Cardiac Arrest vs Heart Attack – What’s the Difference?

Cardiac Arrest vs Heart Attack – What’s the Difference?

What answer would you give if you were asked “What’s the difference between a Cardiac Arrest and a Heart Attack?”  How well do you know your own heart?

Let’s first explore a few facts about the human heart. On average, your own heart will beat around 80 beats per minute or about 4,800 times per hour … which is a tiring 42,048,000 times during a year!  Your heart is one of the oldest organs in your body with heart cells beginning to beat only 4 weeks after your conception and it continues to grow until it’s about the size of two hands clasped together.  A woman’s average heartbeat is faster than a man’s by almost 8 beats per minute but whether you’re a man or a woman your heart will pump 1.5 gallons of blood per minute.

What's a Cardiac Arrest?

The most common cause of a cardiac arrest is an abnormal heart rhythm, known as ventricular fibrillation (VF).  This means that the regular electrical activity within the heart has become so unstable that the heart stops pumping and fibrillates (quivers).  This can be caused by problems with your heart or by external forces.  For example you may have coronary heart disease, cardiomyopathy, congenital heart disease or inflammation of the heart muscle.  Alternatively, if you were electrocuted, used recreational drugs such as cocaine, had lost a large amount of blood or if you were choking and lacking sufficient oxygen, then you could also suffer a cardiac arrest.  

If you get the correct treatment quickly, you can recover from a cardiac arrest.  VF can be corrected and returned to a normal heart rhythm by giving the heart an electric shock through the chest wall.  Defibrillators, once only found in hospitals, are increasingly being used in communities as correct equipment and training becomes more widespread.  The important factor in helping someone to survive a cardiac arrest is CPR.  Using CPR allows oxygenated blood to continue to circulate around the body until a defibrillator can be used to ‘re-set’ the heart.

Did you know that the first pacemakers had to be plugged into a wall socket? 

What's a Heart Attack?

A heart attack is a sudden interruption to the blood supply to part of the heart muscle.  If you’re suffering from a heart attack you’re likely to suffer permanent damage to your heart.  During a heart attack the heart muscle is starved of oxygen-rich blood and is unable to recover.  Heart attack symptoms include chest pain, sometimes described as tightness, heaviness or even a burning feeling in the chest.  You may also experience pain in your arms, neck, jaw, back or stomach.  For some people these symptoms are severe and in others they are less so.  Whilst experienceng a heart attackk you may also sweat and feel light-headed, become short of breath or feel nauseous or vomit.  

Screen Shot 2016-11-28 at 16.14.30The majority of heart attacks are caused when your coronary arteries, that supply your heart muscle with oxygen-rich blood, become narrowed.  Otherwise known as coronary heart disease, the narrowing of these arteries is caused by a build-up of fatty material.  If a piece of this fatty material (atheroma) breaks away, it could block your coronary artery which in turn will cut off the supply of oxygenated blood to your heart and cause a heart attack.  

Several other medical terms are used to describe a heart attack including myocardial infarction (MI), coronary thrombosis or acute coronary syndrome.  

There are several treatment paths for heart attack patients.  The first is an emergency coronary angioplasty which reopens the blocked coronary artery allowing the blood supply to return to the heart and prevent further damage.  Alternatively, a ‘clot buster’ (Thrombolysis) is performed which involves injecting a drug into a vein to dissolve the blood clot and restore the blood supply to the heart.  Paramedics may be able to perform this prior to reaching a hospital.

Some people are able to take 300mg of adult aspirin. This helps to thin the blood and prevent blood clots as aspirin can inhibit circulating blood cells known as platelets.  Whilst platelets are usually very good at sticking together to help heal cuts and breaks in blood vessels, if you’re having a heart attack you don’t want them to cause a clot and stop blood flowing to the heart or brain. 

Interestingly, aspirin was discovered by the British researcher Sir John Vane who showed that it blocks an enzyme called cyclooxygenase. Cyclooxygenase proudces a range of hormones known as prostanoids which make platelets adhere to each other.  These Prostanoids also affect areas with inflammation which is why we used to treat sprains and damaged joints with aspirin.  Today, we have far more effective drugs such as ibuprofen for these conditions, as you need much larger doses of aspirin to work well as a painkiller or to reduce inflammation.  However, in the treatment of heart attack or stroke patients, aspirin is still a very viable treatment.

It’s important that we not only teach people to look after their hearts but also to recognise the symptoms of deteriorating heart health.  How healthy do you think you are?  Have you had a health check recently?

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