The heart’s normal rhythm is called sinus rhythm. Its rate is between 60 and 100 beats per minute (bpm) while you are resting. If the sinus rhythm is slower than 60 bpm, it is called sinus bradycardia. If the sinus rhythm is faster than 100 bpm, it is called sinus tachycardia. (‘Brady’ means slow and ‘tachy’ means fast.) The normal heart rate varies from minute to minute, depending on the demands on the heart. Sinus arrhythmia is a normal variation of sinus rhythm, where the heart rate increases very slightly as you take a breath in. Sinus rhythm, sinus bradycardia, sinus tachycardia and sinus arrhythmia are all normal heart rhythms where the electrical impulses travel in a normal way through the heart.