Tuesday, June 7, 2011

V Tach - Ventricular Tachycardia

Overview, Causes, & Risk Factors

Ventricular tachycardia (VT) is an arrhythmia, or irregular type of heartbeat. It causes a rapid heartbeat, usually 150 to 200 beats per minute.
What is going on in the body?
The heart is divided into two lower chambers and two upper chambers. The lower chambers are called the ventricles. The upper chambers are known as the atria. The ventricles beat in a regular pattern in response to electrical impulses from the atria.
Ventricular tachycardia occurs when the electrical impulse starts in the ventricles instead of the atria. This impulse takes over the heartbeat, causing the heart to beat very rapidly. It also keeps the ventricles from filling with blood. If VT continues, the heart stops pumping, and the blood pressure drops. Unless the heartbeat returns to normal, the person will die.
What are the causes and risks of the condition?
VT can be caused by certain conditions, including:
  • certain medicines that affect the heart, such as digitalis

  • coronary heart disease or other forms of heart disease

  • low levels of potassium, calcium, or magnesium in the blood

  • a previous or current heart attack

  • stimulants, such as caffeine, cocaine, or amphetamines

  • problems in the electrical system of the heart

    • Symptoms & Signs

    What are the signs and symptoms of the condition?
    If an episode of ventricular tachycardia is brief, the person may have no symptoms. Other times, the individual may notice palpitations, or an unusual awareness of the heart beating in the chest. He or she may have a brief period of lightheadedness.
    If the VT continues, the person may show the following symptoms:
  • anxiety or agitation

  • chest pain

  • excessive sweating

  • lethargy or even coma

  • palpitations, or an unusual awareness of the heart beating in the chest

  • shortness of breath

    • Diagnosis & Tests

    How is the condition diagnosed?
    Diagnosis of ventricular tachycardia begins with a medical history and physical exam. An EKG will show a certain abnormal pattern. The healthcare provider may order these additional tests to determine the cause of the VT:
  • blood tests

  • chest X-ray

  • echocardiogram, which uses ultrasound waves to study the heart

    • Prevention & Expectations

    What can be done to prevent the condition?
    VT usually comes on suddenly and cannot be prevented. Future episodes of VT may be avoided by treating the underlying disorder. Individuals with a history of VT should limit intake of caffeine. Cocaine and methamphetamines should be avoided.
    What are the long-term effects of the condition?
    If VT is untreated, it may cause serious long-term effects:
  • cardiac arrest

  • coma

  • congestive heart failure, a condition in which the weakened heart is unable to pump enough blood throughout the body

  • death

  • shock

    • What are the risks to others?
    Ventricular tachycardia is not contagious and poses no risk to others.

    Treatment & Monitoring

    What are the treatments for the condition?
    Treatment will vary, depending on the underlying disorder that causes the VT. Some options include:
  • anti-arrhythmic medicines, such as lidocaine, procainamide, or amiodarone

  • cardiopulmonary resuscitation, or CPR

  • oxygen

  • surgery to implant a device that delivers shocks to the heart when VT occurs

  • synchronized cardioversion, a procedure that delivers a shock to the heart in order to produce a more normal rhythm

    • What are the side effects of the treatments?
    Shocks to the heart may cause new arrhythmias. In some cases, shocks may cause the heart to stop beating entirely. Medicines for VT may cause allergic reactions, stomach upset, and other arrhythmias. Surgery may cause bleeding, infection, or allergic reaction to anesthesia.
    What happens after treatment for the condition?
    If ventricular tachycardia is successfully treated, the person may return to normal activities. He or she may be advised to limit the intake of caffeine and other stimulants. Underlying conditions, such as coronary heart disease, may require lifestyle changes and further treatment.
    How is the condition monitored?
    People with VT that causes symptoms need to be followed closely. They will need regular EKGs, blood tests, and other diagnostic studies. Any new or worsening symptoms should be reported to the healthcare provider.

    Attribution

    Author:Susan Woods, MD
    Date Written:
    Editor:Crist, Gayle P., MS, BA
    Edit Date:08/31/01
    Reviewer:Barbara Mallari, RN, BSN, PHN
    Date Reviewed:07/31/01
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