Monday, April 30, 2012

Paroxysmal supraventricular tachycardia

Sudden onset palpitation
Dizziness
Chest pain
Dyspnea
+/- LOC

Due to
  • AV node re-entry or
  • AV  re-entry  (av node + accessory pathway)- WPW syndrome
ECG : Tachycardia + narrow QRS, retrograde P wave -right after QRS
File:AV nodal reentrant tachycardia.png

In WPW, there's the Delta wave- slurred upstroke of the QRS with a short PR interval bcos the signal evades the normal AV node delay and rather passes thru the accessory pathway.












Treatment:
Initial: vagal maneouvres (vasalva, carotid massage)

Drug Tmt :
Adenosine to block AV node except for Wolff-Parkinson-White (AV blockers  r contraindicated in WPW becos it'll only promote passage thru accessory pathway.) Amiodarone for WPW

2nd line drugs include verapamil, diltiazem, metoprolol, digoxin

Cardioversion for unstable patients or those not responsive to medications.

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