Ventricular tachycardia

A cardiac arrhythmia is a disturbance of the normal heart rhythm known as sinus rhythm. Ventricular tachycardia (VT) is a type of rapid cardiac arrhythmia (greater than 100 beats per minute) that originates in the ventricle and can lead to serious symptoms, including sudden death.

How is it produced?

Under normal conditions, the heart contracts rhythmically and synchronously. This contraction is the result of an electrical impulse that is generated in the atrium, reaches the ventricle and results in a heartbeat. In an arrhythmia there is an alteration of this mechanism that leads to the heart not contracting regularly, generating a rhythm disorder.

In ventricular tachycardia, the heart rhythm is assumed by the ventricle, causing the new electrical signal to not move through the heart muscle in the normal way. The heartbeat accelerates and the patient feels palpitations. This irregular rhythm makes the ventricles unable to fill properly and therefore insufficient blood pumping.

VT can appear associated with heart disease (the most common being coronary disease) or in the normal heart, that is, without there being a structural cause.

Symptoms

Ventricular tachycardia may be asymptomatic or it may manifest seriously.

Symptoms include: palpitations, dyspnea (feeling short of breath), chest pain, and syncope.

The patient may be unconscious and with altered vital signs (hypotension, high heart rate, lack of oxygen).

Diagnosis

The fundamental diagnostic test is the electrocardiogram, the recording of which allows the ventricular heart rhythm to be established.

Other useful data in the diagnosis are the medical history and the physical examination that reveals the symptoms described together with the alteration of the vital signs (such as elevated heart rate).

Holter (24-hour electrocardiographic recording), electrophysiological study, echocardiogram and MRI are other additional tests that can be used to complete the study of the heart and the cause of the arrhythmia.

Cardiac catheterization is a test that allows the anatomy of the heart arteries to be visualized by introducing a catheter into the heart and injecting a contrast medium through it. One of the most common causes of this arrhythmia is coronary artery disease.

Treatment

Treatment depends on the symptoms. VT can be presented as a medical emergency (acute VT) in which the patient requires urgent action by:

• Cardioversion: is a treatment used to restore sinus rhythm (normal rhythm) after applying an electric shock to the chest or using drugs. It is used in emergency situations when the patient has severe symptoms due to arrhythmia.
• Life support measures that include a series of maneuvers and medical actions to maintain the patient's vital signs.

Antiarrhythmic drugs are used to restore and maintain a normal heart rhythm. They are especially indicated in patients susceptible to recurrent VT.

In stable patients, in addition to antiarrhythmic drugs, other treatments may be indicated, such as:

• Radiofrequency ablation: especially in patients with symptomatic and recurrent VT. It is a procedure in which a catheter and a device are used to obtain a map of the electrical conduction pathways of the heart. Using high-frequency electromagnetic waves, the conduction pathways responsible for the arrhythmia can be destroyed.
• DAIS (implantable cardioverter defibrillator). They are indicated in patients at risk of sudden death due to a history of VT. They are implantable devices that basically allow you to maintain an adequate heart rate when they detect an abnormal rhythm.

Prevention

Living a healthy life, avoiding alcohol, tobacco, drugs and stress helps prevent heart disease. It is very important for the prognosis and survival of the patient to institute treatment as soon as possible. In patients at risk of this type of arrhythmia, a device called an implantable cardioverter defibrillator can be placed on the chest that controls the heart rhythm and allows it to reset if it detects a VT episode.