Transcript module h - Macomb

CARDIOVASCULAR
AGENTS
MODULE H
Objectives
• The student will be able to:
• Define inotropic and chronotropic.
• List those cathecholamines classified as Inotropic
Agents.
• State the formula for calculating blood pressure.
• Describe how cardiac output is determined.
• Describe how an increased or decreased systemic
vascular resistance will affect blood pressure.
• State the names and associated cardiac function of
each of the waves seen on a normal ECG tracing.
• List the two types of cardiac cells.
• Define tachycardia and bradycardia.
Objectives
• State the primary drug used treat a bradycardia.
• State the calcium channel blocker used to decrease
tachycardia.
• List the primary antiarrhythmic drugs covered in class.
• List the most common medication used to treat
ventricular ectopy.
• List the primary antihypotensive agents discussed in
class.
• Describe how the effects of dopamine are dosage
dependent.
• State a vascular agent that is used in a hypertensive
crisis.
• State the beta-blocker used to treat hypertension.
Objectives
• Describe why bronchodilators may lose effectiveness
when given to a patient on a beta-blocker therapy.
• Define angina.
• State the primary pharmacologic therapy used to treat
angina.
• Describe the pharmacologic action of nitrate therapy.
• List the cardiac glycosides and describe when they are
indicated in the clinical setting.
• Name two anticoagulants and an antidote for each.
• Name the three thrombolytics used to treat myocardial
infarctions, strokes and pulmonary embolism.
Definitions
• Inotropic: Agents that affect the force of
contraction.
• Positive: Increased force of contraction.
• Negative: Decreased force of contraction.
• Chronotropic: Agents that affect the rate of
contraction (heart rate).
• Positive: Increases heart rate.
• Negative: Decreases heart rate.
• Tachycardia: Heart rate greater than
100/min.
• Bradycardia: Heart rate less than 60/min.
Adrenergic and Cholinergic
Blood Pressure
• Blood Pressure = Cardiac Output x
Systemic Vascular Resistance
• Since Cardiac Output is equal to SV x HR,
BP = SV x HR x SVR
• Medications that regulate blood pressure:
• Increase/Decrease the stroke volume
• Increase/Decrease the heart rate
• Increase/Decrease the SVR
Cardiac Glycosides
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Derived from Foxglove plant.
Positive Inotropic Effect
Negative Chronotropic Effect
Used in the treatment of Congestive Heart
Failure (CHF)
• Cart vs. Horse
• Examples
• digitalis
• digoxin (Lanoxin)
• digitoxin
Cardiac Stimulants
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Positive Inotropic Effect
Positive Chronotropic Effect
Adrenergic Agents
Example
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epinephrine (First drug for all pulseless patients)
dobutamine (Dobutrex)
dopamine (Inotropin)
isoproterenol (Isuprel)
• Rarely used because of increased oxygen consumption.
Positive Chronotropic Agents
• Increase Heart Rate
• Usually no effect on force of contraction.
• Used to treat bradycardias and heart
blocks.
• Example
• Atropine Sulfate
Antihypertensive Agents
• Used to reduce blood pressure.
• Vasodilators
• hydralazine (Apresoline)
• nitroglycerine
• nitroprusside (Nipride)
• Beta Blockers
• propanolol (Inderal)
• verapamil (Calan, Isoptin)
• Can be problematic with patients with reactive
airways.
ACE Inhibitors
• Function by inhibiting the conversion of
Angiotensin I into Angiotensin II.
• ACE Inhibitors
• captopril (Capoten)
• benazepril (Lotensin)
• enalpril (Vasotec)
• Angiotensin II Receptor Blockers
• valsartan (Diovan)
• olmesartan medoxomil (Benicar)
Antihypotensive Agents
• Vasopressors
• Used to raise blood pressure during shock
states.
• Examples:
• Norepinephrine (Levophed)
• Dopamine (Intropin)
• Dopamine is dose dependent
• Low Dose (1-2 mg/kg/min): Vasodilatation
• Medium dose (2-10 mg/kg/min): Positive Inotropic Effect
• High dose (>10 mg/kg/min): Vasoconstrictor
Anti-anginal Agents
• Increase coronary blood flow.
• Coronary vasodilator.
• Used during anginal attacks.
• Angina: A heart condition marked by paroxysms of
chest pain due to reduced oxygen to the heart.
• Nitrates (nitroglycerin)
• Can cause an increase in methemoglobin.
• Beta Blockers
• propanolol (Inderal)
• Calcium-Channel Blockers
• verapamil (Isoptin, Calan)
Conduction System of the Heart
Ectopic Foci
• When an impulse originates from outside
the normal conduction pathway it is said to
be ectopic.
• These impulses arise at any time during
the conduction cycle.
• They are responsible for irregular heart
beats.
• They can arise from tissues in either the
atrial or ventricular wall.
Electrocardiogram (ECG)
• ECG Tracing
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P wave
P-R interval
QRS complex
ST segment
T wave
Antidysrhythmic Agents
• Drugs that suppress cardiac dysrhythmias.
• Example of dysrhythmia is a Premature Ventricular
Contraction (PVC).
• Examples:
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Lidocaine (Xylocaine)
Pronestyl (Procainamide)
Amiodarone (Cordarone)
Adenosine (Adenocard)
Verapamil (Calan)
• Side effects of these agents include hypotension
and conduction defects (heart blocks).
Anticoagulants
• Used to manage blood clots.
• Examples
• Heparin
• Warfarin (Coumadin)
• High risk of bleeding.
• Use with caution after prior-surgery.
• Increased risk of hemorrhagic stroke.
• Antidote:
• Heparin: Protamine Sulfate
• Warfarin: Vitamin K
Thrombolytic Enzymes
• Used to break up existing clots.
• Multiple generations with each being
“better” than the previous.
• Examples
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Alteplase (Activase) tPA
Reteplase (Retavase) tPA
Urokinase
Streptokinase