As a domain expert in cardiology, I can explain that the J point elevation refers to the point on an electrocardiogram (ECG) where the QRS complex ends and the ST segment begins. The QRS complex represents the depolarization of the ventricles, which is the electrical activity that initiates the contraction of the heart muscle. The J point is the transition from this depolarization phase to the repolarization phase, which is when the ventricles return to their resting state. Any elevation or depression of the ST segment from the J point can be significant and may indicate various cardiac conditions, such as ischemia, injury, or infarction. Here's the translation: 在心脏病学领域，我可以解释J点抬高是指心电图（ECG）上QRS波群结束和ST段开始的点。QRS波群代表心室的去极化，这是启动心肌收缩的电活动。J点是从去极化阶段到复极化阶段的过渡点，复极化阶段是心室回到其静息状态的时候。从J点开始的ST段的任何抬高或降低都可能是重要的，并且可能表明各种心脏状况，如缺血、损伤或梗死。 read more >>

On the ECG, the repolarization phase starts at the junction, or j point, and continues until the T wave. The ST segment is normally at or near the baseline. Minor STT changes are not necessarily associated with cardiac ischemia[1]. The T wave is usually concordant with the QRS complex.read more >>