Breithardt Ole A, Stellbrink Christoph, Herbots Lieven, Claus Piet, Sinha Anil M, Bijnens Bart, Hanrath Peter, Sutherland George R
Department of Cardiology, University Hospital Aachen, Aachen, Germany.
J Am Coll Cardiol. 2003 Aug 6;42(3):486-94. doi: 10.1016/s0735-1097(03)00709-5.
We studied the effects of cardiac resynchronization therapy (CRT) on regional myocardial strain distribution, as determined by echocardiographic strain rate (SR) imaging.
Dilated hearts with left bundle branch block (LBBB) have an abnormal redistribution of myocardial fiber strain. The effects of CRT on such abnormal strain patterns are unknown.
We studied 18 patients (12 males and 6 females; mean age 65 +/- 11 years [range 33 to 76 years]) with symptomatic systolic heart failure and LBBB. Doppler myocardial imaging studies were performed to acquire regional longitudinal systolic velocity (cm/s), systolic SR (s(-1)), and systolic strain (%) data from the basal and mid-segments of the septum and lateral wall before and after CRT. By convention, negative SR and strain values indicate longitudinal shortening.
Before CRT, mid-septal peak SR and peak strain were lower than in the mid-lateral wall (peak SR: -0.79 +/- 0.5 [septum] vs. -1.35 +/- 0.8 [lateral wall], p < 0.05; peak strain: -7 +/- 5 [septum] vs. -11 +/- 5 [lateral wall], p < 0.05). This relationship was reversed during CRT (peak SR: -1.35 +/- 0.8 [septum] vs. -0.93 +/- 0.6 [lateral wall], p < 0.05; peak strain: -11 +/- 6 [septum] vs. -7 +/- 6 [lateral wall], p < 0.05). Cardiac resynchronization therapy reversed the septal-lateral difference in mid-segmental peak strain from -46 +/- 94 ms (LBBB) to 17 +/- 92 ms (CRT; p < 0.05).
Left bundle branch block can lead to a significant redistribution of abnormal myocardial fiber strains. These abnormal changes in the extent and timing of septal-lateral strain relationships can be reversed by CRT. The noninvasive identification of specific abnormal but reversible strain patterns should help to improve patient selection for CRT.
我们通过超声心动图应变率（SR）成像研究了心脏再同步治疗（CRT）对局部心肌应变分布的影响。
伴有左束支传导阻滞（LBBB）的扩张型心脏存在心肌纤维应变的异常重新分布。CRT对这种异常应变模式的影响尚不清楚。
我们研究了18例有症状的收缩性心力衰竭且伴有LBBB的患者（12例男性和6例女性；平均年龄65±11岁[范围33至76岁]）。在CRT前后，采用多普勒心肌成像研究从室间隔和侧壁的基底段和中间段获取局部纵向收缩速度（cm/s）、收缩期SR（s⁻¹）和收缩期应变（%）数据。按照惯例，负的SR和应变值表示纵向缩短。
在CRT前，室间隔中间段的峰值SR和峰值应变低于侧壁中间段（峰值SR：-0.79±0.5[室间隔]对-1.35±0.8[侧壁]，p<0.05；峰值应变：-7±5[室间隔]对-11±5[侧壁]，p<0.05）。在CRT期间这种关系发生了逆转（峰值SR：-1.35±0.8[室间隔]对-0.93±0.6[侧壁]，p<0.05；峰值应变：-11±6[室间隔]对-7±6[侧壁]，p<0.05）。心脏再同步治疗使中间段峰值应变的室间隔-侧壁差异从-46±94毫秒（LBBB）逆转至17±92毫秒（CRT；p<0.05）。
左束支传导阻滞可导致心肌纤维应变的显著异常重新分布。室间隔-侧壁应变关系在程度和时间上的这些异常变化可通过CRT逆转。对特定异常但可逆应变模式的无创识别应有助于改善CRT的患者选择。
