Personalized pulmonary vein antrum isolation guided by left atrial wall thickness for persistent atrial fibrillation.

AIMS: Pulmonary vein (PV) antrum isolation proved to be effective for treating persistent atrial fibrillation (PeAF). We sought to investigate the results of a personalized approach aimed at adapting the ablation index (AI) to the local left atrial wall thickness (LAWT) in a cohort of consecutive patients with PeAF. METHODS AND RESULTS: Consecutive patients referred for PeAF first ablation were prospectively enrolled. The LAWT three-dimensional maps were obtained from pre-procedure multidetector computed tomography and integrated into the navigation system. Ablation index was titrated according to the local LAWT, and the ablation line was personalized to avoid the thickest regions while encircling the PV antrum. A total of 121 patients (69.4% male, age 64.5 ± 9.5 years) were included. Procedure time was 57 min (IQR 50-67), fluoroscopy time was 43 s (IQR 20-71), and radiofrequency (RF) time was 16.5 min (IQR 14.3-18.4). The median AI tailored to the local LAWT was 387 (IQR 360-410) for the anterior wall and 335 (IQR 300-375) for the posterior wall. First-pass PV antrum isolation was obtained in 103 (85%) of the right PVs and 103 (85%) of the left PVs. Median LAWT values were higher for PVs without first-pass isolation as compared to the whole cohort (P = 0.02 for left PVs and P = 0.03 for right PVs). Recurrence-free survival was 79% at 12 month follow-up. CONCLUSION: In this prospective study, LAWT-guided PV antrum isolation for PeAF was effective and efficient, requiring low procedure, fluoroscopy, and RF time. A randomized trial comparing the LAWT-guided ablation with the standard of practice is in progress (ClinicalTrials.gov, NCT05396534).

Cardiovascular magnetic resonance determinants of ventricular arrhythmic events after myocardial infarction.

AIMS: To non-invasively characterize, by means of late gadolinium enhancement cardiac magnetic resonance (LGE-CMR), scar differences, and potential variables associated with ventricular tachycardia (VT) occurrence in chronic post-myocardial infarction (MI) patients. METHODS AND RESULTS: A case-control study was designed through retrospective LGE-CMR data analysis of chronic post-MI patients (i) consecutively referred for VT substrate ablation after a first VT episode (n = 66) and (ii) from a control group (n = 84) with no arrhythmia evidence. The myocardium was characterized differentiating core, border zone (BZ), and BZ channels (BZCs) using the ADAS 3D post-processing imaging platform. Clinical and scar characteristics, including a novel parameter, the BZC mass, were compared between both groups. One hundred and fifty post-MI patients were included. Four multivariable Cox proportional hazards regression models were created for total scar mass, BZ mass, core mass, and BZC mass, adjusting them by age, sex, and left ventricular ejection fraction (LVEF). A cut-off of 5.15 g of BZC mass identified the cases with 92.4% sensitivity and 86.9% specificity [area under the ROC curve (AUC) 0.93 (0.89-0.97); P < 0.001], with a significant increase in the AUC compared to other scar parameters (P < 0.001 for all pairwise comparisons). Adding BZC mass to LVEF allowed to reclassify 33.3% of the cases and 39.3% of the controls [net reclassification improvement = 0.73 (0.71-0.74)]. CONCLUSIONS: The mass of BZC is the strongest independent variable associated with the occurrence of sustained monomorphic ventricular tachycardia in post-MI patients after adjustment for age, sex, and LVEF. Border zone channel mass measurement could permit a more accurate VT risk stratification than LVEF in chronic post-MI patients.

Personalized paroxysmal atrial fibrillation ablation by tailoring ablation index to the left atrial wall thickness: the 'Ablate by-LAW' single-centre study-a pilot study.

AIMS: To determine if adapting the ablation index (AI) to the left atrial wall thickness (LAWT), which is a determinant of lesion transmurality, is feasible, effective, and safe during paroxysmal atrial fibrillation (PAF) ablation. METHODS AND RESULTS: Consecutive patients referred for PAF first ablation. Left atrial wall thickness three-dimensional maps were obtained from multidetector computed tomography and integrated into the CARTO navigation system. Left atrial wall thickness was categorized into 1 mm layers and AI was titrated to the LAWT. The ablation line was personalized to avoid thicker regions. Primary endpoints were acute efficacy and safety, and freedom from atrial fibrillation (AF) recurrences. Follow-up (FU) was scheduled at 1, 3, 6, and every 6 months thereafter. Ninety patients [60 (67%) male, age 58 ± 13 years] were included. Mean LAWT was 1.25 ± 0.62 mm. Mean AI was 366 ± 26 on the right pulmonary veins with a first-pass isolation in 84 (93%) patients and 380 ± 42 on the left pulmonary veins with first-pass in 87 (97%). Procedure time was 59 min (49-66); radiofrequency (RF) time 14 min (12.5-16); and fluoroscopy time 0.7 min (0.5-1.4). No major complication occurred. Eighty-four out of 90 (93.3%) patients were free of recurrence after a mean FU of 16 ± 4 months. CONCLUSION: Personalized AF ablation, adapting the AI to LAWT allowed pulmonary vein isolation with low RF delivery, fluoroscopy, and procedure time while obtaining a high rate of first-pass isolation, in this patient population. Freedom from AF recurrences was as high as in more demanding ablation protocols. A multicentre trial is ongoing to evaluate reproducibility of these results.

Cardiac magnetic resonance to predict recurrences after ventricular tachycardia ablation: septal involvement, transmural channels, and left ventricular mass.

AIMS: Ventricular tachycardia (VT) substrate-based ablation has an increasing role in patients with structural heart disease-related VT. VT is linked to re-entry in relation to myocardial scarring with areas of conduction block (core scar) and areas of slow conduction [border zone (BZ)]. VT substrate can be analysed by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Our study aims to analyse the role of LGE-CMR in identifying predictors of VT recurrence after ablation. METHODS AND RESULTS: We analysed 110 consecutive patients who underwent VT ablation from 2013 to 2018. All patients underwent a preprocedural LGE-CMR, and in 94 patients (85.5%), the CMR was used to aid the ablation. All LGE-CMR images were semi-automatically processed using dedicated software to detect scarring and conducting channels. After a median follow-up of 2.7 ± 1.6 years, the overall VT recurrence was 41.8% with an implantable cardioverter-defibrillator shock reduction from 43.6% to 28.2% before and after ablation, respectively. The amount of BZ (26.6 ± 13.9 vs. 19.6 ± 9.7 g, P = 0.012), the total amount of scarring (37.1 ± 18.2 vs. 29 ± 16.3 g, P = 0,033), and left ventricular (LV) mass (168.3 ± 53.3 vs. 152.3 ± 46.4 g, P < 0.001) were associated with VT recurrence. LGE septal distribution [62.5% vs. 37.8%; hazard ratio (HR) 1.67 (1.02-3.93), P = 0.044], channels with transmural path [66.7% vs. 31.4%, HR 3.25 (1.70-6.23), P < 0.001], and midmural channels [54.3% vs. 27.6%, HR 2.49 (1.21-5.13), P = 0.013] were related with VT recurrence. Multivariate analysis showed that the presence of septal LGE [HR 3.67 (1.60-8.38), P = 0.002], transmural channels [HR 2.32 (1.15-4.72), P = 0.019], and LV mass [HR 1.01 (1.005-1.019), P = 0.002] were independent predictors of VT recurrence. CONCLUSION: Pre-procedural LGE-CMR is a helpful and feasible technique to identify patients with high risk of VT recurrence after ablation. LV mass, septal LGE distribution, and transmural channels were predictive factors of post-ablation VT recurrence.

Optimized single-point left ventricular pacing leads to improved resynchronization compared with multipoint pacing.

BACKGROUND: Multipoint pacing (MPP) in cardiac resynchronization therapy (CRT) activates the left ventricle from two locations, thereby shortening the QRS duration and enabling better resynchronization; however, compared with conventional CRT, MPP reduces battery longevity. On the other hand, electrocardiogram-based optimization using the fusion-optimized intervals (FOI) method achieves more significant reverse remodeling than nominal CRT programming. Our study aimed to determine whether MPP could attain better resynchronization than single-point pacing (SPP) optimized by FOI. METHODS: This prospective study included 32 consecutive patients who successfully received CRT devices with MPP capabilities. After implantation, the QRS duration was measured during intrinsic rhythm and with three pacing configurations: MPP, SPP-FOI, and MPP-FOI. In 14 patients, biventricular activation times (by electrocardiographic imaging, ECGI) were obtained during intrinsic rhythm and for each pacing configuration to validate the findings. Device battery longevity was estimated at the 45-day follow-up. RESULTS: The SPP-FOI method achieved greater QRS shortening than MPP (-56 ± 16 vs. -42 ± 17 ms, p < .001). Adding MPP to the best FOI programming did not result in further shortening (MPP-FOI: -58 ± 14 ms, p = .69). Although biventricular activation times did not differ significantly among the three pacing configurations, only the two FOI configurations achieved significant shortening compared with intrinsic rhythm. The estimated battery longevity was longer with SPP than with MPP (8.1 ± 2.3 vs. 6.3 ± 2.0 years, p = .03). CONCLUSIONS: SPP optimized by FOI resulted in better resynchronization and longer battery duration than MPP.

Impact of cryoballoon applications on lesion gaps detected by magnetic resonance after pulmonary vein isolation.

INTRODUCTION: Ablation with second-generation cryoballoon technology evolves as an effective and safe alternative to radiofrequency for atrial fibrillation ablation procedures. Nevertheless, the optimal freezing strategy remains unknown. Our objective was to identify the procedural cryoablation parameters predicting successful peri-pulmonary vein (PV) lesions by directly analyzing Postablation gaps in late-gadolinium-enhanced cardiac magnetic resonance (LGE-CMR). METHODS AND RESULTS: Forty-nine consecutive patients (196 PVs) undergoing ablation with second-generation cryoballoon at our center were included. The number and duration of cryoballoon application to achieve PV isolation were left to operator discretion. Gap number and length were quantified in all patients with a LGE-CMR performed 3 months postablation. Application time (420 ± 217 seconds), number of applications (2.1 ± 1.2), application time after electrical isolation (311 ± 194 seconds) and minimum temperature (-45.8 ± 6.5°C) were similar in the 4 PVs. Gaps were observed in 148 PVs (76%), averaging 1.3 ± 1 gaps per vein. Gaps were longer and more frequent in the right PVs (91% vs 59% in left PVs, P < .001). Neither the number, total duration of applications, nor postisolation application time predicted relative length or number of gaps. CONCLUSIONS: After successful PV isolation was achieved in patients undergoing cryoablation, increasing the number of applications, the total application time or application time postisolation did not result in a reduction in the number or the relative length of gaps.

Very high pacing thresholds during long-term follow-up predicted by a combination of implant pacing threshold and impedance in leadless transcatheter pacemakers.

BACKGROUND: Micra transcatheter pacemaker system (TPS) usually achieves low implant pacing threshold (IPT). However, IPT may increase in some patients during follow-up. AIM: To apply implant parameters in predicting long-term occurrence of very high pacing threshold (VHPT) in patients with Micra-TPS. METHODS: A cohort of 110 consecutive patients implanted with a Micra-TPS from 2014 to 2018 was evaluated at discharge and at 1, 12, 24, 36, and 48 months follow-up. VHPT was defined as greater than 2 V/0.24 ms. VHPT predictors were identified. RESULTS: Micra-TPS was implanted successfully in 108 patients (98.2%). During a mean follow-up of 24 ± 16 months, 18 patients (16.7%) died of causes nonpacemaker-related, and 4 (3.8%) developed VHPT. Patients with VHPT had higher IPT and lower implant impedance than patients with non-VHPT: 1 ± 0.31 vs 0.55 ± 0.29 V/0.24 ms (P = .003) and 580 ± 59 vs 837 ± 232 Ω (P = .03), respectively. IPT and impedance had excellent discriminative power to predict VHPT (area under the curve: 0.85 ± 0.07 and 0.91 ± 0.05, respectively). Negative predictive value (NPV) of IPT ≤ 0.5 V/0.24 ms was 100%; positive predictive value (PPV) was 8% throughout follow-up. Implant impedance ≤ 600 Ω had NPV of 99% throughout follow-up, whereas PPV varied: 16%, 21%, 16%, and 28% at 1, 12, 24, and 36 months, respectively. Sequential combination of IPT greater than 0.5 V/0.24 ms and impedance ≤ 600 Ω improved PPV to 25%, 35%, 27%, and 44%, respectively, whereas NPV remained 99% throughout follow-up. CONCLUSION: Despite favorable long-term electrical performance of Micra-TPS, a small percent of patients developed VHPT during follow-up. A sequential combination of IPT and impedance could allow the implanter to identify patients who will develop VHPT during long-term follow-up.

Magnetic resonance-guided re-ablation for atrial fibrillation is associated with a lower recurrence rate: a case-control study.

AIMS: Our aim was to analyse whether using delayed enhancement cardiac magnetic resonance imaging (DE-CMR) to localize veno-atrial gaps in atrial fibrillation (AF) redo ablation procedures improves outcomes during follow-up. METHODS AND RESULTS: We conducted a case-control study with 35 consecutive patients undergoing a DE-CMR-guided Repeat-pulmonary vein isolation (Re-PVI) procedure. Those with more extensive ablations (e.g. roof lines, box) were excluded. Patients were matched for age, sex, AF pattern, and left atrial dimension with 35 patients who had undergone a conventional Re-PVI procedure guided with a three dimensional (3D)-navigation system. Procedural characteristics were recorded, and patients were followed for 24 months in a specialized outpatient clinic. The primary endpoint was freedom from recurrent AF, atrial tachycardia, or flutter. The duration of CMR-guided procedures was shorter compared to the conventional group (161 ± 52 vs. 195 ± 72 min, respectively, P = 0.049), with no significant differences in fluoroscopy or total radiofrequency time. At the 2-year follow-up, more patients in the DE-CMR-guided group remained free from recurrences compared with the conventional group (70% vs. 39%, respectively, P = 0.007). In univariate Cox-regression analyses, AF pattern [persistent AF, hazard ratio (HR) 2.66 (1.27-5.46), P = 0.006] and the use of DE-CMR [HR 0.36 (0.17-0.79), P = 0.009] predicted recurrences during follow-up; both factors remained independent predictors in multivariate analyses. CONCLUSION: The substrate characterization provided by DE-CMR facilitates the identification of anatomical veno-atrial gaps and associates with shorter procedures and better clinical outcomes in repeated AF ablation procedures.

Effect of pulmonary artery denervation in postcapillary pulmonary hypertension: results of a randomized controlled translational study.

There is scarce evidence for pulmonary artery denervation (PADN) as a potential treatment for chronic postcapillary pulmonary hypertension (PH). We aimed to perform a proof-of-concept of PADN in a translational model of chronic PH. Nineteen pigs with chronic postcapillary PH (secondary to pulmonary vein banding) were randomized to surgical-PADN (using bipolar radiofrequency clamps) or sham procedure. Additionally, 6 healthy animals underwent percutaneous-PADN to compare the pulmonary artery (PA) lesion generated with both approaches. In the surgical-PADN arm, hemodynamic evaluation and cardiac magnetic resonance (CMR) were performed at baseline and at 2 and 3-month follow-up. Histological assessment was carried out at the completion of the protocol. Eighteen pigs (6 following surgical-PADN, 6 sham and 6 percutaneous-PADN) completed the protocol. A complete transmural PA lesion was demonstrated using surgical clamps, whereas only focal damage to adventitial fibers was observed after percutaneous-PADN. In the surgical-PADN arm, the hemodynamic profile did not significantly differ between groups neither at baseline [mean pulmonary artery pressure (mPAP) median values of 32.0 vs. 27.5 mmHg, P = 0.394 and indexed pulmonary vascular resistance (iPVR) 5.9 vs. 4.7 WU m2, P = 0.394 for PADN/sham groups, respectively] nor at any follow-up (mPAP of 35.0 vs. 35.0 mmHg, P = 0.236 and iPVR of 8.3 vs. 6.7 WU m2, P = 0.477 at third month in PADN/sham groups, respectively). Surgical-PADN was not associated with any benefit in RV anatomy or function on CMR/histology. In a large-animal model of chronic postcapillary PH, transmural PADN with surgical clamps was associated with a neutral pulmonary hemodynamic effect.

Electrocardiographic optimization techniques in resynchronization therapy.

Cardiac resynchronization therapy (CRT) is a cornerstone of therapy for patients with heart failure, reduced left ventricular (LV) ejection fraction, and a wide QRS complex. However, not all patients respond to CRT: 30% of CRT implanted patients are currently considered clinical non-responders and up to 40% do not achieve LV reverse remodelling. In order to achieve the best CRT response, appropriate patient selection, device implantation, and programming are important factors. Optimization of CRT pacing intervals may improve results, increasing the number of responders, and the magnitude of the response. Echocardiography is considered the reference method for atrioventricular and interventricular (VV) intervals optimization but it is time-consuming, complex and it has a large interobserver and intraobserver variability. Previous studies have linked QRS shortening to clinical response, echocardiographic improvement and favourable prognosis. In this review, we describe the electrocardiographic optimization methods available: 12-lead electrocardiogram; fusion-optimized intervals (FOI); intracardiac electrogram-based algorithms; and electrocardiographic imaging. Fusion-optimized intervals is an electrocardiographic method of optimizing CRT based on QRS duration that combines fusion with intrinsic conduction. The FOI method is feasible and fast, further reduces QRS duration, can be performed during implant, improves acute haemodynamic response, and achieves greater LV remodelling compared with nominal programming of CRT.

Programming Pacemakers to Reduce and Terminate Atrial Fibrillation.

PURPOSE OF REVIEW: The goal of this paper is to review present knowledge regarding preventive and antitachycardia pacing algorithms, aimed to reduce atrial fibrillation (AF) burden in patients when pacing is indicated. RECENT FINDINGS: Reactive antitachycardia pacing (ATP), the new generation of ATP, is significantly associated with a reduced risk of AF. In patients with indication for pacing and history of AF, pacemakers endowed with atrial preventive pacing and atrial ATP combined with managed ventricular pacing proved superior to standard dual-chamber pacing. Managed ventricular pacing is an algorithm that minimizes unnecessary right ventricular pacing. Progression to persistent AF is prevented by ventricular pacing minimization in patients with normal PR interval. The synergistic effect of pacemakers that combine atrial preventive pacing with reactive ATP and with algorithms that minimize ventricular pacing can reduce AF incidence and decrease the combined endpoint of permanent AF, hospital admissions, and mortality.

Failure-free survival of the Riata implantable cardioverter-defibrillator lead after a very long-term follow-up.

AIMS: Riata® implantable cardioverter-defibrillator (ICD) leads from St. Jude Medical are prone to malfunction. This study aimed to describe the rate of this lead's malfunction in a very long-term follow-up. METHODS: This single-centre observational study included 50 patients who received a Riata 7Fr dual-coil lead between 2003 and 2008. Follow-up was conducted both in person and remotely, and analysed at 8-month intervals. We evaluated the rates of cable externalization (CE), electrical failure (EF), and the interaction of these two complications. Structural lead failure was defined as radiographic CE. Oversensing of non-cardiac signal or sudden changes in impedance, sensing, or pacing thresholds constituted EF. RESULTS: During a mean follow-up of 10.2 ±â€¯2.9 years, 16 patients (32%) died. We observed lead malfunction in 13 patients (26%): three (23%) due to CE, six (46%) to EF and four (31%) to both complications. Of the malfunctioning leads, 77% failed after seven years of follow-up. The incidence rate (IR) of overall malfunction per 100 patients per year was 0.9 during the first seven years post-implantation, increased to 7.0 after the 7th year and more than doubled (to 16.7) after 10 years. Beyond seven years post-implantation, IR per 100 patient-years increased in both EF and CE (from 0.6 to 5.6 vs. 0.3 to 4.2, respectively). Presence of CE was associated with a 4-fold increase in the proportion of EF. CONCLUSION: The incidence of Riata ICD lead malfunction, both for EF and CE, increased dramatically after seven years and then more than doubled after 10 years post-implantation.

A rare cause of severe mitral stenosis and reversible pulmonary hypertension.

Myxoma is a rare cause of severe mitral stenosis. We describe a challenging case of severe mitral stenosis and reversible pulmonary hypertension produced by a giant left atrial myxoma. The greatest risk is a diagnostic delay due to focus on discarding a pulmonary etiology of dyspnea. Physical examination and early echocardiographic assessment are the keys to avoid overlooking this uncommon pathology.

Variations in threshold values for border zone and dense scar produce significant changes in scar parameters obtained by ADAS-3D.

BACKGROUND: ADAS-3D software elaborates cardiac magnetic resonance (CMR) images to obtain a quantitative evaluation of dense scar and border zone (BZ), including BZ channels, which can be useful for ventricular tachycardia ablation and risk stratification. However, most prior reports with ADAS-3D used flexible thresholds (60% ± 5% and 40% ± 5% of maximum pixel signal intensity) to define dense scar and BZ. The impact of such variations of the threshold values on the measurements obtained with ADAS-3D is unknown. OBJECTIVE: This study aimed to quantify the degree of change in ADAS-3D measurements when different thresholds for dense scar and BZ are employed. METHODS: A single-center retrospective observational cohort study including 87 consecutive patients with previous myocardial infarction who underwent CMR was conducted. ADAS-3D software semiautomatically processed CMR sequences. We compared the scar measurements obtained with the 9 possible combinations of thresholds (55%/60%/65% and 35%/40%/45% of maximum pixel signal intensity). RESULTS: The overall comparison between thresholds showed highly significant differences (P < .001) in all scar parameters. Not a single patient maintained the same number of BZ channels with all the thresholds settings. A percentage difference of up to 200% in BZ channel numbers and channel mass was observed in all 36 comparisons. An absolute difference of up to 10 channels was also recorded. Of note, the highest median channel mass (obtained with the thresholds 35-65) was 59-fold higher compared with the lowest one (obtained with the 45-55 cutoffs). CONCLUSION: Variations in threshold values result in statistically significant and high-magnitude changes in the quantification of scar parameters by ADAS-3D.

Clinical impact of aging on outcomes of cardioneuroablation for reflex syncope or functional bradycardia: Results from the cardionEuroabLation: patiEnt selection, imaGe integrAtioN and outComEs-The ELEGANCE multicenter study.

BACKGROUND: Cardioneuroablation (CNA) is a novel treatment for reflex syncope. The effect of aging on CNA efficacy is not fully understood. OBJECTIVE: The purpose of this study was to assess the impact of aging on candidacy and efficacy of CNA for treating vasovagal syncope (VVS), carotid sinus syndrome (CSS), and functional bradyarrhythmia. METHODS: The ELEGANCE (cardionEuroabLation: patiEnt selection, imaGe integrAtioN and outComEs) multicenter study assessed CNA in patients with reflex syncope or severe functional bradyarrhythmia. Patients underwent pre-CNA Holter electrocardiography (ECG), head-up tilt testing (HUT), and electrophysiological study. CNA candidacy and efficacy was assessed in 14 young (18-40 years), 26 middle-aged (41-60 years), and 20 older (>60 years) patients. RESULTS: Sixty patients (37 men; mean age 51 ± 16 years) underwent CNA. The majority (80%) had VVS, 8% had CSS, and 12% had functional bradycardia/atrioventricular block. Pre-CNA Holter ECG, HUT, and electrophysiological findings did not differ across age groups. Acute CNA success was 93%, without differences between age groups (P = .42). Post-CNA HUT response was negative in 53%, vasodepressor in 38%, cardioinhibitory in 7%, and mixed in 2%, without differences across age groups (P = .59). At follow-up (8 months, interquartile range 4-15), 53 patients (88%) were free of symptoms. Kaplan-Meier curves did not show differences in event-free survival between age groups (P = .29). The negative predictive value of a negative HUT was 91.7%. CONCLUSION: CNA is a viable treatment for reflex syncope and functional bradyarrhythmia in all ages, and is highly effective in mixed VVS. HUT is a key step in postablation clinical assessment.

Outcomes of cavotricuspid isthmus-dependent flutter ablation: randomized study comparing single vs. multiple catheter procedures-the SIMPLE study.

BACKGROUND: Catheter ablation is recommended as first-line therapy for patients with symptomatic typical AFl. Although the conventional multi-catheter approach is the standard of care for cavotricuspid isthmus (CTI) ablation, a single-catheter approach was recently described as a feasible alternative. The present study sought to compare safety, efficacy, and efficiency of single vs. multi-catheter approach for atrial flutter (AFl) ablation. METHODS: In this randomized multi-center study, consecutive patients referred for AFl ablation (n = 253) were enrolled and randomized to multiple vs. single-catheter approach for CTI ablation. In the single-catheter arm, PR interval (PRI) on the surface ECG was used to prove CTI block. Procedural and follow-up data were collected and compared between the two arms. RESULTS: 128 and 125 patients were assigned to the single-catheter and to the multi-catheter arms, respectively. In the single-catheter arm, procedure time was significantly shorter (37 ± 25 vs. 48 ± 27 minutes, p = 0.002) and required less fluoroscopy time (430 ± 461 vs. 712 ± 628 seconds, p < 0.001) and less radiofrequency time (428 ± 316 vs. 643 ± 519 seconds, p < 0.001), achieving a higher first-pass CTI block rate (55 (45%) vs. 37 (31%), p = 0.044), compared with the multi-catheter arm. After a median follow-up of 12 months, 11 (4%) patients experienced AFl recurrences (5 (4%) in the single-catheter arm and 6 (5%) in the multi-catheter arm, p = 0.99). No differences were found in arrhythmia-free survival between arms (log-rank = 0.71). CONCLUSIONS: The single-catheter approach for typical AFl ablation is not inferior to the conventional multiple-catheter approach, reducing procedure, fluoroscopy, and radiofrequency time.