Jacobs G, Mahjoob K
Department of Small Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602.
Am J Vet Res. 1988 Apr;49(4):548-52.
M-mode echocardiograms were recorded from 10 conscious, clinically normal dogs at various heart rates during atrial pacing. Heart rate was recorded as cycle length (seconds), and measurements were made only during sustained 1:1 atrial-to-ventricular conduction. In all dogs studied, there was a significant (P less than 0.01) positive correlation of left ventricular internal chamber dimension in diastole and systole to cycle length. Also, there was positive correlation between these left ventricular dimensions and the square root of cycle length, which predicted a plateau in dimensional changes as cycle length increased. Echocardiographic shortening fraction and left ventricular and septal wall thickness measurements did not change consistently during pacing. We concluded that left ventricular chamber dimensions in the dog may be significantly affected by alterations in heart rate.
在心房起搏过程中，从10只清醒、临床正常的犬记录了不同心率下的M型超声心动图。心率记录为心动周期长度（秒），且仅在持续的1:1房室传导期间进行测量。在所有研究的犬中，舒张期和收缩期左心室内径与心动周期长度之间存在显著（P<0.01）正相关。此外，这些左心室径与心动周期长度的平方根之间也存在正相关，这预示着随着心动周期长度增加，径的变化会达到平台期。起搏过程中，超声心动图缩短分数以及左心室和室间隔壁厚度测量值并非持续变化。我们得出结论，犬的左心室腔径可能会受到心率改变的显著影响。
