Page 359 - ECG dr shamol_Slide

Blood supply to the heart:

Right coronary artery - inferior aspect of heart and right ventricle
Left anterior descending - Septal and anterior heart

Left circumflex - Lateral wall of left ventricle

There are 3 phases of infarction:
Acute phase - characterised by ST segment elevation and tall T waves in affected area

(hyperacute T waves may even precede ST elevation). NB in full thickness infarcts there may

be reciprocal ST depression and T wave inversion opposite leads.
Evolving phase (hours to days after) - ST segment starts to return towards baseline,

accompanied by inversion of T waves.

Resolving phase (weeks to months after) - partial or complete recovery from ST and T

changes, may have persisting q waves if infarction. (If ST segment elevation persists, this may
be indicative of aneurysm formation).

NB ST elevation in all leads is seen in pericarditis
ST elevation is relevant if >1mm in limb leads and >2mm in chest leads.

If there is no infarct, transient ischaemia is shown by ST segment depression