Anti-arrhythmia Flashcards
MOA for Class IA drugs (Quinidine, Procainamide)?
1˚ - Preferentially block open or activated Na channels; lengthen the duration of action potential
2˚ - Block K channels increase effective refractory period)
MOA for Class IB drugs (lidocaine)?
Block inactivated sodium channels, shorten duration of action potential (decrease effective refractory period)
MOA for Class IC drugs (Flecainide)?
Binds to all sodium channels, no effect on duration of action potential (no effect on effective refractory period)
MOA for Class II drugs (B-blockers)?
Reduce adrenergic activity on the heart
MOA for class III drugs (Amoidarone, sotalol)?
K+ channel inhibitors (increase effective refractory period)
MOA for class IV drugs (Verapamil, diltiazem)
L-type Ca Channel blockers, decrease HR and contractility
What broad spectrum drug is used to tx acute or chronic supraventricular or ventricular arrhythmias?
Quinidine
What drug has a low therapeutic index can can easily cause:
- Cardiac toxicity (SA/AV block, ventricular arrhythmia
- Blocks alpha receptors –> sever HTN, reflex tachycardia
- Paradoxical Tachycardia (reflex to vasodilation)
- Tosades de pointes
Quinidine
What drug causes widening of QRS, and QT intervals. This can lead to what?
Quinidine
Quinidine syncope
Cinchonism and diarrhea are adverse effects of what drug?
Quinidine
What drug can cause Lupus erythematous in slow slow acetylators: NAT2 gene?
Procainamide (class IA)
What is DOC for ventricular arrhythmias?
IV Lidocaine (class IB)
Has least amount of negative inotropic effects, slows conduction
Adverse effects of Lidocaine (2)
- Bradycardia
2. Convulsions
What drug is last ditch effort for supra-ventricular/life threatening ventricular arrhythmias, but ALSO can cause arrhythmias?
Flecainide (class IC)
BB hack!
Drugs that start w/ A-M = B1 specific blockers
- Metoprolol, Esmolol
Drugs that start w/ N-Z = non-specific BB
- Propranolol
What IV B1-blocker is 2nd line for Paroxysmal supraventricular tachycardia?
Esmolol (Class II)
What is DOC for ventricular arrhythmias?
Amiodarone (Class III)
Also effective against both supreventricular arrhythmiass
T or F: Amiodarone can cause torsades de pointes?
FALSE
No Torsades de pointes
Pulmonary fibrosis, yellow-brown corneas, grey-blue skin and thyroid dysfunction are side effects of what drug?
AmIODarone
Increases IODine –> color changes and thyroid dysfunction
What class III med blocks K+ but also is a non-selective B-blocker?
Sotalol
What class III med is effective in treating ventricular and supraventricular arrhythmias BUT causes torsades de pointes?
Sotalol
What drug is only effective in the atria but is used to tx reentrant SVT, PSVT and Afib/flutter
Verapamil and Diltiazem (class IV)
- Only effective in SVT b/c that is where Ca is important for rate
Adverse effects of Verapamil and Diltiazem? (2)
- Constipation
2. Avoid use w/ B-blocker –> Heart block
Increased K conductance that hyperpolarizes and resets the heart is MOA for what drug?
Adenosine
DOCs for acute PSVT (1-3 in order)
- Adenosine
- Esmolol
- CCVs
DOCs for chronic PSVT?
- BB
2. CCBs
DOC for acute PSVT and WPW syndrome?
Adenosine
What drug is has a t1/2 of 10 seconds and is effective only against reentry arrhythmias
Adenosine
What is DOC for Torsades de pointes?
Magnesium (unknown MOA, IV only)
What happens if you give pt w/ normal Mg levels Mg?
Anti-arrhythmic effect
What medication is used in the management of seizures associated w/ severe toxemia or pregnancy (eclampsia)
Magnesium
T or F: Hyperkalemia and hypokalemia are pro-arrhythmic?
TRUE
T or F: Lidocaine, adenosine, and magnesium are IV only?
TRUE
So used only in acute therapy
What happens when you used anti-arrhythmic agents at high doses? (2)
- Depress conduction in normal tissues
2. Produce drug induced arrhythmias (potentially lethal)
What is causes reentry arrhythmias?
Infarct blocks normal conduction pathway, the conduction then enters in retrograde direction, causing reentry of arrhythmia into circuit
Others: obstacle to homogenous conduction or prolonged conduction time allows for more excitable tissues
T or F: Any drug that is used to tx and arrhythmia can cause an arrhythmia?
TRUE
