Sinus rhythm:The normal regular rhythm of the heart set by the natural pacemaker of the heart called the sinoatrial (orsinus)node. It is locatedinthe wall of theright atrium(the right upper chamber of the heart). Normalcardiacimpulses start there and are transmitted to theatriaand down to theventricles(the lower chambers of the heart).
Sinus arrhythmia refers to the normal increase inheart ratethat occurs during inspiration (when you breathe in). This is a normal response and is more accentuated in children than adults.
Sinus tachycardiarefers to a fast heartbeat (tachycardia) because of rapid firing of the sinoatrial (sinus) node. This occurs in response to exercise, exertion, excitement, pain, fever, excessive甲状腺激素, lowbloodoxygen(hypoxia), stimulant drugs (such as caffeine), etc.
The lack of normalsinus rhythmis an arrhythmia, anabnormalheart rhythm.
