What is a heart attack? Cardiologists explain the condition following death of NBA coach

金州勇士队助理教练德扬·米洛耶维奇最近因心脏病发作去世. 虽然大多数心脏病发作发生在老年人身上，但年轻人也可以经历. The coach was just 46 years old.

Here's an explanation of heart attacks at any age, and what happens when you have one, according to cardiologists.

In a healthy heart, 血液流经被称为动脉的管道，将所需的氧气输送到心脏. But fat, cholesterol and other substances, collectively known as plaque, can build up inside heart arteries. When the plaque ruptures, it exposes the underlying tissue to the blood, causing a clot to form at the site of the rupture. 凝块会阻塞富氧血液，而富氧血液需要通过动脉流向心脏.

你可能不会马上注意到这一点，因为附近为心脏服务的血管会扩张来补偿, said Dr. Karen P. 他是北卡罗来纳州达勒姆杜克大学医学中心的心脏病专家.

但是当心脏——也被称为冠状动脉——狭窄超过70%时, 感到胸痛是很常见的，因为心脏组织需要比它得到的更多的氧气.

当一部分心肌因为没有得到足够的氧气而死亡或受损时, that's called a heart attack, or myocardial infarction. Each year in the United States, 605,000 people have their first heart attack and another 200,000 have their second or even third, according to American Heart Association statistics.

That's why it's critical, Alexander said, 养成健康的习惯，比如饮食均衡，定期锻炼，从一开始就能预防斑块的形成. But even with a healthy lifestyle, heart attacks can happen.

Less often, heart attacks are caused by a severe spasm of a coronary artery, 冠状动脉栓塞或其他减少或停止心脏部分血液流动的疾病. 另一种罕见的心脏病发作原因是自发性冠状动脉剥离, or SCAD, when blood flow is blocked because of a separation, or tear, in the lining of the coronary artery wall.

心脏病发作最常见的症状是胸口中心的不适或疼痛，感觉像是挤压, aching or burning that often radiates up to the neck, shoulder and jaw, and down to the left arm. It can be sudden or start slowly.

人们的脖子、下巴、背部、胃部或手臂也可能会感到疼痛或不适. 呼吸短促、出冷汗、恶心或头晕也可能是症状. Heart attack symptoms can vary between men and women, with women sometimes experiencing the less common symptoms.

And while heart attacks do happen more often in older people, younger people can – and do – have them, too. AHA statistics show that men ages 20-59 account for 4% of heart attacks; for women in the same age range, it's just over 2%.

“许多从意外心脏病发作中幸存下来的年轻人后来透露，他们有一点预先警告," Alexander said. "Some may have a warning cluster of events 12 to 24 hours before.她说，要注意任何新的症状，或者胸痛之前的不寻常的疲劳感.

如果你有任何心脏病发作的征兆，不要等待帮助. Call 911 right away.

“我看到的错误是，人们试图自己开车去医院，或者他们把症状最小化，然后说, 'I'll talk to my doctor next week,'" Alexander said. "If there's an emergency, that's what EMS is for. 如果人们担心发生了什么事，我们宁愿多见他们，而不是少见他们."

拨打紧急医疗服务电话可以确保心脏病发作的人立即得到治疗. And because a heart attack is a common cause of cardiac arrest, EMS also can provide resuscitation to someone whose heart has stopped.

尽管人们有时会混淆这两者，但心脏病发作与心脏骤停是不同的. 心脏病发作是一个管道问题，而心脏骤停是一个电气问题. 管道问题会导致电气故障，心脏的电力基本上就会消失.

“不是所有的心脏病发作都会以心脏骤停结束，但很多都会。. 乔治·绍塞多(Jorge Saucedo)是Froedtert的心脏病专家和心脏和血管服务主任 & the Medical College of Wisconsin health network in Milwaukee.

他说，目睹心脏骤停的人应该拨打911，并以每分钟100到120次的速度用力按压胸部中心，开始心肺复苏术. "Start it as soon as possible. Do not hesitate," Saucedo said.

To reduce the risk of a heart attack, everyone should know their blood pressure and cholesterol numbers, not smoke and be physically active, he said.

A helpful tool, Alexander said, is the AHA's Life's Essential 8, 一份改善和维持心血管健康的关键措施清单，包括充足的睡眠、控制体重和血糖.

"The bottom line is, lifestyle matters a lot," she said.