Ventricular tachycardia or V-tach is an abnormally rapid heartbeat. Three or more heartbeats at a rate of 100 beats per minute or above fit the diagnostic criteria for ventricular tachycardia. In some patients, the rapid heartbeat resolves on its own within 30 seconds, while in others, it may be sustained, lasting more than 30 seconds. This heart rhythm is a sign of an underlying cardiac problem and it can precede a serious medical emergency.
As the name suggests, ventricular tachycardia originates in the ventricles of the heart. The part of the heart muscle responsible for regulating contractions of the ventricles fires prematurely, causing the ventricles to contract too soon. A distinctive heart rhythm can be seen on an electrocardiograph (ECG), allowing a doctor to diagnose ventricular tachycardia. Since the condition can be intermittent, patients at risk may be asked to wear a mobile monitor to record heart rhythms, allowing a doctor to identify periods of rapid heart rate as they occur over the course of the day.
During bouts of ventricular tachycardia, patients can experience a variety of symptoms. Palpitations, where the heart feels like it is beating rapidly, can be observed, along with sweating, pallor, clammy skin, nausea, and a general feeling of malaise. Some causes of this abnormally fast heart rate include chronic heart conditions such as cardiomyopathy, along with scarring from myocardial infarctions. Ventricular tachycardia can also directly precede a heart attack.
If it persists, ventricular tachycardia sometimes leads to a very dangerous medical emergency called ventricular fibrillation. In this type of heart rhythm, the heart beats very rapidly and is not coordinated. Instead of circulating blood, it quivers in the chest. The patient can die within minutes as a result of poor blood circulation to the body. V-fib, as it is also known, produces a very recognizable rhythm on ECGs, making it easy to identify.
Available treatments can include medications to regulate heart rhythm, ablation of damaged areas of the ventricles to restore normal heart rhythm, and the use of external pacing devices to shock the heart into the correct rhythm. Heart surgery may be required for some patients. It is also important to identify and treat the underlying cause, if possible, with the goal of preventing complications like ventricular fibrillation. Patients with a history of episodes of ventricular tachycardia should make sure their doctors are aware of it, especially if they are going into surgery.