Lead definition

  Classically

      Lateral leads :
V5 and V6.

      High lateral leads :
I and aVL.

  In daily clinical practice, many patients show extension of the ischemic changes

      into the neighbouring regions. Additionally, the treatment strategies do not differ for both.

      Therefore, differentiation between lateral and high lateral myocardial infarctions may not be so necessary

      in daily clinical practice.





ECG 1a. The ECG above belongs to a patient who has typical retrosternal chest pain and accompanying
ST segment elevation
in high lateral leads
. However, the lateral leads (C5, C6) do not show ST segment elevation . Thrombolytic therapy was
administered to this patient.


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ECG 1b. The above ECG was recorded after thrombolytic therapy while the patient had no angina.
The ST segment elevation
in high lateral leads have disappeared.
. Later on, when chest pain recurred, coronary angiography was performed which
showed significant stenosis of the first diagonal branch of LAD. Other coronary arteries were normal.

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ECG 2. Acute high lateral myocardial infarction may be without ST segment elevation. The ECG above belongs to a patient with
chest pain and elevated cardiac enzymes. Coronary angiography showed 99% stenosis in the second Diagonal branch of the
LAD of this patient. The finding that suggests non-ST elevation myocardial infarction (NSTEMI) in this patient is
the T wave
negativity in high lateral leads
.


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ECG 3a. The ECG above belongs to a 62 years-old man experiencing acute high lateral myocardial infarction.
The ST segment
elevation in high lateral leads
suggests this diagnosis. This ECG was recorded just before coronary angiography.


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ECG 3b. Coronary angiography showed complete obstruction of the intermedier artery at a very proximal site.
The same patient's ECG just after stenting of the intermediary artery is seen above. The ST segment elevation in high
lateral leads is not seen anymore.

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ECG 4a. This ECG is from another patient with acute high lateral myocardial infarction. Limb leads are seen above.
It was recorded before coronary angiography.
The ST segment elevation in high lateral leads (I and aVL) suggest acute high lateral myocardial infarction.

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ECG 4b. The same patient's chest leads are seen above.
His coronary angiography showed total occlusion of the first Diagonal branch of the LAD.
No other significant lesion was observed in other coronary arteries.

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ECG 5. The compact ECG above is from a 47 years-old man with recent-onset chest pain.
The
ST segment elevation in leads I, aVL and V6 show that he is experiencing acute high lateral myocardial infarction.
After recording of this ECG, thrombolytic therapy with tpA was administered.




Figure 1. Later, coronary angiography was performed and the anteroposterior cranial view showed
significant stenosis in the Diagonal artery. Other coronary arteries were normal.





ECG 6a. Above is the ECG from a 61 years-old man who was admitted to the Emergency Room with the complaint of
retrosternal chest pain. ST elevation in leads I and aVL (high lateral myocardial infarction) and ST depression in leads III and
aVF are seen. The rhythm is atrial fibrillation. He underwent urgent coronary angiography shortly after this ECG.


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ECG 6b. Coronary angiography showed total occlusion of the non-dominant Circumflex (Cx) coronary artery in this patient.
The artery was stented successfully and his chest pain disappeared. His other coronary arteries were normal. Successful
revascularization has resulted in disappearance of the ST elevation in leads I and aVL, and ST depression in leads III and aVF.
The rhythm is atrial fibrillation.

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ECG 6c. Above is his ECG one year after the infarction.
Lead I shows T wave flattening while lead aVL shows negative T wave.

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ECG 7. The above ECG was recorded from a 46 years-old woman with chest pain.
Leads I and aVL show ST segment elevation.
As in the above ECG, acute high lateral myocardial infarction may show only subtle ST segment elevation in leads I and aVL.
Usually, ST segment elevations up to 8-10 mm (as seen in acute anterior myocardial infarction) are not seen
in acute high lateral myocardial infarction.
Coronary angiography in this patient showed severe thrombotic stenosis of the Diagonal artery.

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