Supraventricular tachycardia (SVT) is a condition characterized by a very rapid heartbeat, often 151 and 250 beats per minute. SVT affects both adults and children equally. There are various forms of SVT, each of which affects a different area of the heart or has a distinct origin. Primary signs of SVT include a racing heart and other symptoms that can cause pain, discomfort, or dizziness.
In general, supraventricular tachycardia is basically a group of arrhythmias, or irregular heartbeats, that are distinguished by a disproportionately quick heartbeat.
Types of Supraventricular Tachycardia
Some of the more prevalent SVT subtypes include:
- Atrial fibrillation: Happens when the atria beat more rapidly than the ventricles in an irregular rhythm.
- Atrial flutter: This occurs when a person’s atria beat faster than the ventricles, with the occasional heartbeat of up to 300 bpm, this results in a pulse rate of about 150 bpm.
- Multifocal atria tachycardia: This type is more common in older adults experiencing respiratory problems. Electrical signals coming from different areas result in the contraction of the atria.
- Atria tachycardia: This often makes the atria beat more rapidly. This is because the electrical signals come in from a different location other than the SA node.
- Atrioventricular node re-entrant tachycardia (AVNRT): This type results from an additional channel close to the AV node that causes the heart to beat too quickly or early.
- Paroxysmal SVT (PSVT): Here the episodes of SVT do happen occasionally. They are limited and transitory.
Causes of Supraventricular Tachycardia
Common causes of SVT include:
- Smoking
- Overuse of stimulants
- Thyroid disease
- Heart failure
- Heart disease
- Chronic obstructive pulmonary disease (COPD)
- Excessive usage of caffeine, alcohol, or toxins
Symptoms of Supraventricular Tachycardia
The typical symptom of SVT is a feeling of the heart is racing. It may feel like it’s pounding on one’s chest.
There are also other symptoms which include:
- Sweating
- Light-headedness
- Exercise intolerance
Risk Factors of Supraventricular Tachycardia
- Diabetes
- Congenital heart disease: This is a heart defect present at birth that may cause irregular heartbeat.
- Thyroid disease: Overactive or an underactive thyroid gland can increase the risk of SVT.
- Obstructive sleep apnea
- Nicotine
- Age: Some SVT subtypes are more prevalent in middle-aged or older patients.
Diagnosis of Supraventricular Tachycardia
Since SVT episodes might begin and end abruptly, it becomes difficult to record the irregular heart rate and any changes in the heart rhythm. Therefore, cardiologists recommend the use of 12-lead electrocardiography (ECG) in its diagnosis and management.
If the patient’s heart is not in SVG while undergoing ECG, the doctor may recommend a wearable heart monitor. Another alternative test that can be used is a blood test to check for electrolyte levels and signs of infection.
Treatment of Supraventricular Tachycardia
Most patients with SVT normally don’t need treatment. However, if one experiences long and frequent episodes, the doctor may recommend the following:
- Medication: The doctor may recommend medicine to reduce the heart rate or return the heart to a normal rhythm should the patient experience frequent SVT episodes.
- Cardioversion: This involves electrically shocking the heart to help reset the heart rhythm.
- Catheter ablation: This is a surgical procedure whereby the doctor inserts a catheter (a thin, flexible tube) through an artery or vein, usually in the groin. The sensors on the catheter’s tip deliver heat or cold energy to form small scars in the heart in order to prevent abnormal electrical signals and re-establish a regular heartbeat.
- Pacemaker: This is an implantable device implanted under the skin. It is used to stimulate the heart to beat.
- Carotid sinus massage: This is a therapeutic type of massage that triggers the body to release chemicals that slows the heart rate.
