Understanding Wide Complex Tachycardia (WCT)

Introduction

Wide complex tachycardia (WCT) refers to a rapid heart rhythm (≥100 beats per minute) with a QRS complex duration of ≥120 milliseconds on an electrocardiogram (ECG). WCT is a medical emergency that requires immediate evaluation and appropriate management, as it may indicate life-threatening arrhythmias.

Causes of WCT

The two main categories of WCT are:

1. Ventricular Tachycardia (VT): Originates from the ventricles and is the most concerning cause.
2. Supraventricular Tachycardia (SVT) with Aberrancy: Originates above the ventricles, but presents with a wide QRS due to conduction block or pre-existing bundle branch block.

Differentiating VT from SVT with Aberrancy

Differentiating between VT and SVT is crucial as VT is often life-threatening. Some clues that suggest VT include: - Patient history: History of myocardial infarction, heart failure, or prior ventricular arrhythmias. - ECG features: - AV dissociation (P waves independent of QRS complexes) - Fusion and capture beats - Extreme axis deviation (northwest axis) - Concordance of QRS complexes across precordial leads

Management of WCT

1. Assess hemodynamic stability:

   • Unstable patient (hypotension, altered mental status, chest pain, signs of heart failure): Immediate synchronized cardioversion is required.
   • Stable patient: Further diagnostic evaluation and pharmacologic treatment can be considered.

2. Pharmacologic treatment:

   • If VT is suspected: Antiarrhythmic drugs such as amiodarone, procainamide, or lidocaine.
   • If SVT with aberrancy is suspected: Vagal maneuvers or adenosine may help in diagnosis and treatment.

Conclusion

WCT is a critical cardiac emergency, often requiring rapid diagnosis and intervention. Differentiating VT from SVT is essential for appropriate management. In all cases, evaluation by a cardiologist and possible electrophysiological study may be necessary.

Source recommendations

1. American Heart Association (AHA) Guidelines for the Management of Ventricular Arrhythmias

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
2. https://pubmed.ncbi.nlm.nih.gov/29097320/
3. https://www.ahajournals.org/doi/10.1161/CIR.0000000000001193
4. https://www.sciencedirect.com/science/article/pii/S2405500X22010945
5. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/algorithms

2. European Society of Cardiology (ESC) Guidelines for the Management of Supraventricular Tachycardia

1. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Supraventricular-Tachycardia
2. https://academic.oup.com/eurheartj/article/41/5/655/5556821
3. https://pubmed.ncbi.nlm.nih.gov/31504425/
4. https://www.acc.org/Latest-in-Cardiology/ten-points-to-remember/2019/09/10/12/36/2019-ESC-Guidelines-for-Supraventricular-Tachycardia
5. https://www.ahajournals.org/doi/10.1161/01.cir.0000091380.04100.84

3. ESC 2022 Guidelines for the Management of Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death

1. https://pubmed.ncbi.nlm.nih.gov/36017572/
2. https://academic.oup.com/eurheartj/article/43/40/3997/6675633
3. https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Ventricular-Arrhythmias-and-the-Prevention-of-Sudden-Cardiac-Death
4. https://www.ecrjournal.com/articles/comment-esc-guidelines-2022-management-patients-ventricular-arrhythmias-and-prevention?language_content_entity=en
5. https://guardheart.ern-net.eu/wp-content/uploads/sites/4/2023/02/PMID-36017572_ESCGuideline_Zeppenfeld.pdf