Kadipaşaoglu K A, Sartori M, Masai T, Cihan H B, Clubb F J, Conger J L, Frazier O H
Department of Adult Cardiology, Texas Heart Institute, St. Luke's Episcopal Hospital, Houston 77225-0345, USA.
Ann Thorac Surg. 1999 Feb;67(2):423-31. doi: 10.1016/s0003-4975(98)01135-7.
Transmyocardial laser revascularization creates transmural channels to improve myocardial perfusion. Different laser sources and ablation modalities have been proposed for transmyocardial laser revascularization. We investigated the incidence of cardiac arrhythmias and laser-tissue interactions during transmyocardial laser revascularization of normal porcine myocardium with three different lasers.
We used a continuous-wave, chopped CO2 laser (20 J/pulse, 15 ms/pulse) synchronized with the R wave; a holmium:yttrium aluminum garnet (Ho:YAG) laser (2 J/pulse, 250 micros/pulse, 5 Hz); and a xenon-chloride (excimer, Xe:Cl) laser (35 mJ/pulse, 20 ns/pulse, 30 Hz). Each laser was used 30 times as the sole modality in four consecutive pigs, yielding 120 channels.
The average number of pulses needed to create a channel was 1, 11 +/- 4, and 37 +/- 8 for the CO2, Ho:YAG, and Xe:Cl lasers, respectively. All Ho:YAG and Xe:Cl channels had premature ventricular contractions. Ventricular tachycardia occurred in 70% of the Xe:Cl and 60% of the Ho:YAG channels. Only 36% of the CO2 channels had premature ventricular contractions, and only 3% of the CO2 channels had ventricular tachycardia (p < 0.001 versus Ho:YAG and Xe:Cl). Ho:YAG channels were highly irregular: each had a 0.6-mm-wide central zone surrounded by a ring of coagulation necrosis (diameter, 1.84 +/- 0.67 mm) with effaced cellular architecture in a thin hemorrhagic zone. The Xe:Cl sections exhibited the same patterns on a smaller scale (diameter, 0.74 +/- 0.18 mm). The CO2 channels were straight and well demarcated. The zone of structural and thermal damage extended over half the channel's diameter, measuring 0.52 +/- 0.25 mm.
During transmyocardial laser revascularization, the CO2 laser synchronized with the R wave is significantly less arrhythmogenic than the Ho:YAG and Xe:Cl lasers not synchronized with the R wave. In addition, the interaction of the CO2 laser with porcine cardiac tissue is significantly less traumatic than that of the Ho:YAG and the Xe:Cl lasers.
心肌激光血运重建术可创建透壁通道以改善心肌灌注。已提出多种不同的激光源和消融方式用于心肌激光血运重建术。我们研究了使用三种不同激光对正常猪心肌进行心肌激光血运重建术期间心律失常的发生率及激光与组织的相互作用。
我们使用了与R波同步的连续波、斩波二氧化碳激光（20焦耳/脉冲，15毫秒/脉冲）；钬：钇铝石榴石（Ho:YAG）激光（2焦耳/脉冲，250微秒/脉冲，5赫兹）；以及氯化氙（准分子，Xe:Cl）激光（35毫焦耳/脉冲，20纳秒/脉冲，30赫兹）。每种激光在连续4头猪中各单独使用30次，共产生120个通道。
创建一个通道所需的平均脉冲数，二氧化碳激光为1.11±4次，Ho:YAG激光为37±8次，Xe:Cl激光为1次。所有Ho:YAG和Xe:Cl通道均出现室性早搏。70%的Xe:Cl通道和60%的Ho:YAG通道出现室性心动过速。只有36%的二氧化碳通道出现室性早搏，只有3%的二氧化碳通道出现室性心动过速（与Ho:YAG和Xe:Cl相比，p<0.001）。Ho:YAG通道极不规则：每个通道都有一个0.6毫米宽的中央区，周围是一圈凝固性坏死（直径，1.84±0.67毫米），在一个薄的出血区内细胞结构消失。Xe:Cl切片在较小尺度上呈现相同模式（直径，0.74±0.18毫米）。二氧化碳通道笔直且界限分明。结构和热损伤区域延伸超过通道直径的一半，为0.52±0.25毫米。
在心肌激光血运重建术中，与R波同步的二氧化碳激光诱发心律失常的可能性明显低于未与R波同步的Ho:YAG激光和Xe:Cl激光。此外，二氧化碳激光与猪心脏组织的相互作用造成的创伤明显小于Ho:YAG激光和Xe:Cl激光。
