Cardiac Physiology Flashcards
Heart valves
Tricuspid(R) and Mitral(L) = blood into the Ventricals
Pulmonic(R) and Aortic(L) = blood out of the ventricles
Why Pulmonic valve is important
Maintains diastolic pressure in pulmonary artery
MAP is made up of 2/3 diastolic pressure
Cardiac Output
> 4-8L/min
HR quickest way to increase CO(Q)
Stroke volume (SV) = preload, after load, contractility. Amount of blood ejected during systolic pressure
Tachycardia increases O2 use and decreases O2 supply. Tachycardia = 220-age
Are they hot, hypoxic, or hypovolemic?
Dicrotic notch
End of the T wave
Heart sounds
S1-closing of Mitral and tricuspid
S2-closing of the aortic and pulmonic
S3-ventricular filling sounds like “Ken-TUCKy”. Normal
S4-LV filling when non-compliant. Pathological sound. “Ten-nessee”
RCA
Feeds SA/AV node, RA, RV, and Inferior/Posterior wall
LAD
V1-V4
Pre-cordial leads
V-leads
How and when to perform a right side 12-lead
All patients with an Inferior STEMI should get a right sided 12-lead. Just move V4 to the right side of the chest. That’s all you need to do
Left circomflex artery
Leads 1-aVL(high lat)
V5-V6(low lat)
Hyper acute T wave
Early change suggestive if STEMI
Tall and peaked symmetrical
*Only seen in the affected area
Pathologic Q waves
> 25% of R wave height
2mm in depth
At least 40(0.04)ms wide
Associated with necrotic cells
Usually seen days or weeks after
aVL and Inferiors
If you see as little as 0.5mm of depression in aVL, it’s 97% predictive in identifying inferior MI.
If ACS patient has aVL depression, Inferior MI is likely coming soon
Where is WALDO and his SHIP
W-Wellen’s syndrome
A-aVR STE
L-LBBB
D-DeWinters T wave
O-out of hospital ROSC
S-subtle Inferior-High Lat wall
H-Hyper acute T wave
I-Isolated
P-Posterior
EKG with pericarditis
Global STE without reciprocal changes
Imitators of STEMI
LVH
Paced/Ventricular beats
Pericarditis
Early depolarization
LVH
> S wave depth in V1 + tallest R wave in V5-V6 = >35mm
aVL R wave >11mm
aVF R wave >20mm
Benign Early Repolarization(BER)
Normal
STE
Tall T waves
Often seen in Inferior/Lat leads
Males 20-40 yo and African American
ST segment “fish hook” sign
Patho Left axis deviation
LVH
Left Anterior hemi block
LBBB
Inferior MI
Paced
Causes of Right axis deviation
RVH/COPD
PE
TCA OD
Lat wall MI
Left posterior hemiblock
SCB with bifasicular block?
No!!! No Amio, Lido, or Procainimide to runs of Vtach with a bifasicular block!! You will kill the patient
Wellens Syndrome type 1 and 2
> Type 1
Biphasic T waves in V2-V3(deep symmetric)
Common in Anterior but could be in any precordial lead
Can be pain free
No STE!
Type 2
Negative(inverted) symmetric T wave
**75% had LAD that will lead to AMI within weeks
aVR diagnostic
Anterior depression, aVR STE > STE V1 = left main insufficiency and 3 vessel disease process
Sgarbossa Criteria(LBBB)
Concordant STE >1mm = 5
STD >1mm in V1-V3 = 3
Discordant STE >5mm =2
DeWinters T waves
Tall T waves
Upsloping STD >1mm
Absence of STE in precordial leads
STE 0.5-1mm in aVR
Normal ST morphology
Slow Vtach Tx
QRS duration >200ms or 0.20?
It’s hyper K
Killer drugs- CCB Na+ blockers
**Tx with Calcium and Bicarb
Brugada syndrome
Seen in Asians and young males 20-30 yo
Sodium channel issue
Normal QT
Painless
Ventricular arrhythmias. Biphasic T wave in V1-V2
S/S: dizzy, syncope, SOB, palpitations, young person sudden cardiac arrest
FP-C pharm Qs
Will be solely based on the following:
>Generic vs Trade name
>use and indication
>mech of action
>contraindication
*doses will be pretty standard, nothing out the normal
Agonist vs antagonists
> Agonist: activate receptors
Antagonists: block receptors from being activated
Beta Blockers(BB)
-lol drugs
>Antagonists of the beta receptors in the heart and lungs
>cause decreased Ino/Chromo/Dromo effects on the heart(good); bronchospams in the lungs(bad)
Esmolol
Action: (BB) Selectively antagonizes Beta-1 adrenergic receptors
> Rapid onset and short acting
>decreases force, rate, and BP
Indications: SVT and uncontrolled HTN
Precautions: Asthma/bronchospasm, hypersensitivity, bradycardia, AV blocks, CHF, and Cardiogenic shock
*seen with aneurysm patients
Dose: 500mcg/kg/min
Labetalol
Action: (BB) anti-HTN w/ selective Alpha-1 and non-selective beta-antagonist effects.
Indications:patients with HTN issues(head bleed)
Precautions: Bronchial asthma, cardiogenic shock, >1st degree heart block, severe bradycardia
Dose: 10-20mg slow IVP q 10min max of 300mg
Calcium channel blockers(CCB)
-pine drugs
>acts by blocking Ca++ influx into vascular smooth muscle casuing relaxation especially in the coronary arteries
>negative dromo, slows impulses through SA and AV nodes, and casues vasodilation.
Nicardipine(Cardene)
Action: (CCB) Relaxes cardiac, smooth, and vascular muscle cells
Indications: HTN
Precautions/contraindications: Pregnancy, CHF, advanced aortic stenosis, and hypersensitivity
Dose: 5mg/hr
*Nicardipine(Cardene) preferred prehospital drug
Vasopressors and Inotropes
Vasopressor causes vasoconstriction
Inotropes increase force of contraction
Meds: Dopamine, Epi, Norepi, Dobutamine, Phenylephrine(Neosynephrine), Vasopressin, and Methylene Blue
Norepinephrine(Levophed)
Gold standard vasopressor
Action: stimulates alpha adrenergic receptors resulting in vasocontrictions, increased peripheral vascular resistance, increase in BP.
Indications: Vasogenic shock with tachycardia, sepsis, and neurogenic shock
Dose: 2-12mcg/min and titrate to effect. Peds- 0.1mcg/kg/min titrate to effect.
Dopamine(Intropin)
Alpha/Beta (5-10mcg/kg/min)
mixed stimulation
increased CO, contractility, BP, HR
Loss of renal action
*5-10mcg/kg/min is the theraputic range
Inodilators(Dobutamine and Milrinone)
Sympathomimetic(adrenergic) agents
Action: stimulation of beta-1 receptors, higher ino than chrono, increase contractility, and vasodilation
Indications: actue LV failure, pulmonary vasocontriction, high pulmonary vascular constriction, and low Q states-low perfusion states
Dobutamine
synthetic catecholamine with beta-1 effects
some beta-2 as well causing vasodilation
use caution with hypotensive patients(borderline)
Dose: 2-20mcg/kg/min
*always fill the tank first. If they are not volume responsive, go with Levo instead
Milrinone
like Viagra
Action: increases contractitility and stroke volume
Indications: Ischemic and non-ischemic cardiomyopathy, CHF, and Pulmonary HTN
Precautions: Hypersensitivity, hypertrophic cardiomyopathy, WPW or other bypass tracts
Dose: Adult and peds- 0.25mcg/kg/min max of 1mcg/kg/min
Vasopressors
Phenylephrine(neosynephrine), Vasopressin, Methylene Blue
sympathomimetic (adrenergic) agents
Action: stimulate Alpha-1 & Alpha-2 receptors
>increase vasoconstriction
>low beta properties
Indications: Neurogenic shock, push dose pressors, vasogenic shock states, refractory septic shock
Phenylephrine(Neosynephrine)
Action: stimulates alpha, causes increased BP without tachycardia, and increases aortic root pressure and coronary artey perfusion pressure
Indications: Vasogenic shock with tachycardia, sepsis, neurogenic shock
Dose: 10-100mcg/min and maintenance 40-60mcg/min
Vasopressin
**2nd line drug
Action: releases catecholamine receptors
Indications: Vasodilatory shock/septic shock
Dose: Sepsis-0.01-0.04units/min. Upper GI Blled- 0.5units/min
Good for patients with norepi refractory hypotension
Methylene Blue
Action: Nitric oxide inhibitor. Combats vasodilation from nitric oxide release 2ndary to pro-inflammatory mediator release
Indications: Vasodilatory shock/Septic shock
Dose: 1.5-2mg/kg over 20min-1hr
*decreases the need for other vasopressors or allow for lower vasopressor dosing. NOT SEEN IN PRE-HOSPITAL SETTING
Hydralazine
Vasodilator/ HTN emergencies
Action: dilates arterial system and decreases afterload
Indications: PIH(pregnancy induced HTN) and HTN
Dose: 5-10mg IV max of 40mg
**WATCH OUT- drops both systolic and diastolic pressure
Nitroglycerin
Action: Dilates venous system and arterial system at higher doses, decreases preload and afterload, relieves vasospasm, improves blood flow and myocardial O2 consumption
Indications: Angina, MI, acute LV failure, coronary artery spasm
Dose: 5-20mcg/min(or 5-200mcg/min)
Nitroprusside
Action: relaxes vascular smooth muscle, dilates arterial/venous system, and decreases aferload/preload.
Indications: HTN(hemorrhagic stroke), acute LV failure, cardiogenic shock, acute aortic dissections
Precautions: Pregnancy(cyanide toxicity)
Dose: Adult and ped- 0.5-10mcg/kg/min titrate to effect
Heparin
Action: decreases the ability for the body to form blood clots
Indications: any condition caused by a clot(DVT, ACS, CVA, PE, MI)
Precautions: recent major surgery, ulcer, GI bleed Hx or renal dysfunction
Dose: 60-80units/kg followed by infusion of 15-18units/kg/hr
Alteplase(Activase, t-PA)
Action: desolves formed blood clots
Indications: Ischemic stroke, STEMI, PE
Dose: Stroke- 0.9mg/kg over 1hr max 90mg
STEMI <67kg- 15mg over 1-2min max total 100mg
STEMI >67kg- same as above by all 100mg infused over 1.5 hrs
PE- 100mg over 2 hrs
