Term
| Non-cardiac causes of dysrhythmia (5) |
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Definition
Hyperthyroidism
Hypokalemia
Hypomagnesemia
Ischemia
Drugs |
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Term
| The best antidysrhythmic drug is... |
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Definition
| An antilipemic drug b/c ischemia causes dysrhythmias! |
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Term
| Classifications of antidysrhythmics |
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Definition
1: block Na channels = dec. phase 4 automaticity or inc. threshold potential = wide QRS
2: B-blocker = dec. number of impulses passing through the AV node = control ventricular rate
3: block K channels = slow repol = inc. ERP and prevent propagation of abnormal signal = wide QT interval
4: cardiac CCAs = block conduction in re-entrant pathways to restore normal rhythm |
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Term
| The only antidysrhythmic drugs shown to dec. death long-term are... (2) |
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Definition
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Term
| Class 1 antidysrhythmics (2) |
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Definition
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Term
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Definition
Block Na channels = inc. threshold potential for depol = suppress phase 4 automaticity = dec. conduction velocity = wide QRS
Block K channels = prolongs AP duration w/ inc. ERP = PR interval inc.
-Dec. number of impulses passing through AV node
-Delayed repol of ventricles = wide QT interval
Block M-R = inc. AV conduction and tachycardia, slows over time due to direct suppression |
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Term
| Procainamide: indications (2) |
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Definition
Acute control of afib/flutter ventricular rate
Suppress PVCs
Not long-term due to S/E |
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Term
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Definition
Torsades de pointes
AV block
SHIP! SLE-like syndrome = malar rash |
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Term
| Lidocaine: method of admin, MOA |
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Definition
IV b/c high first pass metab
Blocks Na channels in ventricles! + inc. threshold potential = dec. phase 4 automaticity in partially depol tissue (ischemia, digoxin toxicity)
2-way blockade in areas of retrograde conduction = abolishes ventricular tachycardia
Dec. ERP and APD prob. due to enhanced K current |
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Term
| Class 2 antidysrhythmics (3) |
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Definition
Atenolol
Esmolol
Propanolol: not cardioselective |
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Term
| Class 2 antidysrhythmics: effects |
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Definition
Dec. SA node discharge = dec. HR
Dec. conduction velocity = inc. ERP of AV node = inc. PR interval
Suppress catecholamine-induced automaticity |
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Term
| Class 2 antidysrhythmics: indications (6) |
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Definition
Prevent fatal ventricular dysrhythmias = dec. post MI death
Prevent stress-induced PVCs
Suppress hyperthyroidism tachycardia
Dec. afib/flutter ventricular rate
Suppress AVNRT
Esmolol (short t1/2): control afib/flutter or sinus tachycardia ventricular rate during cardiac cath |
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Term
| Class 2 antidysrhythmics: S/E (2) |
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Definition
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Term
| Class 2/3 antidysrhythmic |
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Definition
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Term
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Definition
L-sotalol: non-selective competitive B-blockade in slow and fast fibers = inc. ERP, dec. conduction velocity = dec. HR, fewer depolarizations passing through AV node
-Inc. ERP, APD everywhere in heart
-Dec. catecholamine-induced automaticity everywhere in heart
D, L sotalol: block K channels = additional inc. ERP, APD in atria, AV node, ventricles = delayed repol = inc. QT interval |
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Term
| Sotalol, amiodarone: indications |
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Definition
Dec. persistent afib ventricular rate
Cardioversion of afib/flutter to sinus rhythm
Chronic: prevent vtach/fib (sotalol better than amiodarone b/c has less S/E but amiodarone better at preventing recurrence) |
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Term
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Definition
Torsades de pointes esp. when K is low
AV block
HF: B-blockade causing systolic dysfxn, dec. dp/dt |
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Term
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Definition
Amiodarone
Dofetilide
Dronedarone |
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Term
| Amiodarone, dronedarone: MOA |
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Definition
Blocks Na channels = suppress automaticity = dec. firing of SA node
Blocks K channels = delays repol = prolongs ERP, APD in atria, AV node (and dec. number of signals), ventricles = prolonged PR, QRS, QT
Noncompetitive B-blocker
Noncompetitive a-blocker |
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Term
| An ICD is superior to medical tx w/ sotalol or amiodarone esp. when the patient is ___ |
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Definition
| Symptomatic or has low EF |
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Term
| Hybrid therapy is an ICD + ___ |
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Definition
Sotalol to dec. number of shocks
Amiodarone not used b/c it inc. energy required to defib. |
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Term
| Amiodarone: pharmacokinetics |
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Definition
Large Vd! (Purple man)
Long t1/2!
Dec. dose to dec. S/E also dec. efficacy |
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Term
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Definition
Severe bradycardia or AV block
Pneumonitis/pulmonary fibrosis
Corneal microdeposits
Peripheral neuropathy
Thyroid issues
Dec. hepatic/renal clearance of many drugs
Does NOT cause Torsades de pointes! |
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Term
| Drugs that cause QT prolongation/Torsades de pointes |
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Definition
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Term
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Definition
Prevent recurrent/paroxysmal afib/flutter
Dec. persistant afib/flutter ventricular rate |
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Term
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Definition
Severe bradycardia
Suppression of dp/dt in HF!!!
N/D
Dec. hepatic clearance of other drugs
Doesn't cause torsades de pointes!
No thyroid, pulmonary, ocular issues |
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Term
| Amiodarone is better at ___ but dronedarone ___ |
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Definition
Maintaining sinus rhythm in patients w/ recurrent afib
Fewer S/E |
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Term
| Verapamil, diltiazem: indications |
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Definition
Dec. afib/flutter ventricular rate
Convert AVNRT to sinus rhythm |
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Term
| Verapamil, diltiazem: MOA/effects |
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Definition
| Inc. ERP in AV node = dec. AV conduction = inc. PR interval, dec. HR, dp/dt |
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Term
| Verapamil, diltiazem: S/E |
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Definition
Bradycardia (counteract w/ CaCl)
SA nodal failure, AV block
Hypotension |
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Term
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Definition
| Inc. K conductance = hyperpolarize AV node = inhibits symp. ability to cause inc. Ca conductance in AV node = inc. ERP = dec. conduction velocity (stops for a bit) |
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Term
| Digoxin: effects (good and bad) |
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Definition
Direct positive inotropic effect (good) = inc. SV
Indirect enhancement of vagal tone (good) = inc. ERP in AV node = dec. conduction velocity, HR
Direct enhancement of dysrhythmia (bad) |
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Term
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Definition
Dec. ventricular rate in pt w/ afib/flutter due to CHF systolic dysfxn
Inc. dp/dt in pt w/ CHF systolic dysfxn |
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Term
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Definition
Diagnose AVNRT
Convert AVNRT to normal sinus rhythm
Produce coronary VD during radionuclide scan in pt unable to exercise |
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Term
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Definition
Transient asystole
Short-live, burning sensation in chest
Flushing
Dyspnea |
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Term
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Definition
Inc. vagal tone causing sinus bradycardia, AV block
Automaticity = PACs, PVCs
Inc. symp. activity
Dec. ERP, ADP in presence of excess Ca |
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Term
| Antidysrhythmic drugs that dec. CO |
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Definition
B-blockers
Diltiazem
Sotalol
Verapamil |
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Term
| Antidysrhythmic drugs that NC CO |
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Definition
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Term
| Antidysrhythmic drugs that inc. CO |
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Definition
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