Pre-excitation syndrome

-anomalous fast Na+ pathway between atria and ventricles (Kent bypass) leads to pre-excitation of ventricles

-two-way path, circumvents the AV node

-accessory path thought to be associated with SVT of Wolff-Parkinson-White (WPW) syndrome

-treat: carotid sinus massage, Valsalva maneuver

•Drugs to use:

-Amiodarone (III)

-prolongs ERP in accessory (Kent bundle) pathway

-Flecanide (IC)

-impairs accessory path more than AV path

-Quinidine and Procainamide (IA)

-increase block in accessory path

-indirect Speed-up in AV path

•Drugs to Avoid: when atrial flutter/fibrillation associated with WPW

-Verapamil

--blockers all 4 slow AV node conduction

-Digoxin

-Adenosine

-Vagal maneuver:  ERP of Kent bundle.

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Ventricular Premature Contraction (VPC) (one for every normal sinus beats)

• often supercedes death in an MI
• β-blockers reduce death in post-MI patients
• Class I agents: ↑ death in post-MI patients

Drugs:

-no drug of choice. Discontinuation of smoking, caffeine, alcohol.
-β -blockers are used

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Sustained Ventricular Tachycardia

Drugs:

• IV Lidocaine (IB): drug of choice
• Procainamide (IA)
• Bretylium (III)

Drugs for long-term prevention:

• β-blockers (II)
• Class IA drugs
• Class IC drugs
• Amiodarone (III)

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Summary only...