Test 1 Flashcards
What is the formula for CPP?
CPP= DBP-LVEDP
What is coronary perfusion pressure (CPP)?
A part of normal blood pressure that is specifically responsible for coronary blood flow… Important during Cardiac arrest for achieving ROSC.
If you have a BP of 95/50, HR 80, and LVEDP of 9….. What is the CPP?
50-9= 41mmHg
What ion is responsible for the negative action potential, or phase 4 in the myocardial action potential?
K+
Describe what happens in phase 0 of the myocardial action potential.
Na+ rushes into the cell causing depolarization.
During phase 1 of the myocardial action potential, K+ and Cl- move out of the cell in response to the inward movement of Na+. What causes the prolonged depolarization in phase 2?
Ca+ moving into the cell…. Prolonged the contraction. It is moving out of the sarcoplasmic reticulum.
Does K+ move into or out of the cell during phase 3 of the myocardial action potential?
Moves into the cell to repolarize to the negative resting membrane potential.
What drugs increase inotropic effects of the heart by increasing the concentration of Ca++ in myocardial cytosol?
Milrinone, digoxin, and epinephrine.
What type of patient is Milrinone typically used for?
Heart failure. Increases heart contractility and is a phosphodiasterase 3 inhibitor. Phosphodiasterase breakdown cAMP which contracts the heart.
What effect does Milrinone have on after load?
It vasodilates vessels which help to alleviate increased pressures (afterload) on the heart.
What effect does digoxin have on the conduction system of the heart and ultimately chronotropy?
Treats pts with afib, aflutter with RVR. Slows conduction in AV node, which increases the refractory period and reduces ventricular rate.
What is the MOA of digoxin?
Decreases the Na+ concentration gradient and subsequent Ca+ outflow, which increases Ca+ concentrations in the cells.
What drugs increase the chance of digoxin toxicity due to increased plasma levels?
Quinidine, verapamil, and amiodarone
What effect does epinephrine have on the airway and on arterioles?
High levels cause smooth muscle relaxation in airways but contraction of smooth muscle that lines most arterioles.
What is the MOA for CCBs and during what phase of the myocardial action potential do they work?
Provides negative chronotropic effects on nodal tissue during phase 4 (non-dihydropyrodines) by disrupting movement of calcium through calcium channels.
Non-Dihydropyrodines are used for what purpose?
decreases blood pressure and used to decrease HR to prevent cerebral vasospasm. blocks V6CCs in cardiac muscle leading to reduction in muscle contraction. Less contraction of vascular smooth muscle and therefore increase in arterial diameter= vasodilation
What makes up your BP?
CO and peripheral vascular resistance
What are beta blockers sometimes used as an adjunct to CCBs?
when BP decreases there can be a sympathetic reflex increase in HR and contractility….. which a beta blocker will help control.