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Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. [1] In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. [1] Heart rates above the resting rate may be normal (such as with exercise) or abnormal (such as with electrical problems within the heart).
Bradycardia, also called bradyarrhythmia, is a resting heart rate under 60 beats per minute (BPM). [1] While bradycardia can result from various pathologic processes, it is commonly a physiologic response to cardiovascular conditioning or due to asymptomatic type 1 atrioventricular block.
The resting heart rate in children is much faster. In athletes, however, the resting heart rate can be as slow as 40 beats per minute, and be considered normal. [citation needed] The term sinus arrhythmia [26] refers to a normal phenomenon of alternating mild acceleration and slowing of the heart rate that occurs with breathing in and out ...
The action potential passes along the cell membrane causing the cell to contract, therefore the activity of the sinoatrial node results in a resting heart rate of roughly 60–100 beats per minute. All cardiac muscle cells are electrically linked to one another, by intercalated discs which allow the action potential to pass from one cell to the ...
If the fast heart rate is poorly tolerated (e.g. the development of heart failure symptoms, low blood pressure or coma) then AVNRT can be terminated electrically using a cardioversion. In this procedure, after administering a strong sedative or general anaesthetic, an electric shock is applied to the heart to restore a normal rhythm. [8]
A lower resting heart rate or slower heartbeat will fill the ventricles/heart better and allow for more of a forceful contraction of blood out to the rest of the body, says Dr. Weinberg.
Heart rate is a measure of ventricular rather than atrial activity. Impulses from the atria are conducted to the ventricles through the atrio-ventricular node (AV node). In a person with atrial flutter, a 12-lead electrocardiogram (ECG) will demonstrate the atrial chambers of the heart contracting at a rate of 280–300 beats per minute whereas ...
The various forms of long QT syndrome, both congenital and acquired, produce abnormal heart rhythms (arrhythmias) by influencing the electrical signals used to coordinate individual heart cells. The common theme is a prolongation of the cardiac action potential – the characteristic pattern of voltage changes across the cell membrane that ...