Kunichika H, Katayama K, Sakai H, Yonezawa T, Matsuzaki M
Second Department of Interial Medicine, Yamaguchi University School of Medicine, Ube, Japan.
Jpn Circ J. 1995 Nov;59(11):762-71. doi: 10.1253/jcj.59.762.
This study was designed to assess the changes in left ventricular (LV) diastolic filling and to evaluate the dynamic determinants of LV diastolic filling during coronary reperfusion after acute myocardial ischemia. We examined LV diastolic pressure-volume relations (D-PVRs) using the conductance catheter technique with a high-fidelity micromanometer, and the transmitral flow using transesophageal pulsed Doppler echocardiography in 9 open-chest anesthetized dogs with the pericardium opened. We measured early diastolic peak flow velocity (E), late diastolic peak flow velocity (A), the ratio of peak E to peak A (E/A), operational chamber compliance at the minimum LV pressure [(dV/VdP) nadir], and the time constant of LV relaxation (TC). Acute regional myocardial ischemia was produced by occluding the proximal portion of the left anterior descending coronary artery. Data were acquired at baseline, 10 min after acute myocardial ischemia, and after 15 and 90 min of reperfusion under left atrial pacing at 100 beats/min. During myocardial ischemia, D-PVRs shifted upward and rightward on the same curvilinear relationship compared with that at baseline (LV end-diastolic pressure (LVEDP) from 7.3 to 10.5 mmHg, LVEDV from 25 to 31 ml, both p < 0.01), accompanied by a decrease in peak E and E/A (E from 41 to 25 cm/sec, E/A from 1.7 to 1.1, both p < 0.01) and a prolongation of TC (from 25.4 to 30.3 msec, p < 0.01). After coronary reperfusion, D-PVRs returned to baseline accompanied by an improvement in the peak E and E/A ratio. No significant changes in peak A were observed in any of the stages. There was no correlation between peak E and TC, however, a significant positive correlation was observed between peak E and (dV/VdP) nadir (r = 0.76, p < 0.01). In conclusion, this study demonstrated that, using pulsed Doppler echocardiography, the improvement of diastolic filling after coronary reperfusion was based mainly on changes in early diastolic filling, and that LV operational chamber compliance at early diastole, rather than a LV relaxation property, might play an important role in determining early diastolic filling during coronary reperfusion.
本研究旨在评估急性心肌缺血后冠状动脉再灌注期间左心室（LV）舒张期充盈的变化，并评估LV舒张期充盈的动态决定因素。我们在9只开胸麻醉且打开心包的犬中，使用带有高保真微测压计的电导导管技术检查LV舒张期压力-容积关系（D-PVRs），并使用经食管脉冲多普勒超声心动图测量二尖瓣血流。我们测量了舒张早期峰值流速（E）、舒张晚期峰值流速（A）、峰值E与峰值A的比值（E/A）、LV压力最低时的操作腔顺应性[（dV/VdP）最低点]以及LV松弛时间常数（TC）。通过阻断左前降支冠状动脉近端产生急性局部心肌缺血。在基线、急性心肌缺血10分钟后以及在100次/分钟的左心房起搏下再灌注15分钟和90分钟后采集数据。在心肌缺血期间，与基线相比，D-PVRs在相同的曲线上向上和向右移位（LV舒张末期压力（LVEDP）从7.3 mmHg升至10.5 mmHg，LV舒张末期容积（LVEDV）从25 ml升至31 ml，两者p < 0.01），同时峰值E和E/A降低（E从41 cm/秒降至25 cm/秒，E/A从1.7降至1.1，两者p < 0.01），TC延长（从25.4毫秒延长至30.3毫秒，p < 0.01）。冠状动脉再灌注后，D-PVRs恢复至基线，同时峰值E和E/A比值改善。在任何阶段均未观察到峰值A有显著变化。峰值E与TC之间无相关性，然而，峰值E与（dV/VdP）最低点之间存在显著正相关（r = 0.76，p < 0.01）。总之，本研究表明，使用脉冲多普勒超声心动图，冠状动脉再灌注后舒张期充盈的改善主要基于舒张早期充盈的变化，并且舒张早期LV操作腔顺应性而非LV松弛特性可能在冠状动脉再灌注期间决定舒张早期充盈方面起重要作用。
