Search

Aims: This study aims to compare procedural parameters and clinical efficacy of remote magnetic navigation (RMN) vs. manual navigation (MAN) approach for radiofrequency ablation (RFA) in patients with atrial fibrillation (AF). Methods: 146 patients with AF were enrolled in the study. In the RMN group (n=57), patients were treated with the CARTO® 3 in combination with the Niobe ES system. In the MAN group (n=89), ablation was performed with the EnSite Velocity and TactiCath™ Quartz catheter with direct contact force measurement. Procedural time, ablation time, fluoroscopy time, radiation dose and ablation counts were measured and compared between the groups. Recurrence of AF was evaluated after 6 months of follow-up. Results: Mean procedure times (236.87±64.31 vs. 147.22±45.19 min, P

Abstract Background Gigantic left atrium is defined in the current literature as an excessive dilatation of the left atrium above 65mm. Chronic mitral valve disease is associated with the development of thrombus in the left atrium in up to 19% of all cases of mitral insufficiency and appropriate treatment must be initiated to prevent thromboembolic events. In order to diagnose thrombi in the left atrium or left atrial appendage, various imaging methods may be used, including cardiac magnetic resonance. Case presentation The case report describes a 73-year-old male who developed recurrent sessile thrombus on the posterior wall of the gigantic left atrium. A large thrombus was first detected following mitral valve surgery despite effective vitamin K antagonist anticoagulation therapy. Echocardiography and cardiac magnetic resonance were used within the diagnostic procedure and to monitor the treatment outcomes. Cardiac magnetic resonance was shown to be beneficial as it provided a more precise description of the intra-atrial masses located on the posterior left atrial wall, and in such situations, is of greater benefit than standard echocardiography. This led to the surgical removal of the intra-atrial mass; nevertheless, it was quickly followed by the recurrence of the thrombus. The anticoagulant therapy was adjusted and fortified by the introduction of acetylsalicylic acid and sequentially clopidogrel, but this also did not resolve the thrombus formation. Finally, employing a combination of rivaroxaban and clopidogrel resulted in partial thrombus regression. Therefore, various pathophysiological aspects of thrombus formation and used anticoagulation strategies are discussed. Conclusions We describe a unique case of a recurrent thrombus located on the posterior wall of the gigantic left atrium. Cardiac magnetic resonance was shown to be beneficial in providing a more precise description of the intra-atrial masses located on the posterior left atrial wall as compared to standard echocardiographic examination. Development of a thrombus after mitral valve surgery despite effective anticoagulant therapy and its final resolution by introducing a combination of rivaroxaban and clopidogrel highlights the complex etiopathogenesis of thrombus formation. This supports the potential use of this combination in tailoring an individual personalized therapy for patients with recurrent atrial thrombi.

IntroductionPulsed field ablation (PFA) exploits the delivery of short high-voltage shocks to induce cells death via irreversible electroporation. The therapy offers a potential paradigm shift for catheter ablation of cardiac arrhythmia. We designed an AC-burst generator and therapeutic strategy, based on the existing knowledge between efficacy and safety among different pulses. We performed a proof-of-concept chronic animal trial to test the feasibility and safety of our method and technology.MethodsWe employed 6 female swine – weight 53.75 ± 4.77 kg – in this study. With fluoroscopic and electroanatomical mapping assistance, we performed ECG-gated AC-PFA in the following settings: in the left atrium with a decapolar loop catheter with electrodes connected in bipolar fashion; across the interventricular septum applying energy between the distal electrodes of two tip catheters. After procedure and 4-week follow-up, the animals were euthanized, and the hearts were inspected for tissue changes and characterized. We perform finite element method simulation of our AC-PFA scenarios to corroborate our method and better interpret our findings.ResultsWe applied square, 50% duty cycle, AC bursts of 100 μs duration, 100 kHz internal frequency, 900 V for 60 pulses in the atrium and 1500 V for 120 pulses in the septum. The inter-burst interval was determined by the native heart rhythm – 69 ± 9 bpm. Acute changes in the atrial and ventricular electrograms were immediately visible at the sites of AC-PFA – signals were elongated and reduced in amplitude (p < 0.0001) and tissue impedance dropped (p = 0.011). No adverse event (e.g., esophageal temperature rises or gas bubble streams) was observed – while twitching was avoided by addition of electrosurgical return electrodes. The implemented numerical simulations confirmed the non-thermal nature of our AC-PFA and provided specific information on the estimated treated area and need of pulse trains. The postmortem chest inspection showed no peripheral damage, but epicardial and endocardial discolorations at sites of ablation. T1-weighted scans revealed specific tissue changes in atria and ventricles, confirmed to be fibrotic scars via trichrome staining. We found isolated, transmural and continuous scars. A surviving cardiomyocyte core was visible in basal ventricular lesions.ConclusionWe proved that our method and technology of AC-PFA is feasible and safe for atrial and ventricular myocardial ablation, supporting their systematic investigation into effectiveness evaluation for the treatment of cardiac arrhythmia. Further optimization, with energy titration or longer follow-up, is required for a robust atrial and ventricular AC-PFA.