Monomorphic Ventricular Tachycardia (MVT)

Introduction

Monomorphic Ventricular Tachycardia (MVT) is a life-threatening cardiac arrhythmia originating in the ventricles. It is classified as a type of ventricular tachycardia (VT) where all QRS complexes have a uniform shape on an ECG. MVT is often associated with structural heart disease and can lead to significant hemodynamic instability, syncope, or even cardiac arrest.

Causes and Risk Factors

MVT can be caused by various underlying cardiac and systemic conditions, including: - Coronary artery disease (CAD): Often due to prior myocardial infarction (heart attack) causing fibrosis and reentry circuits. - Cardiomyopathies: Conditions such as dilated or hypertrophic cardiomyopathy. - Electrolyte imbalances: Low potassium or magnesium levels can predispose to arrhythmias. - Congenital heart disease: Structural abnormalities present from birth. - Drug toxicity: Certain medications like antiarrhythmics or stimulants can trigger VT.

Symptoms

The severity of symptoms depends on the heart rate and the ability of the cardiovascular system to compensate. Common symptoms include: - Palpitations (rapid heartbeats) - Dizziness or lightheadedness - Syncope (fainting) - Chest pain - Shortness of breath - In severe cases, cardiac arrest

Diagnosis

MVT is diagnosed using: - Electrocardiogram (ECG): Shows a wide-complex tachycardia with uniform QRS morphology. - Holter monitoring: Continuous heart monitoring for detecting intermittent episodes. - Echocardiography: Evaluates underlying structural heart diseases. - Cardiac MRI: Helps assess myocardial fibrosis and scarring. - Electrophysiological study (EPS): Determines the mechanism and precise location of VT.

Treatment

Acute Management

The treatment approach depends on symptom severity and hemodynamic stability: - Hemodynamically Unstable Patients: Immediate synchronized cardioversion is necessary. - Hemodynamically Stable Patients: - Antiarrhythmic drugs: IV amiodarone or procainamide may be used. - Correction of underlying causes: Address electrolyte imbalances, ischemia, or drug toxicity.

Long-Term Management

• Implantable Cardioverter Defibrillator (ICD): Recommended for patients at risk of sudden cardiac arrest.
• Catheter Ablation: Used to destroy the abnormal electrical circuits responsible for VT.
• Pharmacological Therapy: Beta-blockers, amiodarone, or sotalol may be prescribed.

Prevention

• Managing risk factors like hypertension, diabetes, and coronary artery disease.
• Regular monitoring in patients with known heart disease.

Conclusion

Monomorphic Ventricular Tachycardia is a serious and potentially fatal arrhythmia. Early diagnosis, appropriate treatment, and preventive strategies can significantly improve patient outcomes.

Source recommendations

1. American Heart Association Guidelines on Ventricular Arrhythmias

1. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000549
2. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate
3. https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/algorithms
4. https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/ventricular-fibrillation
5. https://pubmed.ncbi.nlm.nih.gov/29097320/

2. European Society of Cardiology Guidelines on 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.ahajournals.org/doi/10.1161/CIR.0000000000000549
5. https://pubmed.ncbi.nlm.nih.gov/26320108/