Cardiology Flashcards
A lesion with occlusion occurying in the LAD artery will typically result in
an Anterior Wall MI
When an AWMI extends to the septal and lateral regions as well, the culprit lesion is usually
more proximal in the LAD or even in the left main coronary artery
ST segment elevation in the anterior leads (V3 and V4) and sometimes in septal and lateral leads depending on the extent of the myocardial infarction
Anterior Wall MI
Septal Leads
V1 and V2
Inferior Leads
II, III, avF
Laterial Leads
I, avL, V5, V6
How to ensure precordial leads have been placed correctly
presence of a negative QRS complex in avR and a positive QRS in Lead I
Which lead should be omitted when checking for signs of infact?
avR. It is of no diagnostic value due to the fact that it misrepresents pathological Q waves and obscures them.
standard criteria for diagnosing acute miocardial infarction
ST elevation of 1 mm. or more in the presence of pathological Q waves in 2 or more contigous leads
abnormal q wave
.04 sec (1mm) wide or greater
depth of q wave is greater than 1/3 height of r wave
Cardiac conduction system
SA Node, Internodal Pathways, AV Node, Bundle of His (AV Bundle), Left/Right Bundle Branch, Perkinje Fibers
Anterior Leads
V3, V4
ST segment elevation in leads II, III and avF
Inferior wall MI
MI symptoms with tachycardia
Possible damage to the left Ventricle and an “anterior” or “lateral” infarct.
The Left Circumflex and or Left Descending Coronary Artery may be occluded.
Check for elevation in leads V3, V4, V5, & V6.
MI symptoms with bradycardia
Possible damage to the Right Ventricle and an “inferior” or “posterior” infarct.
The Right Coronary Artery may be occluded.
Check for elevations in the Limb Leads: II, III and avF.
normal PR interval
.12 - .20 seconds (3-5 small boxes)
normal QRS interval
.04 - .12 seconds (not more than 3 boxes)
Some literature states not more than .1 seconds.
Can be shorter for children or after extended periods of exertion.
Wide QRS interval can indicate
V-tach 3rd degree heart blocks Bundle branch blocks Hyperkalemia Tricyclic antidepressant overdose.
Which lead is the only one used to recognize bundle branch blocks
v1
QS complex = left bundle branch block
rSr complex = right bundle branch block
6 Steps to 12 Lead Interpretation
- Rate and Rhythm
- Axis Deviation
- Intervals
- Morphology
- ST Elevations - Mimics
- Ischemia, Injury, Infarct
When should nitro be avoided in the presense of acute MI
inferior wall MI, due to possible right ventricle injury
the right ventricle, in the presence of injury, is dependent on preload. Pump action of the right side is significantly diminshed due to injury. Nitro decreases preload.
Hold the nitro and give fluid bolus
