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Myocardial Infarction: Difference between revisions
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==Diagnosis of myocardial infarction== | ==Diagnosis of myocardial infarction== | ||
[[Image:Stelevatie_en.png|thumb|300px|ST elevation is | [[Image:Stelevatie_en.png|thumb|300px|ST elevation is at the J point]] | ||
The diagnosis of acute myocardial infarction is not only based on the ECG. A myocardial infarction is defined as:<cite>Alpert</cite> | The diagnosis of acute myocardial infarction is not only based on the ECG. A myocardial infarction is defined as:<cite>Alpert</cite> | ||
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So detection of elevated serum heartenzymes is more important than ECG changes. However, the heartenzymes can only be detected in the serum 5-7 hours after the onset of the myocardial infarction. So especially in the first few hours after the myocardial infarction the ECG can be crucial. | So detection of elevated serum heartenzymes is more important than ECG changes. However, the heartenzymes can only be detected in the serum 5-7 hours after the onset of the myocardial infarction. So especially in the first few hours after the myocardial infarction the ECG can be crucial. | ||
; | ;ST elevation | ||
:ST elevation | :New ST elevation at the J-point in two contiguous leads with the cut-off points: ≥ 0.2 mV in men or ≥ 0.15 mV in women in leads V2–V3 and/or ≥ 0.1 mV in other leads | ||
:ST | ;ST depression and T-wave changes | ||
:New horizontal or down-sloping ST depression > 0.05 mV in two contiguous leads; and/or T inversion ≥ 0.1 mVin two contiguous leads with prominent R-wave or R/S ratio ≥ 1 | |||
A study using MRI to diagnose myocardial infarction has shown that more emphasis on ST depression could greatly improve the yield of the ECG in the diagnosis of myocardial infarction (sensitivity increase from 50% to 84%).<cite>martin</cite> | A study using MRI to diagnose myocardial infarction has shown that more emphasis on ST depression could greatly improve the yield of the ECG in the diagnosis of myocardial infarction (sensitivity increase from 50% to 84%).<cite>martin</cite> | ||