Jin X Y, Pepper J R, Gibson D G
Cardiac Department, Royal Brompton Hospital, London.
Heart. 1996 Dec;76(6):495-501. doi: 10.1136/hrt.76.6.495.
Tension development is often incoordinate in the hypertrophic left ventricle (LV). The present study aimed to elucidate the possible effects of incoordination on standard LV force-velocity relations in patients with aortic stenosis (AS).
Prospective study during aortic valve replacement with transoesophageal cross sectionally guided M mode echocardiogram, combined with high-fidelity LV pressure recorded by pressure transducer tip catheter, and thermodilution cardiac output.
Tertiary cardiac referral centre.
37 patients (mean (SD) age 63 (12)) years were studied before and 20 hours after aortic valve replacement.
LV function was assessed regionally by peak velocity of circumferential fibre shortening (peak Vcf), mean systolic wall stress, and peak myocardial power; and globally by LV stroke work index. LV coordination was quantified as cycle efficiency, derived from LV pressure-dimension loop (lower normal limit > or = 76%).
22 patients with a coordinate LV had significantly higher peak Vcf (1.85 (0.47) v 1.46 (0.64) s-1) peak myocardial power (20.8 (8.5) v 12.0 (6.1) mW.cm-3) and global stroke work index (440 (155) v 325 (150) mJ.m-2) than those of 15 patients with an incoordinate ventricle, all P < 0.05; though there was no significant difference in LV end diastolic dimension, mean systolic wall stress, LV mass index, or the incidence of coronary artery disease (P > 0.05, respectively). Furthermore, when contraction was coordinate, mean systolic circumferential wall stress correlated inversely with peak Vcf (r = - 0.71) and positively with peak myocardial power (r = 0.83), both P < 0.01. When contraction was incoordinate, these correlations did not apply; instead peak Vcf (r = 0.65) and peak myocardial power (r = 0.73) both correlated positively with cycle efficiency (P < 0.02 and 0.01, respectively). By 20 hours after surgery, values of cycle efficiency, peak Vcf, and myocardial power were indistinguishable in the previously coordinate and incoordinate groups.
In aortic stenosis, incoordination causes a fall in LV peak Vcf proportional to the increase in systolic wall stress, and thus modifies the standard LV force-velocity relation to mimic depressed contractility. However, incoordination and subsequent ventricular dysfunction were largely reversible once the aortic stenosis had been relieved.
肥厚左心室（LV）的张力发展通常不协调。本研究旨在阐明不协调对主动脉瓣狭窄（AS）患者标准左心室力-速度关系的可能影响。
在主动脉瓣置换术中进行前瞻性研究，采用经食管横截面引导的M型超声心动图，结合压力传感器尖端导管记录的高保真左心室压力和热稀释心输出量。
三级心脏转诊中心。
37例患者（平均（标准差）年龄63（12）岁）在主动脉瓣置换术前和术后20小时接受研究。
通过圆周纤维缩短峰值速度（峰值Vcf）、平均收缩期壁应力和峰值心肌功率对左心室功能进行局部评估；通过左心室每搏功指数进行整体评估。左心室协调性通过循环效率进行量化，循环效率由左心室压力-维度环得出（下限正常范围≥76%）。
22例左心室协调的患者的峰值Vcf（1.85（0.47）对1.46（0.64）s-1）、峰值心肌功率（20.8（8.5）对12.0（6.1）mW.cm-3）和整体每搏功指数（440（155）对325（150）mJ.m-2）显著高于15例左心室不协调的患者，所有P<0.05；尽管左心室舒张末期内径、平均收缩期壁应力、左心室质量指数或冠状动脉疾病发生率无显著差异（分别为P>0.05）。此外，当收缩协调时，平均收缩期圆周壁应力与峰值Vcf呈负相关（r=-0.71），与峰值心肌功率呈正相关（r=0.83），两者P<0.01。当收缩不协调时，这些相关性不适用；相反，峰值Vcf（r=0.65）和峰值心肌功率（r=0.73）均与循环效率呈正相关（分别为P<0.02和0.01）。术后20小时，先前协调和不协调组的循环效率、峰值Vcf和心肌功率值无差异。
在主动脉瓣狭窄中，不协调导致左心室峰值Vcf下降，与收缩期壁应力增加成比例，从而改变标准左心室力-速度关系，模拟收缩功能降低。然而，一旦主动脉瓣狭窄得到缓解，不协调及随后的心室功能障碍在很大程度上是可逆的。
