 (20–73) months. Freedom from atrial tachyarrhythmia at 36 months was lower in the ECV-AF group compared to ECV-SR patients (31.4% vs. 51.2%, respectively; crude HR = 2.58, 95% CI = 1.58–3.70, P < 0.001). The most frequent pattern of atrial arrhythmia recurrence was persistent AF in the ECV-AF group and paroxysmal AF in the ECV-SR group. Freedom from persistent AF at 36 months was 54% and 84.3%, respectively (crude HR = 3.72, 95% CI = 1.94–7.14, P < 0.001). Differences in the risk of the efficacy outcomes were similar after multi-variable adjustment and in all analysed subgroups, including pulmonary vein isolation (PVI)-only procedures. Conclusion: Our findings indicate that the positive response to pre-procedural ECV may be a valuable marker for identifying persistent AF patients in whom a PVI-only strategy is sufficient.

Background: Early defibrillation improves outcomes in cardiac arrest, but the optimal defibrillation strategy and energy requirements remain debated. This study investigated whether arterial blood gas (ABG) parameters could predict optimal defibrillation energy requirements for achieving the highest first-shock success rates in an animal model. Our study focused on clinical scenarios where ABG measurements are readily available, such as ventricular tachycardia and ventricular fibrillation storms requiring multiple shock deliveries. Materials and Methods: In the experimental setting, ventricular fibrillation was induced by 50 Hz direct current (DC), and the defibrillation threshold (DFT) was determined using a stepwise defibrillation protocol. ABG parameters were measured before each defibrillation attempt, recording partial arterial pressure of carbon dioxide (PaCO₂) and oxygen (PaO₂), pH, hematocrit (Hct), sodium (Na⁺), potassium (K⁺), and bicarbonate (HCO₃⁻) levels. The relationships between ABG parameters and the DFT were analyzed for 15 subjects using classical data analysis techniques and machine learning (ML) algorithms. Multiple ML models were trained and tested to predict the higher energy needed for successful defibrillation based on the ABG parameters. Results: Statistically significant differences were found in Hct and Na⁺ levels between the two DFT categories, above 130 Joules (J) and below 40 J (p < 0.01). The DFT negatively correlated with PaO₂ and positively correlated with Hct and Na⁺. However, other ABG parameters did not show significant correlations with DFT. Using ML, we predicted cases requiring higher defibrillation E. Our best-performing model, the Extra Trees Classifier, achieved 83% overall accuracy, with 100% and 67% precision rates for higher and lower DFT categories, respectively. We validated the model using bootstrap resampling and 10-fold cross-validation, confirming consistent performance. We identified Hct, PaCO₂, and PaO₂ as significant contributors to model prediction based on the feature importance value. Conclusions: Modern data analysis techniques applied to ABG parameters may guide personalized defibrillation energy selection, particularly in controlled clinical environments such as catheterization laboratories and intensive care units where ABG measurements are readily available.

Background and aims: Left atrial appendage (LAA) thrombus is the primary cause of stroke and systemic embolism in atrial fibrillation (AF). Non-vitamin-K oral anticoagulants (NOACs) effectively reduce LAA thrombus prevalence and stroke risk. However, the optimal treatment of a NOAC-resistant thrombus remains unclear. We aimed to evaluate therapeutic strategies for resolving LAA thrombus in patients on optimal NOAC therapy. Methods: We retrospectively analyzed patients scheduled for cardioversion or catheter ablation of AF between 2014 and 2023 with LAA thrombus on transesophageal echocardiography (TEE) despite being on optimal NOAC therapy. We assessed how the applied management strategy affected thrombus resolution. Results: Among the analyzed 120 patients, a change to a different NOAC occurred in 41% of cases, a transition to a VKA in 30%, and the supplementation with antiplatelet therapy in 11%. In contrast, 18% of the patients received unchanged therapy. Follow-up imaging at 65 [44 – 95] days showed successful thrombus resolution in 92 (77%) of cases, predicted by a lower CHA2DS2-VASc score ( p = 0.01). Any modification of antithrombotic therapy was an independent predictor of thrombus resolution (OR 5.28 [1.55–18], p = 0.01). Of the four strategies, there was a trend toward better thrombus resolution with switching to a VKA (OR 3.23 [1.03–10.1], p = 0.04). Conclusion: Resolution of LAA thrombus in patients already on adequate NOAC treatment may require a revision of the anticoagulation strategy. In addition, transitioning from NOAC to VKA might be considered. Graphical

The predictive role of local impedance (LI) drop in lesion formation using a novel contact force sensing ablation catheter was recently described. The purpose of our current study was to assess the temporal characteristics of LI drop during ablation and its correlation with acute lesion efficacy. Point-by-point pulmonary vein isolation was performed. The efficacy of applications was determined by pacing along the circular ablation line and assessing loss of capture. Local impedance, contact force, and catheter position data with high resolution were analysed and compared in successful and unsuccessful applications. Five hundred and fifty-nine successful and 84 unsuccessful applications were analysed. The successful applications showed higher baseline LI (P < 0.001) and larger LI drop during ablation (P < 0.001, for all). In case of unsuccessful applications, after a moderate but significant drop from baseline to the 2 s time point (153 vs. 145 Ω, P < 0.001), LI did not change further (P = 0.99). Contradictorily, in case of successful applications, the LI significantly decreased further (baseline–2 s–10 s: 161–150–141 Ω, P < 0.001 for all). The optimal cut-point for the LI drop indicating unsuccessful application was P < 0.001]. Failing to reach this cut-point predicted unsuccessful applications [OR 3.82 (2.34–6.25); P < 0.001]. A rapid and enduring drop of the LI may predict effective lesion formation, while slightly changing or unchanged LI is associated with unsuccessful applications. A moderate LI drop during the first 4 s of radiofrequency application predicts ineffective radiofrequency delivery.

Background: Recurrences due to discontinuity in ablation lines are substantial after pulmonary vein isolation (PVI) with radiofrequency ablation for atrial fibrillation. Data are scarce regarding the durability predictors for very high-power short-duration (vHPSD, 90 W/4 s) ablation. Methods: A total of 20 patients were enrolled, who underwent 90 W PVI and a mandatory remapping procedure at 3 months. First-pass isolation (FPI) gaps, and acute pulmonary vein reconnection (PVR) sites were identified at the index procedure; and chronic PVR sites were identified at the repeated procedure. We analyzed parameters of ablation points (n = 1357), and evaluated their roles in predicting a composite endpoint of FPI gaps, acute and chronic PVR. Results: In total, 45 initial ablation points corresponding to gaps in the ablation lines were analyzed. Parameters associated with gaps were interlesion distance (ILD), baseline generator impedance, mean current, total charge, and loss of catheter–tissue contact. The optimal ILD cut-off for predicting gaps was 3.5 mm anteriorly, and 4 mm posteriorly. Conclusions: Biophysical characteristics dependent on generator impedance could affect the efficacy of vHPSD PVI. The use of smaller ILDs is required for effective and durable PVI with vHPSD compared to the consensus targets with lower power ablation, and lower ILDs for anterior applications seem necessary compared to posterior points.

Recommendations on cardiac resynchronization therapy (CRT) in patients with atrial fibrillation or flutter (AF) are based on less robust evidence than those in sinus rhythm (SR). We aimed to assess the efficacy of CRT upgrade in the BUDAPEST-CRT Upgrade trial population by their baseline rhythm. Heart failure patients with reduced ejection fraction (HFrEF) and previously implanted pacemaker (PM) or implantable cardioverter defibrillator (ICD) and ≥20% right ventricular (RV) pacing burden were randomized to CRT with defibrillator (CRT-D) upgrade (n = 215) or ICD (n = 145). Primary [HF hospitalization (HFH), all-cause mortality, or P = 0.013]. The effect of CRT-D upgrade was similar in patients with AF as in those with SR [AF adjusted odds ratio (aOR) 0.06; 95% CI 0.02–0.17; P < 0.001; SR aOR 0.13; 95% CI 0.07–0.27; P < 0.001; interaction P = 0.29] during the mean follow-up time of 12.4 months. Also, it decreased the risk of HFH or all-cause mortality (aHR 0.33; 95% CI 0.16–0.70; P = 0.003; interaction P = 0.17) and improved the echocardiographic response (left ventricular end-diastolic volume difference −49.21 mL; 95% CI −69.10 to −29.32; P < 0.001; interaction P = 0.21). In HFrEF patients with AF and PM/ICD with high RV pacing burden, CRT-D upgrade decreased the risk of HFH and improved reverse remodelling when compared with ICD, similar to that seen in patients in SR. In AF patients CRT-D upgrade reduced the risk of mortality or HF hospitalization as compared with ICD, additionally echocardiographic parameters, symptoms, and NT-proBNP levels improved. However, the risk of HF hospitalization was higher in AF patients when compared with SR. AF, atrial fibrillation or flutter; aOR, adjusted odds ratio; aHR, adjusted hazard ratio; CI, confidence interval; CRT-D, cardiac resynchronization therapy with defibrillator; ICD, implantable cardioverter defibrillator; HF, heart failure; HFrEF, heart failure with reduced ejection fraction; LVESV, left ventricular end-systolic volume; NT-proBNP, N-terminal pro b-type natriuretic peptide; PCI, percutaneous coronary intervention; PM, pacemaker; RV, right ventricular; SR, sinus rhythm.

Background: The beneficial effects of mineralocorticoid receptor antagonists (MRAs) regarding sudden cardiac death (SCD) risk and cardiac remodeling are well known, moreover, they also reduce episodes of ventricular tachycardia (VT). However, superiority in effectiveness between receptor selective eplerenone and conventional spironolactone is unknown. Purpose: Our aim was to assess the effect of eplerenone and spironolactone on ventricular tachycardia (VT) recurrence in patients with ischemic heart disease (IHD). Methods: We collected data of 563 patients with IHD following hospitalization due to a sustained VT episode in a structured registry. Propensity score matching was performed based on age, hypertension, diabetes, history of acute myocardial infarction, left ventricular ejection fraction (LVEF) and presentation with incessant VT. The matched population consisted of 188 patients and was further analyzed. Predictors were assessed using univariate and multivariate Cox regression models. Kaplan-Meier curves were used for time-to-event analyses. Results: The median age was 70 years with 81% being male. One third of the patients had an ICD implanted, while 43 (23%) had CRT. The median LVEF was 30%. Twenty-five (13%) patients presented with an electrical storm and 19 (10%) had incessant VT. In 86 cases (46%), the VT caused hemodynamic instability. Ablation was performed in 66 patients (35%), while 4 required mechanical circulatory support. During the median follow-up of 856 [399-1624] days, 69 patients had VT recurrence and 118 patients died. Eplerenone use significantly reduced the risk of VT recurrence compared to spironolactone (HR: 0.48 [0.29-0.78], log-rank p=0.003). This effect was consistent in the multivariate model as well (p=0.006). Conclusions: Eplerenone use may be more beneficial in terms of VT recurrence in patients with IHD who present with a sustained VT. Further analysis is required to confirm these findings.

Background: AVIM is a pacing algorithm incorporated into dual-chamber pacemakers to treat hypertension. AVIM delivers repeating sequences of short and longer atrioventricular delays leading to reduced preload and afterload. The therapy lowers blood pressure while simultaneously modulating the autonomic nervous system. The marked blood pressure reducing capability of AVIM has been already confirmed by a previous randomized clinical trial using conventional right ventricular (RV) pacing. Nevertheless, whether a similar blood pressure reduction could be also achieved by AVIM when conduction system pacing (CSP) is applied instead of RV pacing has not been investigated yet. Considering the facts that CSP using Left Bundle Branch Area Pacing (LBBAP) has been found to elicit more synchronous ventricular contraction and improved hemodynamics compared to RV pacing and AVIM is associated with a signficant burden of ventricular pacing, it is tempting to hypothesize that AVIM with CSP could be particularly beneficial. Purpose: To compare the effects of AVIM therapy when delivered via an LBBAP location with the effects when delivered using a traditional RV lead location. Methods: This single-center study evaluated subjects indicated for a dual chamber pacemaker who also had uncontrolled hypertension despite a stable dose of ³ 1 antihypertensive drug. Leads were placed in the RV or the LBBAP position. Subjects entered a run-in period of 4 weeks in which baseline office (oSBP)and 24-hour aSBP were measured. Subjects with baseline aSBP >130 mmHg and oSBP>140 mmHg at week 4 were included in the study. AVIM therapy was activated and a 24-hour aSBP was performed immediately after activation. Results: Using a dedicated CSP pacemaker lab setup, CSP was performed in 5 patients with the Select Secure electrode (model 3830-69 cm) delivered via a fixed curve sheath (C315HIS). During the run in phase, in 3 out of the 5 CSP-AVIM patients, high blood pressure did not reach the level of inclusion and therefore these patients were not used for further analysis. In the remaining two patients, AVIM was activated. These two patients had a V6 stimulus-peak time of 69 ms and 61 ms, while V1 stimulus peak time was: 121ms and 109ms respectively. The effect of AVIM on 24-hour aSBP in the activated CSP-AVIM patients was compared to the average effect seen in patients from the same center enrolled in the prior randomized study with leads in the RV. Table 1 shows individual aSBP values for the two patient groups. Results suggest that delivery of AVIM therapy through leads in either position generates a significant reduction in blood pressure: -24.1 mmHg vs. -15.4 mmHg when the lead is placed in LBBAP or RV positions respectively. Conclusion These results demonstrate a significant reduction in aSBP in both lead locations. Additional studies evaluating larger sample sizes are required to assess if specific lead positions are preferable.Table 1

Background: Atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) is predominantly attributed to pulmonary vein reconnection (PVR). Predictors of AF recurrence have been widely studied; however, data are scarce on procedural parameters that predict chronic PVR. We aimed to study PVR rates and predictors of PVR. Methods: We retrospectively included 100 patients who underwent repeated ablation due to AF recurrence after initial PVI with the CARTO system. PVR was determined during the repeated procedure by electrophysiological evaluation, and initial procedural characteristics predicting PVR were studied, including adherence to the CLOSE protocol, use of high power, first-pass isolation (FPI), and baseline generator impedance (BGI). Results: Thirty-eight patients underwent initial CLOSE-guided PVI, and sixty-two underwent initial non-CLOSE PVI. A repeat procedure was performed 23 ± 16 months after the initial procedure. In total, PVR was found in 192 of 373 PVs (51.5%), and all PVs were isolated in 17/100 (17%) patients. Factors associated with all PVs being isolated were adherence to the CLOSE protocol, a higher power setting, the presence of bilateral FPI, and lower BGI (88% vs. 28%, p < 0.0001; 37.5 W vs. 30 W, p = 0.0276; 88.2% vs. 40.4%, p = 0.0007; and 127.6 Ω vs. 136.6 Ω, p = 0.0027, respectively). In initial procedures with adherence to the CLOSE protocol, the FPI rate was significantly higher (73.7% vs. 25%, p < 0.0001), while there were no significant differences in terms of procedure time and left atrial dwell time (81 vs. 85 min, p = 0.83; and 60 vs. 58 min, p = 0.08, respectively). BGI ≥ 130 Ω (AUC = 0.7403, sensitivity: 77.1%, specificity: 68.8%, p = 0.0032) was associated with a significantly higher probability of PVR (OR = 6.757; p < 0.0001). In multivariable analysis, independent predictors for PVR were non-adherence to the CLOSE protocol and BGI ≥ 130 Ω. Conclusions: Our findings indicate that adherence to the CLOSE protocol and baseline generator impedance < 130 Ω during AF ablation are independent predictors of PVI durability.