Search

The Brugada syndrome (BrS) is a cardiac arrhythmic disorder responsible for sudden cardiac death associated with the onset of ventricular arrhythmias, such as reentrant ventricular tachycardia and fibrillation. The mechanisms which lead to the onset of such electrical disorders in patients affected by BrS are not completely understood, yet. The aim of the present study is to investigate by means of numerical simulations the electrophysiological mechanisms at the basis of the morphology of electrocardiogram (ECG) and the onset of reentry associated with BrS. To this end, we consider the Bidomain equations coupled with the ten Tusscher–Panfilov membrane model, on an idealized wedge of human right ventricular tissue. The results have shown that: (1) epicardial dispersion of repolarization, generated by the coexistence of regions of early and late repolarization, due to different modulation of the $$I_\mathrm{{CaL}}$$ I CaL current, produces ECG waveforms exhibiting qualitatively the typical BrS morphology, characterized by ST elevation and partially negative T-waves; (2) epicardial dispersion of repolarization promotes the onset of reentry during the implementation of the programmed stimulation protocol, because of the conduction block occurring when a premature beat reaches the border of late repolarizing regions; and (3) the modulation of the $$I_\mathrm{{to}}$$ I to current affects the duration of reentry, which becomes sustained with a remarkable increase of $$I_\mathrm{{to}}$$ I to in the subepicardial layers.

In patients with healed myocardial infarction, the left ventricular ejection fraction is characterized by low sensitivity and specificity in the prediction of future malignant arrhythmias. Thus, there is the need for new parameters in daily practice to perform arrhythmic risk stratification. The aim of this study is to identify some features of proarrhythmic geometric configurations of scars and border zones (BZ), by means of numerical simulations based on left ventricular models derived from post myocardial infarction patients. Two patients with similar clinical characteristics were included in this study. Both patients exhibited left ventricular scars characterized by subendo- and subepicardial BZ and a transmural BZ isthmus. The scar of patient #1 was significantly larger than that of patient #2, whereas the transmural BZ isthmus and the subdendo- and subepicardial BZs of patient #2 were thicker than those of patient #1. Patient #1 was positive at electrophysiologic testing, whereas patient #2 was negative. Based on the cardiac magnetic resonance (CMR) data, we developed a geometric model of the left ventricles of the two patients, taking into account the position, extent, and topological features of scars and BZ. The numerical simulations were based on the anisotropic monodomain model of electrocardiology. In the model of patient #1, sustained ventricular tachycardia (VT) was inducible by an S2 stimulus delivered at any of the six stimulation sites considered, while in the model of patient #2 we were not able to induce sustained VT. In the model of patient #1, making the subendo- and subepicardial BZs as thick as those of patient #2 did not affect the inducibility and maintenance of VT. On the other hand, in the model of patient #2, making the subendo- and subepicardial BZs as thin as those of patient #1 yielded sustained VT. In conclusion, the results show that the numerical simulations have an effective predictive capability in discriminating patients at high arrhythmic risk. The extent of the infarct scar and the presence of transmural BZ isthmuses and thin subendo- and subepicardial BZs promote sustained VT.

Funding Acknowledgements Type of funding sources: None. Background Roof Posterior Wall (RPW) debulking may be important in the maintenance of AF activity as reducing the surface area below a critical mass can prevent persistent AF. No data exists on a combined cryoballoon ablation (CBA) approach guided by ultra-high density mapping (UHDM) system. Objective To explore, through UHDM, generation of consistent linear lesions at the left atrial (LA) roof using CBA in patients (pts) with persistent AF. Methods Once PVI was completed, the CB (Arctic Front Advance) was used to perform RPW isolation (RPWI). CBA was applied to create a continuous lesion connecting the ostial areas of the right and left superior PVs. Optimal position of the CB along the different segments of the RPW was obtained by advancing/retracting the inner lumen catheter distally/proximally within the PV. A detailed pre- and post-ablation 3D map was created in each pt using the Orion catheter and the Rhythmia UHDM system. Areas and type of isolation over the RPW and the entire LA were precisely identified and measured. Ablation endpoint was PVI and RPWI as assessed by entrance and exit block and after administration of intravenous adenosine. Results Ten consecutive pts were included (mean LA volume = 126 ± 36 ml, mean points per map = 10800 ± 8500, mean roof area = 22 ± 4 cm²). A mean of 4.6 ± 0.8 freezes at PV and 5.4 ± 2 at the roof per pt were required (mean nadir temperature (T) = −45°C ± 6°C and −41°C ± 3°C, respectively, mean T at the roof = −33°C ± 4°C) during a mean CBA time of 954 ± 73 s for PVs and 810 ± 311 s for the roof. The mean conduction delay along the roof line at the shortest segment was 55 ± 13 ms. Resulting low-voltage areas ( Conclusions In our preliminary experience PVI plus RPWI can be achieved safely and effectively using the CB in conjunction with UHDM. The use of UHDM allowed a precise definition of the effective isolation areas.

Aims: The single-freeze strategy using the second-generation cryoballoon (CB-A, Arctic Front Advance, Medtronic, Minneapolis, MN, USA) has been reported to be as effective as the recommended double-freeze approach in several single-centre studies. In this retrospective, international, multicentre study, we compare the 3-min single-freeze strategy with the 4-min single-freeze strategy. Methods and results: Four hundred and thirty-two patients having undergone pulmonary vein isolation (PVI) by means of CB-A using a single-freeze strategy were considered for this analysis. A cohort of patients who were treated with a 3-min strategy (Group 1) was compared with a propensity score-matched cohort of patients who underwent a 4-min strategy (Group 2). Pulmonary vein isolation was successfully achieved in all the veins using the 28-mm CB-A. The procedural and fluoroscopy times were lower in Group 1 (67.8 ± 17 vs. 73.8 ± 26.3, P

Background: The new version of inner lumen mapping catheter (Achieve Advance™; Medtronic, Minnesota, USA) includes a new solid core which provides improved rotational response, as compared to the current Achieve Mapping Catheter. In the present study, we sought to analyze the rate of visualisation of real-time recordings using this new device comparing it with a large cohort of patients having undergone second generation cryoballoon (CB) ablation using the previous Achieve mapping catheter. Methods: All patients having undergone CB ablation using the Achieve Advance and the last 150 consecutive patients having undergone CB ablation using the previous Achieve were analysed. Exclusion criteria were presence of an intracavitary thrombus, uncontrolled heart failure, moderate or severe valvular disease and contraindications to general anesthesia. Results: A total of 200 consecutive patients (60.1 ± 9.5 years, 75% males) were evaluated (50 Achieve Advance and 150 old Achieve). Real-time recordings were significantly more prevalent in the “new Achieve Advance” population compared with the “old Achieve” group (73.5% vs 56.8%; p = 0.0001). Real-time recordings could be more frequently visualized in the “Achieve Advance” group in all veins except RIPV (LSPV: 86% vs 71.3%, p = 0.04; LIPV: 84% vs 62.7%, p = 0.005; RSPV: 78% vs 52%, p

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.

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.

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.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 aged75 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).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.

Background No data are available about the clinical outcome of pulmonary vein isolation (PVI) as an index procedure for persistent atrial fibrillation (PersAF) ablation using the second-generation cryoballoon (CB-Adv). Objective The purpose of this study was to assess the 1-year efficacy of PVI as an index procedure for PersAF ablation using the novel CB-Adv. Methods Sixty-three consecutive patients (45 male [71.4%], mean age 62.7 ± 9.7 years) with drug-refractory PersAF undergoing PVI using the novel CB-Adv were enrolled. Follow-up was based on outpatient clinic visits including Holter ECGs. Recurrence of atrial tachyarrhythmias (ATas) was defined as a symptomatic or documented episode >30 seconds. Results A total of 247 PVs were identified and successfully isolated with a mean of 1.7 ± 0.4 freezes. Mean procedural and fluoroscopy times were 87.1 ± 38.2 minutes and 14.9 ± 6.1 minutes, respectively. Among 26 of 63 patients (41.3%) presenting with AF at the beginning of the procedure, 7 of 26 (26.9%) converted to sinus rhythm during ablation. Phrenic nerve palsy occurred in 4 of 63 patients (6.3%). At 1-year follow-up, after a 3-month blanking period (BP), 38 of 63 patients (60.3%) were in sinus rhythm. Because of ATa recurrences, 9 patients underwent a second procedure with radiofrequency ablation showing a pulmonary vein reconnection in 4 right-sided PVs (44.4%) and 3 left-sided PVs (33.3%). Multivariate analysis demonstrated that PersAF duration (P = .01) and relapses during BP (P = .04) were independent predictors of AT recurrences. Conclusion At 1-year follow-up, freedom from ATas following PersAF ablation with the novel CB-Adv is 60%. Phrenic nerve palsy is the most common complication. PersAF duration and relapses during the BP appear to be significant predictors of arrhythmic recurrences.

Transseptal puncture was first described by Ross and Cope, independently, in 1959. This technique was developed predominantly for the diagnostic evaluation of valvular heart disease. After a few years, transseptal catheterization has been replaced by indirect measurements of left atrial pressure using the Swan-Ganz catheter. Recently, there has been a renewed interest in transseptal puncture because of emerging therapeutic procedures for structural heart disease and atrial fibrillation ablation. Current transseptal technique has changed very little since the initial reports, but new tools are now available to facilitate transseptal puncture including echocardiographic imaging (three-dimensional, transesophageal, or intracardiac), radiofrequency powered wires and needle-tipped guidewires. Transseptal catheterization can be performed with high success rates and low complication rates. An Italian survey reported a success rate of 99% with a complication rate of 0.76%. Complications included aortic perforation, pericardial tamponade, ST-segment elevation, cerebral air embolization, systemic embolization, and thrombus formation on the transseptal sheath.

Cardiac resynchronization therapy (CRT) is a novel and effective therapy for patients with heart failure. The aim of CRT is to improve the heart's pumping efficiency by the resynchronization of the chambers. Electrical dyssynchrony shows itself as bundle branch block with prolongation of QRS120 ms. Mechanical dyssynchrony (atrioventricular, interventricular and intraventricular) is evidenced by echocardiographic parameters. A cardioverter-defibrillator function can be included with the pulse generator in patients with high risk of sudden death. The estimate of perioperative death associated with CRT was 0.3% with a low rate of complications, similar to that seen in standard pacemaker placement. In 10% of patients there was an implant failure due to the difficulty in accessing the coronary sinus. Approximately one third of patients are non-responder with no significant improvement after implantation. The beneficial effect of CRT on soft endpoints and mortality (symptoms, NYHA class, 6-min walking test, quality of life score, ejection fraction) was demonstrated in the earliest randomized clinical trials. Current guidelines for CRT are based on inclusion and exclusion criteria in the large randomized trials that have been performed and patients with chronic atrial fibrillation are included. Unresolved issues are the identification of non-responders and the efficacy of CRT in patients with mechanical dyssynchrony without electrical dyssynchrony and in NYHA functional class I/II patients with ejection fractionor = 35%.