英语听力文摘 English Digest 471、你的心脏够强大吗？（在线收听）

Bradycardia

Don: Yaël, isn't normal heart rate somewhere between sixty to one hundred beats per minute？

Yaël: That's right, Don. Why?

D: This would be the one time you don't correct me. My heart rate is only 44 beats per minute. That means I have bradycardia. Oh, Yaël, I may be dying.

Y: Hold up! Yes, bradycardia is the term for a heart rate slower than about sixty beats per minute, but bradycardia doesn’t necessarily mean you’re not in perfectly good health. In well-conditioned athletes, bradycardia is a result of being in such good shape that the heart beats more efficiently, and so it doesn’t need to beat as quickly.

An athlete may have a heart rate as slow as thirty and not show any signs of problems. Also, deep relaxation, such as sleep, slows the heart down.

D: Yeah, yeah! Tell me about the bad news.

Y: Well, bradycardia can also be caused by certain medications, by other disorders such as hyperthyroidism, and by dysfunction of the sinus node. I don’t mean the hollow space behind your nose, but the node inside your heart. The sinus node powers your heart by electrical impulses.

Dysfunction of the sinus node then can cause the heart to beat too slowly to keep up with your body’s need for blood. Lightheadedness, weakness, and fainting are symptoms that a heart may be beating too slowly. In such cases, doctors will remove problem medications, correct the underlying disorder, or insert a pacemaker that fills in for the sinus node.

If symptomatic bradycardia goes untreated, it could lead to death, but that’s easy enough to prevent–just go see your doctor.

心动过缓

Don: Yaël,正常人的心跳次数是不是60~100次/分？

Yaël: 是啊。有什么问题吗？

D: 难得有这么一次你没有纠正我。我的心率仅仅是44次/分，我心动过缓！我的天，Yaël，我很可能就要死啦！

Y: 稳住啦！确实，心动过缓专指心脏跳动次数慢于60次/分。但是，心动过缓并不就是说你不健康。对于那些身体非常健康的运动员们来说，心动过缓的情况非常普遍。之所以会这样是由于他们的心脏能够进行更加高效的跳动，因而，运动员心脏无需跳得有多快。

运动员的心率一般会低至30次/分，而他们的身体没有任何问题。同时，在深度放松的情况下，就比如说睡觉，心率会自然而然的降低。

D: 嗯，那给我讲讲不好的方面。

Y: 额，心动过缓也可能是由特殊的药物治疗、甲状腺机能亢进一类的机体功能紊乱、窦房结（位于右心房外膜上）功能障碍——窦房阻滞等原因引起的。窦房结并不是指你鼻后中空的地方（此处是因sinus的意思为“穴”，谈话者将sinus与node分开来讲），而是指心脏内的一个结点。窦房结通过电脉冲为心脏提供动力。

窦房结的功能障碍会使心脏跳动过缓，而无法满足身体对血液的需求。心脏如果跳动过缓就可能会出现头晕、身体疲乏、晕厥等症状。如果出现这样的症状，医生会采取一定的药物治疗、调节机体功能，或是为窦房结安装人工心脏起搏器。

由心动过缓引发的症状治疗无效时会导致死亡，但是，这样的情况也相当容易预防——看医生就得嘞！