The Impact of Heart Rate on Biomechanical Characteristics of Aortic Aneurysm.

Reducing heart rate has been advocated as a pivotal therapeutic approach for patients with aortic aneurysm (AA), aiming to mitigate the risk of rupture. This study aims to investigate the effect of heart rate on the biomechanical characteristics of aneurysms. A patient-specific thoracic aortic aneurysm (TAA) model has been built, and the biomechanical characteristics of the aortic wall under different heart rate conditions, including atrial fibrillation (AF) condition, have been simulated by applying the blood pressure on the inner wall. The viscoelasticity of the aorta has been considered to reflect the cumulative mechanical response under pulsatile blood pressure. Results showed that the heart rate has a weak influence on the stress of the aneurysm wall but has a considerable influence on the deformation and vibration of the aneurysm. The increase in heart rate will increase the deformation of the aneurysm wall, and vice versa, especially at the top site of the aneurysm. Additionally, elevated heart rates were found to increase both the frequency and amplitude of vibrations within the aneurysm wall, especially when AF happened, thereby augmenting the risk of rupture. This research would advance our comprehension of aneurysm biomechanics and furnish valuable biomechanical insights for the formulation of aneurysm treatment strategies.