Wolff parkinson white syndrome

Vignette says a 25 year old male presents to the emergency department with sudden onset of palpitations that started 30 minutes back while he was exercising; He also reports of lightheadedness, chest discomfort and shortness of breath; There is no significant medical history; Vital signs show blood pressure of 110/70 mm of Hg, pulse rate of 158 bpm, respiratory rate of 18 breaths/min, oxygen saturation of 98% in RA and temperature of 96.9 F; Examination findings are normal; ECG shows short PR interval (<120ms), prolonged QRS complex (> 120ms) and delta wave (a slurred upstroke on the QRS complex); Diagnosis?

Diagnosis is Wolff parkinson white syndrome with supraventricular tachycardia.

Wolff parkinson white syndrome (WPW) is characterized by preexcitation of the ventricles via the accessory pathway between atria and the ventricles; WPW syndrome is characterized by the presence of abnormal accessory electrical pathway between atria and ventricle (i.e. bundle of kent); The ECG findings of wolff parkinson white syndrome are short PR interval (<120ms), prolonged QRS complex (> 120ms) and delta wave (a slurred upstroke on the QRS complex). 

Patients with WPW syndrome are predisposed to PSVTs as the accessory electrical pathway provides a potential path for a reentrant loop and may present as:- 

1. Orthodromic Atrioventricular Reentrant Tachycardia 

2. Antidromic Atrioventricular Reentrant Tachycardia 

Accessory pathway also acts as a path when the patient has concurrent AFib, as the refractory periods of the accessory pathway are less; Thus, during AFib, it may result in fast ventricular rates. ECG shows atrial fibrillation with rapid ventricular rates (>250/min) with a wide QRS complex.

Treatment:- 

1. Orthodromic AVNRT (i.e. Presents as a narrow complex SVT) is treated with vagal maneuvers (e.g. carotid massage, modified valsalva maneuver) and AV nodal blocking agents (e.g. adenosine, beta-blocker, calcium channel blocker).

2. Antidromic AVNRT (i.e. Presents as a wide complex SVT) is treated with anti arrhythmics (e.g. procainamide is DOC in antidromic AVNRT).

3. If a patient has atrial fibrillation with rapid ventricular response then procainamide and ibutilide are agents of choice. AV nodal blocking agents (e.g. adenosine, beta-blocker, calcium channel blocker) are contraindicated; Beta blockers, calcium channel blockers adenosine reduces conduction through the AV node and promotes conduction through the accessory pathway. Therefore, they are contraindicated in patients with WPW syndrome patients who develop atrial fibrillation or flutter.

4. Radiofrequency ablation of the accessory pathway is the definitive treatment.

5. DC cardioversion in hemodynamically unstable patients.

Figure:- ECG finding of Wolff-parkinson white syndrome