DYSRHYTHMIAS .docx

ANTI-DYSRHYTHMIC DRUCS Class I: sodium channel blockers Class II: BB Class III: potassium channel blockers Class IV: CCB Others: adenosine, digoxin, and ibutilide Because of their prodysrhythmic actions (can worsen existing dysrhythmias or cause new one\'s) should be used only when symptomatic...

ANTI-DYSRHYTHMIC DRUCS Class I: sodium channel blockers Class II: BB Class III: potassium channel blockers Class IV: CCB Others: adenosine, digoxin, and ibutilide Because of their prodysrhythmic actions (can worsen existing dysrhythmias or cause new one\'s) should be used only when symptomatically significant and only when the benefits outweigh risk +-----------------------------------+-----------------------------------+ | AFIB | \- goal: improvement of | | | ventricular pumping and | | | prevention of stroke | | | | | | \- long-term BB | | | | | | \- cardio selective CCB: | | | diltiazem or verapamil | | | | | | \- for pts who elect to restore | | | normal rhythm: cardioversion, | | | short-term tx w/drugs (amio, | | | sotalol), or ablation | | | | | | \- cardioversion may also be | | | achieved w/ibutilide IV | +===================================+===================================+ | SVT | Carotid massage or Valsalva | | | maneuver | | | | | | If not BB or CCB | +-----------------------------------+-----------------------------------+ | Ventricular dysrhythmias | -Cardioversion is the tx of | | | choice | | | | | | If ineffective amio; lidocaine | | | and procainamide are alternatives | | | | | | \- long-term amio and sotalol or | | | ICD | | | | | | PVCs: | | | | | | \- w/MI: BB | | | | | | Digoxin induced: | | | | | | \- lidocaine and phenytoin | | | | | | Torsades: | | | | | | \- mag IV + cardioversion for | | | sustained VT | +-----------------------------------+-----------------------------------+ | CLASS IA (Na channel blocker) | | +-----------------------------------+-----------------------------------+ | Quinidine: | | | | | | Slows impulse conduction in the | | | atria, ventricles, and Purkinje | | | fibbers. Also, delays | | | repolarization at these sites | | | suppression of dysrhythmias | | | | | | \- widens QRS and prolongs QT | | | interval | | | | | | \- active against | | | supraventricular and ventricular | | | dysrhythmias | | | | | | \- indication: long-term | | | suppression of dysrhythmias | | | including SVT, Aflutter, Afib, | | | and sustained VT | | | | | | \- AE: cinchonism (ring in ears, | | | HA, nausea, vertigo, vision | | | problems), and cardiotoxicity | | | (sinus arrest), AV block | | | ventricular tachyarrythmias, and | | | asystole | | | | | | \- can double digoxin levels | | +-----------------------------------+-----------------------------------+ | CLASS IB (Na channel blocker) | | +-----------------------------------+-----------------------------------+ | Mexiletine | | | | | | \- oral analogue of lidocaine | | | used for symptomatic ventricular | | | dysrhythmias | | | | | | \- indications: PVCs and | | | sustained VT | | | | | | \- eliminated by hepatic | | | metabolism effects are prolonged | | | in liver pts | | | | | | \- AE: GI, neurologic, can | | | exacerbate HF | | | | | | \- BBW: inc risk for mortality | | | when used to treat non-life | | | threatening arrhythmias | | +-----------------------------------+-----------------------------------+ | CLASS IC (Na channel blocker): | | | flecainide and propafenone | | +-----------------------------------+-----------------------------------+ | CLASS II: BB agents propranolol, | | | acebutolol, esmolol, and sotalol | | +-----------------------------------+-----------------------------------+ | \- prolong QT. decreases Ca entry | | | | | | \- AE: HF, AV block, sinus | | | arrest, hypotension, and | | | bronchospasm | | +-----------------------------------+-----------------------------------+ | CLASS III (potassium channel | | | blocker) | | +-----------------------------------+-----------------------------------+ | Amiodarone | | | | | | \- lung damange, visual | | | impairment so approved only for | | | life threatening ventricular | | | dysrhythmias. Used for atrial and | | | ventricular dysrhythmias | | | | | | \- toxicity can continue for | | | weeks-months after dc. To reduce | | | all pts must be provided a | | | medication guide describing | | | potential toxicities | | | | | | \- BBW: pulmonary toxicity and | | | liver toxicity, also causes | | | thyroid toxicity | | | | | | \- check cxr, TSH, and LFTs every | | | 6mo | | | | | | \- oral amio for recurrent vfib | | | and recurrent hemodynamically | | | unstable ventricular tachycardia. | | | Used for amio even though not | | | approved for it | | | | | | \- widening QRS and prolong QT | | | and PR | | +-----------------------------------+-----------------------------------+ | CLASS IV: CCB | | +-----------------------------------+-----------------------------------+ | Verapamil and diltiazem | | | | | | \- uses: afib or flutter, and SVT | | | | | | \- AE: bradycardia, AV block and | | | HF, hypotension, peripheral | | | edema, constipation | | | | | | \- elevate digoxin levels, if | | | given w/BB bradycardia, AV block, | | | HF | | +-----------------------------------+-----------------------------------+ Digoxin - Decreases conduction in the AV prolong PR interval and decreases automaticity in the SA - Used only for supraventricular dysrhythmias - Risk is increased w/hypokalemia