Burkhoff D, Sagawa K
Am J Physiol. 1986 Mar;250(3 Pt 2):H414-8. doi: 10.1152/ajpheart.1986.250.3.H414.
We tested the hypothesis that while absolute extrasystolic (ES) and postextrasystolic (PES) dP/dtmax would be influenced by pacing site, if these values were normalized by the steady-state dP/dtmax obtained with the same pacing site, they would be independent of pacing site. We employed an isovolumetrically contracting isolated heart preparation with a balloon placed in the left ventricle. Pacing electrodes were placed on the atrium and four different epicardial ventricular sites. While pacing from each site separately, a steady mechanical state was established at a constant rate, and the interval between beats was then perturbed. The same pacing sequence was used while pacing from each of the five sites. On each ES and PES beat, dP/dtmax was expressed as a percentage of the steady-state dP/dtmax. The normalized responses measured with each ventricular pacing site (DPventr) were plotted as a function of the normalized responses obtained with atrial pacing (DPatr). On average, DPventr = 1.02 DPatr - 3.2% (n = 6, with r2 = 0.989), indicating that pacing site did not significantly influence the "normalized" force-interval relationship. Thus the basic information retrievable from measurements of the ventricular force-interval relationship is independent of the site from which the heart is paced.
虽然室性期前收缩（ES）和期前收缩后（PES）的最大dp/dt会受起搏部位影响，但如果这些值用在相同起搏部位获得的稳态最大dp/dt进行归一化处理，它们将与起搏部位无关。我们使用了一种等容收缩的离体心脏标本，在左心室内放置一个球囊。起搏电极置于心房和四个不同的心外膜心室部位。在分别从每个部位起搏时，以恒定频率建立稳定的机械状态，然后干扰心动周期。从五个部位中的每个部位起搏时都使用相同的起搏序列。在每次ES和PES搏动时，最大dp/dt表示为稳态最大dp/dt的百分比。将每个心室起搏部位测得的归一化反应（DPventr）绘制成与心房起搏获得的归一化反应（DPatr）的函数关系图。平均而言，DPventr = 1.02 DPatr - 3.2%（n = 6，r2 = 0.989），表明起搏部位对“归一化”的力-间期关系没有显著影响。因此，从心室力-间期关系测量中可获取的基本信息与心脏起搏的部位无关。
