Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
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 |