CV Module 1 Flashcards
(47 cards)
What is an action potential?
the change in voltage of the membrane potential that causes a cell to go from its negative resting state to a positive state for a very brief period of time
What causes an action potential?
Movements of potassium and sodium ions
What are the types of cardiac tissue?
Pacemaker - in the atria (nodal)
Contractile - in ventricles (non-nodal)
What is the 1st phase of action potential?
Phase 4 - inward movement of potassium, increased sodium permeability, return to baseline
When the cell remains at rest before the next depolarization
What is the 2nd phase of an action potential?
Phase 0 - sodium moves into the cell, rapid upstroke, fast depolarization
Rapid depolarization of the ventricle that send the voltage to make it posively charged
What is the 3rd phase of an action potential?
Phase 1- initial repolarization, sodium channels are inactivated, potassium channels up and close,, exit of potassium
Cell continues to lose potassium and chloride ions
What is the 4th phase of an action potential?
Phase 2 - Calcium channels open, slow influx of calcium, potassium continues to leak out, plateau phase
What is the 5th phase of an action potential?
Phase 3 - repolarization, calcium channels close, potassium channels open
Which action potentials have no resting potential, they are spontaneous action potentials?
Pacemaker action potential
What is Frank-Starling Law?
An increase in preload will result in an increase in cardiac output
Where are the main baroreceptors located?
Aortic arch and carotid sinuses
What are the three ion channels by which most of the antiarrhythmic drugs exert their action?
Potassium, sodium, calcium
What is the difference between cardiac preload and afterload?
Preload - blood in ventricle at the end of diastole
Afterload - force against with the heart must beat
What are the two major physiologic components that dictate arterial blood pressure?
Cardiac output
Arteriolar volume
How does norepinephrine impact blood pressure?
Norepinephrine binds to beta 1 receptors, stimulation of beta adrenoreceptors increases cardiac cell rate, contractility, and conductance
What organ regulates angiotensin and aldosterone?
Kidneys
When should HTN treatment be initiated?
BP is greater than or equal to 130/80
ASVCD risk needs to be assessed
What are the first line therapies for Stage 1 HTN?
Thiazide diuretic
CCB
Ace inhibitor or ARB
What are the second line therapies for Stage 2 HTN?
Two first line drugs from different classes
Try to use once daily dosing regiments and combo therapy rather than individual components
What is primary HTN?
It is HTN that cannot be attributed to anything specific. 90-95% of HTN
What is the only direct renin inhibitor?
Aliskiren
What should you avoid when prescribing medications for HTN?
Avoid combining drugs that have similar mechanism of action/clinical effects. Only exception is sometimes diuretics from various classes are combined for max effect
What are the medication recommendation for CKD stage 3-5?
ACE-I, ARB
What are the medication recommendations for post-stroke, TIA?
Ace-I/ARB, thiazide, or combo
