Paroxysmal Supraventricular Tachycardias
The Heart Institute at Virginia Mason in Seattle provides diagnosis and treatment for paroxysmal supraventricular tachycardias.
When the heart beats quickly from time to time it is referred to as paroxysmal supraventricular tachycardia (PSVT). Supraventricular means that the rapid heart rate is occurring above the ventricles (the lower chambers) of the heart. It occurs most often in younger individuals but can occur at any age. PSVT can be caused by alcohol and caffeine use, excessive smoking, thyroid disease, coronary artery disease and heart failure. Some medications also can cause these tachycardias to occur.
Symptoms include a feeling of the heart beating (palpitations), shortness of breath, anxiety, dizziness and fainting.
Diagnosing Paroxysmal Supraventricular Tachycardias
Your doctor may detect that your heart rate is quite high — above 150 beats per minute — when listening to your heart with a stethoscope during a physical exam. He or she may then recommend an ECG and other testing, to help in the diagnosis.
An ECG measures your heart's electrical activity. During this test, electrodes are attached to your skin and record electrical impulses that appear as waves on a monitor. During rapid heart beats, the waves appear taller and closer together than do normal heart rhythms.
To determine the extent or frequency of the heart rhythm disturbance, your physician may recommend that you wear a Holter monitor for 24 hours to record — similar to the ECG — your heart's electrical activity if you have daily symptoms of PSVT. If you have symptoms less often, the diagnosis of PSVT may require a patient symptom-triggered monitor (often called King of Hearts). These small recording devices easily can be worn on a belt or tucked inside a pocket.
Treating paroxysmal supraventricular tachycardias
A number of treatment options are available for patients with PSVT depending on the severity of symptoms. To quickly convert abnormal rhythms to normal rhythm, paramedics or hospital personnel may use an external defibrillator to shock the heart into normal sinus rhythm. Alternatively, intravenous drugs may be used to slow the heart rate.
If symptoms persist, daily anti-arrhythmia medications may be advised such as a beta blocker or verapamil. A non-surgical procedure called radiofrequency catheter ablation — or just catheter ablation — also may be recommended and has a high success rate for treating PSVT. During this procedure, a catheter is inserted into a blood vessel in the groin and carefully maneuvered toward the heart. The catheter is positioned near the area of the heart where the rapid heart rhythms occur. A device that delivers low-voltage, high-frequency radio waves is then inserted through the catheter and the area is treated with the energy, which disrupts the heart's natural electrical conduction. This procedure is performed in the Electrophysiology Lab and usually takes less than 90 minutes.