Cardiovascular crossroads - exploring the impact of atrial fibrillation on mitral valve regurgitation and MitraClip treatment

Abstract Introduction The use of the MitraClip technique is becoming increasingly popular as a treatment option for patients suffering from mitral valve regurgitation who are not suitable for surgery. It is unclear how pre-existing atrial fibrillation impacts patients during the procedure. Purpose The question arises: What is the underlying cause of atrial fibrillation in patients with significant mitral valve involvement and why do some patients remain unaffected? This study aims to compare and identify differences in cohorts of patients with and without atrial fibrillation before the MitraClip procedure. Methods We analyzed a register of 279 patients who underwent MitraClip treatment. The study classified the patients according to the presence (n=140, 50%) or absence (n=139, 50%) of atrial fibrillation prior to the procedure. We utilized univariate analysis to compare demographic, clinical, and echocardiographic parameters. Multivariate logistic regression was also performed to determine significant predictors. Results Both cohorts were of similar size, but there were significant differences in certain parameters. Women were more frequent in the group without atrial fibrillation (45% compared to 34%, p=0.045). The group with atrial fibrillation was slightly older (73 years compared to 70 years, p0.001) and had a lager body surface area (1.95 compared to 1.87, p=0.005). Parameters such as Euroscore II, NT-proBNP and creatinine levels were not significantly different. Nevertheless, it is important to note that the group with atrial fibrillation had a greater transverse dimension of the left atrium (55 compared to 50, p0.001). Additionally, the atrial fibrillation group exhibited a higher degree of tricuspid regurgitation (2.9 vs 2.0, p=0.007) and a slightly lower baseline VO2 max (11.63 vs 12.59, p0.001). Multivariate logistic regression revealed that baseline tricuspid regurgitation is a significant predictor of atrial fibrillation, with and odds ratio of 2.066 (95% CI: 1.041-4.097, p=0.038). Conclusion During the MitraClip procedure, patients with atrial fibrillation demonstrate certain specific characteristics, including older age, increased body surface area, larger left atrial size, and higher grade of tricuspid regurgitation. The significant association of tricuspid regurgitation with atrial fibrillation emphasizes its potential role in clinical evaluation and subsequent treatment.