Heart Failure and Cardiomyopathies Flashcards
resistance heart must overcome to push blood out; McDonald’s straw vs a coffee stirring straw
afterload
amount of myocardial elasticity
contractility
filling pressure of the heart, the more the fill and stretch, the harder the subsequent contraction; think preparatory dip
preload
net equilibrium between filtration and reabsorption
Starling’s law of capillaries
name three drug classes that decrease HR, thus decreasing CO
- Beta-blockers
- CCBs
3 Digoxin
Name three factors that decrease HR
- PNS (vagal stim)
- conduction abnormalities
- Drug effects
Name three drugs that increase HR
- Caffeine
- Cocaine
- Other sympathomimetics
Name three factors that increase HR
- SNS stimulation
- Hypovolemia
- Drug effects
Name the 7 factors the decrease preload, thus decreasing stroke volume
- hypovolemia
- excessive vasodilation
- increased intrathoracic pressure
- cardiac tamponade
- RV infarction/failure
- Tachyarrhythmias
- Loss of atrial “kick”
Name three factors that increase preload, thus increasing stroke volume
- heart failure
- hypervolemia
- bradydysrhythmias
resistance the heart must overcome to push blood out; McDonald’s straw vs coffee stirring straw
Afterload
Name the four drug classes that decrease afterload (McDonald’s straw)
- CCB
- Nitrates
- Alpha blockers
- Vasodilators
Why do calcium channel blockers decrease afterload
by causing vasodilation of the arterial vascular beds; make the straw bigger
Why do nitrates decrease afterload and preload?
dilate vascular smooth muscle, coronary vessels, and peripheral veins, all which lower myocardial oxygen consumption; make the straw bigger
Why do Alpha-blockers decrease afterload?
vasodilate blood vessels; make the straw bigger
Why do beta-blockers decrease HR?
inhibit beta 1 receptors, which affect the heart rate
Why do calcium channel blockers decrease HR?
prevent Ca2+ from entering the myocardial cells = decreases muscle contraction and force
Why does digoxin decrease HR?
reduces the # of electrical impulses that pass through the AV node
Name five factors that increase afterload, thus decreasing SV; coffee stirring straw
- vasoconstriction from SNS or vasopressin
- hypertension
- aortic valve stenosis
- hypercoagulability
- Pulmonary hypertension