Abstract
The microvibration (MV) on the scalp as a substitute for the conventional ballistocardiogram (BCG) and the electrocardiogram (ECG) of the limb lead II were simultaneously recorded on 120 healthy subjects ranging in age from newborn to school children. The duration from the Q wave of the ECG to J deflection of the MV was measured in seconds as the Q-J interval. The Q-J interval may be thought to represent the duration from the ventricular depolarization to the ejection period of the ventricular mechanical systole. The Q-J interval ranges between 0.160 and 0.280 seconds.
