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ECG in ACS

This document discusses electrocardiogram (ECG) patterns seen in ischemia and infarction. It describes: 1) Pathologic Q waves which indicate irreversible necrosis. ST segment and T wave abnormalities are sensitive to ischemia. ST elevation results from injury currents directed away from ischemic tissue. 2) Acute non-ST elevation myocardial infarction results from injury currents directed toward ischemic subendocardial tissue. 3) The ECG evolves during a STEMI, with ST segments returning to normal over time as injury currents subside. Examples of ECG patterns from different coronary artery occlusions are shown.

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75 views45 pages

ECG in ACS

This document discusses electrocardiogram (ECG) patterns seen in ischemia and infarction. It describes: 1) Pathologic Q waves which indicate irreversible necrosis. ST segment and T wave abnormalities are sensitive to ischemia. ST elevation results from injury currents directed away from ischemic tissue. 2) Acute non-ST elevation myocardial infarction results from injury currents directed toward ischemic subendocardial tissue. 3) The ECG evolves during a STEMI, with ST segments returning to normal over time as injury currents subside. Examples of ECG patterns from different coronary artery occlusions are shown.

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ECG of ISCHEMIA

&
INFARCTION

Radityo Prakoso
Division of Pediatric Cardiology and Congenital Heart Disease
Department Cardiology and Vascular Medicine
Faculty of Medicine Universitas Indonesia
National Cardiovascular Center Harapan Kita
Disclosure

Nothing to be disclosed
Conduction System
Pathologic Q waves
Normal : physiologic Q waves are short duration (0.04
seconds or 1 small box
Pathologic Q waves : a width > to 1 small box in
duration or a depth > 25% o the total height o the QRS.
marks of irreversible necrosis of the heart muscle
do not differentiate between an acute event and an MI
that occurred weeks or years earlier.

electrical currents from the healthy tissue > opposite regions on the ventricle
(directed away from the infarct) downward deflection
ST-T segment and T wave
abnormalities
ST-T segment and T wave represents ventricular
repolarization > very sensitive to myocardial ischemia

ST depression and T wave


inversion = transient episodes of
myocardial schema

ST abnormalities : >1mm / 1
small box from baseline or J point

The mechanism by which ST-segment deviations develop


during acute MI has not been established with certainty.
Acute ST-Elevation
infarct zone producing abnormal diastolic or systolic currents.

Diastolic injury current (T-Q interval)

damaged cells ionic leak partial depolarization


relatively negative rather than normal fully depolarised zones
current is directed away from the more negatively charged
ischemic area baseline shift downward
Acute ST-Elevation
Systolic injury current (Q-T interval)

ischemic cells repolarize faster than neighboring


normal myocytes positive surface charge to the
damaged myocytes is restored earlier (voltage
gradient) electrical current directed toward the
ischemic area
Acute Non-ST Elevation
diastolic injury current (T-Q interval)

ionic leak arises from the subendocardial tissue.

partial depolarization before stimulation results in electrical forces


directed toward the recording electrode baseline is shifted
upward.

fully depolarized, the voltage is true zero ST segment appears


depressed compared with the shifted baseline.
Mechanism ST-T Changes in ACS
Infark
Infark Transmural
Subendokard
ECG Evolution during acute
STEMI
High-likely
Ischemia

Unlikely schema (not


specified)
Mid LAD occlusion
after the first septal
perforator (arrow)
Occlusion of diagonal
branch ( arrow )
Proximal large RCA occlusion
Small inferior distal RCA occlusion
CAUTION
THANKYOU

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