ECG: What would you do next?

A 45 year old man presented with shortness and breath and mild chest discomfort. This is his ECG. He is on haemodialysis for renal failure and is known to have aortic stenosis.

Which of the following is/are the most appropriate response(s)?

 
a)    Activate the STEMI page

b)   Check his electolytes

c)    Repeat the ECG in 15 minutes

d)   Ask for an urgent transthoracic echo

e)    Burst into tears because clinical medicine is too hard

 

ANSWER:[expand title=”open” swaptitle=”close”] [box] b, c and possibly e

This man had aortic stenosis and renal failure, his potassium was 6.7.
The worrying feature of this ECG is ST elevation in V2 and V3 – note that the segments are concave and that there are deep S waves in the praecordial leads consistent with LV hypertrophy. It is a rule that the deeper the S wave the greater the ST elevation. LV hypertrophy is one of the conditions most frequently confused with acute MI.
About 90% of young otherwise healthy men have ST elevation of between 1 and 3 mm in the anterior praecordial leads – “early repolarisation”.
Hyperkalaemia is another well-recognised cause of ST elevation.
In this case, his symptoms were not consistent with an acute MI and the most appropriate response is to repeat the ECG in fifteen minutes to look for evolving changes and to check his electrolytes. Answer e reflects the shortcomings of ECGs as a tool and the daily frustrations we face in clinical assessment, however, bursting into tears is unlikely to be helpful.

Other causes of ST elevation other than AMI are:
–       LBBB
–       Acute pericarditis and myocarditis
–       Burgada syndrome
–       Pulmonary embolism
–       Transthoracic cardioversion
–       Prinzmetal’s angina

For a good discussion of causes of ST elevation see: Wang K, NEJM 2003; 349:2128-35
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