Term
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Definition
ABSOLUTE Refractory period
--Cells are not capable of conducting an action potential
--phase 0 midway through pase 3
--RELATIVE refractory period
---strong or multiple impulses may propagate and action potential
---midway throught the end of phase 3 |
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Term
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Definition
Pahse 0
-rapid influx of sodium throught fast channel
-correlates to QRS complex
-PHASE 1
-Sodium influx slows
-repolarization |
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Term
| ACTION POTENTIAL PHASES (cont) |
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Definition
-Phase 2
-Calcium and sodium influx through slow channels
-correlates to ST segment
PHASE 3
Efflux of potassium
-Rapid repolarization
-Correlates to T wave |
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Term
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Definition
-automaticity in pacemeker cells
--pumps sodium out and potassium in
--Less negative membrane potential
---slower phse 0
---decreased automaticity
----Phase 4 is where you are most effected by drugs that effect the heart rate
Ca++ entering the cells initiates the contraction/heart beat-if you shorten that and get to the influx of Ca sooner you effect the heart rate |
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Term
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Definition
FACTORS INCREASING AUTOMATICITY
-Catecholamines
-ischemia
-Decreased potassium, magnesium
-Increased calcium |
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Term
Vaugh-Williams Classification-MEMORIZE!!
CLass IA |
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Definition
-Quinidine
-Procainamide (Procan)
-Disopyramide (norpace)
-Moricizine (ethmozine) |
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Term
Vaughn-Williams Classification
Class IB |
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Definition
anesthetic
-effect the influx of K+
-Lodocaine
-Tocainide (Tonocard)
-Mexiletine (mexitil)
-Phenytoin (dilantin)-no longer used for antiarrhythmic |
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Term
Vaughn-Williams Classifications
Class IC |
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Definition
-Encainide (enkaid)
-Flecainide (Tambocor)
-Propafenone (rhythmol) |
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Term
Vaughn-Williams Classification
CLASS II and CLASS III |
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Definition
CLASS II-Beta adrenergic blocking agents
CLASS III
-AMIODARONE (cordarone)
-Bretyliun (bretylol)
-Sotalol (betapace) |
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Term
Vaughn-Williams Classification
CLASS IV |
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Definition
-Calcium Channel blocking agents
UNCLASSIFIED: Adenosine |
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Term
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Definition
Effects:
-blocks fast sodium channels
-Increas: QRS, QT interval
-moderate effects on ERP, APD
-Decreases automaticity |
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Term
Quinidine
(not used anymore) |
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Definition
Uses
-Atrial Fibrillation
-PACs
-VT
-PVCs
-WPW |
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Term
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Definition
-Increases: PR, QRS, and QT interval
-May increase or decrease AV node conduction
ADVERSE EFFECTS
-GI Intolerance
-Thrombocytopenia
-Proarrythmic |
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Term
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Definition
1/2 LIFE: 6.2hrs
-Metabolized in the liver
-Plasma level: 2-6 mcg/ml
-Drug interactions: Digoxin, beta blockers |
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Term
| Quinidine Drug Interactions |
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Definition
Increased Quinidine Levels: Verapamil, Amiodarone, Cimetidine
Decreased Quinidine levels: Phenobarbital, Rifampin, Phenytoin |
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Term
| Quinidine Drug Interactions |
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Definition
Increased Quinidine Levels: Verapamil, Amiodarone, Cimetidine
Decreased Quinidine levels: Phenobarbital, Rifampin, Phenytoin |
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Term
| Quinidine Drug Interactions |
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Definition
Increased Quinidine Levels: Verapamil, Amiodarone, Cimetidine
Decreased Quinidine levels: Phenobarbital, Rifampin, Phenytoin |
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Term
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Definition
-Sulfate: 100-600mg q4-6hrs
--max 3-4 grams per day
--SR: 300-600 mg q 8-12h
GLUCONATE: 324-972mg q 8-12h |
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Term
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Definition
USES
-same as quinidine
-also VF |
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Term
Procainamide
Pharmokinetics |
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Definition
1/2 life: 3hrs
-metabolized in the liver to NAPA
--active metabolite
--renal eliminated
-Plasma levels
--Procainamide: 4-8 mcg/ml
--NAPA: 10-14 mcg/ml
--total concentration: 25-30mcg/ml |
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Term
Procainamide
ADVERSE EFFECTS |
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Definition
Hypotension-rate related
-SLE-30%
--Arthralgias
--Myalgias
--Rash
Proarrhythmic |
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Term
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Definition
INTRAVENOUS
-Loading dose:
15-17 mg/kg non CHF patient
-12-15 mg/kg CHF patient
-Maintenance dose:
--1 to 4 mg/min
Maximum infusion rate: 30mg/min |
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Term
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Definition
USES-Same as quinidine
Pharmakinetics
-1/2 life: 6hrs
-Adverse Effects
--anticholinergic-dry mouth, blurred vision, urinary retention
-CHF
Proarrhythmic |
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Term
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Definition
Effects
-Minimal effects on phase 0, ERP
-Decreases APD and and automaticity
-no change in QRS or QT interval |
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Term
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Definition
USES-VT, VF, PVCs
EFFECTS-No ECG Effects
PHARMOKINETICS
-hepatic metabolism
-Plasma levels: 2-6 mcg/ml |
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Term
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Definition
-Parasthesias
-Slurred Speech
-Altered consciousness
-muscle twitching
-convulsions
-arrhythmias |
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Term
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Definition
IV bolus only in cardiac arrest
-VT: 1-1.5 mg/kg followed by 0.5-1.5 mg/kg every 5-10min up to 3mg/kg
-Pulsless VT, VF
--1.5 mg/kg repeat x1 in 3-5 minutes |
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Term
Lidocaine
DOSING
"old timer indication" |
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Definition
-0.5 mg/kg every 5-10 min up to 2-3 mg/kg
-continuous infusion: 2-4 mg/min
-not routinely recommended
-narrow therapeutic index
-increases mortality |
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Term
Lidocaine
DECREASED DOSAGE |
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Definition
>70 years
-hepatic dysfunction
-CHF
Concurrent Medications
-Cimetidine, beta blockers
-After 24-48hrs of therapy |
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Term
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Definition
Effects
-Slows Phase 1
-minimal effects on ERP and APD
-Increases pr, QRS
-No change in QT interval
-Life threatening ventricular arrhythmias only
-Cast Trial
-increased mortality |
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Term
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Definition
USES
-SVT
-Paroxysmal atrioventricular fibrillation/flutter
-sustained V-tach
ADVERSE EFFECTS-dizziness,blurred vision, CHF, bradycardia, dyspnea, chest pain, v-fib, v-tach, asystole |
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Term
Flecanide
CONTRAINDICATIONS |
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Definition
-2nd and 3rd degree HB
-Right bundle branch block w/L hemiblock
-cardiogenic shock |
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Term
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Definition
USES
Supraventricular and ventricular tachyarrhythmias
-Decreases conduction velocity and automaticity
-Increases ERP, pr interval |
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Term
Class II-Beta Blockers
Intravenous Agents |
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Definition
-Atenolol
-Metoprolol
-Propanolol
-Esmolol-very short acting
-CONTRAINDICATIONS: HR >60, SBP>100, Severe LV failure, Pulm Edema, Hypoperfusion, 2nd or 3rd deg AV Block |
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Term
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Definition
Pharmokinetics-drops SBP very quickly
-Onset: 2-10 minutes
-Duration: 10-30 min
-1/2 life: 9 minutes
-metabolized by blood esterases |
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Term
Esmolol (Brevibloc)
DOSING |
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Definition
Mix: 5g into 500ml
-10mg/min max concentration
-complicated dosing regimen
-significant hypotension
-No p.o form |
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Term
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Definition
Beta 1 blocker
-used to treat hypertension |
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Term
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Definition
Increase ERP
-Increase PR, QRS, QT intervals |
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Term
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Definition
-Posses electrophysiologic characteristics of al four Vaughn-Williams Classes
-Uses: Life threatening ventricular arrhythmias
-Atrial Fib
-SVT
-Life threatening Ventricular arrythmias
-PHARMOKINETICS
--1/2 life 40-60 DAYS
--Liver metabolism |
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Term
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Definition
400mg q608h x 1-3 weeks
-600-800mg x 1 month
-200-400 mg qd maintenance
Drug interactions
-Digoxin
-Warfarin
-Phenytoin |
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Term
|
Definition
Indications
-Frequently recurring VP
-Unstable VT refractory to other therapy
SIDE EFFECTS
Hypotension
Bradycardia |
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Term
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Definition
150mg x 10minutes (15mg/min)
360mg x 6hrs (1mg/min)
540mg x 18hrs (0.5 mg/min)
-720 mg/24hrs
MAINTENANCE: 540mg x18hrs (0.5mg/min) |
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Term
Amiodarone
ADVERSE EFFECTS |
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Definition
-Nausea, corneal deposits, pulmonary fibrosis, Skin discoloration, Thyroid abnormalities
CARDIAC-Proarrhythmic, bradycardia, heart block
-Increased LFTs |
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Term
| Class IV: Calcium Channel Blockers |
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Definition
Effects
INCREASES: PR interval, ERP
DECREASES: conduction velocity and automaticity in SA and AV nodes |
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Term
|
Definition
USES-Afib, SVT
-narrow complex only
PHARMOKINETICS
--Onset: 3-5 minutes IV
--1/2 life: 3-7 hrs
--Acts on CA++ open channels |
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Term
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Definition
2.5 -5 mg over 2 minutes
-if no response, 5-10mg every 15-30 min up to 20mg
-give over 3min in elderly or dehydrates patients |
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Term
|
Definition
USES
-Narrow complex PSVT
-MAT
-Atrial fibrillation/flutter
PHARMOKINETICS
-ONSET: within 15 minutes
-1/2 life: 3.5-6hrs |
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Term
Diltiazem (Cardizem)
DOSING |
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Definition
0.25 mg/kg over 2min
-if no response in 15min, 0.35 mg/kg over 2minutes
-Infusion: 5-15mg/hr |
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Term
Calcium Channel Blockers
PRECAUTIONS |
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Definition
-Hypotension
-concurrent beta blockers
CONTRAINDICATIONS
-heart block
-CHF
-Sick sinus syndrome
-WPW |
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Term
|
Definition
USES-depresses SA and AV node activity
-Dx and treat arrhythmias
INDICATIONS
-narrow wide complex PSVT
-Wide complex tachycardia of uncertain etiology |
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Term
Adenosine (adenocard)
Pharmokinetics and Dosing |
|
Definition
Pharmokinetics: 1/2 life 10 SECONDS
DOSING:
-6mg RAPID IV bolus followed by saline flush over 2 seconds
-If no response in 1-2 minutes, 12 mg RAPID IV bolus, saline flush
-may repeat x1 |
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Term
Adenosine (Adenocard)
Adverse Effects |
|
Definition
-Flushing
-Dyspnea
-Chest Pain
-Termination arrhythmias
-PSVT recurrence 50-60% |
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Term
Adenosine (Adenocard)
Drug Interactions |
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Definition
-Theophylline inhibits action
-Dipyridamole potentiates action
-Carbamazepine potentiates action |
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