Anti-arrhythmic drugs Flashcards
Flecanide
known to increase pacing thresholds 1c drugs (flecanide, proprafenone) need pacing lead threshold increased
Steroids
reduce pacing thresholds (on tips of some leads)
Class I drugs
Sodium channel blockers
Use dependent - Block enhanced at higher HR
Class III drugs
K channel blockers
Reverse use dependence - block at slower HR (keep in SR) - also causes inc’d QT prolongation - > causes torsades - tx with Mg,K+, if unstable DCCV (or temp overdrive pacing and IV isoproterenol - inc HR, dec QTc) - NO AMIO (inc’s QT)
Dronedarone
Dofetilide (not with HF or perm AF) - renally excreted
Sotolol - renally excreted
DO NOT USE WITH HF patients
Amiodarone
blocks P-450
- raises coumadin and NOAC levels in serum (blocks breakdown)
- raises INR of those on coumadin
better than lidocain survival of patient with out of hospital VF arrest vs vidocaine to hospital admission
Class Ic
Flecande - do not give with CAD/HF/structural heart dz
Propraneone
Contraindicated in HF/CAD
Dronedarone
contraindicated in severe HF(NYHA III/IV) or permanent afib
Class IV CCB
Non-dihydropyramines - verapamil, diltiazem
reduce contractility so DO NOT USE IN HF
Nifedipine
DO NOT USE IN STEMI
Dofetilide
inc’d QT when given with HCTZ,
Class 1a
Quinidine
Disopyramide
Procainamide - for pre-excited AF, unmask brugada - can cause lupus like syndrome
Use dependent - more effective at faster HR
Block mainly Na but also K+ (prolong QT)
Contraindicated in HF 2/2 neg ionotropy
Class 1c
Flecanide Proprafenone Na channel blockade Prolong PR and QRS but no effect on QT Use dependent - more effective at faster HR
Neg ionotropy - do not use with HFrEF or recent MI
Pill in pocket
Pharm cardioversion of recent onset AF <48hrs
- initial rate control
- single bolus of Class Ic antiarrythmic (flecanide 300 or proprafenone 450-600)
- Class Ic drugs contraindicated with structural heart disease or conduction system dz (BBB)
- or Class III (ibutilide, dofetide) - need to do in hospital because of QT prolong/TdP risk
Amiodarone
need loading because of large volume of distribution
Increased automaticity
abnormal phase 4 depolarization - initiates AP that can be provoked by ischemia, catechola, hypoxia