week 4- management of patients experiencing cardiovascular symptoms (conductivity and contractility)

what are beta blockers

antihypertensives. usually end with -olol.

contraindicated in asthma, bronchospasms, heart failure because the drug promotes bronchoconstriction.

indications for beta blockers

hypertension

angina

tachyarrhythmias

myocardial infarctions

heart failure

migraine prevention

examples of beta blockers

atenolol

metoprolol

bisoprolol

sotalol

where are beta 1 receptors located

heart

where are beta 2 receptors located

lungs

mechanism of action of beta blockers

by inhibiting the SNS, beta blockade reduces cardiac hypertrophy, dysrhythmias, and tachycardia leading to HF

decreases myocardial contractility, slows HR, decreases systolic BP.

they depress the rate of the SA node and slow the conduction through the AV node

adverse effects of beta blockers

bradycardia

hypotension

bronchospasm

alteration of glucose metabolism

nursing considerations for beta blockers

slowly reduced when treatment is ceased

what are calcium channel blockers

drugs that prevent calcium ions from entering cells

indications for calcium channel blockers

angina

selected arrhythmias

hypertension

examples of calcium channel blockers

amlodipine

diltiazem

verapamil

mechanism of action of calcium channel blockers

blocks the inward current of calcium into the cells in the cardiac conduction system, this reduces cardiac contractility, heart rate and cardiac conduction

common adverse effects of calcium channel blockers

vasodilatory effects

headaches

flushing

dizziness

hypotension

nursing considerations for calcium channel blockers

differ greatly in duration of action

can further depress cardiac function

what are antiarrhythmics

act on the hearts electrical conduction system to regulate and slow heart rate

types of antiarrhythmics

digoxin

amiodarone

what is digoxin

a cardiac glycoside that prevents arrhythmias and increases heart contraction

mechanism of action of digoxin

inhibition of Na/K ATPase in the plasma membrane

=increased calcium in sarcoplasmic reticulum

= excitation coupling occurs

= increased cardiac contractibility (intropy)

* SA node is depressed by stimulating vagal activity

* prolonged AV node conduction via vagal stimulation

*decreases activation of sympathetic nervous system

* increases CO and cause diuresis

* not as effective in high output failure

*improved quality of life but no decrease in mortality

common adverse effects of digoxin

worsening arrhythmia

narrow therapeutic range

nausea and vomiting

CNS disturbances

digoxin toxicity

nursing considerations for digoxin

assess for signs and symptoms of toxicity

assessment of renal function

assessment of electrolyte levels

what is amiodarone

an anti-arrhythmic drug used for patients with V-fib, pulseless V-tach.

indications for amiodarone

serious tachyarrhythmias

atrial fibrillation

supra ventricular tachycardia

ventricular arrhythmia

mechanism of action of amiodarone

prolongs the duration of cardiac action potential, decreases SA node activity, slows AV conduction and has a weak beta blocking effect

adverse effects of amiodarone

potential worsening arrhythmias

CNS toxicity

pulmonary toxicity

nursing considerations for amiodarone

administration requires close supervision

close monitoring of vital signs and ECG

what is potassium

it is the major intracellular cation and is mainly found in skeletal muscle. it can cause cardiac arrhythmias and muscle dysfunction. plays a vital role in cell metabolism and cardiac and neuromuscular function.

what are normal potassium serum levels

3.5-5 milliequivalents per litre

what is hyperkalaemia

plasma potassium in excess of 5.5 mmol

causes of hyperkalaemia

renal injury

potassium sparing diuretics

excessive potassium intake

symptoms of hyperkalaemia

ventricular fibrillation and cardiac arrest

medications given to treat hyperkalaemia

resins

diuretics

insuline/dextrose

what is hypokalaemia

low potassium level of <3.5mmol/L

causes of hypokalaemia

GI losses

renal losses due to diuretics

inadequate potassium intake

symptoms of hypokalaemia

arrhythmias

ECG changes

anorexia

medications given to treat hypokalaemia

oral potassium replacement

intravenous potassium

what is magnesium

it is obtained through the diet and is vital to many intracellular processes including enzyme reactions and synthesis of proteins and nucleic acids. magnesium exerts a sedative effect on the neuromuscular junction, decreasing acetylcholine release. it is an essential ion for neuromuscular and cardiovascular function

normal magnesium serum levels

1.6-2.6 milligrams per decilitre

what is hypermagnesemia

a serum magnesium level that exceeds 2.6 mg/dL.

causes of hypermagnesemia

renal insufficiency

excess intake of antacids or laxatives

excess magnesium administration

symptoms of hypermagnesemia

hypotension

bradycardia

respiratory depression

muscle weakness

medications given to treat hypermagnesemia

calcium gluconate

diuretics

what is hypomagnesemia

a serum magnesium level les than 1.6 mg/dL.

causes of hypomagnesemia

chronic alcoholism

GI losses

impaired absorption

symptoms of hypomagnesemia

tetany

seizures

dysphagia

hypertension

medications used to treat hypomagnesemia

oral magnesium

IV magnesium sulphate

types of calcium channel blockers

dihydripyridines

verapamil

diltiazem

what are dihydropyridines

a type of calcium channel blocker, a class of medications used to treat conditions like high blood pressure (hypertension) and angina

examples of dihydropyridines

amlodipine

nifedipine

nimodipine

mechanism of action of dihydropyridines

blocks influx of calcium into cells of arteriole vascular smooth muscles (calcium triggers muscle contraction)

no action on AV node

what is verapamil

it is a medication that is used to treat cardiovascular conditions including hypertension (high BP), angina (chest pain) and arrythmias (irregular heartbeats)

mechanism of action of verapamil

decreases SA and AV conduction

dilates coronary and peripheral arteries/arterioles

what is diltiazem

it is used to treat cardiovascular conditions by inhibiting the L-type calcium channel like verapamil, but has a slightly different profile in terms of clinical effects.

mechanism of action of diltiazem

inhibits L-type calcium channels to have cardiac and vascular effects

what are complementary and alternative medications

complementary and alternative medicines (CAMs) are non- prescription medicines that are available on shelves of supermarkets, health food shops and pharmacies for customers to self-select and purchase. this is not like a prescription medicine or an over the counter (OTC) medicine where you need to talk to a health professional who prescribes or selects the medicine for treatment of a health related condition.

examples of complementary and alternative medications

acupuncture

chiropractic care

massage therapy

yoga

aromatherapy

herbal medicine

what does atrial fibrillation effect

upper chambers of the heart (atria) and can be managed

what does ventricular fibrillation effect

lower chambers (ventricles) and is a life-threatening emergency requiring immediate treatment