Search

Funding Acknowledgements Type of funding sources: None. Background Radiofrequency catheter ablation (RFA) of cavotricuspid isthmus–dependent atrial flutter (AFL) is a procedure with a high success rate and a low complication rate. The anatomical variation and irregularity of the isthmus, with the high local blood flow, can reduce the effectiveness of the lesion and consequently of the procedure. Recent data suggests that deeper ablation lesions can be created using open-irrigated catheters (CA) with half-normal saline (HNS). Purpose To assess the acute efficacy and safety of RFA of AFL with half-normal saline (HNS). Compare the results with CA irrigated with normal saline (NS). Methods Randomized, prospective, observational and single-center study. Consecutive patients with first AFL RFA between June 2019 and December 2020 were included. CA with HNS or NS were used, with a limit of 40 watts and 40° C. An RFA line was performed under fluoroscopic guidance or electroanatomic mapping. If necessary, the lesion was repeated until the arrhythmia was interrupted and the bidirectional block was achieved (success). Acute success, total radiofrequency time (RT), number of radiofrequency applications, and complications were analyzed. Results 38 patients with RFA of AFL were analyzed. 19 in the HNS and 19 in the NS group. There were no significant differences between the baseline characteristics of each group. (Table 1) The accute success rate was 100% with a median of 2 RFA applications in both groups. The mean RT in HNS was 7:10 vs 09:16 min in NS group; the t-test analysis did not show a significant difference (p = .2). A subanalysis was performed in those patients who required more than 2 lines of RFA; a mean of 4 in the HNS group vs 6 in the NS group (p = .4). In the HNS group, RT was significantly shorter; 8:17 vs 13:17 min in the NS group (p = .011). (Figure 1) There was a steam pop in the HNS group and no complications or steam pop in the NS group (p = .53). Conclusions RFA of AFL using HNS is an effective and safe procedure. In patients with unfavorable anatomy who required a greater number of applications, the radiofrequency time was significantly shorter using HNS. Baseline characteristicsHNS (19 p)NS(19 p)pAge56 ± 12.3 years61 ± 10.8 years.22Male16 p (84%)16 p (84%)1Heart Disease7 p (36.8%)5 p (26.3%).68Ejection Fraction57.1 ± 11%56 ± 14.3%.49Ejection Fraction < 50%2 p (10.5%)2 p (10.5%)1Electroanatomic mapping10 p (52.6%)8 p (42.1%).7Abstract Figure. Fugure 1

Funding Acknowledgements Type of funding sources: None. Background Catheter ablation of paraseptal accessory pathways (PAP) is associated with longer fluoroscopy and procedure times, more radiofrequency lesions, as well as a higher rate of recurrence and complications. In anteroseptal or midseptal PAP, recurrence and risk of AV block is even higher. Guided ablations with a three-dimensional electroanatomic mapping system (3D) report greater efficacy and safety. Purpose To assess the acute success rate and complications of PAP 3D catheter ablation. Report the recurrence rate at one year of follow-up. Methods Descriptive analysis that included patients with difficult PAP 3D catheter ablation between 2017 and 2019. Acute success was defined as the disappearance of ventricular pre-excitation 15 seconds after starting the application and the absence of retrograde conduction (Figure). In all cases, a one-year follow-up was performed with ECG and 24-hour Holter. Results 25 patients were included during the mentioned period. The average age was 23 years, 60% (15 p) were men and 56% (14 p) were symptomatic due to palpitations. 1 patient had previous heart disease (ebstein"s anomaly). 36% (9 p) had a previous procedure: 5 patients with previous failed radiofrequency ablation, 1 patient with failed anteroseptal cryoablation and 3 patients with suspended ablation due to risk of AV block. The most frequent location was the posteroseptal. (Table) The primary success rate was 92% (23 of 25 p). Ablation was unsuccessful in two patients, one with Ebstein"s disease and the other with a left posteroseptal PAP. None of the patients presented complications associated with the procedure. During the one-year follow-up, one patient was registered with asymptomatic recurrence (1 of 23; 4.35%: right posteroseptal location), demonstrated by manifest preexcitation on the control ECG. Conclusion In our first experience, catheter ablation of difficult accessory pathways guided by three-dimensional electroanatomic mapping showed a high primary success rate without associated complications. Recurrence during follow-up was similar to that reported in the literature. Accessory Pathway locationPatientsRight Posteroseptal11 (44%)Left Posteroseptal5 (20%)Anteroseptal5 (20%)Midseptal4 (16%)Abstract Figure

BackgroundChagas disease (CD), a parasitic disease caused by Trypanosoma cruzi. Parasite persistence is crucial in the development and progression of Chagas cardiomyopathy that occurs in 30% of untreated patients.Methods and findingsA cohort of 95 CD treated children, with at least 6 years post-treatment follow up, was evaluated. Median after treatmeant follow-up was 10 years. At the time of the last visit a group of non infected subjects were also included as a control for cardiological studies.During follow-up, the majority of treated subjects 59/61 (96%) achieved negative parasitemia by qPCR at the end of treatment. A decrease in T. cruzi antibodies titers were observed and seroconversion by two conventional serology tests (IHA, ELISA) occurred in 53/95 (56%).Holter showed alterations in 3/95 (3%) of treated patients: isolated ventricular extrasystoles and nocturnal sinus bradycardia (one patient); asymptomatic and vagal related 1st and 2nd degree AV block (one patient); and complete right bundle branch block (cRBBB) (one patient). Only the last one is probably related to CD involvement. 2D speckle tracking echocardiography was conducted in 79/95 (83%) patients and no alterations in myocardial contractility were observed.In the non infected group Holter evaluations showed similar non pathological results in 3/28 (10%) of subjects: isolated ventricular premature beats (2 patients); asymptomatic 2nd degree AV block with Wenckebach sequences during night time (one patient). 2D speckle tracking echocardiography was conducted in 25/28 (89%) with no alterations.ConclusionsAfter long term follow-up of a cohort of treated children for CD, a good parasiticidal treatment effect and a low incidence of cardiological lesions, related to Chagas disease, were observed. These results suggest a protective effect of treatment on the development of cardiological lesions and strengthen the recommendation of early diagnosis and treatment of infected children.Trial registrationClinicalTrials.govNCT04090489.Author summaryIf left untreated, CD evolves into a chronic oligosymptomatic infection that can progress to cardiac complications in 30% of patients after several years.It is known that the main early marker of cardiac involvement are alterations in the conduction system. There are few studies of long-term after treatment cardiological evolution which have assessed the clinical effectiveness of treatment.The rationale for CD treatment is to avoid the development of cardiological complications. The parasiticidal effect of treatment has been demonstrated but its clinical effectiveness in preventing cardiac involvement requires long term follow-up.In our long term follow-up study of treated children, we observed the preventive effect on cardiac lesions by treatment with benznidazole or nifurtimox. This intensifies the need for early diagnosis and treatment to prevent the development of long term complications observed in CD.