Konishi Katsuhisa, Dohi Kaoru, Tanimura Muneyoshi, Sato Yuichi, Watanabe Kiyotaka, Sugiura Emiyo, Kumagai Naoto, Nakamori Shiro, Nakajima Hiroshi, Yamada Tomomi, Onishi Katsuya, Nakamura Mashio, Nobori Tsutomu, Ito Masaaki
Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu 514-8507, Japan.
Cardiovasc Ultrasound. 2013 Jun 27;11:23. doi: 10.1186/1476-7120-11-23.
We investigated longitudinal right ventricular (RV) function assessed using speckle-tracking strain echocardiography in patient with myocardial infarction (MI), and identified the contributing factors for RV dysfunction.
We retrospectively studied 71 patients with old MI (the OMI group) and 45 normal subjects (the Control group) who underwent a transthoracic echocardiography. Global and free wall RV peak systolic strains (PSSs) in the longitudinal direction were measured by using speckle-tracking strain echocardiography. Left ventricular (LV) PSSs were measured in the longitudinal, radial and circumferential directions. Cardiac hemodynamics including peak systolic pulmonary artery pressure was also assessed non-invasively. Plasma brain natriuretic peptide (BNP) levels were measured in all patients.
In the OMI group, 73% of the patients had a normal estimated peak systolic pulmonary artery pressure of less than 35 mmHg. Global and free wall RV PSS were impaired in the OMI group compared with the Control group, and these RV systolic indices were significantly associated with heart rate, logarithmic transformed plasma BNP, greater than 1 year after onset of MI, Doppler-derived estimated pulmonary vascular resistance, LV systolic indices, LV mass index, infarcted segments within a territory of the left circumflex artery and residual total occlusion in the culprit right coronary artery. Multivariable linear regression analysis indicated that reduced longitudinal LV PSS in the 4-chamber view and BNP levels ≥500 pg/ml were independently associated with reduced global and free wall RV PSS. Moreover, when patients were divided into 3 groups according to plasma BNP levels (BNP <100 pg/ml; n = 31, 100 ≤BNP <500 pg/ml; n = 24, and BNP ≥500 pg/ml; n = 16), only patients with BNP ≥500 pg/ml had a strong correlation between RV PSS and longitudinal LV PSS in the 4-chamber view (r = 0.78 for global RV PSS and r = 0.71 for free wall RV PSS, p <0.05).
Longitudinal RV systolic strain depends significantly on longitudinal LV systolic strain especially in patients with high plasma BNP levels, but not on estimated peak systolic pulmonary artery pressure. These results indicate that process of RV myocardial dysfunction following MI may be governed by neurohormonal activation which causing ventricular remodeling rather than increased RV afterload.
我们使用斑点追踪应变超声心动图研究了心肌梗死（MI）患者的右心室（RV）纵向功能，并确定了导致RV功能障碍的因素。
我们回顾性研究了71例陈旧性MI患者（OMI组）和45名正常受试者（对照组），他们均接受了经胸超声心动图检查。使用斑点追踪应变超声心动图测量纵向方向上的整体和游离壁RV峰值收缩期应变（PSS）。在纵向、径向和圆周方向测量左心室（LV）PSS。还对包括收缩期肺动脉压峰值在内的心脏血流动力学进行了无创评估。测量了所有患者的血浆脑钠肽（BNP）水平。
在OMI组中，73%的患者估计收缩期肺动脉压峰值正常，低于35 mmHg。与对照组相比，OMI组的整体和游离壁RV PSS受损，这些RV收缩指数与心率、对数转换后的血浆BNP、MI发病1年以上、多普勒衍生的估计肺血管阻力、LV收缩指数、LV质量指数、左旋支动脉区域内的梗死节段以及罪犯右冠状动脉的残余完全闭塞显著相关。多变量线性回归分析表明，四腔心切面中纵向LV PSS降低和BNP水平≥500 pg/ml与整体和游离壁RV PSS降低独立相关。此外，当根据血浆BNP水平将患者分为3组时（BNP<100 pg/ml；n = 31，100≤BNP<500 pg/ml；n = 24，以及BNP≥500 pg/ml；n = 16），只有BNP≥500 pg/ml的患者在四腔心切面中RV PSS与纵向LV PSS之间存在强相关性（整体RV PSS为r = 0.78，游离壁RV PSS为r = 0.71，p<0.05）。
纵向RV收缩期应变显著依赖于纵向LV收缩期应变，尤其是在血浆BNP水平较高的患者中，但不依赖于估计的收缩期肺动脉压峰值。这些结果表明，MI后RV心肌功能障碍的过程可能受神经激素激活的支配，神经激素激活导致心室重构，而非RV后负荷增加。
