Haffty B G, Sugiura T, O'Hare N E, Spodick D H
Am J Cardiol. 1983 Jul;52(1):167-71. doi: 10.1016/0002-9149(83)90090-5.
The peak derivative of the ear densitogram (PD) has been shown to track left ventricular (LV) function during exercise. Measured as percent change in amplitude from resting control, PD in normal subjects slowly and consistently increased throughout exercise and to 2 minutes of recovery, followed by return to control level. In contrast, PD in patients with coronary artery disease rapidly increased only to 1 minute of exercise, with no significant subsequent increase. Expressed as a percent change from control, the response of normal subjects differs significantly from that of patients with coronary artery disease at 1 and 4 minutes of exercise, and 2 minutes of recovery. The PD increase in normal subjects from end-exercise to 2 minutes of recovery may be attributable to the heart rate decreasing faster than venous return, associated with LV ejection time, which is significantly shorter than heart rate-predicted values 2 minutes after exercise.
耳部密度图的峰值导数（PD）已被证明可在运动期间追踪左心室（LV）功能。以相对于静息对照的幅度变化百分比来衡量，正常受试者的PD在整个运动过程中缓慢且持续增加，并持续到恢复2分钟，随后恢复到对照水平。相比之下，冠心病患者的PD仅在运动1分钟时迅速增加，随后无显著增加。以相对于对照的百分比变化表示，正常受试者与冠心病患者在运动1分钟、4分钟及恢复2分钟时的反应存在显著差异。正常受试者从运动结束到恢复2分钟时PD的增加可能归因于心率下降速度快于静脉回流，这与左心室射血时间相关，而左心室射血时间在运动后2分钟显著短于心率预测值。
