Mod 4 Flashcards
Inotropic
An agent that increase the force of muscular contracture.
Dromotropic
Affecting the conductivity of nerve or muscle fibers
Chronotropic
Influencing the rate of occurrence of an event such as the heart beat.
Cardiac output
the amount of blood pumped from the heart in 1 minute. (S/V x H/R= CO)
Stroke volume
the amount of blood ejected by the left ventricle (oxygenated blood) with each contraction.
Preload
is volume of unoxygenated blood coming into the heart (rt atrium). Increased in hypervolemia and regurgitation of valves
Afterload
is the resistance in the arterial system against which the left ventricle must contract to get oxygenated blood out the body. It is increased in hypertension and vasoconstriction.
BNP Lab-b-type natriuretic peptide
elevated BNP levels are noted in heart failure. It is used to diagnose heart failure and grade the severity of heart failure
Cardiac Glycosides originate for what plant?
foxglove plant
How are Cardiac Glycosides given?
because of their long half life it take them days to reach therapeutic blood levels. So a loading or digitalizing dose is given, followed by maintenance doses.
How do Cardiac Glycosides work?
They make increased intracellular calcium available to the myocardium, thus an enhanced force of contraction. They stimulate the parasympathetic nervous system, increasing vagal tone and slowing the heart rate
- Positive Inotropic- increase the force of the cardiac contraction
- Negative dromotropic- slow or delays conduction of the heart.
- Negative chronotropic- deceleration of the rate of the heartbeat
If Cardiac Glycosides are re administered they are eliminated after how many half lives?
5 half lives
what are Cardiac Glycosides used to TX?
CHF, atrial fibrillation / flutter and paroxysmal atrial tachycardia. (PAT)
Digoxin ( Lanoxin, Lanoxicaps)
- commonly used; PO or IV
- not used IM - severe pain at site with increased CPK – complicating interpretation of enzyme levels. –Therapeutic serum concentration 0.5-2ng/ml.
- half life is 1.6 days, can’t wait 8 days to reach a steady state for life threatening arrthymias
what is the antidote for digoxin?
digibind- but because of high cost it is used only in life threatening situations. Hold dig, hydrate to flush out of body.
Digitoxin (Crystodigin)
used rarely because of long half life with prolongs duration of adverse effects; PO, therapeutic range is 14-26 ng/ml
what are the adverse effects of Cardiac Glycosides?
- they have a narrow therapeutic range and may produce digitalis toxicity.
- These conditions may predispose a client; hypokalemia
what are early S/S of digitalis toxicity?
visual changes (blue green vision), difficulty reading, GI complaints –N/V, anorexia, diarrhea, bradycardia, headache, malaise, confusion
what drug has a synergistic effect with digoxin?
Quinidine: will cause increased glycoside serum level
what are Bipyridine used to TX?
It is used for short term management of CHF in clients who haven’t responded well to digitalis, positive inotropic effects
Primacor
IV only, pos inotropic and vasodilator, decreases preload and afterload, increases myocardial contractility, increases CO and diastolic function, short term tx for CHF, ordered mcq/kg of body wt
nesiritide (Natrecor)
- formulation of BNP ( b-type natriuretic peptide)
- Elevated BNP levels are noted in HF
- Effects are to reduce preload and afterload which are beneficial in HF
what must the nurse do before giving a cardiac glycoside?
Take apical pulse before administering each cardiac glycoside dose: do not administer if pulse is less than 60.(not radial pulse).
when giving digoxin you will never give it how?
IM
What will the nurse need to monitor while giving a cardiac glycoside?
- -monitor dig levels- draw blood at least 8 hours after last oral dose and preferably immediately before administering daily maintenance dose.
- Monitor client’s blood urea nitrogen (BUN), potassium and creatinine.
- Measure client’s fluid intake and output and weight.
what dose the nurse want to teach a patient taking cardiac glycoside?
- Teach client to take pulse.
- Ensure that client is familiar with symptoms that should be reported immediately, especially sudden weight gain, edema, shortness of breath, nausea and vomiting, and visual disturbances.
- Advise client to prevent deterioration of inotropic agents by always storing medication in a tightly fitting, light- and moisture- resistant container.
- Instruct client to check with physician before taking any nonprescription drug, such as an antacid.
- Do not give Lanoxin with high fiber meals.
Dopamine
- Part of the sympathomimetics system, is -used to: treat shock, & CHF to increase CO.
- It is given IV.
- When administering monitor v/s at least q 15-30 min, especially bp & pulse.
- Systolic should be greater than 90.
- There should be an increase in urine output (assess hourly).
- It improves perfusion to vital organs. It is a vasodilation.
- -Monitor for extravasation & peripheral pulses 2-4 hour.
- Titrate off & monitor for decreased b/p.
- Never use a gravity drip & always used a dedicated line.
what is Antiarrhythmic agents (Antidysrhythmics) used to TX?
Used to treat abnormal electrical activity in the heart by limiting cardiac electrical activity to normal conduction pathways and decreasing abnormally rapid heart rates.
what electrolytes play a major role in myocardial contraction or depolarization?
NA, CA, and K
what does the normal conduction system of the heart consists of?
SA node, atrial pathways, the AV node, the bundle of His, the right and left bundle branches and the Purkinje fibers.
what four groups are Antiarrhythmic agents divided into?
- Group I - sodium channel blockers
- Class II - beta adrenergic blockers
- Class III - prolong cardiac repolarization
- Class IV - Calcium channel blockers
moricizine (Ethmozine) class I
- is a class I sodium channel blocker used to manage life threatening ventricular arrhythmias, such as sustained ventricular tachycardia.
- adverse reactions- the appearance of a proarrhythmia that occurs when another arrhythmia is present
what do class 1A NA Channel Blockers do?
- treat electrical activity abnormalities by blocking NA channels and slowing electrical conduction.
why are class 1A NA Channel Blockers prescribed?
to treat various atrial and ventricular arrhythmias. The drugs ( esp quinidine) are synergistic with digoxin.
Disopyramide ( Norpace) class 1A
) suppresses frequency of ectopic ventricular beats (even ventricular tachycardia); only po
Procainamide ( Procan SR, Pronestyl) Class 1A
suppresses frequency and duration of atrial and ventricular tachycardia, used to convert atrial fibrillation; po, IV.
Prototype: quinidine (Quinidex, Quinaglute) class 1A
after converting atrial fib to a regular rhythm, prevents recurrence, po
what are the adverse effects of class1A NA Channel Blockers?
Anticholingeric effects (3 D effects) and GI changes (diarrhea, anorexia, GI distress)
what is cinchonism?
quinidine overdose
what are the S/S of cinchonism?
- Tinnitus
- headache
- vertigo
- fever
- visual disturbances
- syncope.
what dose Class 1B lidocaine do?
used to treat ventricular arrhythmias, depress depolarization in myocardial cells.
prototype: Lidocain (Xylocaine) class 1B
ventricular arrhythmias; usually IV only; Mg/kg. Treats premature ventricular contractions. (PVC)
( can not be given po due to first pass)
What dose SAMS stand for?
Slurred speech
Altered CNS
Muscle Twitching
Seizures
Lidocaine Toxicity
how do you correct lidocaine toxicity?
Lowering dose or stopping drug reverses these reactions.
What do class 1C NA Channel Blockers do?
blocks sodium channels, depressing automaticity and slowing spontaneous depolarization
Propafenone ( Rythmol)
ventricular tachycardia
What are class 1C NA Channel Blockers used to TX?
used to treat life - threatening ventricular arrhythmias
What are the adverse effects of class 1C NA Channel Blockers?
Proarrhythmias - limit their use.
what do Class II Beta Blockers do?
block beta at the receptors and decrease sympathetic activity at SA and AV nodes. Negative inotropic effect decreasing myocardial 02 demand and may decrease myocardial ischemia
acebutolol ( Sectral)
po
What are the adverse effects of beta Blockers?
- bradycardia, ( will block the tachycardia associated with hypoglycemia) -hypotension
- exacerbate CHF
- bronchoconstriction
- bronchospasm
what do class III potassium blockers do?
prolong action potential of myocardial cells (repolarization), delaying depolarization, thus decreasing ventricular ectopic beats.
amiodarone ( Cordarone)
requires a loading dose; po or IV,
Used for V-FIB, will see used in CCU
adenosine (Adenocard)
injectable ( IV) agent, short acting used to convert PSVT (paroxysmal supraventricular tachycardia). ( asystole will occur first then converts to NSR)
remember: to have the crash cart they will flatline
what are the adverse affects of class III potassium blockers?
- tremor
- ataxia
- N/V (watch for aspiration)
what do Class IV Calcium channel blockers do?
decreasing force of myocardial contraction by blocking flow of calcium ions through cell membranes
what are Class IV Calcium channel blockers used to TX?
tx supraventricular arrhythmias with rapid ventricular response (RVR)
what is rapid ventricular response (RVR)?
it is when A-fib causes the ventricles to beat to fast to keep up with the atria
verapamil ( Calan, Isoptin)
used when vagal stimulation unsuccessful in treating paroxysmal supraventricular tachycardia (PSVT); IV, po.
what are the adverse effects of Class IV Calcium channel blockers?
-dizziness
-headache
-hypotension
- bradycardia
common side effecets: ankle edema, flushing, constipation
should you administer Quinidine with food?
no, May affect absorption
When adm any drug IV what should you monitor?
V/S closely and monitor EKG pattern for new arrhythmias. Have emergency equipment and oxygen available
what are signs of congestive heart failure?
- hypotension
- peripheral edema
- irregular heartbeat
- shortness of breath
- crackles
- jugular vein distention
why should you monitor electrolyte levels Esp K?
hypokalemia exacerbates arrhythmias
what should you teach a patient about taking Antiarrhythmic agents?
- Have clients weigh themselves daily and report a gain or loss of more than 2 – 3 lb per day or 5 lbs in one week.
- Teach clients the signs of hypokalemia and congestive heart failure
- Teach clients how to take a pulse, esp when taking beta blockers. HR over 50
- Teach diabetic clients that beta blockers will block tachycardia associated with hypoglycemia.
when does Angina occur?
when myocardial 02 demand exceeds 02 supply, areas become ischemic causing chest pain.
what are S/S of Angina?
- crushing sensation or feeling of pressure behind sternum
- may radiate to neck, jaw shoulders, down arms. -May confuse with indigestion, heartburn, or chest muscle strain.
Classic angina
stable or effort, occurs with exercise or stress,relieved by rest
Unstable angina
more severe, prior to MI – myocardial ischemia, unrelated to activity
Variant angina
pain occurs while at rest and resembles unstable angina, spasms of coronary arteries, usually occurs with coronary stenosis.
what are the classes of Antianginal agents?
- Nitrates
- Beta blockers
- Calcium channel blockers
