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Other Names:
Dysrhythmias, Abnormal Heart Rhythms
Arrhythmias

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Definition

An arrhythmia is any disorder of the heart rate or rhythm.

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Types

  • Tachycardias - the heartbeat is too fast
  • Bradycardias - the heartbeat is too slow
  • True arrhythmias - a disturbed rhythm of the heart beat.

Arrhythmias can be:

  • Atrial fibrillation
  • Atrial flutter
  • Atrial tachycardia
  • Ventricular fibrillation
  • Ventricular tachycardia
  • Paroxysmal supra-ventricular tachycardia
  • Sinus tachycardia
  • Sinus bradycardia
  • Bradycardia associated with heart block
  • Sick sinus syndrome
  • Ectopic heartbeat.

Arrhythmias can be life-threatening if the pumping function of the heart is severely decreased. Just a few seconds of compromised blood circulation can cause irreversible organ damage (such as brain damage) and cause tissue death.

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Causes

Arrhythmias are caused by a disruption of the normal conduction system of the heart. Normally, the four chambers of the heart i.e. the right and left atria and the right and left ventricles contract in a very specific, co-ordinated, rhythmic manner.

Problems can occur anywhere along the conduction system, causing various arrhythmias. The problem may be in the heart muscle itself, causing it to respond differently to the signal, or causing the ventricles to contract independently of the normal conduction system.

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Risk Factors

Those people who have a history of cardiac conditions such as coronary artery disease or heart valve disorders or those with imbalances of blood chemistries are at an increased risk of developing arrhythmias.

Arrhythmias can also be caused by some medications like beta blockers, psychotropics, sympatho-mimetics, caffeine, amphetamines and cocaine. Sometimes anti-arrhythmic medications which may be prescribed to treat one type of arrhythmia can actually cause another type of arrhythmia.

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Symptoms

  • Palpitations
  • Fainting
  • Light-headedness, dizziness
  • Chest pain
  • Shortness of breath
  • Changes in the rate, rhythm or pattern of the pulse.
  • Paleness
  • Temporarily absent breathing

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Implications

Certain arrhythmias may increase your risk of developing conditions including:
  • Stroke. When there is atrial fibrillation, the heart is unable to pump blood effectively. Stagnant blood in the atria can form blood clots, these clots can travel and lodge in a brain artery where it may block the the blood flow, causing an ischemic stroke. This may damage or kill a portion of your brain or lead to death or a permanent disability affecting any vital centres of the brain or any part of the body. Your risk of having a stroke is higher if you have high blood pressure, if you are older than 65, if you have congestive heart failure, or if you have had a previous stroke.

  • Congestive Heart Failure. This can result if your heart is pumping ineffectively for a prolonged period due to a tachycardia such as atrial fibrillation.

  • Ischemic Heart Disease and angina (chest pain)

  • Heart attack (Myocardial infarction)

  • Sudden death

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What You Can Do

  • Urgent Treatment
    Urgent treatment of this serious and life threatening condition includes electrical shock - also called defibrillation or cardioversion, the implantation of a temporary pacemaker to interrupt the arrhythmia, or the administration of intravenous medications.
  • Vagal Maneuvers
    A supraventricular tachycardia (SVT) may be stopped by using particular maneuvers, which include holding your breath and straining, dunking your face in ice water or coughing. These maneuvers affect the nervous system and the vagal nerves that controls your heartbeat, often causing your heart rate to slow and return to normal rhythm.
  • Medications
    Most antiarrhythmic medications work to slow your heart rate by either suppressing the activity of pacemaking tissue that is initiating impulses too quickly, or to slow the transmission of fast impulses inside the heart. Medications may also be used to speed up the heart beat. Antiarrhythmic drugs may have certain potential side effects like causing a certain type of arrhythmia to occur more frequently or even cause a new arrhythmia to appear that might be worse than the pre-existing condition. Sometimes blood thinners are administered before attempting the cardioversion to prevent the blood clots from traveling to the brain.
  • Cardioversion.
    Life-threatening arrhythmias can be treated with an implantable cardioverter-defibrillator (ICD). This device detects the arrhythmia as soon as it begins, sends an automatic electrical shock to terminate it, or it can activate a pacemaker function to overdrive the arrhythmia. If you have atrial fibrillation, your physician may use an electrical shock to reset your heart to its regular rhythm. Cardioversion is usually done in a hospital, so that your heart activity can be monitored. Done under light anesthesia, the shock stops your heart for a split second. When it starts to beat again, it often resumes a normal rhythm. Electrical cardioversion alone can sometimes permanently restore your heart's normal rhythm. Antiarrhythmic drugs are required to maintain a normal rhythm over the long term.
  • Radio-frequency Catheter Ablation.
    Some patients may be ideal candidates to have a procedure called radiofrequency catheter ablation. Radio-frequency catheter ablation can cure many paroxysmal supra-ventricular arrhythmias as well as some ventricular arrhythmias.
    In this procedure, one or more catheters are threaded through your blood vessels to your inner heart. They are positioned along electrical pathways identified by your physician as causing your arrhythmia. Electrodes at the catheter tips are heated with radiofrequency energy. This destroys a small spot of heart tissue and creates an electrical block along the pathway that is causing the arrhythmia.
  • Lifestyle Changes
    • Eat heart-healthy foods
    • Increase your physical activity
    • Quit smoking.
    • Cut back on caffeine and alcohol
    • Find ways to reduce the amount of stress in your life
  • Prevention
    Methods of preventing heart diseases like coronary artery disease may decrease the likelihood of developing an arrhythmia. These include making lifestyle changes like not smoking; eating a nutritious, well-balanced, low-fat diet; keeping physically fit and active by exercising regularly.

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Arrhythmias