It is called sinus rhythm because the electrical impulses that drive the heartbeat originate from the sinus node, which is the heart's natural pacemaker.
What is Sinus Rhythm?
Sinus rhythm refers to the normal and healthy heart rhythm characterized by consistent electrical activity initiated by the sinus node. This rhythm indicates that the heart is functioning properly. The sinus node is located in the right atrium and generates electrical impulses that spread through the heart, causing it to contract and pump blood. When the heart's rhythm originates from this natural pacemaker, it's classified as a sinus rhythm.
Understanding the Sinus Node
The sinus node is a small group of specialized cells in the right atrium. It acts as the heart's natural pacemaker because it generates electrical signals that trigger the heart's contractions. The rate at which the sinus node fires determines the heart rate, which is typically between 60 and 100 beats per minute in a resting adult.
Key Features of Sinus Rhythm
- Origin: The electrical impulse always starts in the sinus node.
- Regularity: The rhythm is regular, meaning that the time between each beat is consistent.
- Rate: The heart rate is within the normal range of 60 to 100 beats per minute.
- Consistent Pattern: The electrocardiogram (ECG) shows a consistent pattern of electrical activity.
Comparison to Other Rhythms
When the heart rhythm does not originate from the sinus node, it is classified as an abnormal rhythm. These rhythms may include:
- Atrial fibrillation: Rapid and irregular heartbeat originating from the atria.
- Ventricular tachycardia: Fast heartbeat originating from the ventricles.
- Bradycardia: A slow heartbeat, usually below 60 beats per minute.
Reference Information:
According to the provided reference:
- Normal sinus rhythm (NSR) is the rhythm that originates from the sinus node and describes the characteristic rhythm of the healthy human heart.
In Summary
The term "sinus rhythm" directly refers to the heart rhythm that is initiated by the sinus node. This normal pattern indicates healthy electrical activity and proper heart function.
