chapter 24- pharm of cardiac contractility

Question 1

what is the mechanism of action of digoxin and digitoxin in the myocardium

Answer 1

inhibit plasma membrane Na+/K+ ATPase, leading to increased cytoplasmic Ca++ concentration, which results in positive inotropy

Question 2

what is the mechanism of action of digoxin and digitoxin in ANS

Answer 2

inhibit sympathetic outflow and increase parasympathetic (vagal) tone

Question 3

what is the mechanism of action of digoxin and digitoxin at AV node

Answer 3

prolong effective refractory period and slow conductive velocity

Question 4

what drug is used to as symptomatic treatment of chronic systolic heart failure

Answer 4

digoxin

Question 5

what are the serious heart side effects with digoxin/digitoxin

Answer 5

arrhythmias (PVCs), heart blocks

Question 6

what are the major vision change side effects with digoxin

Answer 6

blurred vision, yellow-green halo around visual images

Question 7

what are the contraindications of digoxin/digitoxin

Answer 7

ventricular fibrillation; ventricular tachycardia

Question 8

what is the major thing that alters digoxin levels

Answer 8

chronic kidney disease

Question 9

when is digitoxin used over digoxin

Answer 9

when there is renal failure

Question 10

who should digoxin immune fab be used with caution in

Answer 10

patients allergic to ovine proteins

Question 11

what is given to treat digoxin toxicity

Answer 11

digoxin immune Fab

Question 12

what is digoxin derived from

Answer 12

fox glove plant

Question 13

what are some side effects with dopamine use

Answer 13

widening of QRS complex, cardiac arrhythmias, hypo/hypertension

Question 14

what are the contraindications for dopamine use

Answer 14

pheochromocytoma, uncorrected tachyarrhythmias, ventricular fibrillation

Question 15

what receptors do lose doses of dopamine stimulate

Answer 15

dopaminergic D1 receptors in renal and mesenteric vascular beds

Question 16

what do intermediate doses of dopamine stimulate

Answer 16

Beta2 receptors and increased contractility and heart rate via activation of beta1 receptors

Question 17

what do high doses of dopamine stimulate

Answer 17

cause generalized vasoconstriction via stimulation of alpha1- receptors

Question 18

what drug is used for short-term treatment of cardiac decompensation secondary to depressed contractility (cardiogenic shock)

Answer 18

dobutamine

Question 19

what is the contraindication of dobutamine

Answer 19

idiopathic hypertrophic sub aortic stenosis

Question 20

what can high doses of epinephrine cause

Answer 20

tachycardia and life-threatening ventricular arrhythmias

Question 21

what beta adrenergic agonist can be used for cardiac resuscitation

Answer 21

epinephrine

Question 22

what IV drug can be used for emergency treatment of arrhythmias

Answer 22

isoproterenol

Question 23

what are the contraindications of isoproterenol use

Answer 23

tachycardia caused by digitalis intoxication; angina pectoris; active coronary artery disease

Question 24

what does milrinon inhibit

Answer 24

phosphodiesterase

Question 25

what drug used in co-administration with milrinone cause hypotension

Answer 25

disopyramide

Question 26

what is long-term use of PDE inhibitors linked to

Answer 26

increased mortality

Question 27

what is the mechanism of action of levosimendan

Answer 27

enhances sensitivity of troponin C to calcium, which increases the extent of actin-myosin interactions without a substantial increase in myocardial oxygen consumption

Question 28

what does the EKG look like with side effect of digoxin

Answer 28

scooped concave ST segments

Question 29

what are side effects of digoxin immune fab

Answer 29

heart failure, anaphylaxis

Question 30

what is heart failure most commonly caused by

Answer 30

systolic dysfunction of the LV

Question 31

what are cardiac glycosides

Answer 31

positive ionotropes= agents that increase contractile force of cardiac myocytes

Question 32

what is the definition of preload

Answer 32

intraventricular blood volume