Sinus rhythm is a sinus rhythm that is analyzed by an electrocardiogram to determine if the heart is in sinus rhythm. Any heart rhythm that originates in the sinus node is called sinus rhythm. A normal sinus rhythm in adults is 60-100 beats per minute. If the sinus heart rate is more than 100 beats/minute, it is considered tachycardia. If the sinus heart rate is less than 60 beats/minute, it is sinus bradycardia. The occurrence of impulses showing uneven appearance of P waves with unequal timing of P waves is diagnosed as sinus arrhythmia. Electrocardiogram for the diagnosis of heart rhythm is the most convenient and common clinical examination, but also other instruments can be replaced by a test method.