Chapter 7 - Cardiovascular Drugs Flashcards
What is a syncytium?
an interconnected mass formed from cardiac cells, intercalated disks, and a fusion of cell membranes.
what happens during depolarization?
rapid influx of sodium, slower influx of calcium, outflow of potassium.
What is the importance of a long refractory period?
prevents a constant state of contraction for cardiac cells.
What are chronotropic and inotropic effects in the heart?
Chronotropic - rate of contraction, inotropic - force/strength of contraction.
what is preload vs afterload?
preload - volume of blood in ventricles at the end of diastole (amount of blood that must be pumped out)
afterload - resistance in the arteries that the ventricle must overcome to pump blood.
What are the four basic compensatory mechanisms of the cardio system?
- increase heartrate
- increase stroke volume
- increase efficiency of heart muscle.
- heart enlargement.
5 objectives of treatment for heart failure
- control rhythm disturbances
- maintain or increase cardiac output
- relieve fluid accumulations
- increase oxygenation of blood.
- provide oxygen/sedatives.
4 beneficial effects and one potential toxic effect of glycosides.
beneficial:
- improved cardiac contracility
- decreased heart rate
- antiarrhythmic effect
- decreased signs of dyspnea
Toxic: vomiting
catecholamines (ie epinephrine) are used primarily for:
stimulation of cardiac contraction during arrest.
five risk factors for arrhythmias:
- conditions that cause hypoxia.
- electrolye imbalances
- increased levels or sensitivity to catecholamines
- certain drugs such as digitalis and barbiturates
- cardiac trauma or disease.
6 categories of antiarrhythmic drugs and an example of each
- class 1A (ie quinidine)
- class 1B (ie lidocaine)
- class 1C (Ie flecainide)
- Class 2 (ie propranolol)
- Class 3 (ie Bretylium)
- Class 4 (ie diltiazem)
List 4 vasodilator drugs and classify each as arteriolar dilator, venodilator, or both.
- hydralazine - arteriolar
- nitroglycerin - venodilator
- prazosin - combined
- enalapril - combined
Why is lasix sometimes called a loop diuretic?
It inhibits reabsorption of sodium in the loops of henle
What is the risk of using many diuretics?
A dangerous loss of potassium
5 ancillary methods of treatment for cardio disease
- Bronchodilation
- Oxygen therapy
- Sedation
- Aspiration
- Centesis
What is cardiac output?
The amount of blood that the heart is capable of pumping per minute.
____ is when the pumping ability of the heart is impaired to where sodium and water are retained in an effort to compensate for inadequate cardiac output
Congestive heart failure.
ACE causes conversion of _____ to ____
Angiotensin 1 to angiotensin 2
What 5 precautions should be taken when applying nitroglycerin?
- wear gloves
- rotate application sites
- do not pet at application site
- measure dosage in inches
- contact vet if rash appears
What diuretic is used most commonly to treat heart failure?
Lasix
Hypokalemia
Abnormally low potassium in blood
What are the primary goals of the dietary management of heart disease?
1) sodium restriction
2) maintenance of good body condition
3 effects of administration of catecholamines
1) increased force of contraction
2) increase in blood pressure
3) elevated blood glucose levels
____ is a faster-than-normal heart rate
Tachycardia
what occurs due to abnormalities of the conduction system?
arrhythmia
what are 3 things associated with congestive heart failure?
exercise intolerance, pulmonary edema, ascites.
What kind of drug is digitalis?
cardiac glycoside
Quinidine doses must be ___ in patients being treated with digoxin.
Decreased
concurrent use of nonsteroidal antiinflammatories may ___ the effectiveness of captopril
Decrease
What is one potential side effect of furosemide?
Hypokalemia
