Cardiac arrhythmias occur when the heartbeat becomes irregular due to increased or decreased impulses. Ventricular tachycardia is a dangerous form of arrhythmia. It originates in the ventricles of the heart and is a serious emergency in any case.
What is ventricular tachycardia?
Heart palpitations of more than 100 beats per minute are normal. Especially during physical exertion, this heart rate is reached quickly but is completely harmless. Nevertheless, a doctor should always be consulted in case of frequent tachycardia with arrhythmia at rest. Ventricular tachycardia is a form of cardiac arrhythmia. It occurs when the heart chambers send extra impulses that cause the heart to beat more than 120 beats per minute. In most cases, it develops in the presence of existing coronary heart disease. Depending on the speed of the heartbeat, it can lead to ventricular flutter or even ventricular fibrillation. Therefore, ventricular tachycardia should be treated by an emergency physician as soon as possible, otherwise it can be fatal within a few minutes.
Causes
Ventricular tachycardia is usually caused by coronary artery disease. This, in turn, usually involves narrowing of the coronary arteries (vessels that supply oxygen-rich blood to the heart). These constrictions in turn mean that the heart muscle can no longer be supplied with blood properly. The narrowing itself manifests as a feeling of pressure and tightness in the chest, as well as heart pain, which can occur both with exertion and at rest. Coronary heart disease is favored by several factors. For example, smokers, people who are overweight and predominantly male at an advanced age fall into the risk group. Existing diseases such as diabetes, elevated blood lipid levels (cholesterol) or high blood pressure as well as coronary heart disease in first-degree relatives are also considered major risk factors. External influences such as stress, lack of exercise and an unhealthy diet also have a damaging effect on the blood vessels. In addition to coronary heart disease, other causes of ventricular tachycardia may also be involved. First and foremost are heart muscle diseases (cardiomyopathies), which are based on a functional disorder of the heart. Cardiomyopathies are usually accompanied by an enlargement of the heart, which has a decisive influence on the heart rhythm. However, ventricular tachycardia can also result from an existing inflammation of the heart muscle (myocarditis) or an existing long-QT syndrome (prolonged QT interval in the ECG). It can also result from congenital or acquired heart defects that affect the function of the heart. In addition, they also find their cause in the effect of certain medications, pulmonary embolism, and the derailment of certain electrolytes (e.g., potassium).
Symptoms, complaints, and signs
Ventricular tachycardia rarely occurs in healthy people. It usually affects people with preexisting conditions. For example, an existing hyperthyroidism and an overdose of digitalis may promote a condition. Organic heart damage also promotes a rhythm disorder. The following symptoms can increase to cardiac arrest. There is then a danger to life. In the early stages, patients regularly complain of dizziness and fainting. In addition, discomfort in the area of the chest becomes noticeable. Patients often describe that they can feel their own heartbeat and that it has an unusual frequency. Experts usually diagnose an accelerated heartbeat in this context. In addition, psychological signs appear. Those affected complain of anxiety that can take on life-threatening forms. Sudden sweating and immediate weakness of the entire body also characterize the condition. Respiratory symptoms also develop in the course of ventricular tachycardia. These range from mild breathing difficulties to respiratory arrest. Patients get insufficient air and gasp for it; if the condition is left untreated for a long time, breathing stops altogether. Problems with air coughing can regularly lead to cardiac arrest. Affected persons should therefore consult a doctor immediately or alert an ambulance service.
Complications
The most dangerous complication of ventricular tachycardia is the threat of ventricular fibrillation.Since a heart rate exceeding 320 beats per minute is reached, the patient’s life is in acute danger. Due to the rapidity of the heartbeat, the heart does not have time to fill sufficiently with blood between beats on the one hand, and on the other hand the heart muscle exhausts itself due to the extremely high output. If the oxygen-enriched blood is not pumped into the aorta in sufficient quantity, the heart lacks important nutrients after a short time because the blood circulation is interrupted. A vicious circle begins, which brings the heart more and more out of its natural rhythm, because even the contractions no longer occur in this state. In ventricular fibrillation, the heart no longer pumps, but merely trembles. If this emergency is not treated quickly, the heart becomes completely exhausted, resulting in cardiac arrest. Another complication concerns patients suffering from long-QT syndrome. If they suffer a cardiac arrest after ventricular fibrillation, this cannot be reversed even by resuscitation attempts. A final cardiac arrest is present, after which the patients can no longer be resuscitated.
When should you go to the doctor?
If palpitations, palpitations, or heart palpitations persist for several days, it is important to see a doctor for evaluation. People who suffer from diabetes or high blood pressure should measure their blood pressure and pulse several times a day and note the values so that they can present them to the attending physician if necessary. Under no circumstances should people hesitate if the cardiac arrhythmia persists over a long period of time and if dizziness, shortness of breath or an oppressive feeling of anxiety are added to the symptoms of ventricular tachycardia. Passersby who see an unconscious person or family members who are near them at the time of the emergency should immediately call an emergency physician for help. It could be that the person is experiencing ventricular tachycardia. If help arrives quickly enough, it may save their life! Even if the unconsciousness lasts only a short time, the affected person is far from out of danger of death.
Diagnosis
Ventricular tachycardia can be determined with the help of an electrocardiogram (ECG). Each trace the machine records allows the physician to see all the activity of the heart muscle fibers. The ECG records the length and duration of various phases that the heart goes through during each pumping beat. For this purpose, several electrodes are attached to the patient’s chest, which transmit the impulses to the ECG device. The latter records the pumping impulses and displays them as wave lines. Typical signs of ventricular tachycardia are distorted, wide ventricular complexes lasting longer than 0.14 seconds. These occur independently of atrial action. Physicians refer to this as AV dissociation because said independence reveals that the ventricles and atria are no longer working in sync with each other. If AV dissociation is not complete, the ECG records normal ventricular excitation propagation (QRS complex). These segments occurring in the setting of ventricular tachycardia are also referred to as the “capture beat.”
Treatment and therapy
Treatment of ventricular tachycardias depends on their cause. If it is caused by an organic disorder of the heart (e.g., myocarditis or heart failure), it must be corrected with medication or surgery. In drug therapy, a precise distinction must be made as to whether heart failure is present. Parallel to ongoing emergency medical treatment, the patient’s breathing should be ensured by administering oxygen via a nasal probe. If severe ventricular tachycardia results in cardiac arrest, immediate cardioversion must be performed with the aid of a defibrillator. In this procedure, the emergency physician applies electrical shocks to the heart to stimulate it and get it beating again. If the patient is unconscious, the physician must defibrillate without the time-consuming connection of an ECG in order to save the patient’s life in time.
Outlook and prognosis
In general, individuals experience ventricular tachycardia who have a history of structural heart disease. As an example, consider myocardial infarction patients. If the ventricular tachycardia persists for more than three months after the myocardial infarction, these patients have the worst prognosis.In terms of numbers, the mortality rate (lethality) within one year after the infarction is 85%. In contrast, if ventricular tachycardia occurs in individuals who have had no previous heart disease, there is no increased risk of mortality compared with the average population.
Prevention
Because ventricular tachycardias are life-threatening emergencies, the cause must be determined as soon as possible to prevent them from occurring in the future. Diseases of the heart must be treated and stressful situations avoided. If ventricular tachycardia recurs frequently in a patient despite all therapeutic measures, implantation of a defibrillator is an option. These small systems are called “implantable cardioverter-defibrillator” (ICD for short). They are capable of detecting ventricular tachycardia and automatically treating it with small electrical shocks. However, to prevent the device from having to intervene frequently, catheter ablation should be used to try to stop frequently recurring tachycardia. This method removes tissue that sends false impulses to the heart, causing the high heart rate.
Follow-up care
Patient follow-up is of great importance if the causes of ventricular tachycardia are diseases of the heart muscle or coronary artery disease. Antiarrhythmic drugs are prescribed as drug therapy in order to reduce the excitability of the heart. If these do not help, a catheter ablation is performed. A catheter is inserted into the heart through the patient’s groin. Pathological heart muscle cells, which trigger abnormal excitation, or pathological performance pathways, are obliterated with the help of electric shocks. As a result, the heart beats again in its physiological rhythm. The success of this treatment is permanent in most cases and is monitored by a long-term ECG. If the risk of a recurrence of ventricular tachycardia with possible fatal consequences is too high, the patient receives an implantable cardioverter defibrillator. This is inserted under the skin of the chest and is connected by probes to the atrium and ventricle of the heart. It continuously monitors the heart’s activity. If the defibrillator detects a dangerous rhythm disturbance, it restores the heart to its normal rhythm by means of a direct current pulse. The patient can positively influence his aftercare by preventing his heart rate from increasing unnecessarily. Coffee, nicotine and stress-inducing situations must be avoided. Instead, moderate exercise and relaxation exercises, such as yoga, are emphasized.
What you can do yourself
As mentioned earlier, ventricular tachycardia occurs in most cases due to existing heart diseases. These heart patients can do a lot themselves to prevent tachycardia, in addition to medical treatment. First and foremost, excessive stress should be reduced. Physical activity is a particularly good way of coping with stress, because exercise releases so-called happiness hormones, which contribute to relaxation. For beginners, gentle activities such as a long walk in the fresh air are also suitable. In the case of emotional distress, relaxation exercises such as yoga or meditation should also be tried. If this does not achieve sufficient relaxation, psychological help should not be hesitated. Mental distress causes, among other things, high blood pressure, which in turn can lead to tachycardia. In addition, attention should be paid to a healthy, balanced diet, as the heart is also under great strain when overweight. In addition to obesity, eating a high-fat diet risks increasing cholesterol levels and, with them, the amount of fat in the blood. This deposits in the inner walls of the blood vessels and can lead to dangerous constrictions through which the heart can no longer be optimally supplied with blood. In addition, the consumption of nicotine and caffeine should be avoided, especially in the presence of heart disease. While caffeine has a stimulating effect and increases the heart rate, smokers with nicotine inhale pure poison, which hits both the heart and the lungs.
