Ventricular Tachycardia

Cardiology (12%) Core Clinical Conditions

1B: Able to identify the condition as a possible diagnosis: may not have the knowledge or resources to confirm the diagnosis or to manage the condition safely, but can take measures to avoid immediate deterioration and refer appropriately

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Definition Aetiology Pathophysiology Risk factor Sign and Symptoms Investigations Management

Ventricular tachycardia (VT) is a type of heart rhythm disorder in which the ventricles beat too rapidly and irregularly, causing a decrease in blood flow. It is characterized by three or more extra heartbeats per minute with a ventricular heart rate greater than 120 beats per minute.

• Changes to the structure of the heart: previous MI, coronary artery disease and cardiomyopathy. Which may cause scarring and damage to the heart muscle. Scarring might be the main reason why there is an abnormal electrical activity in the ventricle.

• Electrolyte imbalance: imbalance in potassium, magnesium or calcium might cause abnormal electrical activity of the heart.

• Medications such as antipsychotics, tricyclic antidepressant and antiarrhythmic meds.

• Genetics

• Substance abuse

• Trauma or injury to the heart: for example, previous heart surgery

• Idiopathic causes.

1. An abnormal electrical signal begins in the ventricles, instead of from the heart's natural pacemaker, the sinoatrial (SA) node.

2. The ventricles contract rapidly and inconsistently with the atria.

3. Reduced cardiac output

• Structural damage to heart 

• History of previous MI 

• Family history of sudden heart death 

• Electrolyte imbalance 

• Substance abuse 

• Sleep apnoea 

• Increased age 

• Gender - women more at risk 

• Other chronic health conditions e.g. diabetes, CKD

• Palpitations 

• Dizziness

• Syncope

• Shortness of breath (SOB)

• Chest pain

• Fatigue or weakness

• Sudden cardiac arrest

• ECG (see figure 1)

• Echocardiogram

• Blood tests - check for any electrolyte imbalance e.g. low potassium, phosphate, or magnesium levels.

• Holter monitoring 24 to 48 hours or longer.

• Imaging: CXR, Cardiac MRI or CT

• For Pulseless VT, the advanced life support algorithm should be followed and treated  like Ventricular Fibrillation (VF).

• Medications: Antiarrhythmic medicines, such as amiodarone (300 mg IV, followed by a 24-hour infusion of 900 mg), may be used to modulate the cardiac rhythm and lessen the frequency and severity of VT episodes. Several drugs, including beta-blockers and calcium channel blockers, may be used to lower the risk of VT by regulating heart rate and blood pressure. 

• Electrical cardioversion: if medication treatment fails and the patient is hemodynamically unstable.

• Implantable cardioverter defibrillator (ICD): This is a subcutaneously implanted device that is wired to the heart. It can detect and terminate VT episodes by shocking the heart with an electrical current. Those at high risk for sudden cardiac death or those who have suffered VT or VF.

• Lifestyle changes: Regular exercise, a well-balanced diet, and the avoidance of smoking and excessive alcohol or caffeine consumption are all important components of a healthy lifestyle.

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