What is a sinus rhythm of the heart?

Hello, I'm a healthcare professional with a background in cardiology. I'm here to help answer your questions about heart rhythms. A sinus rhythm is a term used to describe the normal, steady heartbeat that originates from the sinoatrial (SA) node, which is the heart's natural pacemaker. The SA node is located in the upper right chamber of the heart, known as the right atrium. When functioning properly, the SA node sends electrical signals to the atria, causing them to contract and push blood into the ventricles. Then, the signal travels to the ventricles, causing them to contract and pump blood out of the heart and into the circulatory system. The normal rate for a sinus rhythm is typically between 60 and 100 beats per minute (BPM) for adults at rest. However, well-trained athletes may have a lower heart rate, and rates can vary based on age, fitness level, and other factors. Sinus rhythm is considered the baseline for a healthy heart rhythm. Any deviation from this rhythm, such as a faster or slower rate, or an irregular pattern, could indicate a cardiac condition that requires medical attention. Now, let's translate that into Chinese: 你好，我是一位具有心脏病学背景的医疗保健专业人士。我在这里帮助回答有关心律的问题。 窦性心律是用来描述正常、稳定的心跳，这种心跳起源于窦房结（SA node），它是心脏的自然起搏器。窦房结位于心脏右上腔，即右心房。当窦房结正常工作时，它会向心房发送电信号，导致心房收缩并将血液推入心室。然后，信号传播到心室，导致心室收缩并将血液泵出心脏并进入循环系统。 正常心率对于成人静息状态下的窦性心律通常是每分钟60到100次（BPM）。然而，训练有素的运动员可能心率较低，心率会根据年龄、健康水平和其他因素而变化。 窦性心律被认为是健康心律的基线。任何偏离这种心律的情况，如更快或更慢的速率，或不规则的模式，都可能表明需要医疗注意的心脏状况。

Sinus rhythm is the name given to the normal rhythm of the heart where electrical stimuli are initiated in the SA node, and are then conducted through the AV node and bundle of His, bundle branches and Purkinje fibres. Depolarisation and repolarisation of the atria and ventricles show up as 3 distinct waves on ECG.