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25 Cards in this Set
- Front
- Back
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cardiac output |
-amount of blood the heart is capable of pumping per minute -stroke volume x beats per minute |
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preload stroke volume |
quantity of blood filling the chambers during diastole |
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afterload stroke volume |
arterial resistance the heart must pump aginst |
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inotrope |
affects the strength of the heart contraction |
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chronotrope |
-affects the rate of heart beat -positive increase heart rate |
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in what ways can cardiac drugs affect the system |
-chronotrope -inotrope -stroke volume -cardiac output |
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compensatory factors that occur in heart failure are |
-heart beats faster -increase stroke volume (beats harder) -increase efficiency of heart muscle -enlarge the heart (becoming stronger) |
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stroke volume |
-the amount of blood the heart pumps forward -affected by preload and afterload |
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preload |
quantity of blood filling the chambers during diastole |
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afterload |
-arterial resistance the heart must pump against -increase in pulmonic and aortic stenosis |
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cardiac output |
-the amount of blood the heart is capable of pumping per minute -stroke volume x beats per minute |
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ways in which therapies can maintain or increase cardiac output |
-increase strength of contraction -decrease afterload: arterial dilator -decrease preload: venous dilator -reliever fluid accumulation -diuretics/ACE inhibitors -salt restriction - decrease osmotic pressure |
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what are the goals of cardiac therapy |
-control rhythm disturbances -maintain or increase cardiac output -increase oxygenation of blood -ancillary treatments |
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what types of drugs can be used to increase oxygenaiton of blood |
bronchodilators |
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what are some ancillary treatments for heart diseases (and when are they used) |
-narcotics/sedatives: come into play when animals are in end stage heart failure -oxygen: not long term for animals -aspirin: especially for hypertrophic cardiomyopathy in cats |
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refractory |
unresponsive to treatment |
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refractory time |
time between systole and diastole when the heart cannot contract because it is waiting for repolarization |
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what is the goal of using a positive inotrope and when are they used |
-to improve the strength of contraction -as a last resort in late stage 3 or stage 4 cardiac disease |
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what effects do positive inotropes have on the body |
-improve the strength of contraction -improve stroke volume -delay Na/K pump it delays contraction time and slow heart rate, increasing the level of calcium ions available and reduce action Na/K pump, slowing membrane potential |
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examples of positive inotropes |
-cardiac glycosides (digitalis/digoxin) -catecholamines (epinephrine, dopamine, dobutamine, isoproteranol) -pimobendan |
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what is the most commonly used positive inotrope |
-cardiac glycosides: digitalis/digoxin |
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what effects do cardiac glycosides (digitalis/digoxin) have on the body |
-positive inotrope -increase strength of contraction -decreases heart rate -stabilizes heart rhythm -decreases dyspnea |
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what is dopamine |
-positive inotrope -sympathetic precursor to norepinephrine |
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what is dopamine used for |
-acute heart failure -oliguric renal failure -shock |
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side effects of dopamine |
-vomiting -tachycardia -dyspnea -blood pressure abnormalities |
