Last updated 19/11/23

HEART ATTACK and ANGINA

Ischaemic heart disease is a global term that encompasses myocardial infarction (MI - also known as a heart attack) and angina. Severe angina and MI are also known as Acute Coronary Syndrome. In these conditions, there is insufficient oxygen supply in blood flowing to the heart muscle. This is due to narrowing of the coronary arteries which become furred up by fat-rich deposits known as plaques.

Angina can be a chronic condition that is recurrent over months or years. Myocardial infarction is an acute (i.e. sudden onset) event that may strike with little warning. Ischaemic heart disease is currently the most common cause of death in most developed nations and a major cause of hospital admissions.

If flow along the coronary arteries is only slightly impaired, the patient may only get symptoms with severe exercise, when the heart is working hard. In these cases, the patient gets cramp of the heart muscle - angina. The patient experiences pain or breathlessness. This usually subsides quickly when the patient rests as the heart has to work less hard. As the disease progresses, the amount of exercise that the patient can do before the onset of angina gets less and less.

If flow along the artery is completely blocked, no blood will get through to the heart muscle. In others, excess demand triggered by e.g. exercise can lead to angina or myocardial infarction (MI) in some individuals with pre-existing health conditions. These factors can cause sudden onset of severe chest pain. Left untreated, an area of heart muscle will die. In an MI, the death rate at one year is 30%, half of whom die before arrival at hospital. Therefore our response must be an urgent one that gets casualties to hospital without delay.

The Cause Of Angina

Myocardial Infarction (Heart attack)

Myocardial infarction, commonly known as heart attack, can strike without warning.

ESSENTIALS

History

Ask the casualty or any accompanying person if:

  • Previous attacks of angina and/or a MI?
  • Regular medication for angina? Have they taken it today?
  • Previous admission to hospital with an angina attack or a MI? If so, were they in intensive care?
  • Do they have a pacemaker? If so, when was it last checked?
  • Is the chest pain getting worse, better, or no change?

Consider the main risk factors:

  • Age (60+)
  • Male
  • High cholesterol and high fats in the blood (hyperlipidaemia)
  • Smoking
  • High blood pressure (hypertension)
  • Diabetes
  • Overweight especially if obese
  • Family history


Symptoms and Signs

Ask about:

Areas Pain Is Reported During An MI

Pain
Central chest pain which often radiates to the throat, jaw or left arm. Described as ‘heavy, crushing, tight or gripping.’
Upper abdominal pain (heart pain can radiate to the upper abdomen).

The diagram to the right roughly shows the areas pain can occur in an MI. The most typical area is shown highlighted in dark red.

Other important symptoms

  • Shortness of breath

  • Palpitations (an awareness of the heart beating quickly in the chest)

  • Nausea and vomiting

  • Anxiety and light headedness

  • Feeling of doom

Clinical features

  • Looks very ill: cold, clammy (sweaty) and pale

  • Lips may be blue (cyanosis)

  • Reduced SpO₂ reading

  • Abnormal pulse rate & rhythm (very fast, very slow, and/or irregular pulse)

Not All Chest Pain Is From The Heart

Consider what else could it be. Examples are:

  • Indigestion (dyspepsia)

  • Pulmonary embolism

  • Tension pneumothorax

  • Musculoskeletal pain

  • Dissecting aortic aneurysm

Remember – The risk of deterioration to a cardiac arrest is ever present

Angina shares the same symptoms and signs as a heart attack. An attack is commonly triggered  by exercise, eating a big meal, and when it’s cold or windy. The difference between angina and a heart attack is that angina will improve spontaneously within minutes on  resting or after using GTN.

AN ATTACK OF ANGINA THAT LASTS FOR GREATER THAN 15 MINUTES
SHOULD BE CONSIDERED AS A HEART ATTACK AND MANAGED AS SUCH

Management

Angina

A casualty with a known history of angina will recognise the symptoms and often self-manage and self-evacuate. it is likely to be more serious if MR is called.

Rest. Do NOT let them restart exercise.  Always stretcher off to prevent triggering symptom recurrence.

If you think the problem is angina and the casualty has not already taken any medication, try two sprays of GTN under the tongue so long as the blood pressure is >90 and they are not taking Sildenafil (Viagra), or any medication that ends in…fil.  This can be repeated after 30 minutes.  

GTN is commonly carried by people known to suffer from angina. Always ask if they have already taken a dose prior to giving it.

Give O₂ at 15lts per min via a non-rebreathing mask if SpO2 <94%, they are short of breath, cold and shivering or not sure of the diagnosis

A casualty with a history of angina is likely to be on several medications. Be sure to get a complete list.

 

Myocardial Infarction

Lazy W

If they haven’t already done so themself, place them into a half sitting position with their head and shoulders supported and knees bent. If possible, place improvised cushions or padding behind them and under their knees. This is commonly referred to as the ‘lazy W’ position and makes it easier for them to breathe, reducing the workload of the heart.

Be aware that the casualty will be very resistant to attempts to lie them down, and doing so can make breathlessness worse.

Attempt to reassure the casualty. Anxiety can worsen a heart attack. Confidently explain your treatment and evacuation plan.  Emphasise that you’re taking a precautionary approach.

  • Attach AED pads for possible use.  See the diagram on the packaging for the correct placement.

  • Give O₂ at 15lts per min via a non-rebreathing mask if SpO₂ <94%. If you can’t get a good reading with the pulse oximeter or the casualty is clearly breathless, give oxygen.

  • Try two sprays of GTN under the tongue (sub-lingually) if there is a possibility of angina. It can also sometimes help with myocardial infarction. NB only give GTN if the BP is >90 and the casualty is not taking Sildenafil (Viagra) or any other drug ending in…fil.

  • Give 300mg of aspirin (if no contraindications) even if already taken that day.

  • If their pain is manageable, avoid morphine / opiates - they may interact and reduce the effects of other key drug treatments. If the pain is severe and persistent, give 10mg of morphine IM.  See the drugs section for details of how to give morphine. Alternatives would be 1-2 fentanyl lozenges or Entonox if clear there is no evidence of a pneumothorax.

    • Remember: ensure Naloxone is available before giving morphine in case of inadvertent overdose or an unfavourable reaction to the drug.

  • To reduce nausea and vomiting give either:

    • Buccastem (Prochlorperazine) 3-6mg. Remember to give this via the buccal route i.e. place the tablet(s) between the upper lip and gum leave to absorb (takes at least 15 minutes)……Or

    • Ondansetron (Setofilm) film, 4mg, placed on the tongue, without water. It will disintegrate within seconds. Can be repeated after 30 minutes.

Keep the casualty warm as shivering increases the requirement for oxygen and thus cardiac workload.

Monitor closely including regular recording of pulse rate, resp rate, BP, SpO₂ and ECG, watch for trends and always be mindful of the possibility of cardiac arrest.

A very slow heart rate, or a very rapid heart rate, may develop. Both are features of acute coronary syndromes.

This is the type of incident when the portable monitoring equipment will be particularly useful for monitoring the casualty. Take regular assessments and remember to save before shutting down so they can be shown to ambulance staff and downloaded back at base. See the monitoring section for more details.

Urgent evacuation to hospital is warranted in all cases. This is time-critical.

Unresponsive Casualty

If the casualty suddenly becomes unresponsive, immediately assess and treat for cardiac arrest (if indicated). Be prepared to defibrillate and begin CPR if necessary.  See cardiac arrest and resuscitation for further details.

Heart rate abnormalities

SLOW

Sometimes not only the heart muscle is deprived of oxygen, but the electrical conducting system that controls the rate of the heartbeat is too. This can lead to a delay, intermittent, or no conduction of the natural pacemaker impulses. The casualty feels faint, or becomes unresponsive, their pulse is very slow, and their BP low. Use the ECG monitoring to assess further and record analysis. Treat for Cardiac Arrest if indicated.

RAPID

Other times, the dying heart muscle cells release chemicals that cause very rapid electrical discharges and malfunction of the conducting system. This can lead to very rapid heart rates, where the muscular pumping chambers do not have time to fill or empty. The result is an inadequate pumping of blood, and the casualty again is faint or unresponsive. This time their pulse is very rapid or not detectable, and their BP again low. Use the monitoring equipment to assess further and record. Again, treat for Cardiac Arrest if indicated. The AED will be required.

 

ADDITIONAL INFORMATION

The Cause Of A Myocardial Infarction

References

This guidance above has been taken from contemporary (2020) UK National Institute of Clinical Excellence, European Society of Cardiology, and the American Heart Association / College of Cardiology guidelines on Acute Coronary Syndromes. Acute treatment has been adapted from the UpToDate encyclopaedic medical resource (accessed 06/05/21).

Morphine use in ACS

  • Association of intravenous morphine use and outcomes in acute coronary syndromes: results from the CRUSADE Quality Improvement Initiative. Meine TJ, Roe MT, Chen AY, Patel MR, Washam JB, Ohman EM, Peacock WF, Pollack CV Jr, Gibler WB, Peterson ED, CRUSADE Investigators. Am Heart J. 2005 Jun;149:1043-9.