Ventricular tachycardia is a type of arrhythmia that is characterized by a fast beating or heart rhythm that starts with the ventricles, the 2 lower chambers of the heart, that can last for only a few seconds or longer. It is a pulse of more than 100 bpm with at least 3 irregular heartbeats in a row. It is due to a malfunction in the electrical system of the heart.
The heart is controlled by electrical signals that are sent to the tissues of the heart.
A healthy heart usually beats about 60 to 100 times per minute when at rest and it is defined by signals that come from the upper chambers of the heart called atria.
In ventricular tachycardia, the abnormal or unusual electrical signals in the ventricles cause the heart rate to shoot up and be out of sync with the upper chambers, 100 or greater bpm. When this occurs, the heart may not be able to pump enough blood to the lungs and body because the chambers are beating out of sync with each other and they don’t have time to fill properly.
Ventricular tachycardia can be asymptotic or it may not show any symptoms but it can also show symptoms such as palpitations, lightheadedness, dizziness, or sometimes a loss of consciousness. In some instances, it may even cause the heart to stop which is a life-threatening medical emergency. Ventricular tachycardia becomes life-threatening when it occurs with other heart conditions like structural heart diseases or a history of heart attack.
Ventricular tachycardia is usually life-threatening unless experienced by a normal and healthy person who doesn’t have any structural heart disease. It can be very dangerous and it normally needs immediate medical attention. A few beats do not usually cause problems but if the episodes of the disease hold for more than a few seconds, it could be very dangerous. Acute episodes of prolonged ventricular tachycardia are considered as medical emergencies most of the time. Ventricular tachycardia can develop into ventricular fibrillation which is a more dangerous form of arrhythmia. Ventricular fibrillation can cause sudden cardiac arrest that may lead to death if the disease is not treated properly.
There are 2 factors that make ventricular tachycardia a dangerous cardiac arrhythmia:
- Ventricular tachycardia reduces the efficiency of the heart when the heart rate reaches greater than 180 to 200 bpm which is rapid enough.
- Ventricular tachycardia can interrupt the coordinated, orderly, and normal contraction of the muscle of the heart.
Causes of Ventricular Tachycardia
Ventricular tachycardia is caused by a disruption of the normal electrical impulses that regulate the pumping action of the ventricles.
There are other factors though that may contribute or cause problems with the heart’s electrical system such as:
- Congenital heart conditions or abnormal electrical pathways in the heart that is present at birth
- Cardiomyopathy or structural heart disease
- Lack of oxygen to the heart caused by tissue damage from heart conditions
- Side effects of medications
- Sarcoidosis or an inflammatory disease that affects the skin or other tissues
- Imbalance of electrolytes which are essential in conducting electrical impulses
The exact cause of ventricular tachycardia cannot be determined in some instances.
This is in the case of idiopathic ventricular tachycardia where ventricular tachycardia is recorded or can be seen in normal and healthy people who do not have structural heart problems.
Symptoms of Ventricular Tachycardia
Short episodes of ventricular tachycardia may not bring about any symptoms for some individuals. Some individuals may experience the following symptoms though such as:
Sustained ventricular tachycardia (SVT) or more serious episodes of ventricular tachycardia may result in:
- Fainting or loss of consciousness
- Cardiac arrest or sudden death
Complications of Ventricular Tachycardia
The complications of ventricular tachycardia have different severities which depend on various factors such as the heart rate, the duration of a rapid heart rate, the frequency of the episodes, and the presence of other heart diseases. These are the possible complications of ventricular tachycardia:
- Frequent loss of consciousness or fainting
- Heart failure or the inability of the heart to pump enough blood
- Sudden death caused by cardiac arrest
The reason why it’s important to immediately treat associated conditions of ventricular tachycardia is that these heart conditions may cause the complications of ventricular tachycardia and it may put an individual at a higher risk of death.
Any condition or problem that puts a strain on the heart or damages the tissue of the heart can increase the risk of ventricular tachycardia. Medical treatment and changes in lifestyle can help decrease the risk that is linked to these factors:
- Severe abnormalities in electrolytes
- Heart diseases such as history of heart attack, genetic conditions, inflammatory diseases of the heart, hypertrophic cardiomyopathy
- Side effects of medications
- Use of recreational drugs
- Family history of ventricular tachycardia and other heart rhythm problems
Individuals with sustained ventricular tachycardia are at a higher risk. Individuals with cardiac arrest or syncopal ventricular tachycardia which occurs during exercise have a 35% risk. Individuals with a compromised left ventricular function and a cardiac arrest or syncopal ventricular tachycardiardia have a 25% risk. Individuals with a history of multiple myocardial infarctions have a 20% risk.
The 2 main factors affecting survival are:
- Hemodynamic effects of ventricular tachycardia
- Left ventricular function
Not taking into account the other variables, individuals who have any of these 2 risk factors have an increased risk of sudden death by about 10%.