Effect of early catheter ablation of atrial fibrillation in patients with heart failure.

INTRODUCTION: According to current guidelines, pulmonary vein isolation as first-line therapy should be considered for patients with atrial fibrillation (AF), however, optimal timing of the procedure is still unknown in patients with heart failure (HF). We aimed to evaluate the effect of early catheter ablation (CA) in patients with HF and left ventricular ejection fraction (LVEF) below 50%. METHODS: We analyzed data from a structured registry comprising 227 patients with paroxysmal or persistent AF and HF with LVEF < 50% who underwent radiofrequency CA between 2015 and 2022. Early CA was defined as a procedure performed within 12 months of AF diagnosis. The median follow-up duration was 1748 (1176.3-2353.5) days, with a minimum follow-up of 365 days. Our endpoints were AF recurrence after a 3-months blanking period and all-cause mortality. RESULTS: Among the 227 patients with a median age of 64.3 years, 97 (42.7%) experienced AF recurrence and 55 (24.2%) died during the follow-up period. The median LVEF was 40% for early CA and 38% for delayed CA (p = .053). Early CA significantly reduced AF recurrence (HR = 0.25 [0.15-0.42], p < .001), however, the timing of procedure did not affect all-cause mortality (p = .16). These findings were consistent regardless of AF subtype or the burden of comorbidities, as assessed by the CHA2DS2-VASc score. CONCLUSION: The timing of CA of AF appears to be an important factor in patients with HF. Early CA reduced AF recurrence, although it does not impact all-cause mortality. We found similar results regardless of AF subtype or burden of comorbidities.

Adherence to the CLOSE Protocol and Low Baseline Generator Impedance Are Independent Predictors of Durable Pulmonary Vein Isolation.

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.

Long-Term Durability of High- and Very High-Power Short-Duration PVI by Invasive Remapping: The HPSD Remap Study.

BACKGROUND: High-power short-duration ablation has shown impressive efficacy and safety for pulmonary vein isolation (PVI); however, initial efficacy results with very high power short-duration ablation were discouraging. This study compared the long-term durability of PVI performed with a 90- versus 50-W power setting. METHODS: Patients were randomized 1:1 to undergo PVI with the QDOT catheter using a power setting of 90 or 50 W. Three months after the index procedure, patients underwent a repeat electrophysiology study to identify pulmonary vein reconnections. Patients were followed for 12 months to detect AF recurrences. RESULTS: We included 46 patients (mean age, 64 years; women, 48%). Procedure (76 versus 84 minutes; P =0.02), left atrial dwell (63 versus 71 minutes; P =0.01), and radiofrequency (303 versus 1040 seconds; P <0.0001) times were shorter with 90- versus 50-W procedures, while the number of radiofrequency applications was higher with 90 versus 50 W (77 versus 67; P =0.01). There was no difference in first-pass isolation (83% versus 82%; P =1.0) or acute reconnection (4% versus 14%; P =0.3) rates between 90 and 50 W. Forty patients underwent a repeat electrophysiology study. Durable PVI on a per PV basis was present in 72/78 (92%) versus 68/77 (88%) PVs in the 90- and 50-W energy setting groups, respectively; effect size: 72/78-68/77=0.040, lower 95% CI=-0.051 (noninferiority limit=-0.1, ie, noninferiority is met). No complications occurred. There was no difference in 12-month atrial fibrillation-free survival between the 90- and 50-W groups (P =0.2). CONCLUSIONS: Similarly high rates of durable PVI and arrhythmia-free survival were achieved with 90 and 50 W. Procedure, left atrial dwell, and radiofrequency times were shorter with 90 W compared with 50 W. The sample size is too small to conclude the safety and long-term efficacy of the high and very high-power short-duration PVI; further studies are needed to address this topic. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT05459831.

One-Day Interruption of NOAC Is Associated with Low Risk of Periprocedural Adverse Events during Pulmonary Vein Isolation If Combined with Left Atrial Thrombus Exclusion with Computed Tomography.

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.

Feasibility and image quality of bright-blood and black-blood phase-sensitive inversion recovery (BOOST) sequence in clinical practice using for left atrial visualization in patients with atrial fibrillation.

OBJECTIVES: Visualizing left atrial anatomy including the pulmonary veins (PVs) is important for planning the procedure of pulmonary vein isolation with ablation in patients with atrial fibrillation (AF). The aims of our study are to investigate the feasibility of the 3D whole-heart bright-blood and black-blood phase-sensitive (BOOST) inversion recovery sequence in patients with AF scheduled for ablation or electro-cardioversion, and to analyze the correlation between image quality and heart rate and rhythm of patients. METHODS: BOOST was performed for assessing PVs both with T2 preparation pre-pulse (T2prep) and magnetization transfer preparation (MTC) in 45 patients with paroxysmal or permanent AF scheduled for ablation or electro-cardioversion. Image quality analyses were performed by two independent observers. Qualitative assessment was made using the Likert scale; for quantitative analysis, signal to noise ratios (SNR) and contrast to noise ratios (CNR) were calculated for each PV. Heart rate and rhythm were analyzed based on standard 12-lead ECGs. RESULTS: All MTC-BOOST acquisitions achieved diagnostic quality in the PVs, while a significant proportion of T2prep-BOOST images were not suitable for assessing PVs. SNR and CNR values of the MTC-BOOST bright-blood images were higher if patients had sinus rhythm. We found a significant or nearly significant negative correlation between heart rate and the SNR and CNR values of MTC-BOOST bright-blood images. CONCLUSION: 3D whole-heart MTC-BOOST bright-blood imaging is suitable for visualizing the PVs in patients with AF, producing diagnostic image quality in 100% of cases. However, image quality was influenced by heart rate and rhythm. CLINICAL RELEVANCE STATEMENT: The novel 3D whole-heart BOOST CMR sequence needs no contrast administration and is performed during free-breathing; therefore, it is easy to use for a wide range of patients and is suitable for visualizing the PVs in patients with AF. KEY POINTS: • The applicability of the novel 3D whole-heart bright-blood and black-blood phase-sensitive sequence to pulmonary vein imaging in clinical practice is unknown. • Magnetization transfer-bright-blood and black-blood phase-sensitive imaging is suitable for visualizing the pulmonary veins in patients with atrial fibrillation with excellent or good image quality. • Bright-blood and black-blood phase-sensitive cardiac magnetic resonance sequence is easy to use for a wide range of patients as it needs no contrast administration and is performed during free-breathing.

Machine-Learning-Based Prediction of 1-Year Arrhythmia Recurrence after Ventricular Tachycardia Ablation in Patients with Structural Heart Disease.

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.

Incidence and predictors of stroke and silent cerebral embolism following very high-power short-duration atrial fibrillation ablation.

AIMS: Cerebral thrombo-embolism is a dreaded complication of pulmonary vein isolation (PVI) for atrial fibrillation; its surrogate, silent cerebral embolism (SCE) can be detected by diffusion-weighted brain magnetic resonance imaging (bMRI). Initial investigations have raised a concern that very high-power, short-duration (vHPSD; 90 W/4 s) temperature-controlled PVI with the QDOT Micro catheter may be associated with a higher incidence of SCE compared with low-power long-duration ablation. We aimed to assess the incidence of procedural complications of vHPSD PVI with an emphasis on cerebral safety. METHODS AND RESULTS: We enrolled 328 consecutive patients undergoing their PVI procedure using vHPSD. A subgroup of 61 consecutive patients underwent diffusion-weighted bMRI within 24 h of the procedure, and incidence and predictors of SCE were studied. The mean procedure time and left atrial dwell time for the overall cohort were 69.6 ± 24.1 and 46.5 ± 21.5 min, respectively. First-pass isolation was achieved in 82%. No stroke or transient ischaemic attack occurred. Silent cerebral embolism was identified in 5 of 61 patients (8.2%). Silent cerebral embolism following procedures was significantly associated with lower baseline generator impedance (105.8 vs. 112.6 Ω, P < 0.0001) and with intermittent loss of catheter-tissue contact during ablation (14.1% vs. 6.1%, P < 0.0001). CONCLUSION: Very high-power, short-duration PVI is a safe technique with an excellent acute success rate. Silent cerebral embolism incidence in our cohort was below the previously reported range, with no clinically overt cerebral complications. Lower baseline generator impedance and loss of contact during ablation may contribute to a higher risk of SCEs.

Zero fluoroscopy ablation for atrioventricular nodal reentrant tachycardia and typical atrial flutter is equally safe and effective with EnSite NavX, Carto3, and Rhythmia mapping systems.

Purpose: Our 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). Methods: 186 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. Results: The 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]. Discussion: The ZF approach demonstrated non-inferiority in safety and efficacy compared with CF for the AVNRT and Aflu ablations.

Novel protocol for optimal utilization of HPSD approach for pulmonary vein isolation.

Background: The efficiency of pulmonary vein isolation (PVI) depends on the durability of RF lesions. Recent studies documented sustained continuity of ablation lines, improvements in durability, and expected clinical outcomes through altered settings in duration and power. However, the ablation strategy has not been adapted to this new approach and different biophysics of lesion formation. Purpose: The aim of this study was to demonstrate that by adjusting the ablation approach to the broader geometry of lesions by increasing the minimal spacing between adjacent RF, a further significant reduction of procedural time while maintaining sufficient long-term outcomes is achievable. Methods: The presented study was a prospective, observational multi-center trial. The periprocedural data were compared with data from a consecutively collected historical cohort. Results: In total, 196 patients were included (mean age 62 ± 11 years, male 64.3%). Procedural duration, RF time, and LA dwelling time were significantly shorter in the HPSD group compared with the standard group (73 ± 26 min vs. 98 ± 36 min, p < .001; 14 ± 7 min vs. 33 ± 12 min, p < .001; and 59 ± 21 min vs. 77 ± 32 min, p < .001, respectively). Mean AF-free survival in the first year of follow-up was 304 ± 14 days in the HPSD group versus 340 ± 10 days in the standard group (log-rank p = .403). There were no statistically significant differences in the complication rates between the groups. Conclusion: Increasing the minimal distance between individual application points simplifies AF ablation and further reduces procedure time without negative effects on efficacy and safety. Larger studies are needed to optimally utilize this approach.

Routine use of a 3D mapping system in the ablation of supraventricular arrhythmias with as low as reasonably achievable X-ray exposure (AALARA): protocol for a prospective, observational, multicentre, multinational, open-label registry study.

INTRODUCTION: The reduction of fluoroscopic exposure during catheter ablation of supraventricular arrhythmias is widely adopted by experienced electrophysiology physicians with a relatively short learning curve and is becoming standard of care in many parts of the world. While observational studies in the USA and some parts of Western Europe have evaluated the minimal fluoroscopic approach, there are scarce real-world data for this technique and generalisability of outcome in other economic regions. METHODS AND ANALYSIS: The arrhythmias with as low as reasonably achievable X-ray exposure study is a prospective, observational, multicentre and multinational open-label registry study. Up to 700 patients undergoing catheter ablation for right-sided supraventricular arrhythmias (according to national guidelines) will be enrolled for the routine use of the EnSite Precision 3D mapping system. Participating sites are distributed in 13 countries from Central Eastern Europe, North and South Africa, the Middle East and the CIS (Commonwealth of Independent States), with different levels of expertise using minimal fluoroscopic exposure techniques. After electrophysiological procedure, patients will be followed up for 6 months either in-clinic or via telephone interview. Patients will be asked to complete a study questionnaire at enrolment and 6 months after the invasive procedure to assess quality of life changes secondary to the procedure. The study's primary objective is to describe ionising radiation exposure during catheter ablation when the EnSite Precision 3D mapping system is used in supraventricular tachycardia ablation. The study's secondary objective is to assess the safety and efficacy of this method. Furthermore, fluoroscopy timing, total procedure time, success rate and complications will be reported. ETHICS AND DISSEMINATION: The study was approved by the ethics committee at Mohammed Bin Khalifa Specialist Cardiac Centre (BDF/R&REC/2020-504) and the medical ethics committees of all participating sites. Participants will be required to provide informed consent before enrolment in the study. The study results will be published and presented at conferences. TRIAL REGISTRATION NUMBER: NCT04716270.

Use of a new non-contrast-enhanced BOOST cardiac MR sequence before electrical cardioversion or ablation of atrial fibrillation-a pilot study.

Introduction: Left atrial appendage (LAA) thrombus is the most common source of embolization in atrial fibrillation (AF). Transesophageal echocardiography (TEE) is the gold standard method for LAA thrombus exclusion. Our pilot study aimed to compare the efficacy of a new non-contrast-enhanced cardiac magnetic resonance (CMR) sequence (BOOST) with TEE for the detection of LAA thrombus and to evaluate the usefulness of BOOST images for planning radiofrequency catheter ablation (RFCA) compared with left atrial (LA) contrast-enhanced computed tomography (CT). We also attempted to assess the patients' subjective experiences with TEE and CMR. Methods: Patients with AF undergoing either electrical cardioversion or RFCA were enrolled. Participants underwent pre-procedural TEE and CMR scans to evaluate LAA thrombus status and pulmonary vein anatomy. Patient experiences with TEE and CMR were assessed using a questionnaire developed by our team. Some patients scheduled for RFCA also had pre-procedural LA contrast-enhanced CT. In such cases, the operating physician was asked to subjectively define the quality of the CT and CMR scan on a scale of 1-10 (1 = worst, 10 = best) and comment on CMR's usefulness in RFCA planning. Results: Seventy-one patients were enrolled. In 94.4%, both TEE and CMR excluded, and in 1 patient, both modalities reported the presence of LAA thrombus. In 1 patient, TEE was inconclusive, but CMR excluded LAA thrombus. In 2 patients, CMR could not exclude the presence of thrombus, but in 1 of those cases, TEE was also indecisive. During TEE, 67%, during CMR, only 1.9% of patients reported pain (p < 0.0001), and 89% would prefer CMR in case of a repeat examination. The quality of the left atrial contrast-enhanced CT scans was better compared with the image quality of the CMR BOOST sequence [8 (7-9) vs. 6 (5-7), p < 0.0001]. Still, the CMR images were useful for procedural planning in 91% of cases. Conclusion: The new CMR BOOST sequence provides appropriate image quality for ablation planning. The sequence might be useful for excluding larger LAA thrombi; however, its accuracy in detecting smaller thrombi is limited. Most patients preferred CMR over TEE in this indication.

High incidence of newly diagnosed obstructive coronary artery disease regardless of chest pain detected on pre-procedural cardiac computed tomography angiography in patients undergoing atrial fibrillation ablation.

BACKGROUND: Cardiac computed tomography (CT) is often performed before catheter ablation of atrial fibrillation to map atrial and pulmonary anatomy. Incident coronary artery disease (CAD) may also be diagnosed during cardiac CT angiography (CTA). Our aim was to assess whether coronary CTA might be able to identify a significant proportion of patients with obstructive CAD prior to their catheter ablation procedure event, even in asymptomatic patients. METHODS: Consecutive patients undergoing pre-ablation coronary CTA for atrial fibrillation between 2013 and 2020 were retrospectively selected. Patients with previously diagnosed CAD were excluded. Obstructive CAD was defined as ≥50% luminal stenosis. We analyzed the relationship between obstructive CAD, any chest pain, and traditional risk factors. RESULTS: Overall, 2321 patients [median age 63.0 (54.4-69.2), 1052/2321 (45.3%) female] underwent coronary CTA and 488/2321 (21.0%) were diagnosed with obstructive CAD. There was no difference regarding the rate of obstructive CAD in patients with any chest pain compared to patients without any chest pain [91/404 (22.5%) vs. 397/1917 (20.7%), P = 0.416, respectively). The following parameters were associated with obstructive CAD: age > 65 years [odds ratio (OR) = 2.51; 95% confidence interval (CI), 2.02-3.13; P < 0.001), male sex (OR = 1.59; 95% CI, 1.28-1.98; P < 0.001), hypertension (OR = 1.40; 95% CI, 1.08-1.81; P = 0.012), diabetes (OR = 1.50; 95% CI, 1.13-1.99; P = 0.006), dyslipidaemia (OR = 1.33; 95% CI, 1.07-1.66; P = 0.011) and history of smoking (OR = 1.34; 95% CI, 1.07-1.68; P = 0.011). CONCLUSIONS: The high prevalence of obstructive CAD even in patients without chest pain highlights the importance of additional coronary artery diagnostics in patients undergoing left atrial CTA awaiting catheter ablation for atrial fibrillation. These patients regardless of chest pain thus may require further risk modification to decrease their potential ischemic and thromboembolic risk.

Sex differences in one-year recurrence and all-cause mortality following catheter ablation of ventricular tachycardia in structural heart disease.

Aims: We 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. Methods: We analyzed data of 299 patients recorded in our structured registry. These included medical history, echocardiography parameters, laboratory results, VT properties, procedural data. Results: Out 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. Conclusion: According to our investigation, there are pronounced sex differences in predictors of recurrence and mortality following VT ablation.

Asymptomatic left circumflex artery stenosis is associated with higher arrhythmia recurrence after persistent atrial fibrillation ablation.

Background: The pathophysiology of persistent atrial fibrillation (AF) remains unclear. While several studies have demonstrated an association between myocardial infarction and atrial fibrillation, the role of stable coronary artery disease (CAD) is still unknown. As a result, we aimed to assess the association between CAD obstruction and AF recurrence after persistent AF ablation in patients with no history of CAD. Materials and methods: This observational retrospective study included consecutive patients who underwent routine preprocedural cardiac computed tomography (CCT) before persistent AF ablation between September 2015 and June 2018 in 5 European University Hospitals. Exclusion criteria were CAD or coronary revascularization previously known or during follow-up. Obstructive CAD was defined as luminal stenosis ≥ 50%. Results: All in all, 496 patients (mean age 61.8 ± 10.0 years, 76.2% males) were included. CHA2DS2-VASc score was 0 or 1 in 225 (36.3%) patients. Obstructive CAD was present in 86 (17.4%) patients. During the follow-up (24 ± 19 months), 207 (41.7%) patients had AF recurrence. The recurrence rate was not different between patients with and without obstructive CAD (43.0% vs. 41.5%, respectively; P = 0.79). When considering the location of the stenosis, the recurrence rate was higher in the case of left circumflex obstruction: 56% vs. 32% at 2 years (log-rank P ≤ 0.01). After Cox multivariate analysis, circumflex artery obstruction (HR 2.32; 95% CI 1.36-3.98; P < 0.01) was independently associated with AF recurrence. Conclusion: Circumflex artery obstruction detected with CCT was independently associated with 2-fold increase in the risk of AF recurrence after persistent AF ablation. Further research is necessary to evaluate this pathophysiological relationship.

Left atrial anatomical variations correlate with atrial fibrillation sources near the left atrial ridge.

Introduction: Anatomical variations and characteristics of the left atrium (LA) may have a previously undescribed effect on source locations in atrial fibrillation (AF). This is the first study aiming to investigate the relationship between anatomical characteristics of the LA and non-PV sources detected by electrographic flow (EGF) mapping in patients with persistent AF. Materials and methods: We analyzed cardiac computed tomography (CT) and EGF mapping data in patients who underwent radiofrequency catheter ablation (CA). EGF mapping is a novel method based on Horn-Schunk flow estimation algorithm, used to estimate cardiac action potential flow in the atria that can detect AF sources in patients with persistent AF. By analyzing EGF maps obtained during CA procedures, we localized non-PV sources in the LA. Results: Thirty patients were included in this study (mean age 62.4 ± 6.8 years). Ten patients had AF sources near the LA ridge, while twenty patients had no leading source (source activity > 26%) near the LA ridge. LA anatomical characteristics, left atrial appendage (LAA) length, and ostial diameter showed no correlation with the presence of a leading source. We documented 19 patients with abutting LAA and left superior pulmonary vein (LSPV) (distance < 2 mm), and 11 patients with non-abutting LAA-LSPV (distance > 2 mm). Three out of 19 patients presented with a leading source near ridge in the abutting LAA-LSPV group, while 7 out of 11 patients presented with a leading source near the ridge in the non-abutting LAA-LSPV group (p = 0.01). Conclusion: Our data suggests that non-abutting LAA-LSPV is associated with the presence of AF sources near the LA ridge.

Characteristics of Very High-Power, Short-Duration Radiofrequency Applications.

Introduction: Pulmonary 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. Methods: Consecutive 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. Results: Data 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%. Conclusion: The 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.

Randomized comparison of atrioventricular node re-entry tachycardia and atrial flutter catheter ablation with and without fluoroscopic guidance: ZeroFluoro study.

AIMS: Interventional cardiology procedures may expose patients and staff to considerable radiation doses. We aimed to assess whether exposure to ionizing radiation during catheter ablation of supraventricular tachycardia (SVT) can be completely avoided. METHODS AND RESULTS: In this prospective randomized study, patients with SVT (atrioventricular re-entrant tachycardia n = 94, typical atrial flutter n = 29) were randomly assigned in a 1:1 ratio to catheter ablation with conventional fluoroscopic guidance (CF group) or with the EnSite Precision mapping system [zerofluoro (ZF) group]. Acute procedural parameters, increased stochastic risk of cancer incidence and 6-month follow-up data were assessed. Between May 2019 and August 2020, 123 patients were enrolled. Clinical parameters were comparable. Median procedural time was 60.0 and 58.0 min, median fluoroscopy time and estimated median effective dose were 240 s vs. 0 and 0.38 mSv vs. 0 and arrhythmia recurrence was 5% and 7.9% in the CF and ZF groups, respectively. The acute success rate was 98.4% in both groups. No procedure-related complications were reported. At an average age of 55.5 years and median radiation exposure of 0.38 mSv, the estimate of increased incidence was approximately 1 in 14 084. The estimated mortality rate was 1 per 17 857 exposed persons. CONCLUSIONS: The procedural safety and efficacy of the zero-fluoroscopic approach are similar to those of conventional fluoroscopy-based ablation for atrioventricular nodal re-entrant tachycardia and atrial flutter. Under the assumption of low radiation dose, the excessive lifetime risk of malignancy in the CF group due to electrophysiology procedure is reasonably small, whilst totally reduced in zero fluoroscopy procedures.

Impact of High-Power and Very High-Power Short-Duration Radiofrequency Ablation on Procedure Characteristics and First-Pass Isolation During Pulmonary Vein Isolation.

Introduction: High-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. Methods: One 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). Results: Bilateral 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). Conclusion: Our 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.

Selection of an impedance- or magnetic field-based electro-anatomical mapping platform does not affect outcomes of outflow tract premature ventricular complex manual ablation.

Comparative data are virtually missing about the performance of different electro-anatomical mapping (EAM) system platforms on outflow tract (OT) premature ventricular complex (PVC) ablation outcomes with manual ablation catheters. We aimed to compare the acute success-, complication-, and long-term recurrence rates of impedance-based (IMP) and magnetic field-based (MAG) EAM platforms in manual OT PVC ablation. Single-centre, propensity score matched data of 39-39 patients ablated for OT PVCs in 2015-17 with IMP or MAG platforms were analysed. Acute success rate, peri-procedural complications, post-ablation daily PVC burden, and long-term recurrence rates were compared on intention-to-treat basis. Acute success rate was similar in the IMP and MAG group (77 vs. 82%, p = 0.78). There was a single case of femoral pseudo-aneurysm and no cardiac tamponade occurred. PVC burden fell significantly from baseline 24.0% [15.0-30.0%] to 3.3% [0.25-10.5%] (p < 0.001) post-ablation, with no difference between EAM platforms (IMP: 2.6% [0.5-12.0%] vs. MAG: 4.0% [2.0-6.5%]; p = 0.60). There was no significant difference in recurrence-free survival of the intention-to-treat cohort of the IMP and MAG groups (54 vs. 60%, p = 0.82, respectively) during 12 months of follow-up. Ablation with the aid of both impedance- and magnetic field-based EAM platforms can considerably reduce OT PVC burden and give similar acute- and long-term freedom from arrhythmia.

Abutting Left Atrial Appendage and Left Superior Pulmonary Vein Predicts Recurrence of Atrial Fibrillation After Point-by-Point Pulmonary Vein Isolation.

INTRODUCTION: The role of the spatial relationship between the left superior pulmonary vein (LSPV) and left atrial appendage (LAA) is unknown. We sought to evaluate whether an abutting LAA and LSPV play a role in AF recurrence after catheter ablation for paroxysmal AF. METHODS: Consecutive patients, who underwent initial point-by-point radiofrequency catheter ablation for paroxysmal AF at the Heart and Vascular Center of Semmelweis University, Budapest, Hungary, between January of 2014 and December of 2017, were enrolled in the study. All patients underwent pre-procedural cardiac CT to assess left atrial (LA) and pulmonary vein (PV) anatomy. Abutting LAA-LSPV was defined as cases when the minimum distance between the LSPV and LAA was less than 2 mm. RESULTS: We included 428 patients (60.7 ± 10.8 years, 35.5% female) in the analysis. AF recurrence rate was 33.4%, with a median recurrence-free time of 21.2 (8.8-43.0) months. In the univariable analysis, female sex (HR = 1.45; 95%CI = 1.04-2.01; p = 0.028), LAA flow velocity (HR = 1.01; 95%CI = 1.00-1.02; p = 0.022), LAA orifice area (HR = 1.00; 95%CI = 1.00-1.00; p = 0.028) and abutting LAA-LSPV (HR = 1.53; 95%CI = 1.09-2.14; p = 0.013) were associated with AF recurrence. In the multivariable analysis, abutting LAA-LSPV (adjusted HR = 1.55; 95%CI = 1.04-2.31; p = 0.030) was the only independent predictor of AF recurrence. CONCLUSION: Abutting LAA-LSPV predisposes patients to have a higher chance for arrhythmia recurrence after catheter ablation for paroxysmal AF.