Lim Zhan Yang, Maskara Barun, Aguel Felipe, Emokpae Roland, Tung Leslie
Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD 21205, USA.
Circulation. 2006 Nov 14;114(20):2113-21. doi: 10.1161/CIRCULATIONAHA.105.598631. Epub 2006 Nov 6.
Functional reentry in the heart takes the form of spiral waves. Drifting spiral waves can become pinned to anatomic obstacles and thus attain stability and persistence. Lidocaine is an antiarrhythmic agent commonly used to treat ventricular tachycardia clinically. We examined the ability of small obstacles to anchor spiral waves and the effect of lidocaine on their attachment.
Spiral waves were electrically induced in confluent monolayers of cultured, neonatal rat cardiomyocytes. Small, circular anatomic obstacles (0.6 to 2.6 mm in diameter) were situated in the center of the monolayers to provide an anchoring site. Eighty reentry episodes consisting of at least 4 revolutions were studied. In 36 episodes, the spiral wave attached to the obstacle and became stationary and sustained, with a shorter reentry cycle length and higher rate. Spiral waves could attach to obstacles as small as 0.6 mm, with a likelihood for attachment that increased with obstacle size. After attachment, both conduction velocity of the wave-front tip and wavelength near the obstacle adapted from their pre-reentry values and increased linearly with obstacle size. In contrast, reentry cycle length did not correlate significantly with obstacle size. Addition of lidocaine 90 mumol/L depressed conduction velocity, increased reentry cycle length, and caused attached spiral waves to become quasi- attached to the obstacle or terminate.
Anchored spiral waves exhibit properties of both unattached spiral waves and anatomic reentry. Their behavior may be representative of functional reentry dynamics in cardiac tissue, particularly in the setting of monomorphic tachyarrhythmias.
心脏中的功能性折返以螺旋波的形式存在。漂移的螺旋波可固定于解剖学障碍物，从而实现稳定性和持续性。利多卡因是临床上常用于治疗室性心动过速的抗心律失常药物。我们研究了小障碍物固定螺旋波的能力以及利多卡因对其附着的影响。
在培养的新生大鼠心肌细胞汇合单层中电诱导产生螺旋波。将小的圆形解剖学障碍物（直径0.6至2.6毫米）置于单层中央以提供固定位点。研究了80次至少包含4次旋转的折返事件。在36次事件中，螺旋波附着于障碍物并变得静止且持续，折返周期长度更短且频率更高。螺旋波可附着于小至0.6毫米的障碍物，附着可能性随障碍物大小增加。附着后，波前尖端的传导速度和障碍物附近的波长均从折返前的值发生改变，并随障碍物大小呈线性增加。相比之下，折返周期长度与障碍物大小无显著相关性。添加90 μmol/L利多卡因可降低传导速度、增加折返周期长度，并使附着的螺旋波变为准附着于障碍物或终止。
固定的螺旋波表现出未附着螺旋波和解剖学折返的特性。它们的行为可能代表心脏组织中功能性折返动力学，尤其是在单形性快速心律失常的情况下。
