Your heart is a muscle that pumps blood through your body. Your heart rate is how fast your heart beats. Your heart should always have a regular, rhythmic beat, like the ticking of a clock.
Your heart has four chambers. The atria are the two upper chambers in your heart. The ventricles are the two lower chambers in your heart. The atria pump blood into the ventricles. The ventricles pump blood to your lungs and your body (see also Biology of the Heart).
Special pacemaker cells in a part of the atria called the SA node (sinoatrial node) send out regular electrical signals to your heart muscle to make it contract.
Your heart's conduction system has tiny strips of tissue sort of like electrical wires. The conduction system carries the pacemaker signals to the rest of your heart. The signals must get to all your heart muscle cells at just the right time so your heart gives a good, strong beat that pumps blood properly.
What is ventricular tachycardia?
Ventricular tachycardia is a type of abnormal heart rhythm. In ventricular tachycardia, a very fast heartbeat starts in the ventricles of your heart.
The most common symptom is palpitations (feeling your heart beating)
You might also have trouble breathing, chest discomfort, and fainting
Ventricular tachycardia sometimes turns into ventricular fibrillation, which is fatal unless treated quickly
Doctors do an electrocardiogram (ECG/EKG) to diagnose ventricular tachycardia
Doctors often give you an electrical shock (cardioversion) or give you medicines to return your heart beat to normal
If you get ventricular tachycardia a lot, you may need an implantable defibrillator (ICD)
Sometimes ventricular tachycardia is only 3 or 4 ventricular premature beats in a row, and then your heart returns to a normal rate and rhythm. Sustained ventricular tachycardia is when the abnormal rhythm lasts more than 30 seconds. Sustained ventricular tachycardia can go on for a long time.
What causes ventricular tachycardia?
Ventricular tachycardia happens when some of the cells in your ventricle start acting like pacemaker cells. If they go faster than your normal pacemaker cells, they can take over your heart and make it beat very fast.
Sustained ventricular tachycardia usually happens in older people with heart problems, such as a:
Cardiomyopathy (a problem in the walls of the heart that makes it hard for your heart to pump blood)
Other causes may include:
Long QT syndrome (an abnormal electrical circuit that may trigger a sudden ventricular tachycardia or even more dangerous rhythms when you exercise or feel stressed)
Certain medicines
Brugada syndrome (an inherited heart condition that increases the risk of ventricular tachycardia and other arrhythmias)
What are the symptoms of ventricular tachycardia?
Symptoms of ventricular tachycardia include:
Palpitations
Feeling weak and light headed
Chest discomfort
What are the complications of ventricular tachycardia?
Sustained ventricular tachycardia can cause more dangerous problems, such as:
Low blood pressure and sometimes fainting because your heart doesn’t pump blood as well as it should
Cardiac arrest (when your heart stops beating)
How can doctors tell if I have ventricular tachycardia?
Doctors feel your pulse and do:
An ECG is a quick, painless test that measures your heart’s electrical activity using stickers and cables on your chest, arms, and legs.
If the ECG shows ventricular tachycardia, doctors usually do:
Blood tests to check for abnormal electrolyte levels and signs of heart damage
How do doctors treat ventricular tachycardia?
Doctors only need to treat ventricular tachycardia if:
You have symptoms
You have sustained ventricular tachycardia
Right away, doctors treat it with:
Cardioversion
In cardioversion, doctors give a short electrical shock to your heart. They give the shock through sticky pads on your chest or sometimes paddles they hold against your chest. The shock stops the tachycardia so your heart can resume its normal rhythm. You may need several shocks. Doctors will give you medicine directly into your vein (IV medicine) so you're sleepy and it doesn't hurt.
Certain IV medicines can sometimes stop the tachycardia, but doctors usually prefer cardioversion because it's quicker and safer.
If you keep having ventricular tachycardia, you may need:
An implantable cardioverter-defibrillator (ICD)
An ICD is a device implanted under the skin of your chest or stomach. The device is connected to your heart with wires so it can monitor your heart beat. It can automatically give you a shock and restart your heart if you have ventricular tachycardia or ventricular fibrillation.
