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
Get Medical Pearls directly to your inbox every week!
Weekly posts with high yield medical knowledge, directly to your mailbox!
Dr. C Humphreys

Internal Medicine

Share
Published by
Dr. C Humphreys

Recent Posts

Older Age and Obstructive Sleep Apnea (OSA): Mechanism

Older age is recognized as a risk factor for obstructive sleep apnea.[1] But why? Suspected…

2 months ago

How does Weight Affect Obstructive Sleep Apnea (OSA): Mechanism

Being overweight (BMI ≥ 25 kg/m2)/Obese (BMI ≥ 30 kg/m2) is one of the most…

2 months ago

Nocturia and OSA: Mechanism

Nocturia is a common symptom associated with obstructive sleep apnea. [1] Img Cred: Am J…

1 year ago

ASD vs. VSD Murmur Difference

ASD (Atrial Septal Defect) Wide, Fixed split S2 (in contrast to the normal variation in…

1 year ago

Mechanism of a Mixed Apnea

Mixed apneas are characterized by absent respiratory effort and airflow in the first section of…

2 years ago

How Does Hypothyroidism Cause Hypoventilation?

Although rare, the differential diagnosis of hypoventilation and hypercapnia respiratory failure includes hypothyroidism. It is…

2 years ago

This website uses cookies.