Supraventricular tachycardia
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Supraventricular tachycardia (SVT), often referred to as paroxysmal supraventricular tachycardia, is an abnormally fast or irregular heartbeat (arrhythmia) that affects the upper chambers of the heart. The underlying issue lies in the malfunctioning electrical signals and circuitry within the heart. When the heart beats excessively fast, it hinders the proper filling of blood during each beat, thereby impeding the adequate supply of blood to the body.
The average heartbeat is between 60 and 100 beats per minute. A tachycardia is characterized by a heartbeat rate more than 100 per minute. The heart typically beats between 150 and 220 times per minute throughout an episode of SVT, while it can occasionally beat more quickly or slowly.
The three primary types of supraventricular tachycardia (SVT) are as follows:
- Atrial tachycardia: Heart disease patients are more likely to have this type of SVT diagnosed. The AV node is not involved in atrial tachycardia.
- Atrioventricular nodal reentrant tachycardia (AVNRT): Supraventricular tachycardia most frequently occurs in this type.
- Atrioventricular reciprocating tachycardia (AVRT): The AVRT is the second most typical variety of supraventricular tachycardia. Younger individuals are most frequently diagnosed with it.
- Supraventricular tachycardia can also take the following types:
- Premature atrial contractions (PACs)
- Paroxysmal supraventricular tachycardia (PSVTP)
- Accessory pathway tachycardias such as Wolff–Parkinson–White (WPW) syndrome
- Sinus tachycardia
- Sinus nodal reentrant tachycardia (SNRT)
- Inappropriate sinus tachycardia (IST)
- Multifocal atrial tachycardia (MAT)
- Junctional ectopic tachycardia (JET)
- Nonparoxysmal junctional tachycardia (NPJT)
Supraventricular tachycardia (SVT) often does not necessitate treatment or restrictions on daily activities for the majority of patients. However, certain individuals may benefit from making lifestyle modifications, taking medications, or undergoing heart surgeries to control or eliminate their rapid heartbeats and accompanying symptoms.
Symptoms
Supraventricular tachycardia (SVT) is identified by an accelerated heart rate that exceeds 100 beats per minute, surpassing the normal range. This condition can endure for a brief period of a few minutes to several days. It typically occurs sporadically, interspersed with intervals of normal heart rate.
Supraventricular tachycardia signs and symptoms can include:
- Rapid heartbeat
- Chest pain
- Palpitation or pounding in the chest
- Neck pounding sensation
- Weakness or fatigue
- Shortness of breath
- Lightheadedness or dizziness
- Sweating
- Fainting or syncope
- Serious cases can cause cardiac arrest or make a person unconscious.
Identifying signs and symptoms of SVT in infants and young children can pose a challenge. These symptoms include perspiration, pale skin, poor feeding and a rapid heartbeat. It is advisable to consult a healthcare provider regarding the possibility of SVT screening if an infant or young child displays any of these symptoms.
In the absence of heart injury or other underlying heart conditions, supraventricular tachycardia (SVT) is generally not considered life–threatening. However, if an individual encounters their first episode of a significantly rapid heartbeat or if an irregular heartbeat persists for more than a few seconds, it is advisable to seek medical attention by contacting a healthcare provider. In severe instances, an episode of SVT has the potential to lead to loss of consciousness or cardiac arrest.
Certain symptoms and signs of SVT may indicate a significant medical concern. It is crucial to promptly seek medical attention if an SVT episode extends beyond a few minutes or if accompanying symptoms such as chest pain, shortness of breath, weakness, or dizziness are experienced. Taking these indicators seriously and seeking immediate medical evaluation is recommended.
Causes
Supraventricular tachycardia (SVT) arises from an issue with the heart’s electrical signals or circuits, although some individuals may be unaware of the specific causes behind their symptoms. In certain cases, the episodes of SVT can be attributed to clear triggers like physical activity, stress, or inadequate sleep. However, for some individuals, identifying an obvious trigger may be challenging or not possible.
An SVT episode may result from various factors, such as:
- Too much caffeine
- Excessive alcohol intake
- Cigarette smoking
- Heart disease or heart failure
- Wolff–Parkinson–White syndrome
- Chronic lung disease
- Illegal drugs intake, such as methamphetamine and cocaine
- A few medications, such as those for asthma and antihistamines for allergies and colds
- Pregnancy
- Thyroid disease
Risk factors
Factors that could increase the risk of supraventricular tachycardia include:
- Age: The most frequent type of arrhythmia in infants and young children is supraventricular tachycardia (SVT). Short–lived paroxysmal supraventricular tachycardia (PSVT) is more common in young people who exercise or train excessively. Both young adults and the elderly are prone to have AV (atrioventricular) nodal reentrant tachycardia (AVNRT).
- Gender: Though anyone can get it, women tend to have it more frequently, especially during pregnancy.
- Food consumption: Alcohol intake and too much caffeine increases the risk in developing the condition.
- Illegal drug use: A supraventricular tachycardia episode may be brought on by nicotine and illicit substances like cocaine and amphetamines.
- Other medical condition: SVT risk factors include heart disease, heart failure, cardiomyopathy, damaged heart or heart valves, and narrowed heart arteries. Congenital heart diseases, thyroid disease, diabetes, or obstructive sleep apnea increases the risk of supraventricular tachycardia.
Diagnosis
To diagnose supraventricular tachycardia (SVT), a healthcare provider will assess the patient’s symptoms and medical history. Additionally, they may conduct blood tests to rule out other conditions such as thyroid disorders that can present similar symptoms.
The combination of symptom evaluation, medical history assessment, and diagnostic tests helps healthcare providers in identifying SVT.
The following examinations can be performed to assess the heart and identify supraventricular tachycardia (SVT):
- Electrocardiogram (ECG or EKG): The electrical activity of the heart is captured by an ECG. An electrocardiogram (ECG) assesses the timing and duration of each electrical phase within the heartbeat, providing information about the heart’s rhythm and rate, whether it is fast or slow.
- Echocardiogram: Images of the beating heart are produced using sound waves. Information on the heart and heart valves can be obtained through an echocardiography.
- Holter monitor: To record the heart’s activity during regular activities, this portable ECG devices can be worn for up to a day.
- Event recorder: To identify irregular heartbeats, this wearable ECG devices is utilized. As soon as symptoms appear, simply click a button. Normally, an event recorder is worn for up to 30 days or until an arrhythmia or symptoms appear.
- Implantable loop recorder: The chest region is the location of an implanted device, which monitors abnormal heart beats.
- Additional tests that could be performed include:
- Exercise stress test: Stress or physical activity can cause or exacerbate supraventricular tachycardia. The patient usually works out on a treadmill or stationary bike during a stress test while the heart rate is being tracked. During the test, they might be given a medication to stimulate the heart similarly to exercise if they are unable to exercise and the doctor suspects that heart disease may be the cause of the arrhythmia.
- Tilt table test: If they have fainting spells, the healthcare provider might advise this test. They are lying flat on a table while having their heart rate and blood pressure checked. Then it is angled so that they appear to be standing. The healthcare provider watches how the heart and nervous system that regulates it react to the change in angle.
- Electrophysiological (EP) study: A blood vessel, typically in the groin, is used to guide one or more thin, flexible tubes (catheters) to different locations in the heart. The electrical patterns of the heart are captured by sensors on the catheter tips. A medical professional can observe how electrical signals move through the heart with each beating using an EP study.
Treatment
Treatment is typically unnecessary for individuals with supraventricular tachycardia (SVT). Many people find relief by making lifestyle adjustments such as getting sufficient sleep, reducing their consumption of coffee and alcohol, or quitting smoking. However, if prolonged or recurrent episodes occur, a healthcare provider may suggest the following interventions:
- Medications: A healthcare provider may recommend medicine to control heart rate or return the patient’s heart to a normal rhythm if they experience recurrent SVT episodes. To avoid complications, it’s crucial to take the medication exactly as prescribed. The following medicine such as adenosine, atropine, beta blockers, calcium channel blockers, digitalis, or potassium channel blockers can assist in slowing down the heart rate.
- Carotid sinus massage: The area of the neck where the carotid artery divides into two branches is gently pressed by a healthcare provider. This kind of massage causes the body to release chemicals that lower heart rate. Never try to massage your own carotid sinuses.
- Vagal maneuvers: Coughing, bearing down as if having a bowel movement, applying an ice pack to the face, and other straightforward but specific movements can all assist lower heart rate. During an episode of SVT, the healthcare provider might urge patients to carry out these tasks. The vagus nerve, that helps in regulating heartbeat, is affected by these processes.
- Cardioversion: Electrical shocks delivered to the heart through paddles or patches placed on the chest aid in restoring the heart’s rhythm by resetting it. When vagal exercises and medications don’t work, cardioversion is used frequently.
- Catheter ablation: Catheters, which are small, flexible tubes used in this treatment, are inserted by a healthcare provider into veins or arteries, typically in the groin. Utilizing heat or cold energy, sensors located at the tip of a catheter are employed to generate minuscule scars within the heart. These scars serve to block irregular electrical signals, facilitating the restoration of a normal heartbeat.
- Pacemaker: In rare cases, when necessary, a small implanted device called a pacemaker may be used to stimulate the heart’s beating. This involves a brief surgical procedure where the pacemaker is implanted beneath the skin near the collarbone. A wire is then connected from the device to the heart.
