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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Wolff-Parkinson-White Syndrome Resident Survival Guide Microchapters
Overview
Causes
Diagnosis
Management Long-term Management WPW with AF
Do's
Don'ts

Overview

Wolff-Parkinson-White syndrome (WPW) is a syndrome of pre-excitation of the ventricles of the heart due to an accessory pathway known as the Bundle of Kent. The diagnosis is made when a patient with pre-existing WPW patern in the ECG, developes an arrythmia which involves an accessory pathway. The treatment is focused on recovering sinus rythm. Atrial Fibrillation in a patient with WPW is lifethretening and should be managed urgently.

Causes

Life Threatening Causes

Life-threatening causes include conditions which result in death or permanent disability within 24 hours if left untreated. Wolff-Parkinson-White syndrome can be a life-threatening condition and must be treated as such irrespective of the underlying cause.

• Atrial fibrillation

Common Causes

WPW is a congenic disease

Diagnosis

Shown below is an algorithm summarizing the initial approach to Wolff-Parkinson-White syndrome according to the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias.

AVRT: AV reentrant tachycardia

Characterize the symptoms: ❑ Asymptomatic ❑ Palpitations ❑ Dyspnea ❑ Fatigue ❑ Chest discomfort ❑ Lightheadedness ❑ Polyuria Characterize the timing of the symptoms: ❑ Onset ❑ Duration ❑ Frequency

Identify possible triggers: ❑ Infection ❑ Caffeine ❑ Alcohol ❑ Nicotine ❑ Congenital heart disease ❑ Congestive heart failure ❑ Valvular disease ❑ Hypovolemia ❑ Acidosis ❑ Hyperthyroidism ❑ Hypoxia ❑ Anxiety ❑ Hypokalemia ❑ Hyperkalemia ❑ Hypoglycemia ❑ Hypothermia ❑ Toxins ❑ Stress ❑ Pulmonary embolism ❑ Coronary thrombosis ❑ Trauma

Examine the patient: ❑ Patient may apear cool and diaphoretic Vitals ❑ Heart rate: symptomatic patients usually present with heart rates between 150-250 beats per minute (bpm) ❑ Blood pressure: patient may be hypotensive Cardiovascular ❑ Normal heart examination in most cases Respiratory ❑ Search for crackles

Order studies: ❑ ECG ❑ Echocardiography to evaluate cardiac function and dimentions, search for assciated conditions such as: ❑ Hypertrophic cardiomyopathy ❑ Ebstein's anomaly of the tricuspid valve

Orthodromic AVRT The impulse travels from the atrium to the ventricle through the AV node and returns to the atrium through the accessory pathway. 90-95% of WPW EKG findings: ❑ Narrow QRS complexes ❑ Ventricular rate between 150-250 bpm (or more) usually regular ❑ PR interval less than one half of the tachycardia RR interval

Antidromic AVRT The impulse travels from the atrium to the ventricle through the accessory pathway and from the ventricle to the atrium through the AV node. Less than 10% of WPW EKG findings: ❑ Wide QRS complexes ❑ Ventricular rate between 150-250 bpm (or more) usually regular ❑ PR interval more than one half of the tachycardia RR interval

Management

Shown below is an algorithm summarizing the initial approach to Wolff-Parkinson-White syndrome according to the 2003 ACC/AHA/ESC guidelines for the management of patients with supraventricular arrhythmias.

Initial approach ❑ Determine blood pressure ❑ Determine heart rate

Stable patient

Unstable patient

❑ Assess the ECG

❑ Catheter ablation (class I, level of evidence B) ❑ Urgent electrical cardioversion (class I, level of evidence C)

Orthodromic AVRT

Antidromic AVRT

Treatment ❑ Use vagal maneuvers (class I, level of evidence B) ❑ Carotid sinus massage ❑ Valsalva maneuver If not effective initiate IV AV nodal blocking agent ❑ Administer adenosine, 6 mg (initial dose) that could be followed by 12 mg if initial dose not effective ❑ Administer IV followed by 10 cc of saline solution (class I, level of evidence A) Contraindications: second- or third-degree A-V block, sinus node disease If not effective ❑ Administer verapamil, given in boluses of 5 mg every two to three minutes up to cumulative 15 mg (class I, level of evidence A) ❑ Additional ECG monitoring should be perforemed in patients with renal insufficiency ❑ In cirrhosis, reduce dose to 20% and 50% of normal Contraindications: hypotension (systolic pressure less than 90 mm Hg) or cardiogenic shock, patients with known hypersensitivity to verapamil hydrochloride If not effective ❑ Administer procainamide, give intravenusly 20 to 50 mg/minute until the arrythmia is controlled or reach 17 mg/kg. ❑ Must monitor blood pressure every 5 to 10 minnutes (class I, level of evidence B) ❑ Reduce the loading dose to 12 mg/kg in severe renal impairment ❑ Reduce the dosage to 50% in hepatic impaiment Contraindications: complete heart block, lupus erythematosus, idiosyncratic hypersensitivity, torsades de pointes

Treatment ❑ Administer: ❑ ibutilide is the prefered treatment, 1 mg in an infusion over 10 minutes (class I, level of evidence B) ❑ If the tachycardia is not controlled give another 1 mg infusion over 10 minutes Contraindications: hypersensitivity to ibutilide or any component of the formulation, QTc >440 msec Or ❑ procainamide 20 to 50 mg/minute until the arrythmia is controlled or reach 17 mg/kg (class I, level of evidence B) ❑ Must monitor blood pressure every 5 to 10 minnutes ❑ Reduce the loading dose to 12 mg/kg in severe renal impairment ❑ Reduce the dosage to 50% in hepatic impaiment Contraindications: complete heart block, lupus erythematosus, idiosyncratic hypersensitivity, torsades de pointes ❑ adenosine should be used with caution because may produce AF ❑ Administer 6 mg (initial dose) that could be followed by 12 mg if initial dose not effective ❑ Administer IV followed by 10 cc of saline solution Contraindications: second- or third-degree A-V block, sinus node disease

Long-term Management

Long term management

Single or infrequent episodes ❑ No treatment (class I, level of evidence C) ❑ Vagal maneuvers (class I, level of evidence B) ❑ Catheter ablation (class IIa, level of evidence B) ❑ Avoid the use of digoxin (class III, level of evidence C)

Prevention of recurrent AVRT

Asymptomatic ❑ No treatment (class I, level of evidence C) ❑ Catheter ablation (class IIa, level of evidence B)

Orthodromic AVRT ❑ class IC antiarrhythmic drugs such as flecainide and propofenone ❑ Beta blockers are used as second-line therapy ❑ class IA antiarrhythmic drugs such as procainamide and quinidine can be used but are less efective than class IC antiarrhythmic drugs ❑ Amiodarone is very efective in supresing orthodromic AVRT, but has too many adverse efects such as: pulmonary and hepatic toxicity. ❑ Avoid the chronic treatment with verapamil or digoxin

Antidromic AVRT ❑ Catheter ablation is the prefered therapy ❑ Medical therapy: reserved to patients who are not candidates or feeruse to the intervention. ❑ class IC antiarrhythmic drugs such as flecainide and propofenone ❑ class IA antiarrhythmic drugs such as procainamide and quinidine can be used but are less efective than class IC antiarithmic drugs ❑ Amiodarone is also efective, but it should be reserved for patients who doesn't respond to class IC antiarrhythmic drugs and class IA antiarrhythmic drugs, or catheter ablation was ineffective.

Wolff-Parkinson-White syndrome with atrial fibrillation

Shown below is an algorithm summarizing the managment of Wolff-Parkinson-White syndrome with atrial fibrillation according to the ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation.

Initial approach ❑ Control ventricular response ❑ If possible: terminate AF ❑ If possible: catheter ablation of the accessory pathway (class I, level of evidence B)

Stable patient

Unstable patient

❑ Restore sinus rythm (class I, level of evidence C) ❑ Ibutilide administer 1 mg in an infusion over 10 minutes, if the tachycardia is not controlled give another 1 mg infusion over 10 minutes (class I, level of evidence C) Contraindications: hypersensitivity to ibutilide or any component of the formulation, QTc >440 msec Or ❑ Procainamide administer 20 to 50 mg/minute until the arrythmia is controlled or reach 17 mg/kg (class I, level of evidence B) ❑ Must monitor blood pressure every 5 to 10 minnutes ❑ Reduce the loading dose to 12 mg/kg in severe renal impairment ❑ Reduce the dosage to 50% in hepatic impaiment Contraindications: complete heart block, lupus erythematosus, idiosyncratic hypersensitivity, torsades de pointes Or ❑ Amiodarone, administer 5-7 mg/kg over 30-60 minutes (initial dose), then 1.2-1.8 g daily continuous infusion or in divided oral doses until 10 g total (class IIb, level of evidence B) Contraindications: cardiogenic shock, severe sinus-node dysfunction ❑ Avoid AV blocking agents (class III, level of evidence B), such as: ❑ Digoxin ❑ Nondihydropyridine calcium channel antagonists: verapamil, diltizem

❑ Urgent electric cardioversion (class I, level of evidence B) ❑ Catheter ablation (class I, level of evidence B)

Do's

❑ Perform catheter ablation of the accessory pathway if possible (class I, level of evidence B).
❑ Electrical cardioversion can be performed in cases of WPW with AF with rapid ventricular response (class II, level of evidence A).
❑ In asymptomatic patients, either no intervantion (class I, level of evidence C) or catheter ablation (class IIb, level of evidence B) could be performed.
❑ Prescribe propofenone over flecainide for the prefvention of recurrence orthodromic AVRT as it has also a mild beta blocking activity.
❑ Schedule exccercise test and electrophysiology tests for the sudden cardiac death statification (class IIa, level of evidence B).
❑ Consider catheter ablation in asymptomatic patients with structural heart disease (class IIb, level of evidence C)

Don'ts

❑ Don't use AV blocking agents in patients with WPW and antidromic AVRT as it will promote promote conduction down the accessory pathway (class III, level of evidence C).
❑ Avoid the usage of AV blocking agents in patients with WPW and AF (class III, level of evidence B).

References

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