Arrhythmia
Types of Arrhythmias
Arrhythmia can be broadly classified
into two types, based on the speed of heart rate:
- Tachycardia: Heart beat is steady (i.e., sinus rhythm) but the rate
is more than 100 beats per minute.
- Bradycardia: Heart beat is steady (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,
or small, short variations in heart beats, 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 the 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.
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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 that 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 rapidly from the atria to the
ventricles and bounce back leading to very fast heart rates (4, 7).
2. Ventricular arrhythmias: Arrhythmias
originating in the ventricles can be 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 Blockage or Atrioventricular
(AV) block: It is the blockage of electrical signals from
the atria to the ventricles causing abnormal slowing down of contractions.
Heart blockage can be further classified as first degree, second degree,
or third degree (complete).
-
Bundle block branch:
Bundles 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)
Article by Kona Vishnu, MS
Medical Writer,
OmniMedicalSearch.com
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