The heart, and its normal rhythm
Your heart is a muscle which pumps blood through to your lungs, your brain, and the rest of your body. It has four chambers – two upper ones called the right and left atria, and two lower ones called the right and left ventricles.
Your heart’s pumping action is controlled by tiny electrical impulses produced by a part of the right atrium called the Sinus Node. These impulses make the atria contract and push blood into the ventricles. The impulses travel to the ventricles through the AV Node (Atrio-Ventricular Node). This acts like a junction box and is sometimes called the AV junction. When the impulse reaches the ventricles, the ventricles both contract, pushing the blood out of your heart to your lungs, your brain, and the rest of your body. In a normal heart rhythm, each impulse from the sinus node makes the atria and the ventricles contract regularly.
While you are resting, your Sinus Node normally produces between 60 and 100 impulses a minute. It is your heart pumping the blood that produces your pulse. The rate and rhythm of your heart can be measured by taking your pulse. The rate is how quickly your heart beats, and the rhythm is how regular or irregular the beats are. The heart’s normal rhythm is called Sinus Rhythm.
Sometimes your heart will beat faster or more slowly, depending on your general health and whether you have been active or resting. When your heart is beating fast but with a regular rhythm, the rhythm is called Sinus Tachycardia. When it is beating slowly but with a regular rhythm, it is called Sinus Bradycardia. These rhythms do not necessarily mean there is anything wrong with your heart. However, if your heart rate is constantly fast or always feels very slow and you also feel unwell, you should see your consultant.