Wide Complex Tachycardia (WCT)

Introduction

Wide complex tachycardia (WCT) is a heart rhythm disorder that presents with a rapid heart rate (over 100 beats per minute) and a widened QRS complex (≥120 ms) on an ECG. WCT can be life-threatening and requires urgent evaluation and management.

Causes of WCT

The two main categories of WCT are: - Ventricular Tachycardia (VT): Originates from the ventricles and is the most concerning type due to the risk of sudden cardiac death. - Supraventricular Tachycardia (SVT) with Aberrancy: A supraventricular rhythm that appears wide due to underlying conduction abnormalities (e.g., bundle branch block or pre-excitation).

Distinguishing VT from SVT with Aberrancy

Several clinical and ECG criteria help differentiate these conditions: 1. History: VT is common in patients with structural heart disease (e.g., prior heart attack, heart failure), whereas SVT may occur in a structurally normal heart. 2. ECG findings: - Capture or fusion beats suggest VT. - Extreme axis deviation supports VT. - Brugada criteria are commonly used to diagnose VT.

Symptoms

• Palpitations
• Dizziness or syncope (fainting)
• Chest pain
• Shortness of breath
• Cardiac arrest in severe cases

Management

1. Stable Patients:
   • VT: Antiarrhythmic drugs (e.g., amiodarone, procainamide, sotalol)
   • SVT: Vagal maneuvers or adenosine if uncertain
2. Unstable Patients (hypotension, shock, severe symptoms):
   • Immediate synchronized cardioversion
   • Consideration of implantable cardioverter-defibrillator (ICD) for recurrent VT
3. Long-Term Management:
   • Identifying and treating underlying heart disease
   • Catheter ablation for recurrent cases
   • Medication for rhythm control

Conclusion

WCT is a dangerous arrhythmia that requires immediate attention. Differentiating VT from SVT with aberrancy is critical for appropriate treatment. If in doubt, treat as VT, as it is more life-threatening.

Source recommendations

1. American Heart Association (AHA) Guidelines on Tachyarrhythmias

1. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate
2. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
3. https://www.heart.org/en/health-topics/arrhythmia
4. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
5. https://cpr.heart.org/-/media/cpr-files/cpr-guidelines-files/algorithms/algorithmacls_tachycardia_200612.pdf

2. European Society of Cardiology (ESC) Guidelines for the management of ventricular arrhythmias

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
2. https://academic.oup.com/eurheartj/article/43/40/3997/6675633
3. https://pubmed.ncbi.nlm.nih.gov/36017572/
4. https://www.sciencedirect.com/science/article/pii/S2405500X22010945
5. https://pubmed.ncbi.nlm.nih.gov/26320108/