Cardiac/Vascular Circulation Brenda Rowe, RN, MN, JD Georgia Baptist College of Nursing of Mercer University

C.O. = Stroke Vol. X Heart Rate Preload - passive stretching force exerted on ventricle muscle Preload - passive stretching force exerted on ventricle muscle Contractility - force of the squeezing that the ventricle is able to achieve Contractility - force of the squeezing that the ventricle is able to achieve Afterload - amount of pressure the ventricle muscle must overcome to eject Afterload - amount of pressure the ventricle muscle must overcome to eject Contraction - dependent upon conduction system Contraction - dependent upon conduction system

Cardiac Effects of Digoxin Positive inotropin effect: strengthens the force of contraction Positive inotropin effect: strengthens the force of contraction Negative dromotropin effect: decreases conduction Negative dromotropin effect: decreases conduction Negative chronotropin effect: decreases heart rate Negative chronotropin effect: decreases heart rate Improve renal perfusion Improve renal perfusion

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

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

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

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

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

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

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

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

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

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)

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 * has high incidence of adverse effects with most common being GI * monitor renal & liver function

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

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

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

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

Potassium-Removing Resins Sodium polystyrene sulfonate (Kayexalate) Sodium polystyrene sulfonate (Kayexalate) oral or enema oral or enema AE - hypokalemia AE - hypokalemia

Antihyperlipidemics Definition Definition HDL/LDL HDL/LDL

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

Bile acid sequestrants cholestyramine (Questran) cholestyramine (Questran) Lower LDL levels Lower LDL levels Binds bile acids in intestine Binds bile acids in intestine

New drugs How actions differ How actions differ