Pulsed Field versus Very-High Power Short Duration Radiofrequency Ablation for Atrial Fibrillation: Results of a Multicenter, Real-World Experience.

BACKGROUND: Pulsed field ablation (PFA) and very-high power short-duration(vHPSD) radiofrequency ablation are the most recently introduced technologies for atrial fibrillation (AF) ablation. The procedural performance, safety, and effectiveness of PFA versus vHPSD is currently unknown. OBJECTIVE: To compare PFA with vHPSD for the treatment of paroxysmal/persistent AF. METHODS: We conducted an observational, multicenter study enrolling 534 consecutive patients (63±9years, 36% female) with paroxysmal (n=368,69%) or persistent (n=166,31%) AF undergoing ablation using either PFA (Farawave; n=192) or vHPSD (90W/4sec; QDOT Micro; n=342) between 2020 and 2023. Atrial tachyarrhythmia (AT) recurrence after a 1-month blanking period was the primary efficacy endpoint and was assessed both overall and in propensity score-matched patients. The primary safety endpoint was a composite of procedure-related complications. RESULTS: Successful PVI was achieved in all patients, with shorter procedure duration (PFA,70 min; vHPSD,100 min; p<0.001), but with longer fluoroscopy time (PFA,15 min; vHPSD,7 min; p<0.001) in PFA group. PFA was associated with more frequent use of general anesthesia (p<0.001). Primary safety outcome events occurred in 19 patients(3.5%), with similar prevalence in both groups (PFA,4%; vHPSD,3%; p=0.745). After a median follow-up of 12(9-12) months, survival free from recurrent AT was similar between the PFA and vHPSD groups, both overall (12-month estimate: PFA,75%; vHPSD,76%; log-rank p=0.73) and in propensity score-matched patients (n=342; 12-month estimate: PFA,75%; vHPSD,77%; log-rank p=0.980). CONCLUSION: In a large, multicenter experience, PFA was associated with more common use of general anesthesia, shorter procedural times, and longer fluoroscopy exposure compared to vHPSD ablation, with both techniques displaying superimposable safety/efficacy.

Idiopathic Premature Ventricular Contraction Catheter Ablation, Sedentary Population vs. Athlete's Populations: Outcomes and Resumption of Sports Activity.

There are no investigations about the outcomes of idiopathic PVC catheter ablation (CA) in athletes compared to the sedentary population. We conducted a prospective single-centre observational study. The primary and secondary procedural outcomes were the post-ablation reduction of premature ventricular contractions (PVCs) in an athletes vs. non-athletes group and in agonist vs. leisure-time athletes. The third was the evaluation of the resumption of physical activity and the improvement of symptoms in agonist and leisure-time athletes. From January 2020 to October 2022 we enrolled 79 patients with RVOT/LVOT/fascicular PVC presumed origin. The median percentage of decrease between the pre-procedure and post-procedure Holter monitoring in the non-athletes group was 96 (IQR 68-98) and 98 in the athletes group (IQR 92-99) (p = 0.08). Considering the athletes, the median percentage of decrease in the number of PVCs was 98 (IQR 93-99) and 98 (IQR 87-99), respectively, in leisure-time and agonistic athletes (p = 0.42). Sixteen (70%) leisure time and seventeen (90%) agonist athletes (p = 0.24) have resumed physical activity 3 months after PVC CA; among agonistic athletes, 59% have resumed competitive physical activity. Many leisure-time (88%) and agonist (70%) athletes experienced an improvement in symptoms after ablation. PVC CA was effective and safe in both groups, reducing symptoms and allowing a quick and safe return to sports activities in athletes.

Arrhythmic Mitral Valve Prolapse and Sports Activity: Pathophysiology, Risk Stratification, and Sports Eligibility Assessment.

Although mitral valve prolapse (MVP) is the most prevalent valvular abnormality in Western countries and generally carries a good prognosis, a small subset of patients is exposed to a significant risk of malignant ventricular arrhythmias (VAs) and sudden cardiac death (SCD), the so-called arrhythmic MVP (AMVP) syndrome. Recent work has emphasized phenotypical risk features of severe AMVP and clarified its pathophysiology. However, the appropriate assessment and risk stratification of patients with suspected AMVP remains a clinical conundrum, with the possibility of both overestimating and underestimating the risk of malignant VAs, with the inappropriate use of advanced imaging and invasive electrophysiology study on one hand, and the catastrophic occurrence of SCD on the other. Furthermore, the sports eligibility assessment of athletes with AMVP remains ill defined, especially in the grey zone of intermediate arrhythmic risk. The definition, epidemiology, pathophysiology, risk stratification, and treatment of AMVP are covered in the present review. Considering recent guidelines and expert consensus statements, we propose a comprehensive pathway to facilitate appropriate counseling concerning the practice of competitive/leisure-time sports, envisioning shared decision making and the multidisciplinary "sports heart team" evaluation of borderline cases. Our final aim is to encourage an active lifestyle without compromising patients' safety.

Cardiac Magnetic Resonance and Cardiac Implantable Electronic Devices: Are They Truly Still "Enemies"?

The application of cardiac magnetic resonance (CMR) imaging in clinical practice has grown due to technological advancements and expanded clinical indications, highlighting its superior capabilities when compared to echocardiography for the assessment of myocardial tissue. Similarly, the utilization of implantable cardiac electronic devices (CIEDs) has significantly increased in cardiac arrhythmia management, and the requirements of CMR examinations in patients with CIEDs has become more common. However, this type of exam often presents challenges due to safety concerns and image artifacts. Until a few years ago, the presence of CIED was considered an absolute contraindication to CMR. To address these challenges, various technical improvements in CIED technology, like the reduction of the ferromagnetic components, and in CMR examinations, such as the introduction of new sequences, have been developed. Moreover, a rigorous protocol involving multidisciplinary collaboration is recommended for safe CMR examinations in patients with CIEDs, emphasizing risk assessment, careful monitoring during CMR, and post-scan device evaluation. Alternative methods to CMR, such as computed tomography coronary angiography with tissue characterization techniques like dual-energy and photon-counting, offer alternative potential solutions, although their diagnostic accuracy and availability do limit their use. Despite technological advancements, close collaboration and specialized staff training remain crucial for obtaining safe diagnostic CMR images in patients with CIEDs, thus justifying the presence of specialized centers that are equipped to handle these type of exams.

A Novel Approach to Cardiac Magnetic Resonance Scar Characterization in Patients Affected by Cardiac Amyloidosis: A Pilot Study.

Background and Objectives: Cardiac magnetic resonance (CMR) imaging has become an essential instrument in the study of cardiomyopathies; it has recently been integrated into the diagnostic workflow for cardiac amyloidosis (CA) with remarkable results. An additional emerging role is the stratification of the arrhythmogenic risk by scar analysis and the possibility of merging these data with electro-anatomical maps. This is made possible by using a software (ADAS 3D, Galgo Medical, Barcelona, Spain) able to provide 3D heart models by detecting fibrosis along the whole thickness of the myocardial walls. Little is known regarding the applications of this software in the wide spectrum of cardiomyopathies and the potential benefits have yet to be discovered. In this study, we tried to apply the ADAS 3D in the context of CA. Materials and Methods: This study was a retrospectively analysis of consecutive CMR imaging of patients affected by CA that were treated in our center (Marche University Hospital). Wherever possible, the data were processed with the ADAS 3D software and analyzed for a correlation between the morphometric parameters and follow-up events. The outcome was a composite of all-cause mortality, unplanned cardiovascular hospitalizations, sustained ventricular arrhythmias (VAs), permanent reduction in left ventricular ejection fraction, and pacemaker implantation. The secondary outcomes were the need for a pacemaker implantation and sustained VAs. Results: A total of 14 patients were deemed eligible for the software analysis: 8 patients with wild type transthyretin CA, 5 with light chain CA, and 1 with transthyretin hereditary CA. The vast majority of imaging features was not related to the composite outcome, but atrial wall thickening displayed a significant association with both the primary (p = 0.003) and the secondary outcome of pacemaker implantation (p = 0.003). The software was able to differentiate between core zones and border zones of scars, with the latter being the most extensively represented in all patients. Interestingly, in a huge percentage of CMR images, the software identified the highest degree of core zone fibrosis among the epicardial layers and, in those patients, we found a higher incidence of the primary outcome, without reaching statistical significance (p = 0.18). Channels were found in the scar zones in a substantial percentage of patients without a clear correlation with follow-up events. Conclusions: CMR imaging plays a pivotal role in cardiovascular diagnostics. Our analysis shows the feasibility and applicability of such instrument for all types of CA. We could not only differentiate between different layers of scars, but we were also able to identify the presence of fibrosis channels among the different scar zones. None of the data derived from the ADAS 3D software seemed to be related to cardiac events in the follow-up, but this might be imputable to the restricted number of patients enrolled in the study.

High-power short-duration catheter ablation of atrial fibrillation: is it really a new era? Comparison between new and old radiofrequency contact force-sensing catheters.

BACKGROUND: The clinical performance of high-power, short-duration (HPSD) pulmonary vein isolation (PVI) with the novel flexible tip TactiFlex™ (TFSE) catheter, as compared to standard-power, long-duration (SPLD) PVI using the TactiCath™ (TCSE) catheter among patients undergoing catheter ablation (CA) of atrial fibrillation (AF) is currently unknown. METHODS: We conducted a prospective, observational, single-centre study including 40 consecutive patients undergoing PVI for paroxysmal/persistent AF, using HPSD ablation with the novel TFSE catheter (HPSD/TFSE group). Based on propensity score-matching, forty patients undergoing SPLD PVI with the TCSE catheter were identified (SPLD/TCSE group). In the HPSD/TFSE group, RF lesions were performed by delivering 40-50 W for 10-20 s, while in the SPLD/TCSE group, RF power was 30-35 W, targeting a lesion size index (LSI) of 4.0-5.5. The co-primary study outcomes were time required to complete PVI and first pass isolation (FPI). RESULTS: PVI was achieved in 100% of patients in both groups, and no major adverse events were observed. Remarkably, PVI time was shorter in the HPSD/TFSE, compared to the SPLD/TCSE group(9 [7-9] min vs. 50 [37-54] min; p < 0.001), while FPI rate was non-significantly higher in the former group(91% [146/160] vs 83% [134/160]; p = 0.063). Shorter procedural (108 [91-120] min vs. 173 [139-187] min, p < 0.001), total RF (9 [7-11] min vs. 43 [32-53] min, p < 0.001), fluoroscopy times(15 [10-19] min vs. 18 [13-26] min, p = 0.014), and lower DAP (1461 [860-2181] vs. 7200 [3400-20,800], p < 0.001) were recorded in the HPSD/TFSE group. A higher average impedance drop was obtained with HPSD/TFSE CA(17[17-18]Ω vs. 16 [15-17] Ω, p < 0.001). CONCLUSIONS: In our initial clinical experience, HPSD PVI with the TFSE catheter proved faster than SPLD PVI with the TCSE catheter, at least equally effective in terms of FPI, and it was associated with greater impedance drop.

Characteristics and Clinical Value of Electroanatomic Voltage Mapping in Cardiac Amyloidosis.

BACKGROUND: Cardiac amyloidoses (CAs) are an increasingly recognised group of infiltrative cardiomyopathies associated with high risk of adverse cardiac events. We sought to characterise the characteristics and clinical value of right ventricular (RV) electroanatomic voltage mapping (EVM) in CA. METHODS: Fifteen consecutive patients undergoing endomyocardial biopsy (EMB) for suspected CA (median age 75 years, 1st-3rd quartiles 64-78 years], 67% male) were enrolled in an observational prospective study. Each patient underwent RV high-density EVM using a multipolar catheter and EMB. The primary outcome was death or heart failure hospitalisation at 1-year follow-up. We recorded electrographic features at EMB sampling sites and electroanatomic data in the overall RV, and explored their correlations with histopathologic findings and primary outcomes events. RESULTS: A final EMB-proven diagnosis of immunoglobulin light chain or transthyretin CA was formulated in 6 and 9 patients, respectively. Electrogram amplitudes in the bipolar and unipolar configurations averaged 1.55 ± 0.44 mV and 5.14 ± 1.50 mV, respectively, in the overall RV, with lower values in AL CA patients. We found a significant inverse correlation between both bipolar and unipolar electrogram amplitude and amyloid burden according to EMB (P = 0.001 and P = 0.025, respectively). At 1-year follow-up, 7 patients (47%) experienced a primary outcome event; the extent of bipolar dense scar area at RV EVM was an independent predictor of primary outcome events at multivariable analysis (odds ratio 2.40; P = 0.037). CONCLUSIONS: In CA, electrogram amplitudes are around the lower limit of normal yet disproportionately low compared with the increased wall thickness. Out data suggest that RV electrogram amplitude may be a quantitative marker of amyloid burden, and that RV EVM may have prognostic value.

Technological advances in ventricular tachycardia catheter ablation: the relentless quest for novel solutions to old problems.

BACKGROUND: Several novel technologies allowing catheter ablation (CA) with a favorable safety/efficacy profile have been recently developed, but not yet extensively clinically tested in the setting of ventricular tachycardia CA. METHODS: In this technical report, we overview technical aspects and preclinical/clinical information concerning the application of three novel CA technologies in the ventricular milieu: a pulsed field ablation (PFA) generator (CENTAURI™, Galaxy Medical) to be used with linear, contact force-sensing radiofrequency ablation catheters; a contact force-sensing radiofrequency ablation catheter equipped with six thermocouples and three microelectrodes (QDOT Micro™, Biosense-Webster), allowing high-resolution mapping and temperature-controlled CA; and a flexible and mesh-shaped irrigation tip, contact force-sensing radiofrequency ablation catheter (Tactiflex, Abbott). We also report three challenging VT cases in which CA was performed using these technologies. RESULTS: The CENTAURI system was used with the Tacticath™ (Abbott) ablation catheter to perform ventricular PFA in a patient with advanced heart failure, electrical storm, and a deep intramural septal substrate. Microelectrode mapping using QDOT Micro™ helped to refine substrate assessment in a VT patient with congenitally corrected transposition of the great arteries, and allowed the identification of the critical components of the VT circuit, which were successfully ablated. Tactiflex™ was used in two challenging CA cases (one endocardial and one epicardial), allowing acute and mid-term control of VT episodes without adverse events. CONCLUSION: The ideation and development of novel technologies initially intended to treat atrial arrhythmias and successfully implemented in the ventricular milieu is contributing to the progressive improvement in the clinical benefits derived from VT CA, making this procedure key for successful management of increasingly complex patients.

Atrial fibrillation cycle-length (AF-CL) inside the pulmonary veins predicts paroxysmal AF ablation success- the INDUCE-AF study.

BACKGROUND: A novel method to measure atrial fibrillation cycle length (AF-CL) was recently described, based on the average of 10 consecutive signals (FARS10). FARS10 accurately identified pulmonary vein isolation (PVI)-responders among patients with persistent AF. Whether this method is applicable to patients with paroxysmal AF is unknown. OBJECTIVE: The aim of this study is to evaluate the prognostic value of FARS10 measurements in patients with paroxysmal AF. METHODS AND RESULTS: We enrolled paroxysmal AF patients undergoing PVI in a prospective multicenter study. After AF induction with a standardized protocol, the AF-CL was measured using FARS-10 method. The primary endpoint was AF/AT-recurrence. One-hundred and four patients were included (61 ± 14 years, 25% females). After a mean follow-up of 12 ± 4 months, AF/AT recurrence rate was 20%. The fastest PV CL (fPV-CL) was independently associated with the primary endpoint at multivariate analysis (HR 1.02, p < 0.001). Every 10 ms increase in fPV-CL, AF recurrences increased by 20%. The value of 160 ms was found to be the optimal cut-off (specificity 81%, sensitivity 76%). Patients with fPV-CL < 160 ms experienced lower AF recurrences as compared to patients with fPV-CL > 160 ms (8% vs. 32% at 1 year; HR = 0.17, p < 0.001). Progression to persistent AF was observed in 13% of patients with fPV-CL > 160 ms. CONCLUSION: fPV-CL measured with the FARS-10 method accurately predicts PVI success in paroxysmal AF patients undergoing PVI. Patients with slow PV activity (fPV-CL > 160 ms) experience higher AF recurrence rate after PVI and more frequent progression to persistent AF. In 104 patients with paroxysmal atrial fibrillation (AF) undergoing AF ablation, AF was induced at the beginning of the procedure. Pulmonary vein activity was measured using FARS10 measurement (10 consecutive fastest atrial repetitive similar morphology signals). The value of 160 ms was found to be the best cut-off to discriminate outcomes. At 1-year follow-up, patients with fast veins (< 160 ms) experienced significantly fewer AF recurrences as compared to patients with slow veins (> 160 ms). PV activity measured with FARS10 method accurately discriminates pulmonary vein isolation responders, in patients with paroxysmal AF. ABBREVIATIONS: AF atrial fibrillation, AT atrial tachycardia, CL cycle length, FARS10: 10 consecutive fastest atrial repetitive similar morphology signal, fPV fastest pulmonary vein, HR hazard ratio, ms milliseconds.

How an innovative catheter with temperature control and very high-power, short-duration ablation changed our approach to the treatment of persistent atrial fibrillation.

Ablation targets of persistent atrial fibrillation remain poorly understood nowadays: due to structural alterations of the left atrium, isolation of the pulmonary veins alone has proved ineffective. New ablation targets such as the posterior wall, coronary sinus, and left atrial appendage were then sought. A new catheter (QDOT Micro™) has recently been released, which has the potential to increase the safety and efficacy of the procedure: it is connected to a new radiofrequency generator that allows for temperature-controlled ablation by reducing power and increasing irrigation with the increase in tissue temperature and allows to deliver power up to 90 W for few seconds (very high-power short-duration).

Incidence of ventricular arrhythmias related to COVID infection and vaccination in patients with Brugada syndrome: Insights from a large Italian multicenter registry based on continuous rhythm monitoring.

INTRODUCTION: Brugada syndrome (BrS) has a dynamic ECG pattern that might be revealed by certain conditions such as fever. We evaluated the incidence and management of ventricular arrhythmias (VAs) related to COVID-19 infection and vaccination among BrS patients carriers of an implantable loop recorder (ILR) or implantable cardioverter-defibrillator (ICD) and followed by remote monitoring. METHODS: This was a multicenter retrospective study. Patients were carriers of devices with remote monitoring follow-up. We recorded VAs 6 months before COVID-19 infection or vaccination, during infection, at each vaccination, and up to 6-month post-COVID-19 or 1 month after the last vaccination. In ICD carriers, we documented any device intervention. RESULTS: We included 326 patients, 202 with an ICD and 124 with an ILR. One hundred and nine patients (33.4%) had COVID-19, 55% of whom developed fever. Hospitalization rate due to COVID-19 infection was 2.76%. After infection, we recorded only two ventricular tachycardias (VTs). After the first, second, and third vaccines, the incidence of non-sustained ventricular tachycardia (NSVT) was 1.5%, 2%, and 1%, respectively. The incidence of VT was 1% after the second dose. Six-month post-COVID-19 healing or 1 month after the last vaccine, we documented NSVT in 3.4%, VT in 0.5%, and ventricular fibrillation in 0.5% of patients. Overall, one patient received anti-tachycardia pacing and one a shock. ILR carriers had no VAs. No differences were found in VT before and after infection and before and after each vaccination. CONCLUSIONS: From this large multicenter study conducted in BrS patients, followed by remote monitoring, the overall incidence of sustained VAs after COVID-19 infection and vaccination is relatively low.

Microelectrode voltage mapping for substrate assessment in catheter ablation of ventricular tachycardia: A dual-center experience.

INTRODUCTION: The assessment of the ventricular myocardial substrate critically depends on the size of mapping electrodes, their orientation with respect to wavefront propagation, and interelectrode distance. We conducted a dual-center study to evaluate the impact of microelectrode mapping in patients undergoing catheter ablation (CA) of ventricular tachycardia (VT). METHODS: We included 21 consecutive patients (median age, 68 [12], 95% male) with structural heart disease undergoing CA for electrical storm (n = 14) or recurrent VT (n = 7) using the QDOT Micro catheter and a multipolar catheter (PentaRay, n = 9). The associations of peak-to-peak maximum standard bipolar (BVc ) and minibipolar (PentaRay, BVp ) with microbipolar (BVµMax ) voltages were respectively tested in sinus rhythm with mixed effect models. Furthermore, we compared the features of standard bipolar (BE) and microbipolar (µBE) electrograms in sinus rhythm at sites of termination with radiofrequency energy. RESULTS: BVµMax was moderately associated with both BVc (ß = .85, p < .01) and BVp (ß = .56, p < .01). BVµMax was 0.98 (95% CI: 0.93-1.04, p < .01) mV larger than corresponding BVc , and 0.27 (95% CI: 0.16-0.37, p < .01) mV larger than matching BVp in sinus rhythm, with higher percentage differences in low voltage regions, leading to smaller endocardial dense scar (2.3 [2.7] vs. 12.1 [17] cm2 , p < .01) and border zone (3.2 [7.4] vs. 4.8 [20.1] cm2 , p = .03) regions in microbipolar maps compared to standard bipolar maps. Late potentials areas were nonsignificantly greater in microelectrode maps, compared to standard electrode maps. At sites of VT termination (n = 14), µBE were of higher amplitude (0.9 [0.8] vs. 0.4 [0.2] mV, p < .01), longer duration (117 [66] vs. 74 [38] ms, p < .01), and with greater number of peaks (4 [2] vs. 2 [1], p < .01) in sinus rhythm compared to BE. CONCLUSION: microelectrode mapping is more sensitive than standard bipolar mapping in the identification of viable myocytes in SR, and may facilitate recognition of targets for CA.

Pathophysiology of Typical Atrial Flutter.

Nowadays, the pathophysiology mechanism of initiation and maintenance of reentrant arrhythmias, including atrial flutter, is well characterized. However, the anatomic and functional elements of the macro reentrant arrhythmias are not always well defined. In this article, we illustrate the anatomic structures that delineate the typical atrial flutter circuit, both clockwise and counterclockwise, paying attention to the inferior vena cava-tricuspid isthmus (CTI) and crista terminalis crucial role. Finally, we describe the left atrial role during typical atrial flutter, electrophysiologically a by-stander but essential in the phenotypic electrocardiogram (ECG).

Atrial Flutter in Particular Patient Populations.

"Despite being one of the best understood cardiac arrhythmias, the clinical meaning of atrial flutter varies according to the specific context, and its optimal treatment may be limited by both the suboptimal response to rate/rhythm control drugs and by the complexity of the underlying substrate. In this article, we present a state-of-the-art overview of mechanisms, prognostic impact, and medical/interventional management options for atrial flutter in several specific patient populations, including heart failure, cardiomyopathies, muscular dystrophies, posttransplant patients, patients with respiratory disorders, athletes, and subjects with preexcitation, aiming to stimulate further research in this challenging field and facilitate appropriate patient care."

Safety and Efficacy of Stereotactic Arrhythmia Radioablation for the Treatment of Ventricular Tachycardia: A Systematic Review.

Catheter ablation (CA) is a fundamental therapeutic option for the treatment of recurrent ventricular arrhythmias. Notwithstanding the tremendous improvements in the available technology and the increasing amount of evidence in support of CA, in some patients the procedure fails, or is absolutely contraindicated due to technical or clinical issues. In these cases, the clinical management of patients is highly challenging, and mainly involves antiarrhythmic drugs escalation. Over the last 5 years, stereotactic arrhythmia radioablation (STAR) has been introduced into clinical practice, with several small studies reporting favorable arrhythmia-free outcomes, without severe side effects at a short to mid-term follow-up. In the present systematic review, we provide an overview of the available studies on stereotactic arrhythmia radioablation, by describing the potential indications and technical aspects of this promising therapy.

Ablation Index Predicts Successful Ablation of Focal Atrial Tachycardia: Results of a Multicenter Study.

A radiofrequency energy lesion transmurality marker incorporating power, contact force, and time (Ablation Index, AI) was shown to be associated with outcomes of catheter ablation (CA) of multiple arrhythmias, but was never systematically assessed in the CA of focal atrial tachycardias (AT). We aimed to evaluate the role of AI as a predictor of outcomes in focal AT CA, and therefore, retrospectively included 45 consecutive patients undergoing CA for focal AT in four referral electrophysiology laboratories. Clinical and procedural information were collected. For each patient, maximum and mean (by averaging maximum AI values for each radiofrequency ablation lesion) AI were measured. The primary outcome was focal AT-free survival, and was systematically assessed with periodical Holter monitors or cardiac implantable electronic devices. CA was acutely effective in each case; however, 20% (n = 9) of the study population experienced a focal AT recurrence over a median follow-up of 288 days. Both maximum and mean AI values were significantly higher among patients without AT recurrences (maximum AI = 568 ± 91, mean AI = 426 ± 105) than in patients with AT relapses (maximum AI = 447 ± 142, mean AI = 352 ± 76, p = 0.036, and p = 0.028, respectively). The optimal cutoffs associated with freedom from recurrences were 461 for maximum AI (sensitivity, 0.89; specificity, 0.56) and 301 for mean AI (sensitivity, 0.97; specificity, 0.44). In a time-to-event analysis, maximum AI was significantly associated with survival free from AT recurrence (p = 0.001), whereas mean AI was not (p = 0.08). In summary, maximum AI is the best procedural parameter associated with the outcomes of CA for focal AT, and may help standardize the procedural approach.