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The 3 types of supraventricular tachycardia (SVT) include atrioventricular nodal reentrant tachycardia, atrioventricular reciprocating tachycardia, and atrial tachycardia.
Supraventricular tachycardia (SVT) is a type of arrhythmia (a condition in which the heart may suddenly or intermittently beat faster than normal).
3 most common types of supraventricular tachycardia (SVT)
- Atrioventricular nodal reentrant tachycardia: This most common type of SVT affects young women more than others. The cells near the atrioventricular node fail to correctly transmit electrical impulses through the heart. The electric signal moves in a circular circuit instead of passing along the node, which creates the extra beats.
- Atrioventricular reciprocating tachycardia: This second most common type of SVT is most commonly diagnosed in younger people. The electrical signal moves in an extra circle that causes the extra heartbeats.
- Atrial tachycardia: It commonly affects people with heart disease. Apart from the sinoatrial node, an extra area in the atria initiates the electrical impulses.
Other types of supraventricular tachycardia include:
- Sinus tachycardia
- Sinus nodal reentrant tachycardia
- Inappropriate sinus tachycardia
- Multifocal atrial tachycardia
- Junctional ectopic tachycardia
- Nonparoxysmal junctional tachycardia
How does the heart beat?
The heart beats through a person’s life as the heart muscles alternatively contract and relax.
- This rhythmic activity is brought about by the sequential transmission of electrical impulses.
- These impulses originate at the sinoatrial node, travel to the atrioventricular node, the bundle of His, the Purkinje fibers, and, finally, to the heart muscles.
- These structures are called the pacemaking system of the heart and are connected by nerve fibers.
The arrhythmias occur when these pacemakers or the corresponding nerve fibers are affected.
What is SVT?
Supraventricular tachycardia (SVT) is defined as the abnormal rapid beating of the heart that affects the heart's upper chambers, the ventricles. It is called paroxysmal SVT.
Normally, the heart beats at the rate of 60 to 100 beats per minute. However, when it starts to beat rapidly with more than 100 beats per minute, the condition is called tachycardia.
SVT is characterized by episodes of premature beats. It means you do not persistently have a rapid heart rate. However, tachycardia is triggered by certain factors. During an episode of SVT, the heart rate usually becomes 150 to 220 times per minute.
What causes SVT?
Supraventricular tachycardia (SVT) happens when there is a problem with the coordination between the electrical signals that cause your heart to beat correctly and in a rhythmic fashion.
SVT is the most common type of abnormal heartbeat that occurs in infants and children.
SVT can be caused by any of the factors, including:
- Heart conditions
- Coronary artery disease
- Narrowed heart arteries
- Abnormal heart valves, such as mitral valve prolapse
- Heart failure
- Cardiomyopathy (weakening of the heart muscles)
- Wolff-Parkinson-White syndrome (condition present by birth in which there is an abnormal conductive cardiac tissue)
- Heart attack
- Prior heart surgery
- Pregnancy
- Exercise
- Anxiety
- Emotional stress
- Chronic lung disease
- Excessive caffeine intake from coffee, cola, and other caffeinated products
- Excessive alcohol intake
- Drug use
- Cocaine
- Methamphetamines
- Ecstasy
- Smoking tobacco (nicotine)
- Smoking
- Hyperthyroidism (overactive thyroid)
- Obstructive sleep apnea (episodes of cessation of breathing during sleep)
- Certain medications
- Asthma medications (salbutamol)
- Over-the-counter cold and allergy medicines
- Hydralazine (used for treating high blood pressure)
What are the symptoms of SVT?
The symptoms of supraventricular tachycardia (SVT) vary considerably among patients. A patient may not have any symptoms or have minor or severe symptoms.
Symptoms of SVT include:
- Palpitations (racing heartbeats)
- Pressure, tightness, or pain in the chest
- Lightheadedness
- Shortness of breath
- Sweating
Complications of SVT are rare but include:
- Myocardial infarction (heart attack)
- Congestive heart failure (when the heart cannot pump enough blood)
- Fainting episode
- Sudden death
