Antidysrhythmics

Overview

Class I: Fast Na Channel Blockers

Class II: Beta-blockers

Class III: K Channel Blockers

Class IV: Calcium Channel Blockers

Others - Digoxin, Atropine, Adenosine

Class I: Fast Na Channel Blockers

IA - slow conduction, prolong repolarization

Ex = Norpace, ProCAINamide, Quiniglute

IB - slow conduction, shortens repolarization

Ex = LidoCAINe, Mexitil, ToCAINide

IC: prolongs conduction, no effect on repolarization

Ex = Tambacor, Rhythmol

Cardioselective vs Noncardioselective

-olol

EX = Amiodarone, Bretylol, Betapace, Corvert

Decrease HR, increases AV node refractory period, dilates coronary arteries and peripheral blood vessels

Other uses - HTN, angina, h/a

Ex = Verapamil, Diltiazem, Nifedipine, Amlodipine

Other Antidysrhythmics

• Digoxin - more efficient pump in heart failure
• Atropine - Speeds up heart (the ONLY thing it is used for)
• Adenosine - SVT (*TV's found in the "den")
• Stops heart, resets it
• Given bolus, then rapid saline
• Pushed quickly bc of short half-life

• Magnesium

Increases contractility, decreases HR, decreases conductivity

Uses - atrial tachydysrhythmias, heart failure

SE - N/V, bradycardia, visual disturbances

Therapeutic lvl - 0.5 to 2.0

Hypokalemia increases risk for dig toxicity

• Increases HR
• Admin IV push

Uses - bradycardia, complete heart block
SE - tachycardia

Adenosine

Converts SVT to NSR

Short half-life

• Admin IV push with immed. onset
• 6 mg dose
• Continuous ECG recording
• May cause temp asystole

Uses - cardioversion, defib, pacing, AED

Want O2 off and clear from area, jewelry and medication patches off also

Synchronized counter-shock to stop re-entry circuit in the atria or ventricle

Used to treat UNSTABLE supraventricular rhythms and STABLE ventricular tachydysrhythmias not responsive to medical tx

Goal= SA node to regain control

Direct current w/o regard to timing of cardiac cycle

Use to treat Vfib or Unstable (pulseless) Vtach

Uses - sudden death survivors, recurrent vtach, high risk for sudden death

Detects change in heart rate or rhythm

ACTION:

• Admin either cardioversion and/or defib
• Pace
• Record ECG tracing/events

Electrical stimulus to heart by pulse generator when impulse initiator or conduction of heart is ineffective

Temporary - noninvasive (transcutaneous), invasive (transvenous, epicardial)

Permanent Pacemaker

Pacing Terminology

• Mode - asynchronous (fixed rate), synchronous (demand)
• Sensing
• Firing
• Capturing
• Dual vs. Single Chamber Pacing

Stimulates parasympathetic NS

Used to decrease HR in SVT

Types - Carotid massage (dr. only) & valsalva maneuver (bear down, ice to face)

EP lab

Anticoagulant therapy after procedure to prevent clot formation at ablation site

Used for SVT, Afib, Aflutter, paroxysmal Vtach

Nursing care similar to arteriogram