Cardiovascular Biophysics Laboratory, Department of Physics, College of Arts and Sciences, St. Louis, MO, USA.
Ultrasound Med Biol. 2010 Mar;36(3):497-511. doi: 10.1016/j.ultrasmedbio.2009.10.012.
The transmitral Doppler E-wave "delayed relaxation" (DR) pattern is an established sign of diastolic dysfunction (DD). Furthermore, chambers exhibiting a DR filling pattern are also expected to have a prolonged time-constant of isovolumic relaxation (tau). The simultaneous observation of a DR pattern and normal tau in the same heart is not uncommon, however. The simultaneous hemodynamic equivalent of the DR pattern has not been proposed. To determine the feature of the left ventricular (LV) pressure contour during the E-wave that is causally related to its DR pattern we applied kinematic and fluid mechanics based arguments to derive the pressure recovery ratio (PRR). The PRR is dimensionless and is defined by the left ventricular pressure difference between diastasis and minimum pressure, normalized to the pressure difference between a fiducial diastolic filling pressure and minimum pressure [PRR=(P(Diastasis)-P(Min))/(P(Fiducial)-P(Min))]. We analyzed 354 cardiac cycles from 40 normal sinus rhythm (NSR) subjects and 113 beats from nine atrial fibrillation (AF) subjects from our database of simultaneous transmitral flow-micromanometric LV pressure recordings. The fiducial pressure is defined by the end diastolic pressure in NSR and by the pressure at dP/dt(MIN) in the setting of AF. Consistent with derivation, PRR was linearly related to a DR pattern related, model-based relaxation parameter (R(2) = 0.77, 0.83 in NSR and AF, respectively). Furthermore, the PRR successfully differentiated subjects with a DR pattern from subjects with partial DR or normal E-wave pattern (p < 0.05). We conclude that the PRR may differentiate between subjects having a DR pattern and subjects with normal E-waves, even when tau cannot.
二尖瓣血流多普勒 E 波“延迟松弛”（DR）模式是舒张功能障碍（DD）的既定标志。此外，表现出 DR 充盈模式的腔室也预计具有延长的等容松弛时间常数（tau）。然而，在同一心脏中同时观察到 DR 模式和正常 tau 的情况并不少见。尚未提出 DR 模式的同时血液动力学等效物。为了确定与 DR 模式因果相关的 E 波期间左心室（LV）压力轮廓的特征，我们应用运动学和流体力学基于论点来推导压力恢复比（PRR）。PRR 是无量纲的，由舒张末期与最小压力之间的左心室压力差除以基准舒张充盈压力与最小压力之间的压力差来定义[PRR=（P（舒张期）-P（最小值））/（P（基准）-P（最小值））]。我们分析了来自我们的同步二尖瓣血流微压记录数据库的 40 个窦性心律（NSR）受试者的 354 个心动周期和 9 个心房颤动（AF）受试者的 113 个心动周期。基准压力在 NSR 中由舒张末期压力定义，在 AF 中由 dP/dt（MIN）处的压力定义。与推导一致，PRR 与基于模型的松弛参数（R（2）= 0.77、0.83，分别在 NSR 和 AF 中）呈线性相关。此外，PRR 成功地区分了具有 DR 模式的受试者与具有部分 DR 或正常 E 波模式的受试者（p < 0.05）。我们得出结论，即使 tau 不能，PRR 也可以区分具有 DR 模式的受试者和具有正常 E 波的受试者。
