Source: http://www.rnceus.com/ekg/ekghowto.html

Dysrhythmias

• Identified by pattern and origin• Supraventricular

• Atrial

• Junctional

• Ventricular

• Manifestations?

Fast Channel Action Potential

Slow Channel Action Potential

Goals of Dysrhythmic Therapies

• Decrease symptoms

• Prolong survival

Achieved by

Slowing rate of conduction

Decreasing automaticity

Increasing refractory period

Classes of Dysrhythmic Drugs

• Class I—Sodium Channel Blockers

• Class II—Beta Blockers

• Class III—Potassium Channel Blockers

• Class IV—Calcium Channel Blockers

Class I Sodium Channel Blockers

• Depress phase 0

• Block sodium through fast channel

• Slow conduction velocity (SA to AV nodes)

• Prolong refractory period

• Reduce automaticity

• Subclasses based on action in refractory period

Sodium Channel BlockerProcainamide (Procan, Procanbid, Pronestyl)• MOA: blocks sodium channels in myocardial cells, reducing

automaticity and slowing conduction

• Indications: acute/chronic atrial and ventricular dysrhythmias

• Contraindications: AV block, severe CHF, blood dyscrasias, MG; caution in hepatotoxicity

• Side Effects: n/v, HA, abdominal/joint pains (lupus-like syndrome); significant anticholinergic effects

• Assessment/Monitoring: EKG, VS, drug levels, weight, edema, I/O, CBC, electrolytes, BUN/Cr, LFTs, bowel/bladder status, eye pain

• Education: give NSAIDs for joint pains; report weight increase, edema, SOB, fever, syncope, jaundice, eye pain, sxs of stroke, increase fluid/fiber intake; no ETOH or stimulants; don’t skip dose

Other Class I Drugs

• Ia—Quinidine (Diarrhea, tinnitus)• Ib

• Lidocaine* (DOC for ventricular dysrhythmias)• Mexiletine (Mexitil)• Phenytoin (Dilantin)—for Digoxin toxicity

• Ic—most likely to CAUSE arrhythmias• Flecanide (Tambocor)• Propafenone (Rhythmol)

Can local lidocaine given as an Can local lidocaine given as an anesthetic affect the heart?anesthetic affect the heart?

Class IIBeta Adrenergic Blockers

Class IIBeta Blockers

• Decrease automaticity, HR• Decrease input to sinus node

• Block epinephrine, NE in CNS

• Decrease polarization through Purkinge fibers

• Increase refractory period

• Decrease risk of sudden cardiac death

• Primarily supraventricular dysrhythmias

Beta BlockerPropranolol (Inderal)

• MOA: blocks epi, NE at beta-1 & 2 receptors, reducing HR, conduction, velocity; lowers BP

• Indications: primarily SVT, or stress-induced, HTN, angina, prevention of MI, hypermetabolic states; glaucoma, migraines

• Contraindications: cardiogenic shock, bradycardia, heart blocks, heart failure, asthma, COPD; caution in DM

• Side Effects: hypotension, bradycardia, fatigue, depression, sexual dysfunction, hypoglycemia (DM)

• Assessment/Monitoring: VS, EKG, weight, I/O, mood, glucose, lungs, safety

• Education: check HR, BP, weight, report SOB, chest pain, weight gain, edema, syncope (safety), sxs of stroke, depression or ED, DO NOT DISCONTINUE

Class IIIPotassium Channel BlockersClass IIIPotassium Channel Blockers

Class IIIPotassium Channel Blockers

• Prolongs phase 3 of FA potential

• Slows repolarization

• Reduce automaticity

• Used in life-threatening arrhythmias

• Most likely to cause arrhythmias

• Less ventricular fibrillation than Class I

Potassium Channel BlockerAmiodarone (Cordarone)

• MOA: block potassium channels, prolongs refractory period, slows repolarization; also blocks sodium channels

• Indications: resistant, life-threatening V tach

• Contraindications: severe bradycardia, cardiogenic shock, heart blocks; caution in heart failure, hepatic disease

• Side Effects: ARDS, thyroid disorders, blurred vision, n/v, anorexia, fatigue, syncope; skin discoloration

• Assessment/Monitoring: VS, EKG, lungs/CXR/PFTs, TFTs, digoxin and warfarin levels

• Education: hold for HR < 60; report chest pain, palpitations, syncope, SOB, sxs of thyroid dx: monitor weight, I/O, edema, sxs of hepatotoxicity; take with food; wear sun-screen

Additional Class III

• Bretyllium (Bertylol)

• Dofetilide (Tikosyn)

• Ibutilide (Covert)

• Sotolol (Betapace)

Class IV

Calcium Channel Blockers

Class IV

Calcium Channel Blockers

Class IVCalcium Channel Blockers

• Slow automaticity in SA node

• Slowed impulse conduction through AV node

• Prolonged refractory period

• Only for supraventricular dysrhythmias

Calcium Channel BlockerVerapamil (Calan)

• MOA: slows calcium ions in myocardial cells and vascular smooth muscle; slows conduction velocity

• Indications: HTN, angina, supraventricular dysrhythmias

• Contraindications: hypotension, heart block, bradycardia

• Side Effects: hypotension, bradycardia, HA, constipation

• Assessment/Monitoring: VS, BP, EKG, weight, I/O, sxs of HF, bowel status

• Education: hold for syncope or HR < 60; report SOB, chest pain, weight gain, edema, syncope (safety), sxs of stroke; don’t take with GF juice; do not break/chew SR tablets, increase fiber, DO NOT DISCONTINUE

Additional Calcium Channel Blockers

• Diltiazem (Cardizem)

• Adenosine (Adenocard)—PSVT

• Nifedipine (Procardia)—selective for vasculature

Nursing Implications with Antidysrhythmic Drugs

• Any drug that prevents or corrects a dysrhythmia is capable of causing a dysrhythmia.

• Patients, especially on Class I and Class III need to be closely monitored.

RB is a 74 yo male with recent CABG x 3. During the post-op period he developed PVCs and A fib. He is started on a lidocaine drip to control PVCs. What should you monitor?

While receiving IV lidocaine, RB’s HR decreases to 52 with continued PVCs. What should you do?

RB is now in NSR. The MD prescribes amiodarone 200 mg po daily. Why is he getting this drug and what should be monitored?

RB needs more instruction regarding amiodarone when stating

1. “I will take 2 tablets, if I miss a dose.”

2. “I will report fatigue.”3. “I will check my pulse

before taking the pills.”4. “I should use decaffeinated

coffee.”

Additional Dysrhythmic Drugs

• Digoxin (Lanoxin)• Decreases automaticity in SA node

• Slows conduction through AV node

• Supraventricular dysrhythmias

• Phenytoin (Dilantin); for Digoxin toxicity

• Magnesium sulfate (torsades de pointes)

How do we know these drugs are working?

How do we know if they aren’t?

Nursing Intervention

• Screening?• What will will monitor?• Monitor which organs?• Monitor which electrolytes?• Interactions?• Signs of success?• Signs of failure?• Side-effects?• Safety?

All of the following indicate improvement in cardiac status, except

1. Decreased pulse deficit

2. Syncope

3. Weight loss

4. Lungs CTA

Causes of Shock

• Hypovolemic

• Neurogenic

• Cardiogenic

• Anaphylactic

• Septic

Initial Key Steps

• Lay flat with feet elevated

• Keep warm

• Get help

• Call physician

• Initiate IVFs

• Oxygen

• Prepare for code

IV Fluid Replacement

• Crystalloids• Normal Saline (NS)

• Lactated Ringer’s Solution (LR)

• Plasmalyte

• Colloids• Albumin

• Hetastarch

• Dextran

• Plasma Protein Fraction

Colloidal Fluid ReplacementAlbumin (Albuinar, Albutein, Buminate, Plasbumin)

• MOA: maintains plasma oncotic pressure in vasculature

• Indications: restore plasma volume in hypovolemic shock or restore proteins in hypoproteinemia

• Contraindications: severe heart failure

• Side Effects: allergy, fluid overload

• Assessment/Monitoring: VS/PO, lungs, I/O, weight, edema, sxs of anaphylaxis

• Education: report SOB, wheezing, palpitations, edema

Additional Colloids

• Plasma Protein Fraction (Plasmanate)

• Dextran 40 (Gentran, Macrodex)

• Hetastarch (Hespan)

The client at greatest risk from fluid

overload is...

1. 36 yo with sepsis

2. 68 yo with CHF

3. 70 yo with HTN

4. 70 yo with CRF

Vasoconstrictor (Sympathomimetic)Norepinephrine (Levarterenol, Levophed)

• MOA: alpha-1* and beta-1 agonist

• Indications: acute shock (septic) and cardiac arrest

• Contraindications: hypovolemic shock; caution in ischemic disease

• Side Effects: HTN, reflex bradycardia, dysrhythmias, organ ischemia

• Assessment/Monitoring: VS, EKG, organ fx, glaucoma, IV patency, HA, CRT

• Education: report chest pain, palpitations, SOB, eye pain, IV pain, HA

Other Vasoconstrictors

• Isoproterenol (Isuprel); alpha & beta*

• Phenylephrine (Neosynephrine); alpha

• Mephentermine (Wyamine); alpha & beta

The priority nursing action for a client about to receive Levophed for hypovolemic shock

is...

1. Evaluate IV access

2. Measure baseline HR & BP

3. Measure urine output

4. Obtain weight

Perfusion can be evaluated by all, except

1. Vital signs

2. Weight

3. Output

4. CRT

The nurse knows that all are true, relating to NE, except

1. NE should be stopped immediately after BP stabilizes

2. NE may cause organ failure

3. NE requires telemetry

4. NE may aggravate glaucoma

Inotropic AgentDopamine (Dopastat, Inotropin)

• MOA: stimulates dopamine receptors in kidney (activates renin/angiotensin); beta 1 agonist at moderate doses; alpha 1 at high doses

• Indications: maintain renal perfusion, increase CO, shock

• Contraindications: pheochromocytoma, ventricular fibrillation

• Side Effects: dysrhythmia, HTN, tissue necrosis at IV site

• Assessment/Monitoring: VS, EKG, I/O, weight, edema, sxs of HF, CRT, HA, IV site

• Education: report chest pain, palpitations, SOB, pain at IV site, cold/numb extremeties, HA; ICU protocols

Other Inotropic Agents

• Digoxin (Lanoxin)

• Dobutamine (Dobutrex); beta 1

The treatment for dopamine

extravasation is...

1. Atropine

2. Narcan

3. Neostigmine

4. Regitine

Anaphylaxis Drug (Sympathomimetic)Epinephrine (Adrenalin)

• MOA: non-selective sympathomimetic

• Indications: anaphylaxis

• Contraindications: caution in HTN, CVA, CAD, glaucoma, dysrhythmias, organ ischemia, hyperthyroidism

• Side Effects: HTN, dysrhythmias, organ ischemia

• Assessment/Monitoring: VS, EKG, lungs, I/O, CRT, organ perfusion, MS

• Education: report SOB, chest pain, palpitations, cold/numb extremities, anxiety; ICU protocols; injection techniques, reasons for test doses

Additional Drugs for Anaphylaxis

• Antihistamines (-amines)

• Beta 2 agonists (-terols)

• Steroids (-sones)

Key Points for Shock

• Correct hypovolemia before using vasoconstrictors or inotropics

• All drugs given on infusion pumps

• Telemetry required

• Almost all drugs have short ½ life (x digoxin)

• Most have potential to cause tissue damage if extravasation occurs

• All can compromise organ function