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thenursingandparamedicacademy

3 days ago

NREMTP Review-Jabari T. 🚑🚒 Cardiology

Ischemia (Partial Blockage)

A lack of oxygenated blood to the myocardium

Injury (A larger blockage)

Actual injured muscle due to longer ischemia

Infarction (Complete blockage)

Actual muscle death

Pathophysiology

Myocardium=Heart=4 chambers
Blood volume
Electricity=Nodal system
Electrolytes

Nodal System (Conduction System)

SA Node (Top of the right atrium)-"pacemaker"-Intrinsic HR-60-100
AV Node (Bottom of the Right atrium)-Intrinsic HR-40-60
Bundle of His-Intrinsic HR-30-40
Bundle Branches-Intrinsic HR-20-30
Purkinje Fibers-Weak electricity-10-20

Electrolytes

Calcium
Sodium
Potassium

Potassium

Lives inside the cells
Intracellular
Responsible for nerve conduction and muscle contraction (Excitability)

Sodium

Lives outside the cells
Extracellular
Responsible for nerve conduction and muscle contraction (Excitability), Plays a huge role in neurologic brain function and fluid balance

Calcium

Lives outside of the cells
Extracellular
Responsible for nerve conduction and muscle contraction (Excitability), also strengthens bones/teeth

Depolarization (Contraction)

Repolarization (Relaxation)

Magnesium-Relaxes muscles
Bicarbonate
Chloride

What blood vessels supply the myocardium w/ oxygenated blood?

Coronary Arteries
On every beat, the myocardium gets 33% or 1/3 of the oxygenated blood via the coronary arteries
The body gets the other 66%

RCA (Right CA)

Inferior wall
Right ventricle
Right atrium

Left main CA--->LAD (Left anterior descending)

Septal wall
Anterior wall
Left ventricle
Low lateral wall

Circumflex

Left atrium
High lateral wall
Posterior wall

CAD-coronary artery disease

Atherosclerosis-Buildup of fats=plaques=lipids=cholesterol in the coronary arteries
Arteriosclerosis-Hardening and loss of elasticity in the C.A

Angina-onset of CP due to ischemia

Stable Angina (Small blockage)

Onset of CP from exertion
Predictable
The CP goes AWAY w/ rest/NTG
Lasts less than 1 hour

Unstable Angina (Larger Blockage)

Onset of CP while at rest!!!
The CP does NOT go away w/ rest/NTG

Prinz-metals Angina (Variant Angina)

Onset of CP
It is not due to a blockage
It is due to vasospasms in the CA
Causes-Cold temps, caffeine, pre-workout, supplements, energy drinks, meds

Hypoperfusion=lack of oxygenated blood to a muscle, tissues, organs

Biproduct of hypoperfusion=Lactic Acid=PAIN!!!!!!
Shock=Metabolic Acidosis

Myocardial Infarction (Complete Blockage)

Preload-Always think VOLUME

The total amount of blood in the ventricles at the end of diastole
The ventricles are preloading getting ready for the next beat

Afterload-Always think RESISTANCE/PRESSURE

The total resistance the Left ventricle must overcome to pump out the blood

Examples

72 male-JVD, crackles, and pedal edema=Increased Preload
VS as follows-BP-202/110, HR-110, RR-24=Increased Afterload
25 F-syncopal episode-BP-72/40, HR-110=Decreased Afterload
30 M-GSW x 3-Massive internal bleeding=Decreased Preload
VS-62/38, HR-122-W=Decreased Afterload

Hemodynamics

Normal Blood Volume

4-8 Liters

Cardiac Output

The amount of blood the heart pumps out in 1 minute
Normal-4-8 L/min
HR X SV=CO

VS-BP-118/62, HR-84, RR-22, SV-70 mL
84 X 70=5,880 mL=5.8 Liters=Normal

Stroke Volume

The amount of blood pumped out in 1 beat (Stroke)
60-110 mL

Ejection Fraction

The % of the ventricular fill that is being pumped out
Normal->55%

12 lead EKG

Bipolar Leads (Limb leads)

Leads I, II, III
Positive always looks to negative

Augmented Leads

aVF-augmented vector foot
aVR
aVL

Precordial Leads

Leads V1-V6

Inferior Wall MI=Right sided M.I

STE in leads II, III, aVF
Immediate V4R-if positive, the entire right ventricle is affected=Right sided MI
An inferior & right sided MI is a PRELOAD PROBLEM
Only MI we DO give a fluid bolus!!!!
INOTROPIC (Strength of the contraction) Problem