Electrical pulses in the heart are controlled
by special groups of cells called nodes. The SA (sinoatrial) node generates an electrical
signal that causes the upper heart chambers (atria) to contract. The signal then passes
through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing
them to contract, or pump.
The SA node is considered the pacemaker of the heart.
Its electrical signals normally cause the atria to contract at a rate of 60 to 100
times a minute.
Disturbance anywhere along this electrical pathway can cause
irregular heartbeats (arrhythmia).
Adam Husney, MD - Family Medicine & Rakesh K. Pai, MD - Cardiology, Electrophysiology &
Martin J. Gabica, MD - Family Medicine & John M. Miller, MD, FACC - Cardiology, Electrophysiology
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