Ventricular tachycardia is a disorder of the heart rhythm in which the heart beats abnormally. The impulses that stimulate them to contract arise within the ventricular muscularis, and not in the sinus node as they should. This results in abnormal pulse propagation, lack of pulse control and less effective heart contraction. Such a disturbance of the heart work has very serious consequences. Find out who may develop ventricular tachycardia and what are the methods of preventing this arrhythmia.

Ventricular tachycardiais a direct threat to life as it can itself cause or lead to cardiac arrest. In a few cases it happens that it is mild and self-resolving (so-called benign ventricular tachycardias).

It is very important to identify the cause of this arrhythmia and treat it as it greatly reduces the risk of recurrence.

If such therapy is not possible, a subcutaneous cardioverter defibrillator will be implanted to stop the tachycardia attacks or to ablate the site responsible for the abnormal heart rhythm.

How does ventricular tachycardia develop?

In a he althy heart, impulses stimulating it to work arise in the sinus node, from there they spread to the atria, and then through the atrioventricular node to the heart chambers. There, through the bundles of His and Purkinje fibers, the stimulation spreads synchronously throughout the muscle of the ventricles, causing them to contract.

This way of traveling of the electrical signal ensures the proper work of the heart, and its formation in the sinus node is important, among others, because of the possibility of being controlled by the nervous system or the endocrine system.

In some cases, however, there is the formation of so-called ecotopic centers, i.e. places within the muscle of the ventricles that generate electrical impulses.

Such areas are excluded from any control and cause arousal in a completely random manner. If it happens very quickly, you will develop ventricular tachycardia.

Another mechanism is the appearance in the area of ​​the left ventricular muscle of a certain area around which the electrical stimulus is abnormally conducted.

If the impulse begins to circulate at this point, it may result in a continuous,repeated myocardial stimulation and development of tachycardia.

The occurrence of this arrhythmia is dangerous not only due to the lack of control over the work of the heart by the nervous system, but above all because the very fast heart rate, characteristic of ventricular tachycardia, significantly reduces the effectiveness of the contraction and filling the ventricles with blood in the time during diastole.

As a consequence, the work of the heart is impaired and the blood flow in the arteries decreases significantly.

Ventricular tachycardia: symptoms and effects

Ventricular tachycardia is life-threatening for two reasons: this arrhythmia itself causes a significant impairment of the heart's work, sometimes contractions are completely ineffective and the pulse is no longer perceptible - it is one of the mechanisms of cardiac arrest.

On the other hand, ventricular tachycardia can progress to ventricular fibrillation, which is also a mechanism of cardiac arrest and can be fatal.

The spectrum of symptoms and their severity is very wide.

As mentioned, ventricular tachycardia can cause unconsciousness and cardiac arrest.

Other possible symptoms are:

  • exercise-related fainting
  • shortness of breath
  • palpitations
  • dizziness
  • stinging or chest pain

It is not uncommon for a family to have a history of unexplained syncope or cardiac death.

Ventricular tachycardia can also be completely safe, asymptomatic and self-limiting, in such cases it is usually very short-lived.

It's good to know that tachycardia is much more likely, more likely, and likely to have serious complications if you have any of the heart conditions listed below.

Ventricular tachycardia: causes

Such a heart rhythm disturbance can have many causes, from extremely dangerous to completely trivial, which do not cause any symptoms:

  • myocardial infarction: in the course of this disease, ventricular arrhythmias, including tachycardia, are common. They happen both immediately after an infarction and during several days of observation. However, thanks to the universal access to invasive treatment, they are less and less frequent.
  • ischemic heart disease, or coronary artery disease: chronic ischemia, like an infarction, can lead to ventricular tachycardia.
  • dilated cardiomyopathy, hypertrophic cardiomyopathy: these are heart diseases in which the heart muscle is damaged, which is manifested bymay develop tachycardia. Unfortunately, in such cases they have a tendency to recur and increase the risk of death.
  • electrolyte disturbances - significant magnesium deficiency or potassium deficiency
  • poisoning, e.g. with digoxin, antidepressants
  • arrhythmogenic right ventricular cardiomyopathy - a congenital disease that manifests as abnormal heart rhythms, including tachycardia
  • long QT syndrome, catecholamine-dependent ventricular tachycardia and Brugada syndrome are inherited diseases caused by damage to ion transporters. They can lead to disturbances in the electrical activity of the heart muscle cells, which in turn causes ventricular tachycardia. These diseases occur in families and are most often manifested in young people, and episodes of tachycardia are caused by emotions or physical exertion.
  • mild ventricular tachycardia - occurs in people without heart disease, its cause is unknown, mild course - usually causes heart palpitations. They do not increase the risk of ventricular fibrillation nor are they life-threatening.
  • myocarditis
  • valvular disease
  • advanced heart failure

Ventricular Tachycardia: Recognition

We diagnose ventricular tachycardia on the basis of an ECG. If there are successive so-called ventricular beats with a frequency of more than 100 beats per minute, we can make a diagnosis of ventricular tachycardia.

Additional features facilitating diagnosis are the lack of P waves in the recording and the duration of QRS complexes above 120 ms (the so-called broad QRS).

Thanks to the ECG examination, tachycardia can also be classified accordingly, if the ventricular beats occur consecutively in the number of less than 3, this rhythm disturbance is called non-persistent ventricular tachycardia (nsVT), it is milder. However, if at least 3 ventricular beats occur consecutively, it is a sustained ventricular tachycardia (sVT).

It happens that this arrhythmia is caused by excessive exercise, then it can be found during an exercise test, i.e. a test that assesses the ECG recording while riding a stationary bike or walking on a treadmill.

Less often, when the doctor suspects the presence of these arrhythmias, and the ECG fails to detect them, it is necessary to perform a Holter EKG, i.e. a record of the electrical activity of the heart lasting 24 hours.

Another method is an electrophysiological test, in which the areas responsible for the occurrence of a rhythm disturbance can be detected and during thisthe procedure itself "exclude" them from the pulse circulation. If the treatment is fully effective, tachycardias do not recur.

Diagnostics of VT should not be limited to its diagnosis, a series of tests should be performed to determine its cause.

Depending on the presumed etiology, these are:

  • heart echo
  • coronary angiography (imaging of the coronary arteries)
  • heart resonance
  • laboratory tests

Such diagnostics allows for the diagnosis of the underlying arrhythmia and enables treatment of the cause of the ventricular tachycardia.

If this therapy is successful, the tachycardia does not recur, and if the cause cannot be determined, electrophysiological testing and ablation of the arrhythmia site or defibrillator implantation are the best option.

Ventricular tachycardia: treatment

Each case of permanent ventricular tachycardia is an indication for immediate treatment and diagnosis of its cause. In an emergency, if no heart rate is felt during VT, you must deliver immediate defibrillation and CPR, as in VF.

If a pulse is present but the patient is seriously unresponsive or haemodynamically unstable, cardioversion is required (similar to defibrillation but uses less shock energy).

If the person with tachycardia is stable, they are given antiarrhythmic drugs to inhibit the ventricular tachycardia.

What to do next depends on the disease causing the disturbance. In the case of a heart attack and coronary artery disease, coronary angioplasty, i.e. stenting, is performed.

If the cause is electrolyte disturbances or poisoning, initiate their treatment - administer the missing ions or remove toxins.

However, if the cause cannot be removed or remains unknown, implantation of an ICD, or cardioverter-defibrillator, is necessary.

This is a small device that is placed under the skin and is designed to deliver defibrillation or cardioversion in the event of a severe rhythm disturbance.

If the cause can be found during electrophysiological examination, the area of ​​the heart responsible for arrhythmia can be "turned off", this is ablation procedure.

Pharmacological treatment of the tachycardia itself is of less importance, but it should be remembered that it is necessary to treat the causes of tachycardia and sometimes to administerdrugs that inhibit the occurrence of this heart rhythm disturbance.

  • When the heart suddenly speeds up - interview with a cardiologist, prof. Leszek Bryniarski
About the authorBow. Maciej GrymuzaA graduate of the Faculty of Medicine at the Medical University of K. Marcinkowski in Poznań. He graduated from university with an over good result. Currently, he is a doctor in the field of cardiology and a doctoral student. He is particularly interested in invasive cardiology and implantable devices (stimulators).

Category:

Cardiology