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83 Cards in this Set
- Front
- Back
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What is the most common sustained cardiac arrhythmia?
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Atrial Fibrillation
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Atrial fibrillation preferentially affects _____ and ______ .
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men and the elderly
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Lone Atrial Fibrillation
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This means the only cardiovascular defect is A-fib. the heart is otherwise healthy.
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What factors are contributing to Increasing AF prevalence
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* Growing elderly population
* Increasing prevalence of predisposing factors (i.e. diabetes, hypertension) * Increasing rates of cardiac surgical procedures * Improved survival with CV conditions (i.e. myocardial infarction and heart failure) * Improved methods of detection |
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How do HF and AF affect each other?
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A-Fib can cause:
* Loss of atrial contraction * Rapid Ventricular Rate * Energy depletion * Remodeling * Ischemia * Abnormal Calcium handling * Rate and Rhythym variability All of these events can contribute to heart failure In HF: * Volume and pressure overload * Altered atrial refractoriness * Triggered activity * Interstitial fibrosis * Heterogenous conduction Altered refractoriness and conduction sets the patient up for A-fib |
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What is the impact of A Fib on mortality?
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* Stroke
- 5-fold in risk of stroke1 - Stroke severity (and mortality) is worse with AF than without AF2,3 * Hypertension - In the LIFE trial, patients with hypertension and AF higher rates of cardiovascular and all-cause mortality * Myocardial Infarction - Several studies (eg, GISSI-3, TRACE) have shown that post-MI mortality is higher in those with AF5,6 * Sudden Cardiac Death - AF is an independent risk factor for sudden cardiac death7 * Heart failure - Those with AF had a significantly higher mortality than those without AF (SOLVD trial) |
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What is the most common conplication of A Fib?
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* Stroke is the most common and devastating complication of AF
* Incidence of all-cause stroke in patients with AFib is 5%1 * AF is an independent risk factor for stroke * Approximately 15% of all strokes in the U.S. are caused by AF * Risk for stroke increases with age * Ischemic stroke associated with AF is often more severe than stroke from other etiology * Stroke risk persists even in asymptomatic AF |
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Which atria is more likely to develope a thrombus?
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the left atria
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Once the patient has recovered si the risk of stroke still increased?
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YES
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What are the characteristics associated with A Fib?
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* Uncoordinated atrial activation
* Replacement of consistent P waves by rapid oscillations that vary in size, shape, and timing * Irregular wavy baseline without discrete atrial activity |
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What are the mechanisms causing A Fib?
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Automaticity and Re-entry
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Electrical activity of a normal heart
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* The function of each nodal tissue structure is different:
* SA Node: origin of the automatic signal * AV Node: slowing down the signal propagation and conduction * His-Purkinje: accelerating the signal transmission and conduction. * Normal heart beat is 60 to 80 bpm at rest and during effort: up to 150 bpm |
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What will a patient in A Fib experience if their AV node is still fully functional?
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The patient will have a ventricular rate of around 70 BPM and will be asymptomatic.
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What will a patient in A Fib experience if their AV node is no longer functional?
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The patient will have a high ventricular rate (eg. 160 BPM) and will be experiencing symptoms including:
*palpitations or chest pain * dyspnea (SOB) * fatigue * lightheadedness * syncope (rare and may indicated complications) |
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What types of remodeling can be caused by A Fib?
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* Electrophysiologic changes
- Shortening of atrial refractory periods - Loss of normal adaptation of atrial refractoriness to heart rate * Contractile changes - Reduced atrial contractility * Structural changes - Left atrium and left atrial appendage enlargement - Decrease in cardiac output - Histologic changes * Prothrombotic changes - Atrial stasis - Increase prothrombotic factors |
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What are possible causes of Actute A Fib?
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* alcohol
* surgery * electrocution * pulmonary disease or embolism * hyperthyroidism |
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What are possible causes of Neurogenic A Fib?
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* increased vagal or adrenergic tone
* enhanced parasympathetic or sympathetic tone |
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What are possible causes of A Fib with associated CV disease?
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* valvular heart disease
* coronary artery disease * hypertension (with hypertrophy) * Heart Failure |
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Why do we need to treat A Fib even if it is asymptomatic?
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* Risks of being in Afib
- Systemic embolism - 17.5 fold risk in rheumatic disease - 5 fold risk in patients with non-rheumatic afib - Risk factors - Hemodynamic dysfunction - loss of atrial kick - rapid ventricular rate - Cardiomyopathy * Prognosis - 2x the mortality rate as compared to patients in normal sinus rhythm |
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Symptoms of A Fib vary according to:
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* ventricular rate
* functional status * duration of AF * patient perceptions |
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What symptoms are associated with A Fib?
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* palpitations or chest pain
* dyspnea * fatigue * lightheadedness * syncope (rare, may indicate complications) |
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Define First Detected A Fib?
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It is the first diagnosed occurance
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Define Recurrent A Fib
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All diagnosed incidences of A Fib beyond the first
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Define paroxysmal A Fib
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Self terminating - the patient's atria returns to normal sinus rhythm on its own
< OR = 7 DAYS |
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Define Persistant A Fib
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Non self-terminating - the patient requires medical intervention to return to normal sinus rhythm
> 7 DAYS |
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Define permanent A Fib
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Cardioversion was failed or not attempted
The patient cannot be kept in normal sinus rhythm Paroxysmal and Persistant A Fib can both become permanent |
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What are considerations for the treatment of A Fib?
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Stepwise Process For Evaluation of Patients with Atrial Fibrillation
1. Stable versus unstable: Is the patient clinically stable at this time? 2. Risk of thromboembolism: Duration of current episode of atrial fibrillation 3. Rate control and/or rhythm: - Is there a need to control ventricular rate? - Is there a need to restore sinus rhythm? |
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Acute A Fib Treatment Options
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Rate Control
- Ca2+ blockers - β-blockers - Digitalis - Amiodarone Restoration of SR - Pharmacologic - Class IA - Class IC - Class III - New AADs - Nonpharmacologic - Direct Current Cardioversion Stroke Prevention - Warfarin - Thrombin inhibitor - Aspirin |
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What are signs that your A Fib patient is unstable?
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* hypotension
* heart failure * angina pectoris * syncope |
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How are unstable A Fib patients treatment?
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Immediate cardioversion followed by anticoagulation
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What are the ACC/AHA/ESC A Fib guidelines for the use of Direct Current Cardioversion?
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* When a rapid ventricular response does not respond promptly to pharmacological measures for patients with AF with ongoing myocardial ischemia, symptomatic hypotension, angina, or HF, immediate R-wave synchronized DCC is recommended.
* Cardioversion is recommended in patients without hemodynamic instability when symptoms of AF are unacceptable to the patient. |
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If your acute A Fib patient is stable, what is the next question?
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Accept AF or restore normal sinus rhythm?
- First episode: Most cases an attempt at restoration of NSR is made - Transient cause (i.e. surgery): Restore NSR - Attempt to find other acute causes should made - ACS/MI - PE - LV function - Thyroid - ETOH - Repeat Episodes - Course will depend on patient (risk vs benefit) |
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Objectives of Rhythm Control
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- Relief of Symptoms
- Prevent Thromboembolic Events ? - Prevent Electrophysiologic and Structural Remodeling ? |
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What are the ACC/AHA/ESC A Fib Guidelines for Pharmacological Cardioversion?
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- 1st: Administration of flecainide, dofetilide, propafenone, or ibutilide is recommended for pharmacological cardioversion of AF.
- Ok: Administration of amiodarone is a reasonable option for pharmacological cardioversion of AF. - Never: Digoxin and sotalol may be harmful when used for pharmacological cardioversion of AF and are not recommended. |
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What are the ACC/AHA/ESC A Fib Guidelines for Pharmacological enhancement of DCC?
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- Pretreatment with amiodarone, flecainide, ibutilide, propafenone, or sotalol can be useful to enhance the success of DCC and prevent recurrent AF.
- In patients who relapse to AF after successful cardioversion, it can be useful to repeat the procedure following prophylactic administration of AADs. |
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Recommendations/other considerations for Acute Pharmacological Cardioversion
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- Agents thought to be less effective or incompletely studied
- Quinidine - Procainamide - Ventricular rate control and anticoagulation for cardioversion should be addressed prior to restoring normal sinus rhythm |
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Agents to Control Rate of Ventricular Response to Atrial Fibrillation - Acute setting
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- IV beta-blockade
- Metoprolol - Esmolol - Caution in LV dysfunction - IV CCB - Diltiazem - Verapamil - Caution in LV dysfunction - Digoxin - Less effective than BB or CCB - Value is in HF or in combination therapy - IV amiodarone in refractory patients |
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Considerations for Ventricular rate control
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- Target Heart Rate
- Target resting heart rate 60-80 beats per minute - Target heart rate during exercise 90-115 beats per minute - Consequences of elevated ventricular rate - Consider the Patient’s LV Function - Should therapy be given IV or PO? - IV route usually preferred - Oral route can be used if patient stable - Patient in outpatient clinic and may not have access to IV medications |
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Cardioversion to Sinus Rhythm and Thromboembolism
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- Case control series indicate risk of thromboembolism 1%-5% in patients cardioverted without anticoagulation
- Anticoagulation needed for period of time after cardioversion secondary to mechanical dysfunction of the atria - Patients who undergo emergent cardioversion should be anticoagulated as soon as possible |
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Prevention of Thromboembolism with Cardioverson
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***Prior to elective cardioversion***
AF < 48 hrs heparin peri-cardioversion AF > 48hrs and heparin peri-cardioversion no thrombus by TEE AF > 48 hrs warfarin 3 weeks ***Prior to emergent cardioversion*** heparin peri-cardioversion ***Following cardioversion*** AF < 48 hrs warfarin at INR 2-3 for 4 weeks AF > 48 hrs warfarin at INR 2-3 for 4 weeks |
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Patient case:
CS is a 56 year old female with a history of hypertension and Type 2 diabetes. She is currently taking ASA, metformin and lisinopril. CS presented to her ambulatory care center PCP for a routine physical today. She complains of intermittent palpitations for several weeks but denies shortness of breath, chest pain, and dizziness. Her physical exam is normal except for an irregularly irregular rhythm noted on the cardiac exam. ECG reveals the patient to be in atrial fibrillation. Her vitals are: Ventricular Rate – 120-130 BP – 115/70 Temp – afebrile Is CS stable or unstable? |
- Stable b/c:
- minimal symptoms - no hypotension - no chest pain - no symptoms of heart failure - no syncope - Emergent electrical cardioversion unnecessary |
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List drugs used for ventricular rate control in the acute setting
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Esmolol
Metoprolol Propranolol Diltiazem Verapamil Amiodarone Digoxin |
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When would Digoxin be used to control ventricular rate in the acute setting?
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In patients with heart failure
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How is Digoxin dosed for ventricular rate control in the acute setting?
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IV loading dose: 0.25 mg q2hr (up to 1 mg)
Maintenance dose: 0.125 to 0.375 mg daily IV or PO |
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What is the onset of action for DIgoxin?
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60 min or more
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What are major side effects of Digoxin?
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Digoxin toxicity
Heart block decreased heart rate, bradycardia |
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What is the therapeutic range for Digoxin as indicated for Ventricular rate control?
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Serum concentrations fo 0.5 to 2.0 until controlled
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What Class is Digoxin?
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CArdiac Glycoside
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What class are Esmolol, Metoprolol, and Propranolol?
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Class II
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What class is Amiodarone?
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Class III
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How is Esmolol dosed for ventricular rate in the acute setting?
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IV loading dose: 500 mcg/kg over 1 min
Maintenance dose: 60 to 200 mcg/kg/min IV |
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What is the time to onset of action for Esmolol?
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5 min
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What are the major side effects of Esmolol?
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hypotension
heart block bradycardia asthma heart failure |
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How is Metoprolol dosed for ventricular rate in the acute setting?
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IV loading dose: 2.5 to 5 mg over 2 min, up to 3 doses
Maintenance dose: N/A |
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What is the time to onset of action for Metoprolol?
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5 min
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What are the mahor side effects of Metoprolol?
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heart block
bradycardia asthma heart failure |
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How is Propanolol dosed for ventricular rate in the acute setting?
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IV loading dose: 0.15 mg/kg
Mantenance dose: NA |
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What is the time to onset of action for Propanolol?
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5 min
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What are the major side effects of Propanolol?
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hypotension
bradycardia heart block asthma heart failure |
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How is Diltiazem dosed for ventricular rate in the acute setting?
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IV loading dose: 0.25 mg/kg over 2 min
Maintenance dose: 5 to 15 mg/hr IV |
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What is the time to onset of action for Diltiazem?
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2-7 min
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What are the major side effects of Diltiazem?
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hypotension
heart block heart failure |
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How is Verapamil dosed for ventricular rate in the acute setting?
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IV loading dose: 0.075 to 0.15 mg/kig over 2 min
Maintenance dose: NA |
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What is the time to onset of action for Verapamil?
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3-5 min
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What are the major side effects for Verapamil?
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hypotension
heart block heart failure |
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How is Amiodarone dosed for ventricular rate in the acute setting?
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IV loading dose: 150 mg over 10 min
Maintenance dose: 0.5 to 1 mg/min IV |
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What is the time to the onset of action for Amiodarone?
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Days
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What are the major side effects of Amiodarone?
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hypotension
heart block pulmonary toxicity skin discoloration hypothyroidism hyperthyroidism corneal deposits optic neuropathy warfarin interaction sinus bradycardia QT interval prolongation torsafes de pointes (rare) GI upset (PO) constipation phlebitis |
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What class is Diltiazem and Verapamil?
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Class IV
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What class is Dofetilide and Ibutilide?
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Class III
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What class is Quinidine?
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Ia
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What class is Flecainide and Propafenone?
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Ic
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How is Amiodarone dosed for Cardioversion in Acute A Fib?
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Oral:
- Inpatient: - Loading dose: 1.2 mto 1.8 g per day in divided doses until 10 g total - Maintenance dose: 200 to 400 mg per day or 30 mg/kg as a single dose - Outpatient: - Loading dose: 600 to 800 mg per day in divided doses until 10 g total - Maintenance dose: 200 to 400 mg per day IV: - Loading does: 5 to 7 mg/kg over 30 to 60 min - Maintenance dose: 1.2 to 1.8 g per day contintuous infusion |
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How is Dofetilide dosed for cardioversion in Actute A Fib?
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CrCL > 60 500 mcg PO bid
CrCl 40-60 250 mcg PO bid CrCl 20-40 125 mcg PO bid CrCl <20 CONTRAINDICATED |
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What are the contraindications for Dofetilide?
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QT prolongatiion
torsades de pointes CrCl < 20 |
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How is Flecainide dosed for cardioversion in Actute A Fib?
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Oral: 200 to 300 mg
IV: 1.5 to 3 mg/kg over 10 to 20 min |
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What are the major side effects for Flecanide?
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hypotension
atrial flutter with high ventricular rate |
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How is Ibutilide dosed for cardioversion in Actute A Fib?
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IV: 1 mg over 10 min repeat 1 mg as necessary
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What are the major side effects of Ibutilide?
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QT prolongation
torsades de pointes |
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How is Propadenone dosed for cardioversion in Actute A Fib?
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Oral: 600 mg
IV: 1.5 to 2 mg/kg over 10 to 20 min |
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What are the major side effects of Propafenone?
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hypotension
atrial flutter with high ventricular rate |
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How is Quinidine dosed for cardioversion in Actute A Fib?
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Oral: 0.75 to 1.5 g in divided doses over 6 to 12 hours, usually with a rate-slowing drug
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What are the major side effects of Quinidine?
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QT prolongation
torsades de pointes Gi upset hypotension |
