Definition

Paroxysmal supraventricular tachycardia (PSVT) is an abnormal fast heartbeat. It begins and ends suddenly. The heart may beat as fast as 160 to 280 beats per minute.

If it happens a lot and is not treated, it may weaken the heart.

Anatomy of the Heart

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Causes

PSVT is caused by abnormal signals in the heart.

Risk Factors

PSVT is more common in women. It is also most common in those over 65 years old. However, it can happen at any age. Other things that raise the risk are:

• Excess caffeine, alcohol, or nicotine use
• Certain heart problems, such as:
  • Mitral valve defects
  • Heart attack or heart failure
• Long term lung disease
• Hyperthyroidism
• Respiratory illnesses
• Stimulant drugs

Symptoms

Symptoms of PSVT may be:

• Fast or pounding heartbeats
• Weakness, lightheadedness, or feeling faint
• Problems breathing and feelings of fear
• Chest discomfort
• Rarely, loss of consciousness

Diagnosis

The doctor will ask about symptoms and past health. A physical exam will be done. Diagnosis may be based on symptoms.

Tests may be ordered to find the cause. They may include:

• ECG —to measure the electrical activity of the heart
• Holter monitor—a device worn to measure heart activity over 24 to 48 hours
• Implantable loop recorder (ILR)—a small device put in the skin of the chest to find faulty heart rhythms
• Electrophysiology study—wires placed inside the heart to see where the abnormal rhythm starts
• Echocardiogram or ultrasound exam of the heart to look for structural heart disease
• Blood tests—to look for mineral imbalances and thyroid problems

Treatment

The goal is to slow the fast heartbeats. To do this, the doctor may advise:

• Guided breathing—breathing strong through the mouth while blocking the nose
• Carotid massage—the doctor will put brief pressure on an artery in the neck to reset heart signals

An adenosine injection may also be given—to slow the heartbeats.

If these methods do not work, other options are:

• Lifestyle changes—such as avoiding excess caffeine, alcohol, nicotine, or illegal drugs
• Medicines given by injection or pills to slow the heartbeats, such as:
  • Calcium channel blockers
  • Digoxin
  • Beta-blockers
  • Anti-arrhythmic medicines

• Medicines to treat underlying problems, such as hyperthyroidism
• Cardioversion—an electric shock to reset the heart—if needed
• Ablation—destroying some heart tissue with cold or heat, to block abnormal signals

Prevention

There are not guidelines to prevent PSVT.