The role of brain natriuretic peptide in atrial fibrillation: a substudy of the Substrate Modification with Aggressive Blood Pressure Control for Atrial Fibrillation (SMAC-AF) trial.

BACKGROUND: Catheter ablation is an established therapy for atrial fibrillation but is limited by recurrence; efforts have been made to identify biomarkers that predict recurrence. We investigated the effect of baseline NT-proBNP on AF recurrence following catheter ablation in patients randomized to aggressive (< 120/80 mmHg) or standard blood pressure management (< 140/90 mmHg) in the Substrate Modification with Aggressive Blood Pressure Control trial (SMAC-AF). METHODS: The SMAC-AF study included 173 patients resistant or intolerant to at least one class I or III antiarrhythmic drug. We studied the effect of baseline NT-proBNP on the primary outcome of AF recurrence > 3 months post-ablation. RESULTS: Of the 173 patients, 88 were randomized to the aggressive cohort, and 85 into the standard group. The primary outcome occurred in 61.4% of those in the aggressive arm, versus 61.2% in the standard arm. In the aggressive group, logNT-proBNP predicted recurrence (HR 1.28, p = 0.04, adjusted HR 1.43, p = 0.03), while in the standard cohort, it did not (HR 0.94, p = 0.62, adjusted HR 0.83, p = 0.22). NT-proBNP ≥ 280 pg/mL also predicted occurrence in the aggressive (HR 1.98, p = 0.02) but not the standard cohort (HR 1.00, p = 1.00). CONCLUSION: We conclude that pre-ablation NT-proBNP may be useful in predicting recurrence in hypertensive patients and identifying patients who benefit from aggressive blood control and upstream therapies. TRIAL REGISTRATION: NCT00438113, registered February 21, 2007.

Prospective Assessment of an Automated Intraprocedural 12-Lead ECG-Based System for Localization of Early Left Ventricular Activation.

BACKGROUND: To facilitate ablation of ventricular tachycardia (VT), an automated localization system to identify the site of origin of left ventricular activation in real time using the 12-lead ECG was developed. The objective of this study was to prospectively assess its accuracy. METHODS: The automated site of origin localization system consists of 3 steps: (1) localization of ventricular segment based on population templates, (2) population-based localization within a segment, and (3) patient-specific site localization. Localization error was assessed by the distance between the known reference site and the estimated site. RESULTS: In 19 patients undergoing 21 catheter ablation procedures of scar-related VT, site of origin localization accuracy was estimated using 552 left ventricular endocardial pacing sites pooled together and 25 VT-exit sites identified by contact mapping. For the 25 VT-exit sites, localization error of the population-based localization steps was within 10 mm. Patient-specific site localization achieved accuracy of within 3.5 mm after including up to 11 pacing (training) sites. Using 3 remotes (67.8±17.0 mm from the reference VT-exit site), and then 5 close pacing sites, resulted in localization error of 7.2±4.1 mm for the 25 identified VT-exit sites. In 2 emulated clinical procedure with 2 induced VTs, the site of origin localization system achieved accuracy within 4 mm. CONCLUSIONS: In this prospective validation study, the automated localization system achieved estimated accuracy within 10 mm and could thus provide clinical utility.

Automated intraprocedural localization of origin of ventricular activation using patient-specific computed tomographic imaging.

BACKGROUND: To facilitate catheter ablation of ventricular tachycardia (VT), we previously developed an automated method to identify sources of left ventricular (LV) activation in real time using 12-lead electrocardiography (ECG), the accuracy of which depends on acquisition of a complete electroanatomic (EA) map. OBJECTIVE: The purpose of this study was to assess the feasibility of using a registered cardiac computed tomogram (CT) rather than an EA map to permit real-time localization and avoid errors introduced by incomplete maps. METHODS: Before LV VT ablation, 10 patients underwent CT imaging and 3-dimensional reconstruction of the cardiac surface to create a triangle mesh surface, which was registered to the EA map during the procedure and imported into custom localization software. The software uses QRS integrals from leads III, V2, and V6; derives personalized regression coefficients from pacing at ≥5 sites with known locations; and estimates the location of unknown activation sites on the 3-dimensional patient-specific LV endocardial surface. Localization accuracy was quantified for VT exit sites in millimeters by comparing the calculated against the known locations. RESULTS: The VT exit site was identified for 20 VTs using activation and entrainment mapping, supplemented by pace-mapping at the scar margin. The automated localization software achieved incremental accuracy with additional pacing sites and had a mean localization error of 6.9 ± 5.7 mm for the 20 VTs. CONCLUSION: Patient-specific CT geometry is feasible for use in real-time automated localization of ventricular activation and may avoid reliance on a complete EA map.

Impact of an additional right pulmonary vein on second-generation cryoballoon ablation for atrial fibrillation: a propensity matched score study.

PURPOSE: Cryoballoon (CB) technology in the context of anatomical pulmonary vein (PV) variants might hypothetically hamper successful PV isolation (PVI). Our aim was to assess the impact of a right middle PV (RMPV) in the setting of second-generation cryoballoon (CB advance-CB-A), on procedural parameters and on mid-term follow-up. METHODS: Consecutive patients with AF presenting RMPV (RMPV+) at the pre-procedural computed tomography who underwent PVI by CB-A were enrolled. Comparison with propensity score-matched patients without RMPV (RMPV-) was performed. Acute procedural parameters and clinical follow-up were assessed. RESULTS: A total of 240 patients (80 RMPV+) were included in the analysis. Twelve of 80 (15%) RMPV+ patients underwent a direct cryo-application in this variant and accomplished the isolation without phrenic nerve palsy, whereas in 25 of 80 (31%) RMPV+ patients, the RMPVs were not targeted directly nor indirectly (by co-occlusion during application at a major PV). At a median follow-up of 17.3 [interquartile range 11.3-26.5] months, there was no significant difference in AF-free survival between RMPV+ and RMPV- patients (78.8 vs 78.1%, P = 1.00), and the recurrence of atrial arrhythmias among patients with versus without an intentional or indirect cryo-application to the RMPV was not different (22 vs 20%, P = 1.00). CONCLUSIONS: Mid-term outcome after CB-A ablation did not differ between RMPV+ and RMPV- patients. Within RMPV+ patients, outcome was similar between those with versus without a cryo-application (either direct or indirect) to the additional vein.

Continuous monitoring after second-generation cryoballoon ablation for paroxysmal atrial fibrillation in patients with cardiac implantable electronic devices.

BACKGROUND: The second-generation cryoballoon (CB) is effective in achieving pulmonary vein isolation. Continuous monitoring would eliminate any over- or underestimated freedom from atrial fibrillation (AF) postablation. OBJECTIVE: The purpose of this study was to differentiate between arrhythmias occurring after cryoballoon ablation (CBA), detecting true AF in symptomatic patients and detecting silent subclinical AF. METHODS: Between June 2012 and January 2015, 54 patients with a preexisting cardiac implantable electronic device (CIED) who had undergone CBA for paroxysmal atrial fibrillation (PAF) were included in our retrospective study. Regular CIED controls, physical examination, and ECG recordings were performed by an experienced cardiologist blinded to the ablation procedure. Data on any hospitalization during follow-up were gathered. Patients were encouraged to note all clinical symptoms during follow-up. RESULTS: Continuous monitoring showed a success rate of 83.3% after 1 year and 75.93% after 3 years of follow-up. During the first year, 68% of episodes of palpitations after ablation were due to sinus tachycardia, nonsustained ventricular tachycardia, or supraventricular tachycardia. AF recurrence was detected in 15.6% of asymptomatic patients during follow-up. Total AF burden post-CBA had decreased to 0.64% ± 4.34% (P <.001) during long-term follow-up of 3.3 years. CONCLUSION: Although this is a selected group of patients with a preexisting CIED, continuous monitoring showed freedom from AF in 83.3% of patients post-CBA after 1 year and 75.93% after 3 years of follow-up.

Second-Generation Cryoballoon Ablation for Atrial Fibrillation　- A Detailed Analysis of the Impact of Left Atrial Volume Index on Clinical Outcome.

BACKGROUND: Pulmonary vein isolation (PVI) by means of cryoballoon is increasingly being used for the treatment of atrial fibrillation (AF). This study assessed whether the left atrial volume index (LAVI) predicts AF recurrence following PVI by means of 2nd-generation cryoballoon (Cryoballoon Advance; CB-A) when comparing persistent AF (PeAF) and paroxysmal AF (PAF). Methods and Results: Patients with drug-resistant AF and undergoing preprocedural computed tomography (CT) and PVI with CB-A were included. LAV was estimated from 3D CT images. A total of 417 patients with AF were included (95 PeAF, 322 PAF patients). After a mean of 22.1±9.4 months follow-up, 45/95 (47%) PeAF patients and 254/322 (79%) PAF patients had no recurrence. LAVI was an independent predictor for AF recurrence in PeAF patients (hazard ratio 1.042 per 1 mL/m2; 95% confidence interval 1.006-1.080, P=0.02), but not in PAF patients. In PeAF patients with LAVI ≤61 mL/m2, the freedom from recurrence was 78.5% vs. 22.2% in those with LAVI >61 mL/m2 (hazard ratio 5.771, 95% confidence interval 2.434-13.682, P<0.001), and the mid-term success rate was comparable with PAF patients. CONCLUSIONS: LAVI predicted AF recurrence after PVI using CB-A in PeAF patients but not in PAF patients. If LAVI was ≤61 mL/m2, the mid-term efficacy among PeAF patients was equivalent to that for PAF patients.

'CLOSE'-Guided Pulmonary Vein Isolation and Changes in Local Bipolar and Unipolar Atrial Electrograms: Observations from the EP Lab.

BACKGROUND: 'CLOSE'-guided pulmonary vein isolation (PVI) is a point-by-point, contact force (CF)-guided radiofrequency (RF) approach aiming to enclose the PVs with contiguous RF lesions by targeting strict criteria for interlesion distance and ablation index (AI). We characterized real-time changes in bipolar (B-EGMs) and unipolar electrograms (U-EGMs) during AI-targeted RF delivery. METHODS: EGM changes during 56 RF applications in 7 patients with paroxysmal atrial fibrillation (AF) undergoing 'CLOSE'-guided PVI were studied. CF-guided RF was delivered with 35W targeting an AI of 400 at posterior and 550 at anterior wall. 336 B-EGMs and 336 U-EGMs before, during and after RF delivery were analyzed with their RF characteristics. Amplitude of the B-and U-EGM and morphology of the U-EGM were measured at each 5-second step using custom-made software. RESULTS: We observed a significant reduction in B-EGM amplitude (0.43 [IQR=0.25, 0.55] to 0.11 [0.07, 0.22] mV, p<0.001) and U-EGM amplitude (0.57 [0.40, 0.87] to 0.22 [0.10, 0.34] mV, p<0.001) within 5 seconds, after which no more changes were observed. Impedance drop was 18.3±1.1Ω. Loss of the unipolar terminal S-wave occurred in 59% of applications. There was no correlation between U-EGM morphology changes and RF characteristics. CONCLUSION: In AI-guided RF delivery there is a significant reduction in EGM amplitude within 5 seconds. Loss of the unipolar terminal S wave occurred in 59% of applications and was not related to RF characteristics suggestive of adequate lesion formation. These findings suggest that there is a limited value in monitoring electrograms to further optimize 'CLOSE'-guided PVI.

Acute pericarditis following second-generation cryoballoon ablation for atrial fibrillation.

PURPOSE: Acute pericarditis is a minor complication following atrial fibrillation (AF) ablation procedures. The aim of the study was to evaluate the incidence and clinical aspects of pericarditis following cryoballoon (CB) ablation of AF investigating a possible association with procedural characteristics and a possible relationship with post-ablation recurrences. METHODS: Four hundred fifty consecutive patients (male 73%, age 59.9 ± 11.2 years) with drug-resistant paroxysmal AF who underwent CB ablation as index procedure were enrolled. Exclusion criteria were any contraindication for the procedure including the presence of intracavitary thrombus and uncontrolled heart failure and contraindications to general anesthesia. RESULTS: Acute pericarditis following CB ablation occurred in 18 patients (4%) of our study population. Pericardial effusion occurred in 14 patients (78%) and was mild/moderate. The total number of cryoapplications and the total freeze duration were significantly higher in patients with pericarditis compared with those without (respectively, p = 0.0006 and p = 0.01). Specifically, the number of applications and freeze duration in right inferior pulmonary vein were found significantly higher in patients with pericarditis (p = 0.007). The recurrence rate did not significantly differ between the two study groups (respectively, 16.7 vs 18.1%; p = 0.9). CONCLUSIONS: The incidence of acute pericarditis following CB ablation in our study population accounted for 4% and was associated with both total freezing time and number of cryoapplications. The clinical course was favorable in all these patients and the occurrence of acute pericarditis did not affect the outcome during the follow-up period.

Clinical value of induction protocol after second generation cryoballoon ablation for paroxysmal atrial fibrillation.

Aims: The predictive value of induction studies after catheter ablation for atrial fibrillation (AF) is still debatable. To date, these studies have not been implemented in patients after cryoballoon (CB) ablation. Our aim was to analyse the clinical value of AF induction in patients treated by second generation CB for paroxysmal AF. Methods and results: Seventy patients underwent at first an isoproterenol challenge after pulmonary vein (PV) isolation to assess AF induction and early PV reconnections (EPVR). Patients without EPVR were evaluated for premature atrial contraction (PAC) induction; atrial ectopy was considered frequent (PAC+) if >1/10 cycles or >6/min. After restitution of baseline heart rate, rapid atrial pacing (RAP) was performed on all patients. AF induction by isoproterenol occurred only in 3/70 (4%) patients of whom 2/3 (66%) patients with an EPVR of a triggering vein. In the 62 patients without EPVR, PAC+ occurred in 17 patients (27%). RAP could induce AF in 23/70 (33%) patients. At a mean follow-up of 13.5 months, there were 11/70 (16%) AF recurrences. There was no significant difference in the AF recurrence rate between RAP inducible vs. non-inducible patients (log-rank P = 0.33). A 41% recurrence rate (7/17 patients) was seen in the PAC+ group with significantly different AF-free survival for PAC+ vs. PAC- patients (log rank P < 0.0001). PAC+ was the only independent determinant to predict AF recurrence after multivariate analysis. Conclusion: PAC occurrence in response to isoproterenol could predict AF recurrence after PV isolation by CB, while RAP showed no prognostic implication.

Long-term outcome of pulmonary vein isolation in patients with paroxysmal atrial fibrillation and Brugada syndrome.

Aims: The therapeutical management of atrial fibrillation (AF) in the setting of Brugada syndrome (BS) might be challenging as many antiarrhythmic drugs (AADs) with sodium channel blocking properties might lead to to the development of ventricular arrhythmias. This study sought to evaluate the clinical outcome in a consecutive series of patients with BS having undergone pulmonary vein (PV) isolation by means of radiofrequency (RF) or cryoballoon (CB) ablation and the efficacy of catheter ablation for preventing inappropriate interventions delivered by implantable cardioverter defibrillators (ICD) on a 3-year follow up. Methods and results: Twenty-three consecutive patients with BS (13 males; mean age was 47 ± 18 years) having undergone PV isolation for drug-resistant paroxysmal AF were enrolled. Eleven patients (48%) had an ICD implanted of whom four had inappropriate shocks secondary to rapid AF. Over a mean follow-up period of 35.0 ± 25.4 months (median 36 months) the freedom from AF recurrence after the index PV isolation procedure was 74% without AADs. Patients with inappropriate ICD interventions for AF did not present futher ICD shocks after AF ablation. No major complications occurred. Conclusion: Catheter ablation is a valid therapeutic choice for patients with BS and paroxysmal AF considering the high success rates, the limitations of the AADs and the safety of the procedure, and it should be taken into consideration especially in those patients presenting inappropriate ICD shocks due to rapid AF.

Second generation cryoballoon ablation for atrial fibrillation in young adults: midterm outcome in patients under 40 years of age.

Aims: Pulmonary vein isolation (PVI) has been demonstrated more effective in young patients, in which the substrate for atrial fibrillation (AF) is probably more confined to pulmonary vein potentials. The present study sought to focus on the midterm outcomes in patients under 40 years having undergone PVI with the Cryoballoon Advance because of drug resistant AF. Methods and results: Between June 2012 and December 2015, 57 patients having undergone Cryoballoon ablation (CB-A) below 40 years of age for AF in our centre were retrospectively analysed and considered for our analysis. All patients underwent this procedure with the 28 mm Cryoballon Advance. All 227 veins were successfully isolated without the need for additional focal tip ablation. Median follow-up was 18 ±10 months. The freedom from AF after a blanking period of 3 months was 88% in our cohort of patients younger than 40 years old. The most frequent periprocedural complication was related to the groin puncture and occurred in 2 patients. After a single procedure, the only univariate predictor of clinical recurrence was the diagnosis of hypertrophic cardiomyopathy. Conclusion: Young patients affected by AF can be effectively and safely treated with CB-A that grants freedom from AF in 88% of the patients at 18 months follow-up following a 3-month blanking period. All veins could be isolated with the large 28 mm Cryoballoon Advance only.

Role of Electrocardiographic Tpeak-Tend for the Prediction of Ventricular Arrhythmic Events in the Brugada Syndrome.

Some previous studies have proposed the electrocardiographic Tpeak-Tend (TpTe) as a possible predictor of ventricular arrhythmic events in patients with Brugada syndrome (BrS). We sought to analyze the association between the parameters of repolarization dispersion (TpTe, TpTe/QT, TpTe dispersion, QTc, and QTd) and ventricular fibrillation/sudden cardiac death in a large cohort of patients with type 1 BrS. A total of 448 consecutive patients with BrS (men 61%, age 45 ± 16 years) with spontaneous (n = 96, 21%) or drug-induced (n = 352, 79%) type 1 electrocardiogram were retrospectively included. At the time of the diagnosis or during a mean follow-up of 93 ± 47 months (median 88 months), 43 patients (9%) documented ventricular arrhythmias. No significant difference was observed in TpTe, TpTe/QT, maximum TpTe, and TpTe dispersion between asymptomatic patients and those with syncope and malignant arrhythmias. TpTe/QT ratio did not also significantly differ between patients with ventricular fibrillation/sudden cardiac death and those asymptomatic ones. In conclusion, TpTe was not significantly prolonged in those patients with type 1 BrS presenting with unexplained syncope or malignant arrhythmic events during follow-up.

Role of the burden of premature atrial contractions during the blanking period following second-generation cryoballoon ablation in predicting late recurrences of atrial arrhythmias.

PURPOSE: Recent data suggests that high burden of premature atrial complexes after pulmonary vein isolation predicts recurrences of atrial arrhythmias. The present study sought to assess the role of premature atrial complexes burden in predicting atrial arrhythmias recurrences in patients with atrial fibrillation (AF) who have undergone second-generation cryoballoon ablation (CB-Adv). METHODS: Consecutive patients with drug-resistant paroxysmal atrial fibrillation who underwent pulmonary vein isolation using CB-Adv technology as the index procedure were retrospectively included. Twenty-four-hour Holter recordings were performed for every patient. Based on previously published data, a burden of more than 76 premature atrial complexes per day was considered as being high. RESULTS: One hundred and seven patients were included in the analysis. The recurrence rate among the group of patients with more than 76 premature atrial complexes per day was significantly higher compared with the group with a lower burden of premature atrial complexes (47.5 vs 11.9%, respectively; p < 0.001). In the multivariate analysis, the documentation of more than 76 premature atrial complexes per day registered at 1 month and at the end of the blanking period, predicted late recurrence of atrial arrhythmias. CONCLUSIONS: Frequent premature atrial complexes in the early stages after CB-Adv ablation strongly predict late recurrences of atrial arrhythmias.

Single freeze strategy with the second- generation cryballoon for atrial fibrillation: a multicenter international retrospective analysis in a large cohort of patients.

PURPOSE: The second-generation cryoballoon (CB-A, Arctic Front Advance, Medtronic, Minneapolis, MN, USA) has proven to be highly effective in achieving freedom from atrial fibrillation; nonetheless, the ideal number and duration of freezing cycles is still a matter of debate. We investigated the acute success, procedural complications, and clinical outcome of a single freeze strategy using the CB-A in a large, retrospective, international multicenter study. METHODS: Between January 2013 and September 2015, 818 consecutive patients (58 ± 12 years, 68% males) with drug-resistant atrial fibrillation (AF) who underwent a CB-A using a single freeze strategy were taken into consideration for our analysis. RESULTS: Paroxysmal AF was documented in 74.1% of the patients, while 25.9% presented with persistent AF. Additional freezes were needed in a mean 1.4 veins per patient. 0.2% of the patients experienced persistent PNP that was still documented at the last follow-up. After a median follow-up of 14 ± 8 months, taking into consideration a blanking period (BP) of 3 months, 692 patients (84.6%) were free from arrhythmia recurrence. After a single procedure, AF recurrence during BP and persistent AF were identified as predictors of clinical recurrence after BP. CONCLUSIONS: Single freeze CB-A ablation is effective in treating drug-resistant AF and affords freedom from arrhythmia recurrences in 84.6% of patients during a 14-month follow-up. Persistent AF and recurrence during BP are predictors of arrhythmia recurrences.

Second-generation cryoballoon ablation in the setting of left common pulmonary veins: Procedural findings and clinical outcome.

BACKGROUND: A left common pulmonary vein (LCPV) accounts for the most frequent PV variation. Use of the cryoballoon (CB) for isolating these veins is still debatable. To date, no data are available regarding the feasibility, acute PV isolation, and clinical outcome of the second-generation CB (CB-A) in this setting. OBJECTIVE: The purpose of this study was to investigate the performance of the CB-A in patients with LCPVs. METHODS: In a total cohort of 433 patients having undergone CB-A ablation for drug-refractory atrial fibrillation together with preprocedural computed tomographic scanning, 146 patients presented an LCPV. Measurement of ostial area and trunk distance was performed, together with analysis of procedural and fluoroscopic data in order to determine the ablation strategy. The latter 146 LCPV+ patients were compared for outcome with a cohort of 146 propensity-score matched LCPV- patients. RESULTS: Electrical isolation could be achieved in all left-sided veins. A long left common trunk (>15 mm) was found in 25% (37/146) of the LCPV+ patients. LCPVs treated with a single-shot freeze strategy presented a longer trunk (22 ± 5 mm vs 9 ± 4 mm, P <.001) and smaller ostial area (305 ± 109 mm2 vs 400 ± 108 mm2, P <.001) compared to LCPV patients in whom a segmental (superior and inferior) freeze was delivered. Survival free from atrial fibrillation was similar between LCPV+ and LCPV- patients during mean follow-up of 19 ± 10 months (log rank P = .33). CONCLUSION: CB-A ablation in LCPV+ patients is effective and showed no difference in clinical outcome compared to LCPV- patients.

Comparison of the Incidences of Complications After Second-Generation Cryoballoon Ablation of Atrial Fibrillation Using Vitamin K Antagonists Versus Novel Oral Anticoagulants.

Data evaluating the impact of the periprocedural administration of novel oral anticoagulants (NOACs) on complications in the setting of pulmonary vein (PV) isolation using cryoballoon (CB) is limited. In the present study, our aim was to analyze procedural characteristics and incidence of complications in those patients who underwent CB ablation for atrial fibrillation and the impact of NOACs on adverse events compared with vitamin K antagonists (VKAs). Consecutive patients with drug resistant atrial fibrillation who underwent PV isolation by CB as index procedure were retrospectively included in our analysis. In group I, 290 of 454 patients (63.9%) received VKAs (warfarin: n = 222 and acenocoumarol: n = 68), and in group II, 164 of 454 patients (36.1%) were treated with NOACs (rivaroxaban: n = 71; dabigatran: n = 60; and apixaban: n = 33). Age was significantly higher in the group II (62.8 ± 9.7 vs 58.6 ± 11.3; p <0.001). During the study period, 454 consecutive patients (male 71%, age 60.1 ± 10.9 years) were enrolled. Major complications occurred in 9 patients (2.0%): peripheral vascular complications were observed in 6 patients (1.3% per procedure), persistent phrenic nerve palsy occurred in 2 (0.4%), and transient ischemic attacks in 1 (0.2%). In both groups, the incidence of major complications was similar (group I [VKAs]: 7 patients [2.4%] vs group II [NOACs]: 2 patients [1.2%]; p = 0.5). In conclusion, CB ablation is a safe procedure for PV isolation and is associated with low complication rates. The incidence of adverse events in PV isolation using the second-generation CB with the periprocedural administration of NOACs is not significantly different than VKA treatment.

Determinants of Acute and Late Pulmonary Vein Reconnection in Contact Force-Guided Pulmonary Vein Isolation: Identifying the Weakest Link in the Ablation Chain.

BACKGROUND: Pulmonary vein reconnection (PVR) still determines recurrences of atrial fibrillation after contact force (CF)-guided pulmonary vein isolation. We studied whether acute PVR (adenosine and waiting time) and late PVR (at repeat) are explained by incomplete transmurality and contiguity within the deployed radiofrequency circle. METHODS AND RESULTS: We analyzed 42 CF-guided ipsilateral pulmonary vein isolation procedures. For each radiofrequency tag within the circle, we collected data reflecting lesion depth (time of application, power, impedance drop [Δ-Imp], CF, force-time integral [FTI], and ablation index [AI]) and contiguity (automated interlesion distance [ILD]). Ablation line contiguity index (ALCI) was developed as a novel automated algorithm combining depth and contiguity into one single criterion. Each circle was subdivided into 10 segments. For each segment, we determined its weakest link by annotating timemin, powermin, Δ-Impmin, CFmin, FTImin, AImin, ILDmax, and ALCImin. Compared with segments without PVR (n=758), PVR segments (n=44) were characterized by lower Δ-Impmin (4.8 versus 7.4 Ω), CFmin (8.5 versus 11.8 g), FTImin (351 versus 473 gs), AImin (367 versus 408 arbitrary unit [au]), and higher ILDmax (6.8 versus 5.5 mm). ALCImin was significantly lower in segments with PVR (74% versus 104%; P<0.001) and was associated with the highest accuracy to predict durable segments (area under the curve=0.73). CONCLUSIONS: In CF-guided pulmonary vein isolation, PVR is explained by lack of both lesion depth and contiguity within the deployed radiofrequency circle. ALCI, a novel measure combing contiguity and depth, is the most accurate predictor for durable segments. By avoiding weak links in the ablation chain, ALCI-guided ablation is expected to improve success rate of point-by-point radiofrequency ablation.

Efficacy and safety of the second generation cryoballoon ablation for the treatment of paroxysmal atrial fibrillation in patients over 75 years: a comparison with a younger cohort.

AIMS: In this double centre, retrospective study, we aimed to analyse the 1-year efficacy and safety of cryoballoon ablation (CB-A) in patients older than 75 years compared with those younger than 75-years old. METHODS AND RESULTS: Fifty-three consecutive patients aged 75 years or older with drug-resistant paroxysmal AF (PAF) who underwent pulmonary vein isolation (PVI) by the means of second generation CB-A, were compared with 106 patients aged <75 years. The mean age in the study group (>75 years) was 78.19 ± 2.7 years and 58.97 ± 8.5 in the control group. At 1-year follow-up the global success rate was 83.6% and did not significantly differ between older (10/53) and younger patients (16/106) (81.1 vs. 84.9%, P = 0.54). Transient phrenic nerve palsy was the most common complication which occurred in eight patients in the younger group and in three in the older group (7.5 vs. 5.7%, respectively, P = 0.66). CONCLUSIONS: The results of our study showed that CB-A for the treatment of PAF is a feasible and safe procedure in elderly patients, with similar success and complications rates when compared with a younger population.