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Conditions & Diseases: Cardiovascular System

Arrhythmia

See Also:
Arrhythmia: Introduction & Overview
Arrhythmia: Types
Arrhythmia: Causes & Risk Factors
Arrhythmia: Signs & Symptoms
Arrhythmia: Medical Tests & Diagnosis Methods
Arrhythmia: Treatment & Prevention Options

Types of Arrhythmias

Arrhythmia can be broadly classified into two types, based on the speed of heart rate:

  1. Tachycardia: Heart beat is regular (i.e., sinus rhythm) but the rate is more than 100 beats per minute.
  2. Bradycardia: Heart beat is regular (i.e., sinus rhythm) but the rate is less than 60 beats per minute. (5)

Ecotopic Beats are a third type and are extra heartbeats which are very common. Ecotopic beats are usually not dangerous and do not damage the heart (6).

Further arrhythmias are categorized based on their origin in the heart.

1. Atrial arrhythmias: Arrhythmias originating in atria are as follows:

  • Atrial Fibrillation: In this type, the heart’s electrical signals lose their regular pattern and the heart’s atria (upper two chambers) start emitting uncoordinated electrical signals. The atria pump the blood at a faster and uneven rate without contracting fully. The heart may contract 5-7 times faster than normal i.e., about 300-400 beats per minute. Atrial fibrillation is not life threatening but can lead to rhythm problems, chronic fatigue, congestive heart failure and in worst cases, a stroke. It is important to note that electrical signals originate in a different part of the atrium other than the sinoatrial node.

  • Supraventricular Tachycardia (SVT) or Paroxysmal Supraventricular Tachycardia (PSVT): Supraventricular tachycardia involves both the atria and the ventricles. This type of tachycardia originates either in the atria or in the middle region.

  • Atrial Flutter: This is similar to atrial fibrillation but for the electrical signals spreading through the atria in a fast and irregular rhythm. The key difference being that in atrial flutter is the electrical impulses are more organized and more rhythmic as compared to that in atrial fibrillation.

  • Premature Atrial Contraction (PAC): In this type, premature beats or extra beats cause irregular heart rhythms which start in the atria. They are very common in normal children and teenagers.

  • Sick Sinus Syndrome: The heart rate slows down when the sinoatrial node does not fire the signals properly and the heart rate may switch between a slow rate (Bradycardia) and a fast rate (tachycardia).

  • Sinus Arrhythmia: Cyclic changes in heart rate during breathing are called sinus arrhythmia.

  • Sinus Tachycardia: In this type, a normal increase in the heart rate occurs due to fever, excitement and exercise leading to passage of electric signals at a faster pace than usual.

  • Wolff-Parkinson-White (WPW) Syndrome: Abnormal pathways between the atria and ventricles cause the electrical signals to move speedily from atria to ventricles and bounce back leading to very fast heart rates (4) & (7).

2. Ventricular arrhythmias: Arrhythmias originating in ventricles are fatal and require immediate medical attention.

  • Ventricular Tachycardia (VT): Ventricular tachycardia involves only the ventricles and originates in the ventricles. VT is a fast regular beating of the heart that last a few seconds or longer.

  • Premature Ventricular Contraction (PVC): PVCs originate in the ventricles causing irregular heart rhythms. PVCs are very common in normal children and teenagers.

  • Ventricular Fibrillation: Disordered electrical activity causes ventricular fibrillation leading to rapid, unsynchronized and uncoordinated contraction of the heart. Little or no blood is pumped by the heart during ventricular fibrillation resulting in collapse or even sudden death of the patient (4) & (8).

3. Bradycardia: Bradycardia can be classified into following types:

  • Heart Block or Atrioventricular (AV) block: It is the blockage of electrical signals from the atria to the ventricles causing abnormal slowing down of contractions. Heartblockage can be further classified as first degree, second degree or third degree (complete).

  • Bundle block branch: Bundles involved can be either left or right bundles that could be blocked from transmitting heart signals to the ventricles. Left bundle branch block (LBBB) is further classified as complete or partial (anterior fascicular block or posterior fascicular block). Right bundle branch block (RBBB) is also similarly classified as partial or complete. Other types of bundle branch block are bifascicular block and trifascicular block (2).

See Also:
Arrhythmia: Introduction & Overview
Arrhythmia: Types
Arrhythmia: Causes & Risk Factors
Arrhythmia: Signs & Symptoms
Arrhythmia: Medical Tests & Diagnosis Methods
Arrhythmia: Treatment & Prevention Options

Article by Kona Vishnu, MS
Medical Writer,
OmniMedicalSearch.com

 

 

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Page Last Modified:
07/05/2009