心跳過緩

Bradycardia is a condition wherein an individual has a slow heart rate, typically defined as a heart rate of under 60 beats per minute ( BPM ) in adults. Bradycardia typically does not cause symptoms until the rate drops below 50 BPM. When symptomatic, it may cause fatigue, weakness, dizziness, sweating, and at very low rates, fainting. During sleep, a slow heartbeat with rates around 40 – 50 BPM is common, and is considered normal. Highly trained athletes may also have athletic heart syndrome, a very slow resting heart rate that occurs as a sport adaptation and helps prevent tachycardia during training. The term relative bradycardia is used in explaining a heart rate that, although not actually below 60 BPM, is still considered too slow for the individual's current medical condition. 心跳過慢 （ Bradycardia ） 也稱心動過緩 、 心跳過緩 、 心動徐緩 、 徐脈 。 是指心臟跳動速度低於正常水平 ， 達到每分鐘60次以下的現象 。 心跳過慢可能是由迷走神經亢奮 、 竇房結病變 、 竇房結的衝動波遭到阻擋等原因引起 ， 常見於老年人 、 心臟病患者