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54 Cards in this Set

  • Front
  • Back

Heart rate

Frequency of depolarization of the ventricles
Resting heart rate
60-100 bpm
Common symptoms of arrhythmias
Palpitations
Lightheadedness
SOB
Chest pain
Fatigue

Can lead to syncope, heart failure, death
Normal sinus rhythm
Acitvation of the heart in the normal sequence through the cardiac conduction system and at the usual rate of 60-100 bpm
Normal sequence of formation and conduction of an electrical impulse in the heart
1.) Sinoatrial node initiates an electrical impulse
2.) Impulse spreads through the right and left atria, resulting in atrial conduction
3.) Impulse reaches the atrioventricular node, where conduction is slowed
4.) Impulse travels down the bundle of HIS
5.) Impulse divides into the right bundle branch for the right ventricle, and the left bundle branch for the left ventricle
6.) Impulse spreads through the ventricles via Purkinje fibers, resulting in a coordinate and rapid contraction of both ventricles
Causes of arrhythmias
*Myocardial ischemia or infarction secondary to coronary artery disease*
Heart valve disorders, HTN, heart failure
Electrolyte imbalances, esp. K, Mg, Na, Ca
Hyperthyroidism
Infection

*Drugs* can cause or worsen arrhythmias, including drugs used to treat arrhythmias
Monophasic action potential
Resting phase

Phase 0 (Depolarization) - Na channels open (entering cell); determines conduction velocity

Phase 1 (Peak) - Na channels close

Refractory Period

Phase 2 (Plateau) - Ca channels open (entering cell); K channels open (exiting cell)

Phase 3 (Repolarization) - Ca channels close; K channels still open; Na may enter cell (late inward Na current)

Resting period

Phase 4 (Automaticity) - slow increase in potential
Classification of arrhythmias
Supraventricular (originating above the AV node)
*Sinus tachycardia
*Atrial fibrillation, atrial flutter
*Focal atrial tachycardias
*Supraventricular re-entrant tachycardias (AKA paroxysmal superventricular tachycardias or PSVTs)

Ventricular (originating below the AV node)
*Premature ventricular contractions (PVCs)
*Ventricular tachycardia
*Ventricular fibrillation
Atrial fibrillation
*Most common supraventricular arrhythmia*
- Results from multiple waves of electrical impulses in the atria, resulting in an irregular and rapid ventricular response

Can result in hypotension, worsen underlying ischemia and heart failure
Increased risk of thromboembolism and stroke
Premature ventricular contractions
*One of the most common arrhythmias*

Occurs in people w/ and w/o heart disease

"Skipped heartbeat" that everyone will occasionally experience

Can be related to stress, too much caffeine or nicotine, or too much exercise
Ventricular tachycardia
A series of PVCs in a row resulting in a heart rate > 100 bpm

Classified based on the presence or absence of a detectable peripheral pulse

W/ a pulse - tx w/ antiarrhythmics
W/o a pulse - medical emergency

*Untreated ventricular tachycardia can degenerate into ventricular fibrillation --- medical emergency*
QT Prolongation
*Risk factor for Torsade de Pointes*

Measured from the beginning of the QRS complex to the end of the T wave --- reflects ventricular depolarization and repolarization

Drug-induced QT prolongation is dose-dependent
Torsade de Pointes
Lethal ventricular tachyarrhythmia

Most commonly associated w/ drugs

Can result in sudden cardiac death
Drugs and conditions that cause additive QT prolongation risk
*ANY pre-existing cardiac condition*
*Class Ia and III antiarrhythmics - amiodarone, dofetilide, dronedarone, procainamide, quinidine, sotalol)
*Quinolones, macrolides*, bactrim
*Azole antifungals
*Antidepressants - TCAs, SSRIs
*Antiemetic agents
*Antipsychotics - thioridazine, ziprasidone
*Methadone

Anticancer agents
Protease inhibitors
Antidepressant preferred in cardiac patients
Sertraline
Use of antiarrhythmics in tx of cardiac arrhythmia
- Terminate the arrhythmia and restore and maintain normal sinus rhythm --- Class I and III

- Slow ventricular rate during a supraventricular arrhythmia --- Class II and IV
Class Ia antiarrhythmics
Sodium channel blockers --- intermediate
Block potassium channels
Decrease conduction velocity, increase refractory period, decrease automaticity

Quinidine
Procainamide
Disopyramide
Class Ib antiarrhythmics
Sodium channel blockers --- fast
*ONLY useful for ventricular arrhythmias*

Cross blood-brain barrier --- cause CNS SEs
Decreased conduction at higher heart rates, little effect on refractory period, decreased automaticity

Lidocaine
Mexiletine
Phenytoin
Class Ic antiarrhythmics
Sodium channel blockers --- long

*ABSOLUTELY CONTRAINDICATED in pts w/ heart failure or just experienced acute MI*

Decrease conduction velocity and automaticity

Flecainide
Propafenone
Class II antiarrhythmics
Beta blockers (ex. esmolol, propranolol)

Block beta receptors; indirectly block calcium channels in the SA and AV nodes, resulting in decreased automaticity and conduction velocity

*SLOW the ventricular rate in supraventricular tachyarrhythmias*
Class III antiarrhythmics
Block K channels --- significant increase in refractory period

Amiodarone
Dofetilide
Dronedarone
Ibutilide
Sotalol
Class IV antiarrhythmics
Block L-type calcium channels, slowing SA and AV nodal conduction velocity
Used to *slow the ventricular rate* in supraventricular tachyarrhythmias

Verapamil
Diltiazem
Quinidine Info
BLACK BOX - may increase mortality in tx of AFib or flutter - control AV conduction before initiating

SE - *diarrhea, stomach cramping, QT prolongation, N/V, anorexia, lightheadedness, cinchonism*, thrombocytopenia, pruritis, rash

MAJOR 3A4 substrate, 2C9 and P-glycoprotein substrate
Inhibitrs 2D6, 2C9, 3A4, p-glycoprotein

CONTRA - 2/3rd degree heart block, quinolones that prolong QT interval, amprenavir, ritonavir, TTP, thrombocytopenia
Quinidine
Injection, oral

Class 1a antiarrhythmic

IR - 200-400 mg PO Q6hr
ER - 300-324 mg PO Q8-12hr

Take w/ food or milk to decrease GI upset

267 mg gluconate = 200 mg sulfate
Procainamide Info
BLACK BOX - blood dyscrasias, drug-induced lupus erythematosus-like syndrome, recent MI patients w/ asymptomatic, non-life-threatening ventricular arrhythmias did not benefit and may have been harmed

SE - *hypotension, rash, lupus-like syndrome, QT prolongation, agranulocytosis*

CONTRA - 2nd/3rd degree hear block, SLE, torsade de pointes, procaine or other ester-type local anesthetics

2D6 substrate
Procainamide
Injection

Has active metabolite - N-acetyl procainamide (NAPA) - renally cleared

Therapeutic levels:
- Procainamide - 4-10 mcg/mL
- NAPA - 15-25 mcg/mL
- Combined - 10-30 mcg/mL

Draw levels 6-12 hrs after IV infusion has started
Disopyramide Info
BLACK BOX - recent MI patients w/ asymptomatic, non-life-threatening ventricular arrhythmias did not benefit and may have been harmed

SE - *anticholinergic effects*, hypotension, QT prolongation, HF exacerbation

CONTRA - 2nd/3rd degree heart block, cardiogenic shock, congenital QT syndrome, sick sinus syndrome, BPH/urinary retention/narrow-angle glaucoma, myasthenia gravis

- 3A4 substrate
Norpace, Norpace CR
Disopyramide

IR - 150 mg PO Q6hr
CR - 300 mg PO Q12hr

CrCl < 40 mL/min - decrease frequency of IR and DO NOT use CR formulation

*TAKE on empty stomach*
Class Ib antiarrhythmic Info
SE - lightheadedness, dizziness, incoordination, N/V, tremor, CNS effects

CAUTION - severe hepatic dysfunction, elderly

CONTRA - 2nd/3rd degree heart block, Wolff-Parkinson-White syndrome, Adam-Stokes syndrome, allergy to corn or related products or amide type anesthetic
Xylocaine
Lidocaine - injection

Class Ib antiarrhythmic

1-1.5 mg/kg IV bolus; repeat 0.5-0.75 mg/kg up to 3 mg/kg (cumulative dose); followed by 1-4 mg/min IV infusion

Decrease in HF or hepatic dysfunction

CAN be given via endotrachial tube - increase dose 2-2.5x IV dose

Substrate - 3A4, 1A2, 2C9
Inhibits 1A2
Mexiletine
Class Ib antiarrhythmics

200 mg PO Q8hr

MAX 1.2 g/d

Take w/ food

Reduce dose in hepatic impairment

Substrate of 1A2, 2D6
Inhibits 1A2
Flecainide
Class 1c antiarrhythmic

100 mg PO Q12hr (MAX 400 mg/d)

CrCl < 50 mL/min - decrease dose by 50%

BLACK BOX - 1:1 atrioventricular conduction may occur; pro-arrhythmic effects (not recommended for chronic afib); DO NOT use in structural heart disease

SE - dizziness, visual disturbances, HA, dyspnea, proarrhythmic

CONTRA - 2nd/3rd degree heart block, cariogenic shock, CAD, amprenavir, ritonavir

2D6, 1A2 substrate
Inhibits 2D6
Rythmol, Rythmol SR
Propafenone --- Class 1c antiarrhythmic

IR - 150-300 mg PO Q8hr
SR - 225-525 mg PO Q12hr

BLACK BOX - DO NOT use in structural heart disease

SE - metallic taste, N/V, new or worsening arrhythmia, dyspnea, dizziness, bronchospasm, worsening HF

CONTRA - 2nd/3rd degree heart block, sinus bradycardia, cardiogenic shock, hypotension, CAD, bronchospastic disorder, ritonavir

Substrate of 2D6, 3A4, 1A2
Inhibits 1A2, 2D6
Digoxin Patient Counseling
DO NOT stop taking, even if feeling well

Avoid becoming overheated or dehydrated --- increases risk of overdose/toxicity

Overdose --- N/V/D, loss of appetite, vision changes (yellow/green vision), uneven heart beats, may pass out

Many meds can interact w/ digoxin ---> check w/ physician before starting any new meds

Will need to test blood on regular basis
Amiodarone Patient Counseling
May take w/ or w/o food, but be consistent

Severe lung or liver issues have occurred --- cough, fever, chills, chest pain, difficult or painful breathing, coughing up blood, severe stomach pain, fatigue, yellowing eyes or skin, dark urine, new SOB

Can cause irregular heartbeat to become worse

Can cause serious vision changes; muscle weakness, pins and needles feeling

Can cause metabolism to speed up or slow down

Will be photosensitive; protect skin from sun

DO NOT take grapefruit or grapefruit juice

DO NOT take a double dose if you skip one
Brevibloc
Esmolol --- Class II antiarrhythmic

Beta-1 selective

0.5-1 mg/kg ---> then 50-150 mcg/kg/min
MAX --- 300 mcg/kg/min

*IS A VESICANT --- monitor IV site*
Inderal LA, InnoPran XL
Propranolol --- Class II antiarrhythmic

Nonselective beta blocker; crosses BBB

PO - 10-30 mg Q6-8hr
IV - 1-3 mg slow IV push (5 mg max initially)
Amiodarone Info
MOA - block alpha and beta receptors, block Na and Ca channels

BLACK BOX - toxicity risk (use only for life-threatening arrhythmias); pulmonary toxicity w/o symptoms; liver toxicity; proarrhythmic

SE - *Hypotension (IV); GI upset; thyroid imbalance; dizziness; bradycardia; peripheral neuropathy; ataxia; tremor; corneal microdeposits; optic neuritis; pulmonary fibrosis; photosensitivity; increased LFTs; slate blue skin discoloration*

PREG Category D

Half-life --- 40-60 days

DOC in pts w/ concomitant heart failure
Cordarone, Pacerone, Nexterone
Amiodarone --- Class III arrhythmic

Pulseless VT/VF - 300 mg IV push x 1; repeat 150 mg x 1 if needed
VT w/ pulse - 150 mg IV bolus; 1 mg/min x 6 hrs; 0.5 mg/min x 18 hrs or longer

A fib - 1.2-1.8 g/d for a 10 gram LD, then 200-400 mg/d

Ventricular arrhythmias - 800-1600 mg/d x 1-3 wks, then 600-800 mg/d x 4 wks, then 400 mg/d

Infusions > 2 hrs - use non-PVC container; flush line w/ saline; add to D5W

Premixed IV - PVC bag not an issue; if hypotension, slow rate or d/c
Class III antiarrhythmic drug interactions
- Avoid coadmin w/ QT prolongation drugs
- Extreme caution w/ negative chronotropes d/t increased risk of bradycardia (ex. beta blockers, verapamil, diltiazem)
- Correct electrolyte abnormalities before initiating tx
- DO NOT use grapefruit juice/products
- AVOID ephedra, St. John's wort
Amiodarone Drug Interactions
Moderate inhibitor of 2C9, 2D6, 3A4, and p-glycoprotein

MAJOR substrate of 3A4, 2C8, p-glycoprotein

AVOID any major QT prolonging meds

When starting amio, decrease dose of digoxin by 50%, decrease dose of warfarin by 30-50%

Use lower doses of simvastatin, lovastatin, and atorvastatin
Dronedarone Drug Interactions
Moderate inhibitor of 2D6, 3A4, p-glycoprotein

Major substrate of 3A4

Monitor INR after initiating dronedarone in pts w/ warfarin
Dofetilide Drug Interactions
Minor 3A4 substrate

Avoid w/ other QT prolonging meds
Multaq
Dronedarone --- Class III antiarrhythmic

MOA - block alpha and beta receptors, and Na and Ca channels

400 mg PO BID *w/ food*

BLACK BOX - HF, permanent AFib

SE - QT prolongation, bradycardia, increased SCr, D/N, hypokalemia, hypomagnesemia

***PREG CATEGORY X***

Only used in pts who can be converted to normal sinus rhythm
Betapace, Betapace AF, Sorine
Sotalol --- Class III antiarrhythmic

- Significant beta blocking activity (NON SELECTIVE)

80 mg PO BID; can increase to 160 mg PO BID
CrCl < 60 mL/min - decrease frequency

BLACK BOX - initiation and dosage increase should be done in hospital; adjust interval based on CrCL; QT prolongation is directly related to sotalol conc.; Injection can cause life-threatening ventricular tachycardia and QT prolongation; DO NOT substitute Betapace and Betapace AF
Corvert
Ibutilide --- Class III antiarrhythmic

MOA - activates the late inward sodium current, resulting in a significant increase in refractory period

1 mg IV over 10 min; may repeat x 1 (after 10 min)

BLACK BOX - potentially fatal arrhythmias may occur; do not use in chronic afib as they often revert back

SE - ventricular tachycardias, hypotension, increased QT interval
Tikosyn
Dofetilide --- Class III antiarrhythmic

500 mcg PO BID if CrCl > 60 mL/min --- reduce dose in renal impairment or if QT interval increases

BLACK BOX - initiate in hospital setting

CONTRA - use of HCTZ, azole antifungals, megestrol, prochlorperazine, trimethoprim, verapamil; HR < 50; CrCl < 20 mL/min; QTc > 440 msec, hypokalemia, hypomagnesemia

SE - HA, dizziness, ventricular tachycardias, increased QT interval

REMS program; TIPS (Tikosyn in Pharmacy System)
Cardizem IR, CD, LA
Diltzac
Dilacor XR
Dilt-CD, XR
Cartia XT
Tiazac
Taztia XT
Diltiazem --- Class IV antiarrhythmic

120-480 or 540 mg/d PO depending on the max dose of the product
Calan IR, SR
Verelan, Verelan PM
Covera HS
Verapamil

240-480 PO mg/d
Other antiarrhythmics
Adenosine
*slows conduction through the AV node via activation of adenosine-1 receptors
*used to restore normal sinus rhythm in supraventricular re-entrant tachyarrhythmias

Digoxin
*causes direct AV node suppression, increases refractory period, and decreases conduction velocity
*enhances vagal tone, resulting in decreased ventricular rate in atrial tachyarrhythmias
Adenocard
Adenosine

*Used in PSVTs only*

6 mg IV push; may increase to 12 mg if not responding

SE - transient new arrhythmia, facial flushing, HA, chest pain/pressure, neck discomfort, dizziness, GI distress, transient hypotension, dyspnea
Lanoxin
Digoxin

0.125-0.25 mg QD
Decrease when CrCl < 50 mL/min

Therapeutic range - 0.8-2 ng/mL

PREG Category C

NOT given alone; use w/ BB or CCB
Digoxin toxicity
Antidote --- DIgifab

N/V, loss of appetite, bradycardia
Blurred/double vision, altered color perception, greenish-yellow halos, abdominal pain, confusion, delirium, arrhythmia
Digoxin Interactions
Caution w/ other drugs that slow HR

Mostly renally cleared; partial hepatic clearance

Substrate of p-glycoprotein and 3A4

Digoxin levels may decrease w/ bile acid resins (separate admin times), St. John's wort

Hypokalemia, hypomagnesemia, and hypercalcemia increase risk of digoxin toxicity

Hypothyroidism can increase digoxin levels