Acute Cardiac Ischaemia Flashcards
What is acute cardiac ischaemia
Stable angina
Acute coronary syndrome (ACS)
- unstable angina
- non ST elevated Myocardial infarction (NSTEMI)
- ST elevation Myocardial infarction (STEMI)
Stable angina
Chronic condition caused by the narrowing of the coronary arteries restricting blood flow
Acute coronary syndrome (ACS)
Umbrella term used to describe unstable angina and myocardial infarction whilst still in the diagnostic phase of treatment.
Associated with a more severe interruption of blood flow to the heart.
Unstable angina
Suggests a deterioration of the chronic condition without damage to the heart muscle.
Non-ST elevation myocardial infarction (NSTEMI)
Damage to the heart muscle is not significant enough to be visible in the ST segment on ECG.
ST elevation Myocardial infarction (STEMI)
STEMI
Damage to the heart muscle is significant enough to be visible in the ST segment on ECG.
How are symptoms of ischaemia produced during stable angina
Normal blood flow:
- atherosclerotic plaque in the vessel reduces lumen size, impacting blood flow and o2 delivery
- at rest, vessel size is sufficient to meet o2 demand
Increased demand
- when demand increased due to exertion / heightened emotion, the lumen size is then insufficient and symptoms of ischaemia are experienced.
How are symptoms of ischaemia produced during acute coronary syndrome
Normal blood flow:
- when larger atherosclerotic plaques are present, blood flow may be reduced further so that symptoms of ischaemia are experienced without a link to exertion or emotional trigger
Increased demand:
- if exertion / heightened emotional triggers are present, symptoms of ischaemia may be compounded
Clot formation at a rupture site on the atheroma plaque
- narrowing of the lumen site increases blood pressure = erosion of the plaque = bleeding and a blood clot to form at the rupture site.
- presence / movement of clot may occlude vessel further
Recognising acute cardiac ischaemia
- experiencing chest pain first time- treat for ACS and call 999
- risk factors for cardiac ischaemia include diabetes, hypertension, obesity and smoking
Typical presentation
- chest pain
- radiation of pain to arm / back / jaw
- shortness of breath
- nausea
(Not all have pain, some just breathless)
When identifying Acute Cardiac Ischaemia use the acronym THE DRS - Stable Angina
Trigger: exertion / emotional
History: known angina
Episodes: no increased frequency of episodes
Duration: symptoms resolved in less than 15mins
Resolution: may resolve with rest or fast response to nitrates (4 activations of GTN or fewer)
Severity: symptoms typical of pt normal angina
When identifying Acute Cardiac Ischaemia use the acronym THE DRS - Acute coronary syndrome
Trigger: unclear
History: no devious chest pain
Episodes: increased frequency of episodes
Duration: symptoms continue in excess of 15mins
Resolution: slow / minimal response to nitrates (more than 4 activations of GTN)
Severity: symptoms worse or different to pt typical angina
Management of stable angina
- Rest - reduce oxygen demand
- Glyceryl trinitrate (GTN)
- dilated blood vessels improving oxygen delivery
- 1-2 sprays at 5min intervals
- max 6 doses - Monitor
- ABCDE approach to monitor patient condition and inform need for further GTN
- if symptoms persist after 4 doses of GTN, last longer than 15mins or any other features of ACS identified, call 999 and treat as ACS
Management of ACS
- Glyceryl trinitrate GTN
- dilated blood vessels
- improves oxygen delivery
- 1-2 sprays at 5min intervals
- max 6 doses - Aspirin
- inhibits clot formation, reducing damage to their heart muscle
- single administration of 300mg - Oxygen
- only required when hypoxia identified
- oxygen saturations of less than 94% indicate hypoxia - Monitor
- use ABCDE approach to monitor pt condition and to inform need for further GTN
