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23 Cards in this Set
- Front
- Back
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Atrial Fibrillation (AF)
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Chaotic, rapid, irregular beating of the top chambers of the heart (atria)-->then irregular beating of the lower chambers (can be any rate)
ATRIA do not pump blood (10-20% reduction in cardiac output) |
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Multiple-wavelet mechanism of AF
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Abnormal atrial tissue substrate
Propagation of wave fronts depends on refractory period (short), mass (large) and conduction velocity (delayed) In PERSISTANT/PERMANENT AF |
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Enhanced Automaticity
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Originates from muscular sleeves extending from certain areas
Location-PULMONARY VEINS, SVC, coronary sinus In PAROXYSMAL AF |
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Paroxysmal AF
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Episodes terminate spontaneously in less than 7 days (usually 24 hours)
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Persistent AF
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Fails to terminate within 7 days
Can terminate spontaneously or by cardioversion Can have recurrent AF which would then be paroxysmal |
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Permanent AF
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Lasts more than one year
Cardioversion has failed or not attempted AF that lasts more than 30 seconds and are unrelated to secondary causes |
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Symptoms of AF
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Palptations (most common)
Chest pain, fatigue Dizziness, pre-syncope, syncope |
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What factors predispose you to AF?
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Hypertension (causes Atrial pressure elevation)
Alcohol and caffeine Sleep apnea Others include hyperthyroidism, pericarditis, changes in autonomic tone, mutations in Na and K channels (familial) |
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AF is associated with?
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Increases Thromboembolic Risk: major cause of stroke in elderly; stroke risk even in asymptomatic AF
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3-part approach to tx of AF
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Rate control (ensure appropriate ventricular rate control)
Rhythm control Anticoagulation (prevent embolic stroke) |
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AF management for Anticoagulation
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Warfarin, Dabigatran, Rivaroxiban
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What are two predictors of two major bleeding events
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Age and an INR greater than 3
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Warfarin necrosis
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paradoxical increase in coagulation when imitating warfarin d/t early drop in protein C
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Dabigatran
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Oral anticoagulant; Direct thrombin inhibitor; DOESNT require INR checks
150 mg is superior to warfarin in preventing strokes At 110 mg no difference |
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What are the risk factors for a stroke?
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History of recent CHF
Hypertension Age >75 Diabetes History of stroke or TIA |
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What is the INR range for anticoagulant treatment?
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2-3
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Cardioversion risk
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Highest stroke risk during conversion to sinus rhythm and for 2-3 weeks afterwards
Rec. warfarin 3 weeks prior and 4 weeks after |
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AF management of rate control
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Digoxin and AV node ablation with permanent pacemaker implantation
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AF management of rhythm control
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Cardioversion
Antiarrhythmic drugs (propafenone, sotalol, etc) Catheter ablation Surgery (Maze procedure and minimally invasive AF ablation) |
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Amiodarone is better than Sotalol at what?
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Remaining in sinus rhythm
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Torsade de Pointes
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Consequence of Class III and IA drugs in Anti-arrhythmic drugs that block the cardiac ion channels
Incidence caries within drug class Prolonged QT interval; preceded by long and short RR intervals; Triggered by an early premature ventricular contraction |
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Monomorphic VT
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Consequence of class I AAD in Structural Heart Disease
All the beats match each other in every leads Scar related |
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Ventricular fibrillation
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May degenerate from Torsade de pointes or VT
can be idopathic |
