Arrhythmia, sinus
The normal increase in heart rate that occurs during inspiration (when you breathe in). This is a natural response and is more accentuated in children than adults. The "sinus" refers to the natural pacemaker of the heart which is called the sinoatrial (or sinus) node. It is located in the wall of the right atrium (the right upper chamber of the heart). Normal cardiac impulses start there and are transmitted to the atria and down to the ventricles (the lower chambers of the heart). Sinus tachycardia refers 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 thyroid hormone, low blood oxygen (hypoxia), stimulant drugs (such as caffeine), etc. The lack of normal sinus rhythm is an arrhythmia, an abnormal heart rhythm.

Medical dictionary. 2011.

Look at other dictionaries:

  • Sinus rhythm — is a term used in medicine to describe the normal beating of the heart, as measured by an electrocardiogram (ECG). It has certain generic features that serve as hallmarks for comparison with normal ECGs. ECG Structure There are typically five… …   Wikipedia

  • Arrhythmia — An abnormal heart rhythm. In an arrhythmia the heartbeats may be too slow, too rapid, too irregular, or too early. Rapid arrhythmias (greater than 100 beats per minute) are called tachycardias. Slow arrhythmias (slower than 60 beats per minute)… …   Medical dictionary

  • Sinus rhythm — The normal regular rhythm of the heart set by the natural pacemaker of the heart called the sinoatrial (or sinus) node. It is located in the wall of the right atrium (the right upper chamber of the heart). Normal cardiac impulses start there and… …   Medical dictionary

  • Sinus arrhythmia — The normal increase in heart rate that occurs during inspiration (when you breathe in). This is a natural response and is more accentuated in children than adults. The sinus refers to the natural pacemaker of the heart which is called the… …   Medical dictionary

  • Arrhythmia absoluta — Vorhofflimmern ist eine vorübergehende (paroxysmale oder intermittierende) oder dauerhafte (permanente) Herzrhythmusstörung mit ungeordneter Tätigkeit der Herzvorhöfe. Gebräuchliche Abkürzungen sind AF oder AFib (von englisch Atrial fibrillation) …   Deutsch Wikipedia

  • arrhythmia — n. any deviation from the normal rhythm (sinus rhythm) of the heart. The natural pacemaker of the heart (the sinoatrial node), which lies in the wall of the right atrium, controls the rate and rhythm of the whole heart under the influence of the… …   The new mediacal dictionary

  • sinus arrhythmia nonrespiratory — nonphasic a …   Medical dictionary

  • sinus arrhythmia respiratory — phasic a …   Medical dictionary

  • sinus arrhythmia — a normal variation in the heart rate, which accelerates slightly on inspiration and slows on expiration. It is common in healthy individuals …   The new mediacal dictionary

  • juvenile arrhythmia — sinus arrhythmia occurring in children …   Medical dictionary

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