-
P-wave
produced as impulse from SA node and causes atrial contraction
-
P-R interval
time between atrial depolarization and the start of ventricular conduction (depolarization)
-
QRS complex
conduction of impulse through the bundle of HIS to Perkinje fibers causing contraction of ventricles
-
S-T segment
heart's resting period
-
T-wave
ventricular repolarization
-
-
inotropic
force of contraction
-
dromotropic
heart rhythm (conduction)
-
preload
volume of blood in ventricles at end of diastole (end-diastolic pressure)
-
preload increased in:
- hypervolemia
- regurgitation of cardiac valves
-
afterload
resistance left ventricle must overcome to circulate blood
-
afterload increased in:
- hypertension
- vasoconstriction
-
increased afterload =
increased cardiac workload
-
ACE inhibitors
- angiotensin-converting enzyme inhibitors
- ends in -pril
-
ACE inhibitor meds
- captopril (Capoten)
- enalapril (Vasotec)
- benzapril (Lotensin)
-
ACE inhibitor action
- blocks ACE from converting angiotensin I to angiotensin II, leading to decrease in BP and aldosterone production, and small increase in serum potassium levels with sodium and fluid loss
- decreases peripheral vascular resistance without increased cardiac output, rate, or contractility
-
ACE inhibitor effects
- hacking cough
- dizziness
- orthostatic hypotension
- GI distress
-
ACE contraindications
- allergies
- impaired renal function
- pregnancy/lactation
-
ACE cautions
heart failure
-
ACE nursing responsibilities
- assess BP prior to administration (hold for BP 90-100/60)
- administer on empty stomach 1 hour before or 2 hours after meals
-
ARB (angiotensin II receptor blockers) action
- blocks binding of angiotensin II to specific tissue receptors
- blocks vasoconstriction and release of aldosterone
-
ARB nursing considerations
- take with food
- watch for syncope, cough, alopecia
- discontinue if pregnant/lactation
-
ARB effects
dizziness, headache, diarrhea, URI, cough, fever, muscle weakness, hypotension
-
beta-blocker meds
- end in -lol (haha, I blocked you)
- propranolol (Inderal)
- atenolol (Tenormin)
- metoprolol (Lopressor)
-
beta-blocker action
blocks beta receptors in the heart causing decreased heart rate, force of contraction, and rate of A-V conduction
-
beta-blocker effects
- bradycardia
- lethargy
- GI disturbances
- CHF
- decreased BP
- depression
-
beta-1 blockers affect:
heart (1 heart)
-
beta-2 blockers affect:
lungs (2 lungs)
-
beta-blocker mneumonic
- B - Bronchospasms - do not give to patients with bronchoconstrictive disease
- E - Elicits decrease in cardiac output and contractility
- T - Treats hypertension
- A - AV conduction decreases - treats arrhythmias
-
can you discontinue beta-blockers abruptly?
NO - causes rebound angina, confusion in elderly and psychosis
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