What does it mean to be in sinus rhythm?

As a medical professional with expertise in cardiology, I can explain what it means to be in sinus rhythm. Sinus rhythm is a term used in cardiology to describe the normal pattern of electrical activity that controls the beating of the heart. The heart's rhythm is regulated by a natural pacemaker called the sinoatrial (SA) node, which is located in the upper part of the right atrium. When the heart is in sinus rhythm, it means that the electrical signals are initiating from the SA node and are spreading through the heart in a coordinated manner, resulting in a regular and effective heartbeat. The characteristics of a normal sinus rhythm include a heart rate typically between 60 and 100 beats per minute for adults at rest. The rhythm is regular, meaning that the time between each heartbeat is consistent, and the electrical signals are originating from the SA node, which is considered the heart's natural pacemaker. Being in sinus rhythm is considered the healthiest and most efficient way for the heart to function. Any deviation from this rhythm could indicate a cardiac issue, such as arrhythmia, which may require medical attention.

Sinus rhythm means a normal heart beat, both with respect to the heart rate and rhythm. Heart rate will fall between 60 and 100 beats per minute. The shape of the electrocardiogram (EKG) tracing will exhibit certain key attributes to be considered normal, as discussed below.