Cardiology

Wolff Parkinson White Syndrome: Why to avoid Beta Blockers?

Wolff Parkinson White Syndrome (WPW) is a pre-excitation tachyarrhythmia (SVT or Afib) characterized by a shortened PR interval along with a delta wave (a delay in initial deflection of the QRS complex) on the ECG. It occurs due to conduction from the SA node to the ventricle through an accessory pathway that bypasses the AV node (aka the bundle of Kent).

Agents such as: β-blockers, adenosine, amiodarone, and calcium channel blockers should be avoided. They act as AV nodal blockers; blocking the heart’s normal electrical pathway. Therefore favoring a 1:1 atrial to ventricle conduction ratio, through the accessory pathway. This has the potential to generate unstable ventricular arrhythmias.

REFERENCES

  1. Chapter 18: Cardiac Rhythm Disturbances. William J. Brady; Thomas S. Laughrey; Chris A. Ghaemmaghami. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e
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Dr. C Humphreys

Internal Medicine

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Dr. C Humphreys

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