What is Paroxysmal Supraventricular Tachycardia?
Paroxysmal supraventricular tachycardia (PSVT) is a condition where the heart sometimes suddenly beats very fast. Around 2.5 out of 1000 people generally experience this. It’s often seen in emergency rooms and usually affects people with no pre-existing heart problems. PSVT is a common feature of certain heart issues, including atrioventricular nodal reentrant tachycardia (AVNRT), atrioventricular reentrant tachycardia (AVRT), and focal atrial tachycardia, with AVNRT being the most common cause in adults.
While PSVT can cause obvious symptoms like a rapid heartbeat, it can sometimes show less typical symptoms like shortness of breath, feeling dizzy, chest pain, and fainting. This is especially true for older people with heart problems. Some people with PSVT even experience non-heart related symptoms like ringing in the ears, burping, feeling cold, sweating, seizure-like events, panic attacks, and symptoms similar to asthma.
If you’re suspected to have PSVT, a doctor will probably start by doing a 12-lead electrocardiogram (ECG). This test measures the electrical activity of your heart. The results can show whether the heartbeats are fast but regular, which is common in PSVT. In certain cases, though, the results might show other patterns related to problems with the way electrical signals are passing in the heart.
People with PSVT can be treated in several ways. Common treatments include medications like adenosine, beta-adrenergic antagonists, and calcium channel blockers. Doctors might also suggest certain maneuvers that affect the vagus nerve to slow down your heart rate. In some rare cases, electrical cardioversion, which uses a shock to bring your heartrate back to normal, may be used. In recent years, a procedure called catheter ablation has become the safest and most effective treatment for PSVT. This procedure uses a thin tube inserted into the heart to destroy the tissue causing the fast heart rate. It has also been shown to significantly improve patients’ quality of life.
What Causes Paroxysmal Supraventricular Tachycardia?
Paroxysmal supraventricular tachycardia (PSVT), including two forms known as AVNRT and AVRT, are heart conditions that are identifiable by certain physical markers and anomalies in the heart, present from birth. However, these markers don’t necessarily cause PSVT in everyone.
Accessory pathways, which are extra routes in the heart’s electrical system, are often associated with certain birth defects of the heart, like Ebstein anomaly and transposition of the great arteries. The heart can sometimes get caught in a loop, causing fast heartbeats in both AVNRT and AVRT. This is often initiated by extra heartbeats that come either from the upper or lower chambers of the heart. This means that PSVT can be started by anything that causes these extra heartbeats.
Common triggers of these conditions include physical activity, stress, caffeine, nicotine, an overactive thyroid, a lack of sufficient blood flow to the heart, infections, low levels of oxygen in the body, and a low amount of blood volume in the body.
Atrial tachycardia, a rare form of PSVT, is generally found in patients with heart diseases that cause changes in the heart’s structure. However, this condition can also happen in young, healthy people without any heart diseases and disorders of the heart muscle. This rare form of PSVT is often associated with birth defects of the heart, heart diseases acquired over time, diseases of the heart muscle, a weak pumping function of the left side of the heart, rheumatic heart diseases, holes in the heart, and scar tissue from heart surgery.
Atrial tachycardia can also happen in patients with rheumatoid arthritis and systemic lupus erythematosus, even without any underlying heart diseases.
Risk Factors and Frequency for Paroxysmal Supraventricular Tachycardia
PSVT, or Paroxysmal Supraventricular Tachycardia, is a type of rapid heart rate condition. It’s the second most common type, after atrial fibrillation. Roughly 0.2% of people in the United States experience PSVT, with 1 to 3 new cases cropping up for every 1000 patients. PSVT, particularly with age and in women, has been shown to be more prevalent. Middle-aged or older individuals are more likely to have AVNRT, a form of PSVT. However, adolescents are more likely to have PSVT related to an accessory pathway, but this declines over time. PSVT can also be seen in people with other health problems, such as heart attack, rheumatic heart disease, mitral valve prolapse, pneumonia, chronic lung disease, and pericarditis. Overuse of the medication Digoxin can also lead to PSVT.
- Over 90% of PSVT cases are due to AVNRT or atrioventricular reciprocating tachycardia.
- More than 60% of people with PSVT have AVNRT, which is more frequent in women than men.
- AVNRT often presents in people’s second and third decades of life, but some might not experience symptoms until their sixties or seventies.
- AVRT is the second most common cause of PSVT and is seen in up to 1% of the general population.
- People with AVRT often first experience symptoms at a young age, with the average age of diagnosis being 34 for men and 21 for women. The chances of having AVRT decrease as age increases.
- Atrial tachycardia is a relatively rare type of PSVT, with a prevalence of 0.3% to 0.46%. However, it’s more common in people with PSVT who have symptoms or underlying heart conditions.
- Research suggests that 5% to 10% of patients having an electrophysiology study for PSVT are diagnosed with atrial tachycardia.
Signs and Symptoms of Paroxysmal Supraventricular Tachycardia
Paroxysmal supraventricular tachycardia (PSVT) symptoms can vary quite a bit, depending on any existing heart conditions, how often PSVT episodes occur, and an individual’s physical tolerance to changes in blood flow. Often, people with PSVT experience palpitations, a feeling of fullness in the neck, anxiety, and fatigue. Additional symptoms can include dizziness, fainting, nausea, shortness of breath, chest pain or discomfort, sweating, and increased urination due to the release of a hormone called the atrial natriuretic factor, which responds to stretching of the atria in the heart. Dizziness and palpitations are the most common symptoms.
People with PSVT who also have a history of coronary artery disease may experience a heart attack due to the added stress on the heart. If a person with PSVT also has a history of heart failure, an episode of PSVT might bring on severe heart failure. Regular occurrences of PSVT, particularly atrial tachycardia, can even lead to the development of heart failure due to damage caused by the too-rapid heartbeat.
- Palpitations
- Feeling of fullness in the neck
- Anxiety
- Fatigue
- Dizziness
- Fainting
- Nausea
- Shortness of breath
- Chest pain or discomfort
- Sweating
- Increased urination
When assessing someone with PSVT, it’s important to get detailed information about their medical and heart history, when symptoms started, any previous episodes, and treatments they’ve had. It’s also vital to know what medications they’re currently taking. Understanding their physical activity habits, particularly exercise or outdoor sports, is also crucial since people with symptomatic PSVT tend to avoid such activities. Anyone with suspected PSVT should be given a thorough physical exam, including the measurement of vital signs – such as respiratory rate, blood pressure, temperature, and heart rate – to evaluate their overall physical stability. However, the clinical examination of patients with PSVT is typically unremarkable. During a PSVT episode, patients usually have a fast heartbeat, visibly full neck veins, and a loud first heart sound. In patients with heart failure, the sound of the heartbeat (specifically a third heart sound or S3) and other signs may indicate severe heart failure.
Testing for Paroxysmal Supraventricular Tachycardia
Paroxysmal supraventricular tachycardia (PSVT) is commonly identified in the emergency room. When a patient comes in with symptoms that suggest they may have PSVT, the first things doctors do are assess their heart’s function and do a thorough physical exam. After that, they perform a test called a 12-lead ECG. This gives doctors a detailed look at the patient’s heart activity, and comparing an ECG taken during a tachycardia (when the heart beats too fast) to one taken during a normal rhythm can be very illuminating.
In many instances, a reading from the ECG taken during tachycardia can give doctors a good idea of the kind of PSVT the patient has. However, it’s worth mentioning that the ECG may fail to distinctly differentiate certain types of AVNRT (a kind of fast heartbeat that originates from faulty electrical activity in the heart) from atrial tachycardia (rapid heartbeat caused by signals starting from the atria, the top chambers of the heart), and orthodromic AVRT (a kind of arrhythmia, or abnormal heart rhythm).
Key elements that doctors look at in an ECG in these situations include: the rate of tachycardia, the shape of the P-wave (a specific part of the ECG reading), the relationship between the P wave and QRS complex (another specific part of the ECG reading), and the shape of the QRS complex itself. Usually, PSVT shows up as a narrow QRS complex, but sometimes it can appear wider due to a number of reasons like problems with one of the heart’s conduits (bundle branch block), or a phenomenon called preexcitation, which involves an additional pathway in the heart.
Additional tests may need to be done as needed on certain patients, such as evaluating kidney function, checking electrolyte levels, or assessing thyroid function. An echocardiogram (a kind of heart ultrasound) is necessary to look at the heart’s pumping ability and to rule out any structural problems with the heart.
Recognizing specific markers in the ECG can help doctors in the emergency room distinguish between various types of PSVT. However, this process is often complicated by the very fast heartbeat rate, unclear association between the atria (upper chambers) and ventricles (lower chambers), and unrecognizable P waves. Based on the duration of the PR and RP intervals (specific parts of the ECG), the tachycardia can be classed as either “short RP tachycardia” or “long RP tachycardia” – this gives doctors an idea about the specific type of PSVT to consider.
An electrophysiology study, which is a test where doctors study the electrical signals in the heart, is recommended for patients who have experienced symptomatic, documented PSVT. This is done not just to understand what’s causing the tachycardia but also to plan out how to get rid of the abnormal electrical route that’s causing the problem. This procedure typically follows a specific study of the heart’s electrical system and cements the diagnosis while also treating the problem using a technique called catheter ablation.
Treatment Options for Paroxysmal Supraventricular Tachycardia
For those experiencing symptoms of Paroxysmal Supraventricular Tachycardia (PSVT), a condition that makes the heart race momentarily, they often first seek help at the emergency department. Here, how the healthcare team responds will depend on the type of heart rhythm shown on the patient’s EKG or electrocardiogram, a test that measures the heart’s electrical activity, and how the patient is doing overall.
Patients who experience low blood pressure, difficult breathing, chest pain, shock, or changes in consciousness are deemed unstable. These people should immediately undergo a procedure called electric cardioversion, which helps to restore a regular heartbeat using electric shocks.
If the patient’s vital signs like heart rate and blood pressure are stable, healthcare professionals could recommend something called vagal maneuvers. These are simple exercises such as the carotid sinus massage or Valsalva maneuvers, that can sometimes help the heart restore its regular rhythm. But these maneuvers work in less than 30% of people.
If vagal maneuvers don’t work, a drug called adenosine might be given. It has been shown to halt PSVT in 75% to 95% of patients. However, it can also cause shortness of breath, flushing, and a temporary block in the heart’s electrical system, but these effects don’t last long due to the drug’s short half-life. Other medication options include beta blockers or non-dihydropyridine calcium channel blockers.
Electric cardioversion could be considered as well if these treatments fail to restore the normal heart rhythm in symptomatic, but stable patients.
In the long term, managing PSVT is crucial, particularly for people with repeated symptoms that result in frequent hospital visits. One highly effective treatment that has evolved over the years is catheter ablation. This involves targeting and removing the heart tissue that is causing the abnormal rhythm. In the process, a critical part of the abnormal heart circuit is targeted— the slow pathway in an AVNRT (Atrioventricular nodal reentrant tachycardia) or the accessory pathway in an AVRT (Atrioventricular reentrant tachycardia).
Many guidelines suggest going for an electrophysiological study and ablation as the primary treatment in symptomatic PSVT. In fact, catheter ablation works so well that it can even be considered in asymptomatic patients, especially those in high-risk professions. The procedure not only lowers the cost of repeated hospital visits but also improves the quality of life by curing AVNRT and AVRT in more than 95% of patients with symptoms.
In cases where ablation can’t be carried out, medication can be used for long-term management of PSVT. Often prescribed drugs include oral beta-blockers and non-dihydropyridine calcium channel blockers, while others like amiodarone, flecainide, digoxin, and sotalol can be given to certain patients. However, patients with obvious pre-excitation and symptomatic PSVT should avoid these node-blocking drugs as they can potentially speed up the conduction of atrial fibrillation through the accessory pathway, increasing the risk of life-threatening ventricular fibrillation.
Finally, it is crucial for all patients with symptomatic PSVT to know how to perform vagal maneuvers. The success rate of these maneuvers drops the longer the tachycardia episodes last, due to an increased adrenaline response. As such, patients should be advised to do this as soon as they feel the telltale signs of PSVT begin.
What else can Paroxysmal Supraventricular Tachycardia be?
When a doctor is trying to determine if a patient has Paroxysmal Supraventricular Tachycardia (PSVT), they must consider other conditions that have similar symptoms. These could include:
- Atrioventricular Nodal Reentry Tachycardia (AVNRT)
- Atrioventricular Reciprocating Tachycardia (AVRT)
- Focal Atrial Tachycardia
- Multifocal Atrial Tachycardia
- Atrial Flutter
- Atrial Fibrillation
- Inappropriate Sinus Tachycardia
- Sinoatrial Node Reentrant Tachycardia
- Junctional Ectopic Tachycardia
- Nonparoxysmal Junctional Tachycardia
These considerations and appropriate testing are crucial for making an accurate diagnosis.
What to expect with Paroxysmal Supraventricular Tachycardia
Paroxysmal Supraventricular Tachycardia (PSVT), a type of arrhythmia, generally carries a good prognosis for people who do not have heart disease, with their lifespan being similar to that of the general population. However, for those who have heart disease, the prognosis is determined by the severity of their existing heart condition.
PSVT can happen abruptly, lasting from a couple of seconds to several days. Many people experience feelings of anxiety and impending doom, and some may develop issues affecting blood flow. Some people with repeated episodes may report that their quality of life has been impacted due to frequent trips to the emergency department.
For symptomatic patients with Wolff-Parkinson-White (WPW) syndrome, a type of PSVT, there’s an estimated yearly risk of sudden cardiac death ranging from 0.1% to 0.3%. Earlier studies suggest a lifetime risk of sudden cardiac death between 3% to 4% for patients with symptomatic WPW syndrome. Factors predicting sudden cardiac death may include a short refractory period, which is the recovery time in which the heart can’t respond to a new nerve signal, having multiple pathways that electrical impulses can take through the heart, inducible AVRT, which is a type of arrhythmia induced during a medical procedure, being male, and having a history of fainting.
Possible Complications When Diagnosed with Paroxysmal Supraventricular Tachycardia
Younger individuals who don’t have heart-related structural issues usually handle Paroxysmal Supraventricular Tachycardia (PSVT) well. On the other hand, those with pre-existing heart structural complications may experience fainting or symptoms indicative of heart failure, leading to repeated hospital visits. PSVT sometimes leads to a heart disease characterized by a fast heartbeat in some patients. An extremely fast heart rate during a PSVT episode can cause a lack of blood supply to the heart muscle in older individuals and those suffering from coronary artery diseases. Rarely, constant PSVT can deteriorate to ventricular arrhythmias – a life-threatening abnormal heart rhythm.
Common outcomes of PSVT:
- Well tolerated in younger individuals without heart diseases
- Fainting or heart failure symptoms in individuals with structural heart diseases
- Heart disease characterized by rapid heartbeat
- Shortage of blood supply to heart muscle in elderly and individuals with coronary artery diseases
- Rarely, a life-threatening abnormal heart rhythm
Preventing Paroxysmal Supraventricular Tachycardia
It’s important for patients to understand the usual signs and complications of PSVT (Paroxysmal Supraventricular Tachycardia), a heart condition where the heart unexpectedly starts beating very fast. Improving discussions between patients and their doctors can help better manage these heart rhythms. Helpful materials including online articles, videos, and brochures should be provided for patient education whenever possible.
Patients should also be made aware of the potential risk of SCD (Sudden Cardiac Death) that can be associated with WPW (Wolff-Parkinson-White) syndrome, another heart condition wherein extra electrical pathway exists in the heart. The doctor might recommend a procedure called catheter ablation as the primary course of treatment. Catheter ablation is a process to cure the heart rhythm problems by scarring or destroying tissue in your heart that’s allowing incorrect electrical signals to cause abnormal heart rhythm.
