Clinical features

• chest pain
• tachycardia
• dyspnoea
• syncope
• weakness

Ask about

• the pain: specifically 
  • its position ^b  
  • its duration ^{a b c}  
  • its nature ^{a b} 
  • any radiation ^a  particularly to the right arm or shoulder ^b  
  • any similarity to previous infarcts or angina attacks ^a  
  • any exacerbating or relieving factors ^b  
    
• any nausea or vomiting ^b
• any sweating ^b  
• a history of  
  • angina or MI ^{a b}  
  • heart failure ^a  
  • an acute respiratory infection in the previous 10 days ^b  
    
• cardiovascular risk factors
  • hypertension ^{a  b} 
  • smoking ^b  
  • diabetes mellitus ^{a b}  
  • elevated total cholesterol or triglycerides ^{a  b}  
  • long-term elevated inflammatory markers: CRP, fibrinogen ^a
    
• usual levels of activity ^a  
• a parental history of angina or MI before the age of 60 ^a  

• sweating ^b  
• hypotension ^b  
• Kussmaul's sign (JVP rising during quiet inspiration) ^c  
• a third ^b or fourth heart sound ^c  
• chest pain that is reproduced on palpation ^{a  b} 
• pulmonary crackles ^b  

In the elderly, the following features are less helpful at diagnosing a myocardial infarction ^a

• pain location and similarity to previous myocardial infarction or angina
• ECG changes in the emergency department

Elevated Chlamydia pneumoniae IgG titres are not clearly associated with an increased risk of cardiovascular disease ^b , and a three month course of antibiotics does not clearly reduce the risk. ^b