Ventricular Tachycardia and Ventricular Fibrillation.

What is Ventricular Tachycardia?

The ventricles are the heart's two lower chambers. They fill with blood from the top chambers of the heart (atria) and send it to the lungs and through the aorta to be circulated throughout the body. Tachycardia is a heart rate of greater than 100 beats per minute. A normal heart rate is 60 to 100 beats per minute at rest. Ventricular tachycardia is a regular, faster-than-normal heart rate that begins in the heart's lower chambers. In most patients with ventricular tachycardia the rate is in the range of 170 beats per minute or more.

What Causes Ventricular Tachycardia?

Your heart rate is controlled by electrical signals transmitted across the heart muscle. When something goes wrong and signals are sent too rapidly, tachycardia can occur.

Most often, ventricular tachycardia is caused by other heart problems such as coronary artery disease, high blood pressure, an enlarged heart (cardiomyopathy) or heart valve disease. It also can develop after a heart attack (myocardial infarction) or after heart surgery because of scar tissue that forms on the heart.

Ventricular tachycardia can develop in people who do not have heart disease, but this is less commonly the case. In these individuals, the condition can be caused by certain medications, an imbalance in electrolytes (the minerals that regulate heart rhythm), excessive caffeine or alcohol consumption, recreational drugs or exercise, or certain genetically transmitted conditions. In others, it occurs in the absence of heart disease or any other clearly identified causes.

Older people and those with a family history of heart rhythm disorders are more likely to develop ventricular tachycardia.

A Ventricular Arrhythmia Begins In The Lower Chambers Of The Heart

Heart Rhythms on EKG

The heart's electrical system triggers the heartbeat. Each beat of the heart is represented on the electrocardiogram (EKG or ECG) by a wave arm.

Normal Heart Rhythm:

The normal heart rhythm (normal sinus rhythm) shows the electrical activity in the heart is following the normal pathway. The rhythm is regular and the node is normal (about 50 to 100 beats per minute).


Fast heart rhythm (greater than 100 beats per minute)