Myocardial ischaemia

Condition

• Myocardial ischaemia

History

• Any pain waist line and above is cardiac until proven otherwise
• Quality of the pain is usually described as pressure, heaviness or tightness
• May have associated symptoms: dysnoea, dizziness, nausea and vomiting and sweating
• Ask family and risk factors

Examination

• could be normal
• variable ? arrhythmias
• Gallop rhythm 
• Murmur of MI
• Basal crackles

Ix

• ECG is a must
• Troponin probably does not have a role at general practice unless you have a cath lab
• CXR helps to exclude causes e.g. pneumothorax
• Myocardial perfusion study
• High negative predictive score
• Risk stratify into 3 categories: reversible ischaemia, normal/equivocal and non diagnostic
• Normal/Equivocal --> CTCA
• Limitations: patients' compliance to the exercise requirements of the study, low sensitivity and radiation dose 
• Stress echocardiagraphy
• can use to risk stratify like myocardial perfusion study
• needs expert operator
• CTCA
• Needs the HR < 60 bp
• Be able to breath hold
• very high negative value approaching 100 %
• Limitations: sometimes can be difficult to get the heart rate down (anyone ever works at ED will tell you that) and high calcium in the arteries can also obscure the view
• Scan protocol (Triple rule out) using CTCA to rule out PE, Aortic dissection and MI have been employed by some centres in the state. Watch out for this space in Australia

Management

• For GPs, the main thing is recognising it and send the patient to ED. This could be life saving. 
• I used to feel terrible for sending someone in who end up did not have a MI. Feeling that I have wasted their time and ED's time and ED's discharge letter will definitely make you feel that way. 
• Don't forget that we will never be 100 % correct. We got some and we missed some. For those who did not have MI, you have just excluded a life threatening condition! Well done!

References

1. John Murtagh

2. http://www.racgp.org.au/afp/2014/may/imaging-for-cardiac-disease/