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N306 Patho/Pharm
Cardiac Dysrhythmias and Rx
40
Nursing
Undergraduate 3
11/14/2009

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Cards

Term
What are the 4 ways to characterize dysrhythmias?
Definition
1. too slow
2. too fast
3. inappropriate extra beats
4. complete disorganization or dissociation
Term
What happens when the heart beats too slow (bradycardia)?
Definition
*Sinus bradycardia
*Blockade of conduction (AV blocks) = slows conduction from atria to ventricles
*First, second, third degree blocks = 3rd is medical emergency (tx c Atropine)
Term
What happens when the heart beats too fast (tachycardia)?
Definition
*Sinus tachycardia
*Impulse originates above ventricles
Term
What is Atrial fibrillation (A-fib)?
Definition
*Disorganized electrical activity in the atria
*Poor ventricular filling
*Risk of thrombus
*Ventricular response variable
Term
What happens with inappropriate extra beats?
Definition
*Abnormal cardiac impulses which arise superimposed on an underlying rhythm
Term
What is ventricular fibrillation (V-fib)?
Definition
*Complete disorganization or dissociation
*No effective CO = no pulse
*Cardiovascular collapse
*Most "treatable" form of CA
*Tx = electricity
Term
What does enhancing or blocking ion flow do?
Definition
*Changes conduction and muscle cell function in the heart
Term
What are the 4 classes of Rxs used to treat dysrhythmias?
Definition
Class I: Sodium Channel Blockers= dec conduction velocity (Qinidine, Lidocaine)
Class II: Beta Blockers (metoprolol)
Class III: Potassium Channel Blockers = delay depolarization (Amiodarone)
Class IV: Calcium Channel Blockers (diltazem)
Term
What are some other drugs used to treat dysrhythmias?
Definition
*Adenosine for SVT = dec automaticity; slows AV conduc; extremely short 1/2life
*Digoxin = esp. for A-fib = dec AV conduc
*For bradycardia: Artopine, Isoproterenol
Term
What is special about Quinidine?
Definition
*Dec conduction velocity
*Potent effect on Dig levels
*More powerful ppb & bumps Dig off
Term
What is a major ADR of all anti-dysrhythmics?
Definition
*All can worsen existing dysrhythmias or create new ones
Term
How is Cardiac Output calculated?
Definition
Heart rate x stroke volume = CO
Term
What is stroke volume? What is it effected by?
Definition
*Quantity of blood pumped out with each cardiac contraction = ejection fraction
*Effected by: blood entering heart (preload), force of contraction, force against which heart must pump (afterload)
Term
How can the body maintain adequate CO?
Definition
*Increase heart rate = inc preload & retain Na & H2O in kidneys
*Increase stroke volume = fluid retention, preload, or hypertrophy
Term
What is Angina? What causes myocardial ischemia?
Definition
*Chest pain cause by myocardial ischemia
*Workload exceeds oxygen supply
Term
When are the coronary arteries perfused?
Definition
*During Diastole
Term
What are the three types of Angina?
Definition
1. Stable angina = exertional d/t CAD & partial occlusion
2. Prinzmental's angina = spasm of coronary arteries; may occur @ rest
3. Unstable angina = CAD complicated by vasospasm, aggregation, trombi or emboli
Term
What is acute myocardial infarction?
Definition
*Cardiac tissue death = loss of blood supply or oxygen = not functional in conduction elect
Term
What is acute coronary syndrome?
Definition
*A continuum or spectrum of conditions jeopardizing myocardial oxygen supply
*Progresses from UA to AMI
Term
What three drugs are used to treat angina?
Definition
1. Beta-blockers = stable angina, not vaiant
2. Ca-Channel blockers = Stable, variant or unstable angina
3. Organic nitrates
Term
What do beta-blockers do for angina?
Definition
*Dec O2 demand by dec contractility, HR, CO
*Longer diastole = improved coronary O2 supply
Term
What do Ca-Channel Blockers do for angina?
Definition
*Peripheral vasodilation lowers preload/afterload
*Dec HR, slows AV conduc, dec O2 demand
Term
What do organic nitrates do for angina?
Definition
*Promote vasodilation in VEINS
*Reduces preload & O2 demand
Term
How can Organic Nitrates be administered? What is a common side effect? What must be monitored?
Definition
*PO sublingual or spray = terminate acute angina = usually dosed 3x
*Long acting PO = Isosorbide = not for acute attack = first pass
*Patch = slow onset
*Ointment = faster acting than patch
*IV
*Headache common c PO
*MONITOR BP
Term
What are the ADRs of organic nitrates?
Definition
*HypoTN = intesifies other HypoTN drugs
*Reflex tachycardia
*Pounding headache; facial flushing
*N/V
*Life-threatening hypoTN c Viagra
*Rapid tolerance development
Term
What surgical interventions can be done for ACS?
Definition
*Coronary artery bypass graft (CABG)
*Percutaneous Coronary Intervention (PCI) = stent placement
Term
What is heart failure? What causes it?
Definition
*Heart is unable to pump sufficient blood to meet metabolic needs of tissues
*Chronic HTN, MI, Valvular dysfunction, congenital abnormality, aging tissue
Term
What are compensatory mechanisms for chronic increased cardiac demands?
Definition
*Starlings law = inc stretch of myocradium = inc FOC
*Hypertrophy of myocardium = inc FOC
*Fluid retention = inc preload
*Symp NS = inc rate & FOC & vasoconstric
*Cardiac remodeling
Term
What does left ventricular failure cause?
Definition
*Pulmonary congestion
*Dyspnea
*Cough
Term
What does right ventricular failure cause?
Definition
Peripheral edema
Term
S/S of heart failure?
Definition
*Cardiac enlargement
*Elevated BNP = proteins released by myocard r/t stress
*Inadequate tissue perfusion = fatigue, dyspnia, end organ damage
*Volume overload = edema, crackles, JVD
Term
Tx for heart failure?
Definition
*Valve repair
*Cardiac repair/re-vascularizaiton (exercise)
*Control HTN
*Limit Na intake
*Lifestyle modification
*Rx
Term
What drugs are used to treat HF?
Definition
*Diuretics
*Selected Beta-blockers
*ACE Inhibs/ARBS
*Inotropic agents = gympathomimetic, cardiac glycosides
Term
How do diuretics work for HF?
Definition
*Reduce fluid overload
*Risks: HypoTN, hypokalemia
Term
How do Beta-blockers work for HF?
Definition
*diminishes cardiac contractility
*contraindicated c asthma
Term
How do ACE Inhibitors/ARBS work for HF?
Definition
*ACE Inhib: decreased cardiac remodeling. ADR = cough
*ARBs: same as above
*Aldosterone inhibitors = prevents fluid retention
Term
How does Digoxin work for HF (Cardiac Glycoside)?
Definition
*Increases contractility
*Lowers HR s elevating O2 requirements
*Positive inotrope (inc force)
*Negative chronotrope (dec rate)
*High doses: dec AV conduc = helps c atrial flutter/fib
Term
ADRs of Digoxin?
Definition
*Dysrhythmias (brady or heart block)
*N/V/D, anorexia
*Fatigue, HA
*Hypokalemia
Term
What drugs does Digoxin interact with?
Definition
*MANY
*Diuretics
*Other anti-arrhythmics
*ACE inhib & ARBs
Term
What precautions must be taken with Digoxin?
Definition
*Loading dose then daily maintenance
*Very narrow therapeutic range
*Dig levels drawn as indicated
*S/S toxicity = abd pain, N/V, bradycardia
*Know elyts
*Apical pulse one minute prior to admin if less than 60 don't give
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