Bioenergetic consequences of left ventricular remodeling.
Bioenergetic consequences of left ventricular remodeling.
复制标题
左心室重塑的生物能后果。
DOI：
10.1161/01.cir.92.4.1011
复制
发表时间：
1995
期刊：
影响因子：
37.8
通讯作者：
McDonald,KM
中科院分区：
文献类型：
--
作者：
Zhang,J;McDonald,KM
研究背景左心室重构与左心室功能不全和冠脉血流储备减少有关。造成这些变化的潜在机制尚不清楚。心肌高能磷酸盐水平的变化可能与这些改变有关。方法与结果12只犬经心肌DC休克后继发于离散性坏死后左室重构，与8只正常犬比较。在直流电休克前7d和直流电休克后12.9±1.3个月分别用磁共振成像测量左心室重量和舒张末容积。在基础状态和起搏频率为200次/分钟和240次/分钟的条件下，通过跨壁血流测量(微球)同时获得跨室壁五层的31P核磁共振波谱。直流电休克后左室重量和舒张末容量显著增加(分别为33%和26%，P均<0.01)。在基础状态下，重建组的心内膜下磷酸肌酸(CP)/ATP比值显著低于对照组(1.71±0.09比2.04±0.09，P<0.05)。心内膜下CP/ATP值与LV质量和LV舒张末容量的增加呈负相关(r=−.77，r=−.70，P<；.01和P<；.05)。在重建心肌中，起搏引起LV舒张末压力显著升高(从8±1至20±3 mm Hg，P<0.05)，心内膜下/心外膜下血流比值显著降低(从1.01±0.10至0.63±0.11，P<；0.05)，心内膜下CP/Δ比值显著降低(从1.78±0.07至1.61±0.10，P<；05)，心内膜下/心外膜下血流比值显著升高(从0至0.24±0.05，P<；01)。心内膜下CP/ATP比值的降低与Endo/Epi血流比值的降低呈正相关(r=0.79，P<0.05)。结论心肌高能磷酸盐水平的改变与LV重构程度密切相关。在重塑心脏中，起搏诱发的心动过速会导致心内膜下心肌高能磷酸盐水平的进一步变化，这似乎与心功能不全和心内膜下血流重新分配有关。
BackgroundLeft ventricular (LV) remodeling is associated with LV dysfunction and decrease of coronary flow reserve. The underlying mechanisms responsible for these alterations are unclear. Changes in myocardial high-energy phosphate levels may be associated with these alterations.Methods and ResultsTwelve dogs with LV remodeling secondary to discrete necrosis produced by transmyocardial DC shock were compared with 8 normal dogs. LV mass and end-diastolic volume were measured by magnetic resonance imaging 7 days before and 12.9±1.3 months after DC shock. Transmurally localized31P nuclear magnetic resonance spectra from five layers across the LV wall were obtained simultaneously with transmural blood flow measurements (microspheres) under basal conditions and during pacing at 200 and 240 beats per minute. LV mass and end-diastolic volume were significantly increased after DC shock (33% and 26%, respectively, eachP<.01). Under basal conditions, the subendocardial creatine phosphate (CP)/ATP ratio was significantly lower in remodeled LV compared with the control group (1.71±0.09 versus 2.04±0.09,P<.05). The subendocardial CP/ATP ratio was inversely correlated with both the increase in LV mass and LV end-diastolic volume (r=−.77 andr=−.70,P<.01 andP<.05, respectively). In remodeled myocardium, pacing induced a significant increase in LV end-diastolic pressure (from 8±1 to 20±3 mm Hg,P<.05), which was accompanied by a significant decrease of subendocardial/subepicardial (Endo/Epi) blood flow ratio (from 1.01±0.10 to 0.63±0.11,P<.05) and a significant decrease in subendocardial CP/ATP ratio (from 1.78±0.07 to 1.61±0.10,P<.05) and increase of ΔPi/ATP ratio (from 0 to 0.24±0.05,P<.01). The decrease in subendocardial CP/ATP ratio was correlated with the decrease in Endo/Epi blood flow ratio (r=.79,P<.05).ConclusionsThese results demonstrate that alterations in myocardial high-energy phosphate levels are correlated with the extent of LV remodeling. In remodeled hearts, pacing-induced tachycardia produces further changes of myocardial high-energy phosphate levels in the subendocardium that appear to be related to ventricular dysfunction and redistribution of blood flow away from the subendocardium.