From the Guidelines
The diagnostic criteria for Wolff-Parkinson-White (WPW) syndrome are based on the presence of ventricular pre-excitation on a resting ECG, which participates in arrhythmias, as stated in the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
Key Diagnostic Features
- A short PR interval (less than 120 milliseconds)
- A widened QRS complex (greater than 120 milliseconds)
- A delta wave, which appears as a slurred upstroke at the beginning of the QRS complex
Importance of Symptoms and ECG Findings
Diagnosis typically requires both these ECG findings and symptoms of tachyarrhythmias, such as palpitations, dizziness, shortness of breath, or syncope. The presence of an accessory pathway (bundle of Kent) allows electrical impulses to bypass the normal AV node delay, resulting in ventricular pre-excitation, as described in the guideline 1.
Risk Stratification and Definitive Diagnosis
Risk stratification is essential as some patients, particularly those with rapid conduction through the accessory pathway, may be at risk for sudden cardiac death due to the development of atrial fibrillation with rapid ventricular response or other life-threatening arrhythmias. Definitive diagnosis may involve electrophysiological studies, particularly in patients being considered for ablation therapy, as noted in the guideline 1.
From the Research
Diagnostic Criteria for Wolf Parkinson White Syndrome
The diagnostic criteria for Wolf Parkinson White Syndrome (WPW) include:
- A PR interval less than 0.12 seconds 2
- A slurring of the initial segment of the QRS complex, known as a delta wave 2, 3
- A QRS complex widening with a total duration greater than 0.12 seconds 2
- Secondary repolarization changes reflected in ST segment-T wave changes that are generally directed opposite (discordant) to the major delta wave and QRS complex changes 2
Electrocardiographic Features
The electrocardiographic features of WPW syndrome are characterized by:
- The presence of an accessory pathway that bypasses the atrioventricular (AV) node, creating a direct electrical connection between the atria and ventricles 2, 4
- A delta wave, which is an important indicator to diagnose the WPW syndrome 3
- The PR duration, the QRS duration, and the upstroke of the QRS complex are used to determine the presence or absence of the delta wave 3
Risk Assessment and Management
The management of WPW syndrome may be quite challenging and can vary from only acknowledging the presence of the accessory pathway to pharmacological treatment or radiofrequency ablation 4
- Early diagnosis, risk assessment, and appropriate treatment are critical steps in the management of WPW syndrome, aiming to improve the quality of life and reduce the risk of life-threatening arrhythmias 4
- Electrophysiology testing and catheter ablation are helpful when evaluating asymptomatic patients with Wolff-Parkinson-White pattern 5
- Recent guidelines recommend invasive evaluation for asymptomatic patients where pre-excitation clearly does not disappear during exercise testing 6