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PurposeOur purpose was to compare the procedural characteristics, success rate, and complication rate of the conventional fluoroscopic (CF) and the zero-fluoroscopic (ZF) approach in patients undergoing catheter ablation of AVNRT or typical atrial flutter (Aflu).Methods186 consecutive patients with an indication for AVNRT or Aflu ablation were enrolled. Based on the operator's preference, the patients were assigned to either CF or ZF group. In the ZF group EnSite NavX, Carto3, or Rhythmia EAMS were used for catheter guidance.ResultsThe median age was 56 (IQR = 42−68) years, 144 patients had AVNRT, and 42 had Aflu ablation. CF approach was chosen in 123 cases, while ZF in 63 cases. ZF approach was used more often in case of AVNRT patients [56 (39%) vs. 7 (17%), p = 0.006] and in the case of female patients [43 (68%) vs. 20 (32%), p = 0.008]. Acute procedural success was obtained in all cases. There was no difference in the complication rate (1 vs. 1, p > 0.99) between the two groups. No difference was found regarding the procedure time between the CF and ZF groups [CF: 55 (46–60) min, ZF 60 (47–65) min; p = 0.487] or in the procedure time for the different EAMS [EnSite NavX: 58 (50–63) min, Carto3: 60 (44.5–66.3) min, Rhythmia: 55 (35–69) min; p = 0.887]. A similar success rate was seen at the 3-month follow-up in the two groups [41 (100%) vs. 96 (97%); p = 0.55].DiscussionThe ZF approach demonstrated non-inferiority in safety and efficacy compared with CF for the AVNRT and Aflu ablations.

Background: Safety, efficacy, and patient comfort are the expectations during pulmonary vein isolation (PVI). We aimed to validate the combined advantages of pre- and periprocedural anticoagulation with non-vitamin K anticoagulants (NOACs) and rigorous left atrial appendage thrombus (LAAT) exclusion with computed tomography (CT). Methods: This study included a population of consecutive patients, between March 2018 and June 2020, who underwent cardiac CT within 24 h before PVI to guide the ablation and rule out LAAT. NOAC was omitted 24 h before the ablation. Results: A total of 187 patients (63% male) underwent CT before PVI. None of the patients experienced stroke during or after the procedure. The complication rate was low, with no thromboembolic events and 2.1% of patients experiencing a major bleeding event. Conclusions: Omitting NOAC 24 h before the ablation might be safe if combined with left atrial thrombus exclusion with computed tomography.

Background: Ventricular tachycardia (VT) recurrence after catheter ablation remains a concern, emphasizing the need for precise risk assessment. We aimed to use machine learning (ML) to predict 1-month and 1-year VT recurrence following VT ablation. Methods: For 337 patients undergoing VT ablation, we collected 31 parameters including medical history, echocardiography, and procedural data. 17 relevant features were included in the ML-based feature selection, which yielded six and five optimal features for 1-month and 1-year recurrence, respectively. We trained several supervised machine learning models using 10-fold cross-validation for each endpoint. Results: We observed 1-month VT recurrence was observed in 60 (18%) cases and accurately predicted using our model with an area under the receiver operating curve (AUC) of 0.73. Input features used were hemodynamic instability, incessant VT, ICD shock, left ventricular ejection fraction, TAPSE, and non-inducibility of the clinical VT at the end of the procedure. A separate model was trained for 1-year VT recurrence (observed in 117 (35%) cases) with a mean AUC of 0.71. Selected features were hemodynamic instability, the number of inducible VT morphologies, left ventricular systolic diameter, mitral regurgitation, and ICD shock. For both endpoints, a random forest model displayed the highest performance. Conclusions: Our ML models effectively predict VT recurrence post-ablation, aiding in identifying high-risk patients and tailoring follow-up strategies.

AimsWe aimed to establish sex-specific predictors for 1-year VT recurrence and 1-year all-cause mortality in patients with structural heart disease undergoing catheter ablation.MethodsWe analyzed data of 299 patients recorded in our structured registry. These included medical history, echocardiography parameters, laboratory results, VT properties, procedural data.ResultsOut of the 299 patients, 34 (11%) were female. No significant difference was found between women and men in terms of VT recurrence (p = 0.74) or mortality (p = 0.07). In females, severe mitral regurgitation (MR), tricuspid regurgitation (TR), presentation with incessant VT, and preprocedural electrical storm (ES) were associated with increased risk of VT recurrence. Diabetes, implanted CRT, VT with hemodynamic instability, ES and advanced MR were the risk factors of mortality in women. ACEi/ARB use predicted a favorable outcome in both endpoints among females. In men, independent predictors of VT recurrence were the composite parameter of ES and multiple ICD therapies, presentation with incessant VT, severe MR, while independent predictors of mortality were age, LVEF, creatinine and previously implanted CRT.ConclusionAccording to our investigation, there are pronounced sex differences in predictors of recurrence and mortality following VT ablation.

IntroductionHigh-power short-duration (HPSD) radiofrequency ablation has been proposed to produce rapid and effective lesions for pulmonary vein isolation (PVI). We aimed to evaluate the procedural characteristics and the first-pass isolation (FPI) rate of HPSD and very high-power short-duration (vHPSD) ablation compared to the low-power long-duration (LPLD) ablation technique.MethodsOne hundred fifty-six patients with atrial fibrillation (AF) were enrolled and assigned to LPLD, HPSD, or vHPSD PVI. The energy setting was 30, 50, and 90 W in the LPLD, HPSD, and vHPSD groups, respectively. In the vHPSD group, 90 W/4 s energy delivery was used in the QMODE+ setting. In the other groups, ablation index-guided applications were delivered with 30 W (LPLD) or 50 W (HPSD).ResultsBilateral PVI was achieved in all cases. Compared to the LPLD group, the HPSD and vHPSD groups had shorter procedure time [85 (75–101) min, 79 (65–91) min, and 70 (53–83) min], left atrial dwelling time [61 (55–70) min, 53 (41–56) min, and 45 (34–52) min], total RF time [1,567 (1,366–1,761) s, 1,398 (1,021–1,711) s, and 336 (247–386) s], but higher bilateral FPI rate (57, 78, and 80%) (all p-values < 0.01). The use of HPSD (OR = 2.72, 95% CI 1.15–6.44, p = 0.023) and vHPSD (OR = 2.90, 95% CI 1.24–6.44, p = 0.014) ablation techniques were associated with a higher probability of bilateral FPI. The 9-month AF-recurrence rate was lower in case of HPSD and vHPSD compared to LPLD ablation (10, 8, and 36%, p = 0.0001). Moreover, the presence of FPI was associated with a lower AF-recurrence rate at 9-month (OR = 0.09, 95% CI 0.04–0.24, p = 0.0001).ConclusionOur prospective, observational cohort study showed that both HPSD and vHPSD RF ablation shortens procedure and RF time and results in a higher rate of FPI compared to LPLD ablation. Moreover, the use of HPSD and vHPSD ablation increased the acute and mid-term success rate. No safety concerns were raised for HPSD or vHPSD ablation in our study.

IntroductionPulmonary vein isolation is the cornerstone of rhythm-control therapy for atrial fibrillation (AF). The very high-power, short-duration (vHPSD) radiofrequency (RF) ablation is a novel technology that favors resistive heating while decreasing the role of conductive heating. Our study aimed to evaluate the correlations between contact force (CF), power, impedance drop (ID), and temperature; and to assess their role in lesion formation with the vHPSD technique.MethodsConsecutive patients who underwent initial point-by-point RF catheter ablation for AF were enrolled in the study. The vHPSD ablation was performed applying 90 W for 4 s with an 8 ml/min irrigation rate.ResultsData from 85 patients [median age 65 (59–71) years, 34% female] were collected. The median procedure time, left atrial dwelling time, and fluoroscopy time were 70 (60–90) min, 49 (42–58) min, and 7 (5–11) min, respectively. The median RF time was 312 (237-365) sec. No steam pop nor major complications occurred. A total of 6,551 vHPSD RF points were analyzed. The median of CF, maximum temperature, and ID were 14 (10–21) g, 47.6 (45.1–50.4) °C, and 8 (6–10) Ohms, respectively. CF correlated significantly with the maximum temperature (p < 0.0001). A CF of 5 g and above was associated with a significantly higher temperature compared to those lesions with a CF below 5 grams (p < 0.0001). Bilateral first-pass isolation rate was 84%. The 6-month AF-recurrence rate was 7%.ConclusionThe maximum temperature and CF significantly correlate with each other during vHPSD applications. A CF ≥ 5 g leads to better tissue heating and thus might be more likely to result in good lesion formation, although this clinical study was unable to assess actual lesion sizes.

IntroductionOur pilot study aimed to evaluate the role of local impedance drop in lesion formation during pulmonary vein isolation with a novel contact force sensing ablation catheter that records local impedance as well and to find a local impedance cut-off value that predicts successful lesion formation.Materials and methodsAfter completing point-by-point radiofrequency pulmonary vein isolation, the success of the applications was evaluated by pacing along the ablation line at 10 mA, 2 ms pulse width. Lesions were considered successful if loss of local capture was achieved.ResultsOut of 645 applications, 561 were successful and 84 were unsuccessful. Compared to the unsuccessful ablation points, the successful applications were shorter (p = 0.0429) and had a larger local impedance drop (pConclusionThe measurement of the local impedance may predict optimal lesion formation. A local impedance drop > 21.80 Ohms on the anterior wall and > 18.30 Ohms on the posterior wall significantly increases the probability of creating a successful lesion.

BackgroundRecognition of HLA-C2 group alleles on recipient cells by activating killer immunoglobulin like receptors, KIR2DS1 on donor natural killer cells may lead to increased graft-versus-leukemia effect or immunomodulation in patients treated by allogeneic hematopoietic stem cell transplantation (allo-HSCT) influencing disease free and overall survival (OS).ObjectiveIn the present study, 314 consecutive, allo-HSCT recipient and donor pairs were included with retrospective donor KIR-genotyping and clinical parameters analyzes.ResultsAfter a median follow-up of 23.6 months, recipients with HLA-C2 group allele (rC2) showed improved (p = 0.046) OS if transplanted with KIR2DS1 positive donors (d2DS1) compared to those without one or both of this genetic attribute. Within the myeloablative conditioning (MAC) subgroup (n = 227), rC2 homozygous+d2DS1 patients (n = 14) showed a 5 years OS of 93% followed by rC2 heterozygous+d2DS1 patients (n = 48, 65%) compared to rC2 and/or d2DS1 negatives (47%, p = 0.018). Multivariate analyses indicated rC2+d2DS1 positivity as an independent predictor of OS (HR:0.47, 0.26-0.86, p = 0.014) besides donor type, presence of CMV-reactivation or chemoresistant disease. Among MAC-treated patients, the combined rC2+d2DS1 presence was associated with a markedly decreased cumulative incidence of transplant related mortality (p = 0.0045).ConclusionThe combination of rC2+d2DS1 may be a favorable genetic constellation in allo-HSCT with MAC potentially reducing transplant related mortality.