Aims: Ablation of outflow tract ventricular arrhythmias may be limited by a deep intramural location of the arrhythmogenic source. This study evaluates the acute and long-term outcomes of patients undergoing ablation of intramural outflow tract premature ventricular complexes (PVCs). Methods and results: This multicenter series included patients with structurally normal heart or nonischemic cardiomyopathy and intramural outflow tract PVCs defined by: (a) ≥ 2 of the following criteria: (1) earliest endocardial or epicardial activation < 20ms pre-QRS; (2) Similar activation in different chambers; (3) no/transient PVC suppression with ablation at earliest endocardial/epicardial site; or (b) earliest ventricular activation recorded in a septal coronary vein. Ninety-two patients were included, with a mean PVC burden of 21.5±10.9%. Twenty-six patients had had previous ablations. All PVCs had inferior axis, with LBBB pattern in 68%. In 29 patients (32%) direct mapping of the intramural septum was performed using an insulated wire or multielectrode catheter, and in 13 of these cases the earliest activation was recorded within a septal vein. Most patients required special ablation techniques (one or more), including sequential unipolar ablation in 73%, low-ionic irrigation in 26%, bipolar ablation in 15% and ethanol ablation in 1%. Acute PVC suppression was achieved in 75% of patients. Following the procedure, the PVC burden was reduced to 5.8±8.4%. The mean follow-up was 15±14 months and 16 patients underwent a repeat ablation. Conclusion: Ablation of intramural PVCs is challenging; acute arrhythmia elimination is achieved in 3/4 patients, and non-conventional approaches are often necessary for success.

Advanced ablation strategies are needed to treat ventricular tachycardia (VT) and premature ventricular complexes (PVC) refractory to standard unipolar radiofrequency ablation (Uni-RFA). Bipolar radiofrequency catheter ablation (Bi-RFA) has emerged as a treatment option for refractory VT and PVC. Multicentre registry data on the use of Bi-RFA in the setting of refractory VT and PVC are lacking. The aim of this Bi-RFA registry is to determine its real-world safety, feasibility, and efficacy in patients with refractory VT/PVC. Consecutive patients undergoing Bi-RFA at 16 European centres for recurring VT/PVC after at least one standard Uni-RFA were included. Second ablation catheter was used instead of a dispersive patch and was positioned at the opposite site of the ablation target. Between March 2021 and August 2024, 91 patients underwent 94 Bi-RFA procedures (74 males, age 62 ± 13, and prior Uni-RFA range 1–8). Indications were recurrence of PVC (n = 56), VT (n = 20), electrical storm (n = 13), or PVC-triggered ventricular fibrillation (n = 2). Procedural time was 160 ± 73 min, Bi-RFA time 426 ± 286 s, and mean Uni-RFA time 819 ± 697 s. Elimination of clinical VT/PVC was achieved in 67 (74%) patients and suppression of VT/PVC in a further 10 (11%) patients. In the remaining 14 patients (15%), no effect on VT/PVC was observed. Three major complications occurred: coronary artery occlusion, atrioventricular block, and arteriovenous fistula. Follow-up lasted 7 ± 8 months. Nineteen patients (61%) remained VT free. ≥80% PVC burden reduction was achieved in 45 (78%). These real-world registry data indicate that Bi-RFA appears safe, is feasible, and is effective in the majority of patients with VT/PVC.

Safe and efficient radiofrequency catheter ablation depends significantly on the proper placement of dispersive patch electrodes (DPEs), on the skin. This viewpoint describes the role of DPE positioning in optimizing lesion creation and reducing the risk of complications. Incorrect DPE placement can lead to suboptimal energy delivery, prolonging the procedure and/or increasing the risk of adverse events, such as steam pops and potentially fatal atrio-oesophageal fistula. Despite its importance, there is no consensus on the optimal positioning of DPE, and current studies require further improvement in predictive modelling.

Background: Subtypes of atrial fibrillation (AF) can differ, and exact mechanisms in which patients benefit from the pulmonary vein isolation (PVI) remain not fully understood. During PVI, vagal innervation of the heart may also be affected. Thus, non-invasive methods of intraprocedural assessment of such PVI impact are sought. Methods: From 1-minute ECG recordings performed before and after PVI, we investigated short-term deceleration capacity (ST-DC) and short-term heart rate variability (ST-HRV) to determine their potential as indicators of parasympathetic activity before and after ablation. Results: In 24 consecutive patients with paroxysmal AF included in the study, there were a significant differences in ST-DC and ST-HRV parameters measured before and after PVI. After 3 months, patients with baseline ST-DC ≥ 7.5 ms were less likely to experience AF recurrence when compared to patients with baseline ST-DC < 7.5 ms (0% vs 31%, p = 0.0496). There were no differences in AF recurrence after 12 months of follow-up (36% vs 38%, p = 0.52). Conclusion: PVI leads to significant changes in ST-DC and ST-HRV, and these parameters can serve as indicators of vagal denervation after AF ablation. Patients with more prominent baseline ST-DC are less likely to experience AF recurrence during the post-PVI 3-month blanking period. Graphical

Background: The symbiotic relationship between the gut microbiota and cardiovascular health has become a main point in contemporary research, offering valuable insights into the pathogenesis of cardiovascular diseases (CVDs). This review aims to comprehensively examine the bidirectional communication between gut microbial communities and the cardiovascular system, explaining the intricate mechanisms that connect gut dysbiosis to the initiation and progression of CVDs. Material and Methods: A systematic literature review was conducted to compile and analyze relevant studies investigating the impact of the gut microbiota on cardiovascular health. Emphasis was placed on explaining the molecular and physiological mechanisms underlying the interaction between gut microbes and cardiovascular function. Results: Our review confirmed evidence linking gut microbiota-derived metabolites, such as short-chain fatty acids, trimethylamine N-oxide and lipopolysaccharides to vascular function and inflammation. Additionally, we explored the modulation of host metabolism and immune responses by gut microbes, providing insights into their roles in atherosclerosis and hypertension. The review highlight the influence of diet and lifestyle on shaping the gut microbiome and, consequently, cardiovascular outcomes. Conclusions: Gut microbiota plays a crucial role in cardiovascular health and is involved in the start and development of various heart diseases. The identified molecular and physiological mechanisms highlight the need for complete understanding of the gut-cardiovascular axis. Moreover, the review emphasizes the potential of microbiota-targeted interventions, including probiotics and fecal microbiota transplantation, as innovative strategies for preventing and managing CVDs.