Purpose Advanced non-fluoroscopic mapping systems for radiofrequency ablation (RFA) have shown to be an effective treatment of atrial fibrillation. This study analyzes the resource usage and subsequent costs associated with the implementation of an ultra-high density mapping system (UHDMS) compared to non-ultra-high density mapping systems (NUHDMS). Methods This retrospective observational study included 120 patients (18 years or older) with paroxysmal or persistent atrial fibrillation who underwent RFA for de novo pulmonary vein isolation guided either by an UHDMS (n=63) or NUHDMS (n=57) for their index procedure. We compared patient characteristics, short- and long-term procedural outcomes, resource usage, and clinical outcomes followed up to 16 months between the two treatment groups. The cost analysis was conducted from the perspective of a single center in Spain (Clinica Universidad de Navarra). Results Neither baseline patient characteristics nor complication rate differed between groups. Repeat RFAs following recurrent arrhythmia at 16 months was lower in the UHDMS patient group than in the NUHDMS group (6 vs. 14, respectively; P=0.027). The average total cost per patient was euro1,600 lower in the UHDMS group, compared to the NUHDMS group (euro11,061 and euro12,661, respectively; P=0.03). Conclusion In patients treated with an NUHDMS, 25% had a repeat ablation for recurrent arrhythmia, whereas only 9% of patients treated with a UHDMS had one (61% relative risk reduction), resulting in an average cost saving per patient of euro1,600.

Background The antral region of pulmonary veins (PV)s seems to play a key role in a strategy aimed at preventing atrial fibrillation (AF) recurrence. Particularly, low-voltage activity in tissue such as the PV antra and residual potential within the antral scar likely represent vulnerabilities in antral lesion sets, and ablation of these targets seems to improve freedom from AF. The aim of this study is to validate a structured application of an approach that includes the complete abolition of any antral potential achieving electrical quiescence in antral regions. Methods The improveD procEdural workfLow for cathETEr ablation of paroxysmal AF with high density mapping system and advanced technology (DELETE AF) study is a prospective, single-arm, international post-market cohort study designed to demonstrate a low rate of clinical atrial arrhythmias recurrence with an improved procedural workflow for catheter ablation of paroxysmal AF, using the most advanced point-by-point RF ablation technology in a multicenter setting. About 300 consecutive patients with standard indications for AF ablation will be enrolled in this study. Post-ablation, all patients will be monitored with ambulatory event monitoring, starting within 30 days post-ablation to proactively detect and manage any recurrences within the 90-day blanking period, as well as Holter monitoring at 3, 6, 9, and 12 months post-ablation. Healthcare resource utilization, clinical data, complications, patients' medical complaints related to the ablation procedure and patient's reported outcome measures will be prospectively traced and evaluated. Discussion The DELETE AF trial will provide additional knowledge on long-term outcome following a structured ablation workflow, with high density mapping, advanced algorithms and local impedance technology, in an international multicentric fashion. DELETE AF is registered at (NCT05005143).

Objectives: This analysis was performed to evaluate the transition of local impedance (LI) drop during pulmonary vein isolation (PVI) to durable block and mature lesion formation based on 3-month mapping procedures. Background: A radiofrequency catheter measuring LI has been shown to be effective for performing PVI in patients with paroxysmal atrial fibrillation. Previous analysis has demonstrated LI drop to be predictive of pulmonary vein segment conduction block during an atrial fibrillation ablation procedure. Methods: Fifty-eight patients who had undergone LI-blinded de novo PVI returned for a 3-month mapping procedure. PVI ablation circles were divided into 16 anatomic segments for classification (durable block or gap), and the median LI drop within segments with an interlesion distance of ¿6 mm was compared. A total of 51 data sets met the criteria for segmental analysis of LI performance. Results: At the 3-month procedure, PV connection was confirmed in at least 1 PV segment in 35 of the included patients. LI drop outperformed generator impedance drop as a predictor of durable conduction block (area under the receiver-operating characteristic curve: 0.79 vs 0.68; P = 0.003). Optimal LI drops were identified by left atrial region (anterior/superior: 16.9 ¿ [sensitivity: 69.1%; specificity: 85.0%; positive predictive value for durable conduction block: 97.7%]; posterior/inferior:14.2 ¿ [sensitivity: 73.8%; specificity: 78.3%; positive predictive value: 96.9%]). Starting LI before radiofrequency (RF) application was significantly different among healthy, gap, and mature scar tissue and was also a contributing factor to achieving an optimal LI drop (85.2% of RF applications with a starting LI of ¿110 ¿ achieved the optimal regional drop or greater). Conclusions: LI drop is predictive of durable PV segment isolation. Preablation starting LI is associated with the magnitude of LI drop. These findings suggest that a regional approach to RF ablation guided by LI combined with careful interlesion distance control may be beneficial in patients with paroxysmal atrial fibrillation (Electrical Coupling Information From the Rhythmia HDx System and DirectSense Technology in Subjects With Paroxysmal Atrial Fibrillation [LOCALIZE]; NCT03232645).

Objective: To analyze the anatomic characteristics of the left atrium and pulmonary veins in individuals undergoing ablation for atrial fibrillation and to identify possible anatomic factors related with recurrence. Material and methods: We retrospectively reviewed the CT angiography studies done to plan radiofrequency ablation for atrial fibrillation in 95 patients (57 men; mean age, 65 +/- 10 y). We reviewed the anatomy of the pulmonary veins and recorded the diameters of their ostia as well as the diameter and volume of the left atrium. We analyzed these parameters according to the type of arrhythmia and the response to treatment. Results: In 71 (74.7%) patients, the anatomy of the pulmonary veins was normal (i.e., two right pulmonary veins and two left pulmonary veins). Compared to patients with paroxysmal atrial fibrillation, patients with persistent atrial fibrillation had slightly larger diameter of the left pulmonary veins (left superior pulmonary vein 17.9 +/- 2.6 mm vs. 16.7 +/- 2.2 mm, p = 0.04; left inferior pulmonary vein 15.3 +/- 2 mm vs. 13.8 +/- 2.2 mm, p = 0.009) and larger left atrial volume (91.9 +/- 24.9 cm(3) vs. 70.7 +/- 20.3 mm(3), p = 0.001). After 22.1 +/- 12.1 months' mean follow-up, 41 patients had sinus rhythm. Compared to patients in whom the sinus rhythm was restored, patients with recurrence had greater left atrial volume (81.4 +/- 23.0 mm(3) vs. 71.1 +/- 23.2 mm(3), p = 0.03). No significant differences in pulmonary vein diameters or clinical parameters were observed between patients with recurrence and those without. Conclusion: The volume of the left atrium is greater in patients with persistent atrial fibrillation and in those who do not respond to ablation.

Aims Radiofrequency ablation creates irreversible cardiac damage through resistive heating and this temperature change results in a generator impedance drop. Evaluation of a novel local impedance (LI) technology measured exclusively at the tip of the ablation catheter found that larger LI drops were indicative of more effective lesion formation. We aimed to evaluate whether LI drop is associated with conduction block in patients with paroxysmal atrial fibrillation (AF) undergoing pulmonary vein isolation (PVI). Methods and results Sixty patients underwent LI-blinded de novo PVI using a point-by-point ablation workflow. Pulmonary vein rings were divided into 16 anatomical segments. After a 20-min waiting period, gaps were identified on electroanatomic maps. Median LI drop within segments with inter-lesion distance <= 6 mm was calculated offline. The diagnostic accuracy of LI drop for predicting segment block was assessed using receiver operating characteristic analysis. For segments with inter-lesion distance <= 6 mm, acutely blocked segments had a significantly larger LI drop [19.8 (14.1-27.1) Omega] compared with segments with gaps [10.6 (7.8-14.7) Omega, P < 0.001). In view of left atrial wall thickness differences, the association between LI drop and block was further evaluated for anterior/roof and posterior/inferior segments. The optimal LI cut-off value for anterior/roof segments was 16.1 Omega (positive predictive value for block: 96.3%) and for posterior/inferior segments was 12.3 Omega (positive predictive value for block 98.1%) where inter-lesion distances were <= 6 mm. Conclusion The magnitude of LI drop was predictive of acute PVI segment conduction block in patients with paroxysmal AF. The thinner posterior wall required smaller LI drops for block compared with the thicker anterior wall.

Purpose Remote system operation technology was developed and applied to a non-fluoroscopic navigation system in order to overcome Spanish mobility restrictions caused by Covid-19 pandemic infection and subsequently used routinely. Methods and results Fifty consecutive complex ablations were performed in different days using this technology. All these procedures were assisted remotely with the only intervention of a field clinical specialist located at his home who took full control of the navigation system (keyboard, mouse, and screen) and had bidirectional real-time audio/video feedback with the operating physician. Once the connection was established, the remote field clinical specialist replicated the Rhythmia screen at the remote location with all its features, and interacted identically with the physician, essentially with no perceptible differences from being physically present. There were neither interruptions nor perceptible delays in the bidirectional communications between the remote field clinical specialist and the operating physician during the procedures. Video signal delay ranged from 265 to 325 ms. All the procedures were uneventful. Conclusions Remote system operation allowed full teleoperation of a non-fluoroscopic navigation system (keyboard, mouse, and screen) as well as bidirectional real-time audio/video feedback with the operating physician, providing a fully autonomous remote assistance in 50 complex ablation procedures. This technology ensures workflow continuity and optimal workforce flexibility and has relevant and promising implications in the field of training, teaching, and resource optimization that deserves further development.

Background: The Prevention With Mediterranean Diet (PREDIMED) trial supported the effectiveness of a nutritional intervention conducted by a dietitian to prevent cardiovascular disease. However, the effect of a remote intervention to follow the Mediterranean diet has been less explored. Objective: This study aims to assess the effectiveness of a remotely provided Mediterranean diet-based nutritional intervention in obtaining favorable dietary changes in the context of a secondary prevention trial of atrial fibrillation (AF). Methods: The PREvention of recurrent arrhythmias with Mediterranean diet (PREDIMAR) study is a 2-year multicenter, randomized, controlled, single-blinded trial to assess the effect of the Mediterranean diet enriched with extra virgin olive oil (EVOO) on the prevention of atrial tachyarrhythmia recurrence after catheter ablation. Participants in sinus rhythm after ablation were randomly assigned to an intervention group (Mediterranean diet enriched with EVOO) or a control group (usual clinical care). The remote nutritional intervention included phone contacts (1 per 3 months) and web-based interventions with provision of dietary recommendations, and participants had access to a web page, a mobile app, and printed resources. The information is divided into 6 areas: Recommended foods, Menus, News and Online resources, Practical tips, Mediterranean diet classroom, and Your personal experience. At baseline and at 1-year and 2-year follow-up, the 14-item Mediterranean Diet Adherence Screener (MEDAS) questionnaire and a semiquantitative food frequency questionnaire were collected by a dietitian by phone. Results: A total of 720 subjects were randomized (365 to the intervention group, 355 to the control group). Up to September 2020, 560 subjects completed the first year (560/574, retention rate 95.6%) and 304 completed the second year (304/322, retention rate 94.4%) of the intervention. After 24 months of follow-up, increased adherence to the Mediterranean diet was observed in both groups, but the improvement was significantly higher in the intervention group than in the control group (net between-group difference: 1.8 points in the MEDAS questionnaire (95% CI 1.4-2.2; P<.001). Compared with the control group, the Mediterranean diet intervention group showed a significant increase in the consumption of fruits (P<.001), olive oil (P<.001), whole grain cereals (P=.002), pulses (P<.001), nuts (P<.001), white fish (P<.001), fatty fish (P<.001), and white meat (P=.007), and a significant reduction in refined cereals (P<.001), red and processed meat (P<.001), and sweets (P<.001) at 2 years of intervention. In terms of nutrients, the intervention group significantly increased their intake of omega-3 (P<.001) and fiber (P<.001), and they decreased their intake of carbohydrates (P=.02) and saturated fatty acids (P<.001) compared with the control group. Conclusions: The remote nutritional intervention using a website and phone calls seems to be effective in increasing adherence to the Mediterranean diet pattern among AF patients treated with catheter ablation.

Background Atrial fibrillation (AF) is the most common cardiac arrhythmia. Catheter ablation aims to restore sinus rhythm. However, relapses occur in up to 30% of patients. A Mediterranean diet (MedDiet) enriched with extra-virgin olive oil (EVOO) substantially reduced the incidence of AF in the PREDIMED trial. The PREDIMAR will test a similar intervention in secondary prevention. Methods PREDIMAR is a multicenter, randomized, single-blind trial testing the effect of a MedDiet enriched with EVOO to reduce tachyarrhythmia relapses after AF ablation. The primary outcome is the recurrence of any sustained atrial tachyarrhythmia after ablation (excluding those occurring only during the first 3 months after ablation). The target final sample size is 720 patients (360 per group) recruited from 4 Spanish hospitals. A remote intervention, maintained for 2 years, is delivered to the active intervention group including periodic phone calls by a dietitian and free provision of EVOO. The control group will receive delayed intervention after trial completion. Routine electrocardiogram (ECG) and Holter ECG are performed, and a portable cardiac rhythm monitoring device is provided to be worn by participants during 15 months. Results Recruitment started in March 2017. Up to July 2019, 609 patients were randomized (average inclusion rate: 5.3 patients/wk). Retention rates after 18 months are >94%. Conclusions If our hypothesis is confirmed, the utility of the MedDiet enriched with EVOO in slowing the progression of AF will be proven, preventing recurrences and potentially reducing complications.