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dano7744 eNotes educator| Certified Educator

The zone of infarction , cellular death, and necrosis on the EKG can be noted by the presence of pathological Q waves. Q waves reflect a lack of depolarization to that specific area of the heart. Myocardial cells in the area of the Q wave are replaced by scar tissue. When this scar tissue forms, it means that the area is now avascular, or without a blood supply. Individuals that have survived a myocardial infarction are at increased risk of fatal ventricular dysrythmia's because of the zones of necrotic and scar tissue. Ejection fractions are adversely affected which predisposes the person to additional cardiac events like congestive heart failure and other vascular events like hypotension and pulmonary embolism.

giorgiana1976 | Student

Q wave is another interesting aspect.It's about a heart attack that someone did not felt but it is seen on the ECG.

What's the trick to discover the hidden heart attack when we are reading an ECG: those who had a heart attack, in front of QRS complex there is another spike, which is lying down and it has at least one quarter of the size of the high up spike (this "negative" stake is found on normal ECG but it is insignificant in size, compared to the positive spike from QRS Complex).

This large spike lying down is called the Q wave and persists 2-3 years after a heart attack.

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