Background and aims: Activation wavefront is rapid and uniform in normal myocardium. Fibrosis is associated with deceleration zones (DZ) and late activated zones. Our aim was to study the right ventricular outflow tract (RVOT) endocardial activation duration (EAD) in sinus rhythm, and assess the presence of DZs, in patients with PVCs and controls. Methods: We studied 29 patients with idiopathic PVCs from the outflow tract, subjected to catheter ablation and an activation and voltage map of the RVOT in sinus rhythm. A control group of 15 patients without PVCs that underwent ablation of supraventricular arrhythmias was also studied. The RVOT EAD and number of 10 ms isochrones were assessed. DZ were defined as a zone with>3 isochrones within 1 cm radius. Low voltage areas (LVA) defined as areas with local electrogram amplitude <1.5mV. Results: The two groups did not differ in relation to age, gender or number of points in the map. EAD and number of 10 ms isochrones were higher in the PVC group; 56 (41-66) ms vs 39 (35-41) ms, p=0.001 and 5 (4-8) vs 4 (4-5), p=0.001. Presence of DZs and LVAs were more frequent in the PVC group; 20 (69%) vs 0 (0%), p<0.0001 and 21 (72%) vs 0 (0%), p<0.0001. Patients with LVAs had longer EAD 60 (52-67) vs 36 (32-40) ms, p<0.0001. Conclusions: EAD was longer and DZs were more frequent in patients with PVCs and were associated with presence of LVAs.

Introduction: Cardiac autonomic system modulation by endocardial ablation targeting atrial ganglionated plexi (GP) is an alternative strategy in selected patients with severe functional bradyarrhythmias, although no consensus exists on the best ablation strategy. The aim of this study was to evaluate if a simplified approach by a purely anatomical guided ablation of just the atrial right GP is enough for the treatment of these patients. Methods: We prospectively enrolled patients with significant functional bradyarrhythmias and performed endocardial ablation purely guided by 3D electroanatomic mapping directed at the atrial right GP and accessed parameters of parasympathetic modulation and recurrence of bradyarrhythmias. Results: Thirteen patients enrolled (76.9% male, median age 51, 42-63 years). After ablation, a median RR interval shortening of 28.3 (25.6–40.3)% occurred (111, 937.5-1395.4ms to 722.9, 652.2-882.4ms, p=0.0015). The AH interval also shortened (19, 10.5–35.7%) significantly after the procedure (115, 105-122ms to 85, 71-105ms, p=0.002) as well as Wenckebach cycle length (11.1, 5.9–17.8% shortening) from 450, 440-510ms to 430, 400-460ms, p=0.0014. On 24-hour Holter monitoring there was significant increase in heart rates (HR) of patients after ablation (minimal HR increased from 34 (26-43)bpm to 49 (43–56)bpm, p=0,0063 and mean HR from 65 (47-72)bpm to 78 (67-87)bpm, p=0.0015). No patients had recurrence of symptoms or significant bradyarrhythmias during a median follow-up of 8.4 months. Conclusions: A purely anatomic guided procedure directed only at the atrial right ganglionated plexi seems to be enough as a therapeutic approach for cardiac parasympathetic modulation in selected patients with significant functional bradyarrhythmias.

INTRODUCTION: Most of avoidable defibrillator therapies can be reduced by evidence-based programming, but defining tachycardia configurations across all device manufacturers is not straightforward. The aims were to determine if a uniform programming of tachycardia zones, independently of the manufacturer, result in a lower rate of avoidable shocks in primary-prevention heart failure (HF) patients and also if programming high-rate or delayed therapies can have some benefit. METHODS AND RESULTS: Prospective cohort with historical controls. HF patients with a primary-prevention indication for a defibrillator were randomized to receive one of two new programming configurations (high-rate or delayed therapies). A historical cohort of patients with conventional programming was analyzed for comparison. The primary endpoint was any therapy [shock or anti-tachycardia pacing (ATP)]. Secondary endpoints were appropriate shocks, appropriate ATP, appropriate therapies, inappropriate shocks, syncope and death. 89 patients were assigned for new programming group [high rate (n=47) or delayed therapy (n=42)]. They were compared with 94 historical patients with conventional programming. During a mean follow-up of 20±7 months, the new programming was associated with a reduction of any therapy (HR = 0.265, 95% CI 0.121-0.577, p=0.001), even after adjustment. Aproppriate ATP and any shock were also reduced. Syncope did not occur. Sudden, cardiovascular and all-cause deaths were not different between the groups. In the new programming group, neither high-rate nor delayed programming were better than the other. CONCLUSIONS: In our study, programming tachycardia zones homogeneously across all manufacturers was possible and resulted in a lower rate of therapies, shocks and appropriate ATP.

Background and aims: Cardiac magnetic resonance (CMR), has shown conflicting data regarding existence of structural abnormalities in patients with idiopathic premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT). Our aim was to evaluate the prevalence of low voltage areas (LVA) in the RVOT of patients with PVCS from the outflow tract and in a control group. Secondly, assess for the presence of a non-invasive electrocardiographic (ECG) marker. Methods: 56 consecutive patients, 45 with frequent PVCs (>10000/24h) LBBB, vertical axis, negative in aVL and 11 subjects without PVCs. Arrhythmogenic right ventricular cardiomyopathy was ruled out in all patients. An ECG was performed with V1-V2 at the 2nd intercostal space and the presence of a Brugada ECG pattern (BrP) was assessed. Bipolar voltage map of the RVOT was performed in sinus rhythm (0.5 mV-1.5 mV colour display). Areas with electrograms < 1.5 mV represented the LVA. We tested for the association between high BrP and LVA. Results: None of the patients in the control group had BrP or LVA. In the PVC group, 29 patients (64%) had type 2 BrP and 28 (62%) had LVAs. LVAs were more frequent in patients with BrP; 93% versus 4%, p<0.0001, which was associated with LVA, OR (95% CI): 202.50 (16.92- 2423), p<0.0001. Conclusions: LVAs were frequently present in the RVOT of patients with idiopathic PVCs. They were absent in controls and can be unmasked by the presence of BrP in high right precordial leads.