Tachycardia

Tachycardia

Tachycardia = Too fast

A heart rate of more than 100 beats per minute (BPM) in adults is called tachycardia. What's too fast for you may depend on your age and physical condition.

There are three types of tachycardias:

Atrial or Supraventricular tachycardia (SVT)
 
Atrial or Supraventricular tachycardia (SVT) is a fast heart rate that starts in the upper chambers of the heart.

Some forms are called paroxysmal atrial tachycardia (PAT) or paroxysmal supraventricular tachycardia (PSVT).

How it happens

Electrical signals in the heart's upper chambers fire abnormally, which interferes with electrical signals coming from the sinoatrial (SA) node --- the heart's natural pacemaker. A series of early beats in the atria speeds up the heart rate. The rapid heartbeat does not allow enough time for the heart to fill before it contracts so blood flow to the rest of the body is compromised.

Who is likely to have Atrial or SVT? SVT is the most common type of arrhythmia in children More common in women, but may occur in either sexAnxious young peoplePeople who are physically fatiguedPeople who drink large amounts of coffeePeople who drink alcohol heavilyPeople who smoke heavilyAtrial tachycardia occurs less commonly with: Heart attackSerious mitral valve diseaseSymptoms and Complications of Atrial or SVT

Some people have no symptoms; others may feel: DizzinessLightheadednessRapid heartbeat or "palpitations"Angina (chest pain)Shortness of breathIn extreme cases, atrial or SVT may cause: UnconsciousnessCardiac arrestTreatment for Atrial or SVT

Many people don't need medical therapy. Treatment is considered if episodes are prolonged or occur often.

Your doctor may recommend or try:

Carotid sinus massage: gentle pressure on the neck, where the carotid artery splits into two branches. Must be performed by a healthcare professional to minimize risk of stroke, heart or lung injury from blood clots.Pressing gently on the eyeballs with eyes closed.

Valsalva maneuver: holding your nostrils closed while blowing air through your nose.Dive reflex: the body's response to sudden immersion in water, especially cold water.Sedation.Cutting down on coffee.Cutting down on alcohol.Quitting tobacco use.Getting more rest.

In patients with Wolfe-Parkinson-White syndrome, medications or ablation may be needed to control PSVT.

Sinus tachycardia
 
Sinus tachycardia = fast but steady

Sinus tachycardia is a normal increase in the heart rate.

How it happens

The sinoatrial (SA) node --- the heart's natural pacemaker - sends out electrical signals faster than usual. The heart rate is fast, but the heart beats properly.

Causes of sinus tachycardia

A rapid heartbeat may be your body's response to common conditions such as:

  • Fever
  • Anxiety
  • Some medicinal and street drugs
  • Severe emotional distress
  • Fright
  • Strenuous exercise

Less commonly, it may indicate:

  • Anemia (low blood count)
  • Increased thyroid activity
  • Heart muscle damage from heart attack or heart failure
  • Hemorrhage (severe bleeding)

Symptoms of sinus tachycardia

Your heart beats faster than usual.

Treatments for sinus tachycardia

Your doctor should consider and treat the cause of sinus tachycardia rather than the condition itself.

If your rapid heartbeat is a symptom of a more serious or longer term problem, simply slowing the heart rate could cause more harm and leave the underlying condition untreated.

Ventricular tachycardia
 
Ventricular tachycardia is a fast heart rate that starts in the heart's lower chambers (ventricles). It often occurs in life-threatening situations that dictate rapid diagnosis and treatment.

How it happens

Electrical signals in the ventricles fire abnormally, which interferes with electrical signals coming from the sinoatrial (SA) node --- the heart's natural pacemaker. The rapid heartbeat does not allow enough time for the heart to fill before it contracts so blood flow to the rest of the body is compromised

Causes of Ventricular Tachycardia

Usually associated with heart problems including:

  • Coronary artery disease
  • Cardiomyopathy
  • Mitral valve prolapse
  • Valvular heart disease

Other causes of ventricular tachycardia include:

  • Sarcoidosis (an inflammatory disease affecting skin or other body tissues)
  • Medications such as digitalis and antiarrhythmics
  • Change in posture, exercise, emotional excitement or vagal stimulation.

Symptoms of Ventricular Tachycardia

  • Dizziness
  • Lightheadedness
  • Unconsciousness
  • Cardiac arrest

Consequences of Ventricular Tachycardia

This type of arrhythmia may be either well-tolerated or may be life-threatening. The seriousness depends largely on whether other cardiac dysfunction is present, and on the rate of VT.

Treatment of Ventricular Tachycardia

The type and length of treatment depends on what's causing the problem.

If required, treatment may include:

  • Medication (prescribed for home use and/or administered by healthcare professionals)
  • Radiofrequency ablation
  • Surgery
  • May require immediate cardioversion when unstable