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Heart attack

Diagnosing a heart attack

Most heart attacks are diagnosed from the results of an electrocardiogram [ECG] and a blood test, which can confirm whether or not a heart attack is occurring and if so, how it is affecting the heart. An ECG is often done in the ambulance by paramedics to make a preliminary diagnosis of a heart attack. While the final diagnosis rests in the hands of doctors, that preliminary diagnosis is important because it allows paramedics to begin treatment immediately - often while still in the patient's home (see ‘Pre-hospital care in the ambulance for a heart attack’). An ECG can also be done in a GP’s surgery.

 

An ECG taken in the ambulance suggested a heart attack and a second ECG in casualty confirmed it.

An ECG taken in the ambulance suggested a heart attack and a second ECG in casualty confirmed it.

Age at interview: 63
Sex: Male
Age at diagnosis: 63
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So I managed to get out of the cab without any problems whatsoever, walked to the ambulance. He got me laying down in the back of the ambulance and connected me up to the ECG machine with six connections, did a trace, looked at it and he said "Well," you know he wasn't sure that there was a problem but he'd do another one with twelve leads which he put the additional connections on and did that. 

And again he said, 'he wasn't sure there was a problem but he felt that he really ought to take me to [the local hospital] and get me checked out in the A & E department'.

As soon as they reversed back up to the entrance there was a doctor there, straight into the ambulance and I was out, into A & E and rather surprised to find that I was being taken into the resuscitation room. 

And I was immediately put on an ECG and as the trace came out the doctor turned to me and said "Well the good news is you haven't had a heart attack, the bad news is you're having it at the moment." And I was astounded because I was not in pain, okay I didn't feel at all well but it was more lethargy than anything that I felt.  

The classic sign of a heart attack on the ECG is known as ST elevation. This is the electrical signal produced by a damaged segment of the heart muscle, and heart attacks which display this are known as "STEMI" - ST- elevation myocardial infarction. If a heart attack occurs without this ECG signal, it is known as NSTEMI (the N standing for non-). Such heart attacks are usually diagnosed on the basis of blood tests such as troponin-T and other enzymes released by damaged heart cells. These can take a few hours to show up in the blood so it is common practice to admit patients with possible heart attacks for a period of hours to get a second blood test. These blood tests are not used as a way to decide on immediate treatment but can be used to assess the level of damage to your heart and how well you are responding to treatment. Both STEMI and NSTEMI heart attacks are also referred to as "Acute Coronary Syndromes" (ACS), together with the separate condition of unstable angina, which we do not cover here.
 

Stemi and non-stemi heart attacks

Stemi and non-stemi heart attacks

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The terms STEMI and non-STEMI are in the literature and what STEMI refers to is something called ST elevation myocardial infarction. So the ST refers to the pattern of one of the segments which we look for on the ECG. So an ST elevation heart attack is, essentially, a pattern of ECG recording which tells us that the heart artery is blocked completely. That area is not getting a blood supply and the ECG recordings change in a way that past, gives us that information and the treatment for that sort of heart attack with that sort of ECG is to rush to the cardiac hospital to try and open the blocked artery as quickly as possible.
 
Sometimes we find that patients have that sort of blocked artery ECG but, by the time they arrive in hospital, the ECG has got better because their own clot busting in the blood and their own ability to dissolve the clot, has dissolved the clot and opened the artery. Often they will still undergo an emergency angiogram, which is the x-ray pictures of the arteries, to see whether there is a narrowing that is still at risk of blocking again. So the and the non-ST elevation heart attacks are, basically, when the ECG doesn’t show us that very specific pattern but it shows us other changes on the ECG where we know that an area of the heart muscle has not got an adequate blood supply, may have suffered some damage but we don’t have that very marked change that tells us that the artery is blocked at that time. So it may be that the artery is blocked and then unblocked but left a signature that that process is going on and those patients, at the moment, are not managed with very, very emergency angiography i.e. getting the pictures and looking at the heart arteries but are conventionally treated with drugs to thin the blood and then undergo that same investigation of an angiogram and possibly an angioplasty within a few hours or days rather than having it very, very early on as an emergency procedure.

One woman described the series of tests she had done, in the ambulance, and over the next few days while she was in hospital to assess the amount of damage caused by the heart attack and a few months later to establish whether she would need further treatment for narrowing of her coronary arteries.

 

She describes the series of tests she had done in the ambulance and in hospital.

She describes the series of tests she had done in the ambulance and in hospital.

Age at interview: 37
Sex: Female
Age at diagnosis: 36
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They wired me up to the ECG monitor [in the ambulance] which actually goes straight through to the coronary care unit at the hospital so at the coronary care unit the Sister there could see whether or not it was anything wrong with my heart which she could see it was, so when I got to the hospital it was just straight to coronary care. 

In coronary care it was just, everything happened so fast and the team were, just working on you like from all directions, there's a doctor, there's nurses, you know, they're taking blood, they're doing this, they're doing that. So that all happened so, so fast and some of it was like a bit of a blur as well. 

I can't really recall everything that happened while I was actually in coronary care. All I know is that they worked really fast to get me stable. So that's when, you know, they actually realised that I was having a heart attack and just spoke to me obviously to make sure that they were going to give me the correct drugs, just asked me a few questions and, basically, that's all I can remember there for a little while because then I was just in a daze. 

It felt like I was drifting and I just recall people and, I didn't, I wasn't actually unconscious but I think I might have been drifting in and out while I was in coronary care. So, but then they got me stable and then, over the next few days in coronary care it was, obviously they just wanted me to rest and get better the best that I could. 

They did an echo of my heart which, there was some slight damage to my heart but not a great deal of damage to my heart. And then, before they'd let me come home I had to go on a sort of like it was a stress test, they call it, where I just had to go on a treadmill and be all wired up and monitored up to, to see whether my heart got into any difficulty, which it did after so many minutes of doing exercise. 

So they decided then that I'd have to have an angiogram and I had to wait a few months to have the angiogram and it, and when I had the angiogram they decided that because of one of my arteries was narrowed 90% that I would benefit from having an angioplasty and, and a stent. 

Occasionally, making a diagnosis is not straightforward and it can take some time before a heart attack is confirmed. One woman said that a series of ECGs carried out in hospital at first showed no changes - to confirm she was having a heart attack, even though she was getting attacks of chest pain.

The timing and type of blood tests taken are important in diagnosis. A man in his thirties explained that when he had a heart attack after bypass surgery, the ECG showed no significant changes in his heart.

 

When he had a heart attack after bypass surgery, the ECG showed no new changes.

When he had a heart attack after bypass surgery, the ECG showed no new changes.

Age at interview: 39
Sex: Male
Age at diagnosis: 37
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I wasn't feeling well and I parked up deliberately as close to the door in the cardiac unit as I possibly could. I walked very, very slowly, really slowly, because it was aching. And I went in, took myself and told them and they put me on the ECG and they said there was an ST elevation. 

But that in itself doesn't mean anything with me because [pause] apparently postoperative coronary artery bypass graft, my ST elevation is raised anyway now, that's my normal ECG. So I have to carry one around with me so if I ever go to hospital they ever need to compare that with that and it's the changes. 

So although there was an ST elevation it wasn't anymore significant than before, but as it happened my consultant was around and they went to speak to him. And this is the weird thing, I'm, I'm telling the truth now, but this, this, this is how it was put to me, 'Well, if you want to come in and stay you can but it's up to you, you can go home if you want'. 

And this is twice now, once the ambulance [laugh] and this time. It shouldn't really I don't think ever be my decision, particularly when you're in that state and [pause] I think, you should, if anyone is listening to this err on the side of caution. If you're not sure at all, go, stay a night, you've wasted nothing, we did.  

I was still in pain, they gave me diamorphine, they didn't thrombolyse me this time, they took the troponin I think they take it 15 minutes, then they take it within 24hours later and I think the first one came back; it was 'You're okay'. But the next one, the next day ooh, heart attack. And they're 'We can't believe this', I'm like, 'Believe it, it was, I don't make it up', so he would have sent me home in the middle of a heart attack. So I was actually having a heart attack at the time.

Another man in his forties said that the x-ray and the blood tests at first showed no abnormalities and he was sent home, but the stress test (treadmill ECG) he had two days later showed he had had a heart attack.

 

Initial tests did not show a heart attack but an echocardiogram two days later did.

Initial tests did not show a heart attack but an echocardiogram two days later did.

Age at interview: 46
Sex: Male
Age at diagnosis: 42
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But I was seen very quickly so I knew that they, what they suspected. And I was put in a side ward, got a, what are those called, the rooms off casualty, and I had oxygen. Something went under my tongue, I think it was for angina and I was put on a drip that was a clot busting or blood thinning. But it was all sort of precautionary because you know a bit like back ache, you can't see sort of immediately. 

I sort of felt a bit better, I think some of it was because I was in hospital and you sort of feel well nothing can happen now. So we were there all night. I had an x-ray, I had blood tests and I now know that they were looking for enzymes or something in the blood, which is another indication. 

I had cardiograms and about six o clock in the morning the sort of, someone in charge came in and said, "Well I didn't like the look of you when you came in but you do look a lot better now. There's nothing really shown up to say what's happened so we want you to come in on Monday to have a stress test.' 

And I had an [echo] cardiogram before they did the stress test and it wasn't very long. It seemed very, very short and I was sitting out in the waiting room in the hospital with loads of other people and the sort of the girl on the desk came over, looking absolutely shocked and said that I was going to have to see the doctor straight away, and so I went to get up and she said, "No, no we'll get you a wheelchair," and I said, "Well I've just driven here and walked in, I don't need a wheelchair," and promptly got up and walked in. 

And she was saying, "Do you want to phone anyone?" and I said, "Why would I want to do that?" and I walked, I sat down and the doctor said, "Well there's no easy way of taking this, but you've had a heart attack, probably on Saturday, early hours of Saturday morning".

Other tests such as a chest x-ray, an echocardiogram, other heart scans or a coronary angiogram may be used to assess the severity of the heart attack and to help decide on the best form of treatment. Whether these further tests are done at once or later will depend both on what is immediately available and on the patient's condition. See 'The general ward and discharge home after a heart attack' for more on the exercise ECG (also known as the 'treadmill' test).

Most people said having an echocardiogram, which is an ultrasound picture of the heart shown on a TV monitor, was very straightforward. One man, who after a week in hospital was still unstable, was sent for an angiogram, which showed that further treatment was necessary.

 

During his echocardiogram, the doctors could see that further treatment was necessary.

During his echocardiogram, the doctors could see that further treatment was necessary.

Age at interview: 71
Sex: Male
Age at diagnosis: 65
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When you actually go in to have the [echo] cardiogram, I didn't appreciate, again you're so unaware, the conditions at [the specialist hospital] to me it was space age, you go in and it's unbelievable. I hadn't been anywhere like it before, I hadn't been anywhere near the medical profession and there's this huge screen and the guy says, by now you're trying to get yourself up to speed so that when they talk, you can talk reasonably intelligently to them you know. 

You have to take a decision, either I'm going to be like an idiot or I'll try and respond and they had said there were three areas on coronary arteries that they would look at. The first one came up and all I saw was this huge great fat black line and he said, 'That's excellent, that's how a coronary artery should be.'  

The next one came up, which I now know no is like an inverted wand and I now know it's known as 'the widow maker' because if that's blocked above it, you're in trouble and he wasn't at all happy and they did a quick third one, said, 'That's okay.' 

Came back to this other one, everything went quiet. I was looking at it thinking, 'well it's obviously nothing like the first one, he couldn't really see that the lines were connected even' and then his head appeared and said, 'We're requesting surgical intervention immediately' and bang, that's when it hits you. So that was it.

A coronary angiogram is a test that shows which, if any, arteries supplying the heart are narrowed. Usually, it is a day case procedure done under local anaesthetic. Some people we interviewed in 2006 had to wait eight or nine months to have a coronary angiogram, others waited one or two months and some had the test a few days after their heart attack while they were still in hospital recovering.

Those who had waited a long time said they were anxious to have the tests done soon, so that if treatment was necessary it could be done as soon as possible. Waiting times vary around the country. How long you wait depends how urgently your doctor considers you need the coronary angiogram. A few people decided to pay to have the coronary angiogram done privately. One man had asked to be put on the cancellation waiting list in the hope of getting it done sooner.

Some had been anxious before or during the test, but said it was nothing to be frightened of and it wasn't as bad as they had expected. One man said that it helped that his doctor explained to him what was happening all the way through the procedure.

 

He found the angiogram frightening but accepted it was necessary so that a decision could be made...

He found the angiogram frightening but accepted it was necessary so that a decision could be made...

Age at interview: 51
Sex: Male
Age at diagnosis: 49
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And the doctors showed me on a TV screen that this artery was closed, stopped and you can see that, and after the angiogram, he told me that now you see that screen now.

What is that like having that done?

You know that's a very frightening place, it's all machines, angiogram machines. The first time everybody is scared and when they put this tube and put pressure like this, you know. Feeling this, feeling very bad but you must be accepting.

Do you think they gave you enough information to explain what was happening?

Yes, yes. After that explanation, I felt better because the doctor told me that 'now, no problem, you feel better because this is clean now. No need to send you for a bypass operation.' That's very lucky for any heart patient if they are saved from any bypass operation or angioplasty.

 

Describes what the angiogram was like.

Describes what the angiogram was like.

Age at interview: 57
Sex: Female
Age at diagnosis: 53
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Oh, the angiogram, it takes approximately 20 minutes but you're wide awake. You can have a sedative if you want one, but you go down to the, it's like a theatre and they put a catheter in through your groin which goes into the heart, and then they inject dye so it can see if there's any blockages in your arteries. 

And you just lie there flat and they, they give you a local anaesthetic so you don't feel a thing. And you can see on the monitor where the dye is going and it's quite interesting, actually. The only thing, you have like this hot flush and it's, it goes all through you, this warm feeling, it doesn't hurt or nothing but it's just this warm feeling all through your body [for about two minutes]. 

And you have that, but [the angiogram] it only lasts about 20 minutes and then you have to go back to the ward. And you have to lie flat for a couple of hours and they, because they've cut into your artery, they just make sure that that's not going to bleed. 

And then after, I think it's about 4 hours, all told, and you can, I think you can get out of bed then. I'm not 100%, I think it's about 4 hours, and you can get out of bed. And you're not long in going home, it's only a day thing and it's nothing to be frightened of, it's fine.

 

The angiogram was less alarming than he had expected.

The angiogram was less alarming than he had expected.

Age at interview: 63
Sex: Male
Age at diagnosis: 63
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So on the Friday the angiogram was just a one day procedure. Went into the hospital at eight o clock in the morning, because I was diabetic they made me the first on the list which is very nice. I knew exactly what the angiogram entailed and I'd read several times with the various booklets that I'd been given that there would be no discomfort or what have you. 

But the thought of something being put from your groin up to your heart I found very disturbing and I was not looking forward to it one little bit. 

But I have to say that the, I asked for a pre-med to try and calm me down a little bit because I did, I did feel very het up about it and the whole procedure was quite innocuous, other than the moving tilting bed and the xray machine on a powered arm over your head within inches of your nose and constantly changing position, it was, it's not a thing to get worried about.

Were you awake for the whole time.

Oh yes, yes completely awake. I didn't ask to see the xray screen, see what was going on, I couldn't face that [laughs] but I never felt a thing.

Some found it interesting to watch the procedure on the television screen. People are given a local anaesthetic and most said they had no pain. The only thing they felt was a warm sensation as the “dye” (which shows up on the x-ray pictures) flushes round their body. 

 

Last reviewed June 2017.

Last updated June 2017.

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