What is paroxysmal supraventricular tachycardia (PSVT)?
Paroxysmal supraventricular tachycardia (PSVT) is a type of abnormal heartbeat that originates in heart tissue other than the ventricles, causing the heart to contract rapidly (160 to 220 beats per minute). It begins and ends suddenly and only happens from time to time. PSVT is a type of arrhythmia and may also be called supraventricular tachycardia.
What causes paroxysmal supraventricular tachycardia (PSVT)?
Our heartbeat is generated by an electrical impulse originating from the sino-atrial node, which is a group of specialized cardiac conduction cells located in the wall of the upper right atrium of the heart. From the SA node, the signal travels down to the atrioventricular (AV) node and then through the bundle of His, bundle branches, and Purkinje fibers. An electrocardiogram (ECG) can be used to monitor this electrical signal.
Normally, this impulse is regular and causes the chambers of the heart (the atria and ventricles) to conduct in a regular and coordinated manner.
In people with paroxysmal supraventricular tachycardia (PSVT), abnormal electrical pathways occur which causes a “short-circuit” of the electrical signal. This allows the signal to speed around in a circle, causing the chambers to contract rapidly, and causing symptoms such as lightheadedness or shortness of breath.
Three main conditions can cause PSVT, each with a different location and behavior.
- Atrioventricular Nodal Re-entrant Tachycardia (AVNRT): The extra conduction pathway exists near the AV node which causes a sudden fast heartbeat in both the atria and the ventricles. AVNRT is not life-threatening but can cause fainting and lightheadedness. This is the most common cause of PSVT.
- Wolff-Parkinson-White Syndrome (WPW): This occurs when an extra muscle fiber connects the upper and lower chambers of the heart. Normally, the only connection between the upper and lower chambers is the AV node. This extra fiber can encourage a short circuit to develop, known as atrioventricular reciprocating tachycardia (AVRT). Symptoms can vary widely from mild heart racing to fainting and people with WPW have an increased risk of sudden cardiac death. Curative catheter ablation is usually recommended. WPW develops in the womb, and although the rapid heartbeats are present from birth it often takes years or decades before they become a problem.
- Atrial Tachycardia: An electrical impulse fires rapidly from a site outside the SA node and circles the atria. Responsible for about 5 percent of PSVTs.
People at higher risk of PSVT include those who:
- Drink alcohol
- Drink caffeine
- Exercise a lot
- Smoke
- Abuse substances or drugs.
What are the symptoms of paroxysmal supraventricular tachycardia (PSVT)?
Symptoms of PSVT can vary depending on the location of the electrical circuit shortcut and generally include:
- A racing but regular heartbeat of 120 to 230 beats per minute that starts and stops abruptly, lasting several minutes to several hours
- Heart palpitations (fluttering in the chest)
- Anxiety
- Chest pain or tightness
- Fainting, dizziness, or lightheadedness
- Shortness of breath
- Tiredness or fatigue
How is paroxysmal supraventricular tachycardia (PSVT) diagnosed?
Paroxysmal Supraventricular Tachycardia (PSVT) is often misdiagnosed as a panic attack. See your doctor if you are experiencing any symptoms suggestive of PSVT.
Your doctor will ask you about your symptoms and will perform a physical examination. If you are having a PSVT episode during the examination, it will show a rapid heart rate and sometimes forceful pulses in the neck. Between episodes of PSVT, the heart rate is normal (60 to 100 bpm).
Your doctor will order electrophysiology studies (EPS) which may include wearing a 24-hour Holter monitor or another type of rhythm recording device.
How is paroxysmal supraventricular tachycardia (PSVT) treated?
Treatment depends on the location of the PSVT and the risk of sudden death. PSVT that occurs only rarely may not need treatment. Treatments may include:
- Valsalva maneuver: This is a way of breathing that increases pressure in the chest that can be used to help regulate heart rhythms or cause the ears to pop. It involves pinching the nose and closing the mouth then straining, as if trying to exhale or have a bowel movement, for 10 to 15 seconds
- Coughing while sitting with your upper body bent forward
- Splashing ice water on your face
- Medications
- Catheter ablation: has the potential to cure the arrhythmia
- Electrical cardioversion
- Pacemakers
- Surgery.
People with PSVT should avoid smoking, caffeine, alcohol, and illicit drugs.
