Infarction Flashcards
Most common area that suffers from MI
Left Ventricle
EKG can be used to… (diagnostic implications)
Diagnose occlusion
Can tell which coronary artery is occluded
Reveals any blocks in ventricular conduction caused by infarction
Can help determine if coronary vessel is narrowed
…thus providing lifesaving information
Left Ventricle
Commonly the area that suffers from MI
Uses greatest blood supply (actually using the O2 and nutrients that the blood transports)
Reference for describing infarct location
Necrotic
Lack of blood supply reduces the tissue to functionally dead
Does not depolarize
No contraction
HYPOXIC VENTRICULAR FOCI NEARBY ARE OFTEN THE SOURCE OF SERIOUS VENTRICULAR ARRHYTHMIAS
Ventricular arrhythmias caused by
hypoxic ventricular foci
Think of this as a last cry for help
Foci depolarize as they are “dying” causing ventricular arrhythmia
The widow Maker aka
Left Anterior Descending coronary artery
Primary Coronary Vessels of the Heart
Left Coronary Artery "Left Main Artery" Circumflex Artery Left Anterior Descending Artery Posterior Descending Artery Right Coronary Artery
Myocardial Infarction Triad
Ischemia —> Injury —> Necrosis
Ischemia
Means reduced blood supply
can cause chest pain (angina)
significant EKG: T wave inversion (inverted and symmetrical)
Do not exercise this person! can cause MI!!
Ischemia on EKG
T Wave inversion at rest (inverted and symmetrical)
T wave inversion in V1-V6 is considered pathological
Do not exercise this person
T wave inversion
In adults flat or minimal T wave inversion IN LIMB LEADS may be normal
T wave inversion in V1-V6 is PATHOLOGICAL
Ischemia
Injury
Part of Infarction Triad
Means acute or recent
can be transient
EKG: ST elevation
Myocardial Injury EKG
ST elevation
>1mm is out of normal range
ST elevation
normal limit for ST segment is 1mm is pathological
Myocardial injury
Injury (past injury)
can be subendocardial infarction
indicates compromised coronary blood flow
EKG: ST depression
subendocardial infarction
below the surface/deep in the myocardium
ST Depression
Normal limit for ST segment is 1mm depression is pathological
past myocardial injury/subendocardial infarction
Necrosis
can be subendocardial infarction
indicates compromised coronary blood flow
EKG: significant Q wave
necrotic areas cannot depolarize and so cannot contract
can lead to an enlarged heart (not necessarily thickened muscle, but stretched)