Home » Diseases & Conditions » Paroxysmal Supraventricular Tachycardia – Symptoms, Treatment, Diagnosis

Paroxysmal Supraventricular Tachycardia – Symptoms, Treatment, Diagnosis

Definition of Paroxysmal Supraventricular Tachycardia

Supraventricular tachycardia (SVT) is a term that describes the presence of a rapid heart rhythm that originates above the ventricles. SVT is milder compared to the fatal ventricular tachycardia (VT) where the rapid heart rate which originates from the ventricles may lead to life-threatening ventricular fibrillations. Paroxysmal supraventricular tachycardia (PSVT) specifically describes a form of supraventricular tachycardia that is caused by atrioventricular nodal reentrant tachycardia (AVNRT). PSVTs are tachycardias, which often presents with an immediate and sudden onset. A person who might be suffering from PSVT may have an increased heart rate from 60 to as high as 300 beats per minute just by picking something on the floor. PSVT can be a part of Wolff-Parkinson-White syndrome, a condition characterized by concealed PSVT or SVT which is not evident on ECG tracings.


PSVT is commonly caused by a reentry mechanism where the impulses in the heart reenter the myocardium, causing another heart beat. PSVT may be directly induced by premature ventricular or atrial ectopic beats or skipped heartbeats. The presence of alcohol, drugs, caffeine, or hyperthyroidism may trigger PSVT. PSVT may also be associated with other activities such as driving and exercising, with indications of syncope.

Symptoms of PSVT

Patients with PSVT may exhibit mild or severe symptoms, depending on a person’s hemodynamic function or the presence of structural diseases of the heart. Common manifestations of PSVT include:

Palpitations

Palpitations are the most common symptom of PSVT. This is due to the fast heart rate, thereby making the person consciously feel the heart pounding. Almost 96% of patients with PSVT experience palpitations.

Dizziness

Dizziness is also a common manifestation of PSVT. This may be due to the diminished blood flow to the heart as a result of a very rapid heart rate, possibly reducing the quality of cardiac output. Up to 75% of clients may experience dizziness.

Chest tightness

Chest discomfort may be due to the presence of a rapid heart rate which increases the myocardial workload, thereby increasing the need for oxygen. Chest discomfort is usually relieved when tachycardia is resolved. Only 35% of clients may suffer from chest discomfort.

Shortness of breath

The presence of a fast heart beat may also cause lung to compensate and oxygenate the blood that goes in the pulmonary circulation as a way of compensation. As a result, the patient breathes faster but shallower, leading to shortness of breath.

Syncope

Syncope is characterized by sudden loss of consciousness. This may result from the diminished circulation to the brain tissues. Syncope is usually preceded by episodes of dizziness.

Fatigue

Fatigue may also be secondary to the diminished cardiac output as a result of very fast heartbeats which diminish the quality of myocardial contractility. Due to the diminished cardiac output, there is also poor oxygenation in the peripheral areas of the body, leading to poor energy production, weakness, and fatigue.

Diaphoresis

Diaphoresis is another manifestation of PSVT. When there is a diminished circulation in the body, the blood vessels compensate by dilating to increase the blood flow to the body. Moreover, there is heat loss from the body through excessive perspiration.

Patients with poor hemodynamic reserves may also manifest more severe symptoms such as hypotension due to the vasodilatation of blood vessels. There may also be crackles auscultated in the lungs due to ventricular heart failure because the heart is unable to pump blood adequately to the systemic circulation, thereby increasing blood accumulation in the lungs. Right ventricular heart failure, which may be characterized by distended jugular veins, may also develop.

Diagnosis of PSVT

The main diagnostic tool for PSVT is through an electrocardiogram, also known as ECG or EKG. On the electrocardiogram tracing, there may be indications of:

  • Narrow QRS complex: This denotes ventricular depolarization, which means that there is poor ventricular contraction along with a fast heart rate. However, some SVTs with aberrant conduction may have a widened QRS complex similar to VT. Distinguishing PSVT from VT is very essential because VTs are relatively dangerous and required immediate managements to prevent fatal ventricular fibrillations.

Other diagnostic procedures include:

  • Cardiac enzyme evaluation

For people who experience chest pains, identifying the cardiac enzymes such as CPK-MB and Troponin T are very essential in order to determine myocardial infarction.

  • Electrolyte levels

Electrolytes such as sodium and potassium need to be checked because an electrolyte imbalance, especially potassiumm may be causative factor for PSVT.

  • Complete blood count

Anemia may also be a causative factor for PSVT as the body tries to compensate for low red blood cells (RBC) by an increased heart rate in order to supply cells with oxygens.

  • Digoxin level determination

Patients who are under digoxin therapy may need to be checked for digoxin toxicity which often leads to PSVT.

  • Chest X-ray

A chest X-ray may be needed to assess the presence of pulmonary edema for those with long standing PSVT. A chest X-ray may also identify cardiomyopathies.

  • Echocardiogram and cardiac MRI

These two tests are very important to patients with structural heart abnormalities. These tests help identify the presence of heart valve problems which may indicate heart failure or structural problems.

Treatments of PSVT

The treatments for PSVT are employed in cases when PSVT occurs. Other treatments may also be used to prevent the recurrence of PSVT. Those PSVT cases caused by problems on the AV node may require slowing the conduction in the AV node. AV nodal blocking treatments involve:

Physical maneuvers

Physical maneuvers are undertaken through the action of the parasympathetic nervous system. These are done through vagal maneuvers that reduce the conduction of the heart through the vagus nerve. One of the vagal maneuvers that can be employed includes valsalva maneuver, similar to straining when defecating. Coughing, drinking cold water, plunging the face in cold water, holding one’s breath, and standing on one’s head are other vagal maneuvers. Carotid sinus massage may also be employed, but is not advisable for people with thromboembolic episodes due to the risk for stroke.

Medical therapy

Medications may employ antiarrhythmic medications such as verapamil, diltiazem, metoprolol, and adenosine. PSVTs that are not related to the AV node may be treated with amiodarone or sotalol.

Cardioversion

When patients do not respond to medications as well as vagal maneuvers, cardioversion, which uses electrical shocks to the chest to stabilize the heart contractiliy, is often employed.

Leave a Reply


© 2017 HealthZene.com. All Rights Reserved. Privacy Policy
This website is for informational purposes only and Is not a substitute for medical advice, diagnosis or treatment.