Department of Biomedical Engineering, Indiana University Purdue University, Indianapolis, Indiana, United States of America.
PLoS One. 2013 Sep 5;8(9):e73485. doi: 10.1371/journal.pone.0073485. eCollection 2013.
Atrial fibrillation (AF) is the most common sustained dysfunction in heart rhythm clinically and has been identified as an independent risk factor for stroke through formation and embolization of thrombi. AF is associated with reduced cardiac output and short and irregular cardiac cycle length. Although the effect of AF on cardiac hemodynamic parameters has been reported, it remains unclear how the hemodynamic perturbations affect the potential embolization of blood clots to the brain that can cause stroke. To understand stroke propensity in AF, we performed computer simulations to describe trajectories of blood clots subject to the aortic flow conditions that represent normal heart rhythm and AF. Quantitative assessment of stroke propensity by blood clot embolism was carried out for a range of clot properties (e.g., 2-6 mm in diameter and 0-0.8 m/s ejection speed) under normal and AF flow conditions. The simulations demonstrate that the trajectory of clot is significantly affected by clot properties as well as hemodynamic waveforms which lead to significant variations in stroke propensity. The predicted maximum difference in stroke propensity in the left common carotid artery was shown to be about 60% between the normal and AF flow conditions examined. The results suggest that the reduced cardiac output and cycle length induced by AF can significantly increase the incidence of carotid embolism. The present simulations motivate further studies on patient-specific risk assessment of stroke in AF.
心房颤动（AF）是临床上最常见的持续性心律失常，已被确定为通过血栓形成和栓塞导致中风的独立危险因素。AF 与心输出量降低以及心脏周期长度缩短和不规则有关。尽管已经报道了 AF 对心脏血流动力学参数的影响，但尚不清楚血流动力学干扰如何影响潜在的血栓向大脑的栓塞，从而导致中风。为了了解 AF 中的中风倾向，我们进行了计算机模拟，以描述在代表正常心律和 AF 的主动脉血流条件下的血栓轨迹。对于正常和 AF 血流条件下的一系列血栓特性（例如直径为 2-6 毫米和 0-0.8 米/秒的喷射速度），通过血栓栓塞对中风倾向进行了定量评估。模拟表明，血栓的轨迹受到血栓特性以及血流动力学波形的显著影响，从而导致中风倾向的显著变化。在检查的正常和 AF 血流条件之间，预测的左颈总动脉中风倾向的最大差异约为 60%。结果表明，AF 引起的心输出量和周期长度降低会显著增加颈动脉栓塞的发生率。目前的模拟结果促使对 AF 中风的患者特定风险评估进行进一步研究。
