CardiacVascular Circulation

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Cardiac/Vascular Circulation

• Brenda Rowe, RN, MN, JD
• Georgia Baptist College of Nursing
• of Mercer University

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C.O. Stroke Vol. X Heart Rate

• Preload - passive stretching force exerted on
  ventricle muscle
• Contractility - force of the squeezing that the
  ventricle is able to achieve
• Afterload - amount of pressure the ventricle
  muscle must overcome to eject
• Contraction - dependent upon conduction system

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Cardiac Effects of Digoxin

• Positive inotropin effect strengthens the force
  of contraction
• Negative dromotropin effect decreases conduction
• Negative chronotropin effect decreases heart
  rate
• Improve renal perfusion

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Digoxin

• CHF, atrial fib
• digitalization
• toxic effects - NV, diarrhea, green/yellow
  vision, double vision, headache, dizziness,
  fatigue, weakness
• monitor effectiveness
• watch for hypokalemia
• education
• antidote - digoxin immune FAB

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Nursing Interventions

• Monitor HR - apical for 1 minute
• Monitor Dig level - 0.5-2.0 ng/ml
• Monitor K, Calcium, Mag - increase in calcium or
  decrease in K or Mag will potentiate the effect
  of Digoxin

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Other Cardiac Glycosides

• inamrinone (Inocor) milrinone (Primacor)
  increase force of contraction and produce a
  vasodilatory effect which increases cardiac
  output
• Used for short term management of CHF

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Critical Thinking Exercise

• A patient with CHF
• Is on Digoxin, Lasix, and potassium supplement
• What is the desired therapeutic effect?
• Why should hypokalemia be prevented?
• What blood work should be monitored?

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Nitroglycerin

• Relaxes vascular smooth muscles dilates
  arterial venous vessels thus reducing afterload
  myocardial consumption
• Acute angina sublingual, transmucosal, or
  translingual spray
• Prophylactic for angina above topical oral
  SR
• IV used to treat primarily hypertension

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Tolerance Adverse Effects

• Tolerance may develop
• Less likely in sublingual translingual spray
• Most common adverse effects headache, can have
  hypotension, tachycardia, syncope

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Anginal Episode

• Have a person lie down
• Give nitroglycerin tabs x 3, if needed, 5 minutes
  apart
• If no relief call 911

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Education

• Smoking causes vasoconstriction which may cause
  angina
• Sublingual keep in original bottle with tight
  cap
• Transdermal nonhairy area but avoid distal parts
  of extremities, remove patch for 10-12 hours

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Education (cont.)

• Increase absorption with broken skin, increase
  with exercise, increase temperature (avoid sauna)
• Ointment choose a different application site,
  use tissue to remove any old ointment, do not
  massage or rub in ointment

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Antiarrhythmics

• see after MI, cardiac surgery, CAD,
  electrolyte imbalance, thyroid disease
• abnormality with initiation of impulse or in
  impulse conduction or both
• should be monitored, most meds given IV,
  monitor AP (rate rhythm)

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Antiarrhythmic Agents

• Quinidine (Cardioquin) class 1A depresses Phase
  0 in depolarization
• depresses cardiac function, however inhibits
  vagal action so may have sinus tachycardia
• has high incidence of adverse effects with
  most common being GI
• monitor renal liver function

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Lidocaine

• Lidocaine (Xylocaine) - Class 1B depresses phase
  0 but not as much as Quinidine
• brief action so less chance of cumulative drug
  toxicity, make sure you have correct type of
  Lidocaine, tx ventricular arrhythmias
• give IV

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Antiarrhythmic Agents (cont.)

• Flecainide (Tambocor) - Class 1C markedly
  depresses phase 0, tx PAF or flutter
  ventricular arrhymias, suppress conduction, many
  adverse effects
• Propranolol (Inderal) - Class II depresses phase
  4 depolarization, beta adrenergic blocking agent,
  tx arrhythmias secondary to dig toxicity, also
  used to tx hypertension, angina MI

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amiodarone (Cordarone)

• Amiodarone (Cordarone) - Class III prolongs phase
  III repolarization
• increases refractory period, increases myocardial
  contractility, vasodilatory action
• used to prophylaxis and therapy of vent fib
• keep pt supine - most common AE is orthostatic
  hypotension

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Verapamil HCL (Calan)

• Class IV depresses phase 4 depolarization
  lengthens phase 1 2 of repolarization
• calcium channel blocker, decrease myocardial
  contraction, decrease SA node impulse, decrease
  conduction, also causes CA dilatation
  peripheral vasodilatation
• also used to tx angina
• watch for bradycardia hypotension
• AE - most common is constipation
• IV solution must be protected from light
• Administer slowly greater than 2 minutes

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Potassium-Removing Resins

• Sodium polystyrene sulfonate (Kayexalate)
• oral or enema
• AE - hypokalemia

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Antihyperlipidemics

• Definition
• HDL/LDL

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Statins

• lovastatin (Mevacor)
• Blocks synthesis of cholesterol in liver
• Decrease LDL, increase HDL

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Bile acid sequestrants

• cholestyramine (Questran)
• Lower LDL levels
• Binds bile acids in intestine

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New drugs

• How actions differ