As a medical professional with expertise in cardiology, I can provide you with an accurate description of the normal QRS complex. The QRS complex is a graphic representation of the electrical activity of the ventricles during depolarization on an electrocardiogram (ECG or EKG). The normal QRS complex has the following characteristics: 1. Duration: The normal QRS complex duration is typically between 0.06 to 0.10 seconds, which translates to 1.5 to 2.5 small squares on a standard ECG strip. 2. Amplitude: The height of the QRS complex should not exceed 2.5 millivolts (mV) in lead II for males and 2.0 mV for females. 3. Morphology: The complex should have a smooth, continuous curve without notches or slurring, which could indicate an abnormality such as a bundle branch block or ventricular hypertrophy. It is important to note that the P-R interval, which you mentioned, is the time from the beginning of the P wave (atrial depolarization) to the beginning of the QRS complex (ventricular depolarization). A normal P-R interval is 0.12 to 0.20 seconds, which is slightly longer than the QRS complex duration. Now, let's translate that into Chinese: 作为一位在心脏病学领域具有专业知识的医学专家，我可以为您提供关于正常QRS波群的准确描述。 QRS波群是在心电图（ECG或EKG）上表示心室去极化期间电活动的图形。正常的QRS波群具有以下特征： 1. 持续时间：正常的QRS波群持续时间通常在0.06到0.10秒之间，这相当于标准ECG纸上的1.5到2.5个小方格。 2. 幅度：QRS波群的高度在II导联不应超过2.5毫伏（mV）对于男性，对于女性则不应超过2.0 mV。 3. 形态：波群应具有平滑、连续的曲线，没有切迹或模糊，这可能表明异常，如束支传导阻滞或心室肥大。 需要注意的是，你提到的P-R间期是从P波（心房去极化）开始到QRS波群（心室去极化）开始的时间。正常的P-R间期是0.12到0.20秒，这比QRS波群的持续时间略长。 read more >>

The P-R Interval. The first measurement is known as the "P-R interval" and is measured from the beginning of the upslope of the P wave to the beginning of the QRS wave. This measurement should be 0.12-0.20 seconds, or 3-5 small squares in duration.read more >>