Clinical trials

This study investigates the impact of transcatheter aortic valve implantation (TAVI) on the composition and function of the gut microbiota in patients with severe aortic valve stenosis. The improvement in haemodynamics following TAVI may positively influence gut microbial balance by increasing splanchnic perfusion and reducing intestinal congestion. A total of 40 patients undergoing TAVI at the "Hippokration" General Hospital of Athens will be enrolled, with the aim of analysing stool and blood samples before and after the procedure. The primary endpoint is the change in gut microbiota composition two months post-TAVI, assessed via 16S rRNA sequencing. Secondary endpoints include changes in serum TMAO levels and their association with the severity of aortic stenosis and post-procedural valve haemodynamics. Data will be collected at two timepoints (1 month up to 1 day pre-TAVI and 3 to 4 months post-TAVI), along with dietary questionnaires to account for potential confounding factors. This observational study aims to highlight the potential relationship between cardiac function and the gut microbiome, offering new perspectives for targeted therapeutic strategies in cardiovascular disease.

Current guidelines for the cardioversion of paroxysmal Atrial Fibrillation at the Emergency Department do not prioritize between antiarrhythmic agents and do not consider the time taken for successful cardioversion. Furthermore, the use of flecainide -a class 1C antiarrhythmic agent- is contraindicated for the cardioversion of patients with revascularized coronary artery disease, as well as patients with ischemic cardiomyopathy and preserved ejection fraction. These recommendations stem from insufficient data, mainly from the CAST study. The present study is a prospective, multicentre, randomized clinical trial. The primary goals of this clinical trial are to prove the superiority of flecainide over amiodarone in the successful cardioversion of paroxysmal atrial fibrillation at the Emergency Department, and to prove that the safety of flecainide is non-inferior to amiodarone, in patients with coronary artery disease without residual ischemia and ejection fraction over 35%. The secondary goals of the study are to prove the superiority of flecainide over amiodarone in the reduction of hospitalizations from the Emergency Department due to atrial fibrillation, in the time taken to achieve cardioversion, and to the reduction of the need to conduct electrical cardioversion. The study population will be all consecutive new-comers to the Emergency Department with primary diagnosis of paroxysmal atrial fibrillation and history of coronary artery disease without angina, without residual ischemia and with ejection fraction \> 35%. The sample size will be 200 patients, who will be monitored for 30 days. At the Emergency Department, all patients will be under continuous ECG monitoring, and a 24-hour ECG device will also be placed (Holter). The patients will be randomized to the treatment group (flecainide) and the control group (amiodarone). Patients in both arms will stay at the ED for a total of 6 hours after therapy initiation. If no adverse events occur in this time, the patient will be discharged from the ED. Otherwise, the patient will be admitted to the hospital. At 24 hours, the patients will visit the study centre for physical examination, ECG, cardiac ultrasound, 24-hour ECG removal and adverse events evaluation. At 30 days, follow-up via phone calls will be conducted for the evaluation of the study outcomes and adverse events. As of June 2025, an interim analysis has been completed, and preliminary study results have been submitted for presentation at the European Society of Cardiology (ESC) Congress. Based on the interim findings, the study's target sample size has been revised to a total of 80 patients.