INTRODUCTION
Normal sinus rhythm (NSR) is the characteristic rhythm of the healthy human heart. NSR is considered to be present if the heart rate is in the normal range, the P waves are normal on the ECG, and the rate does not vary significantly. If, however, the R-R interval is variable, the rhythm is called sinus arrhythmia. A sinus rhythm faster than the normal range is called a sinus tachycardia (see “Sinus tachycardia”), while a slower rate is called a sinus bradycardia (see “Sinus bradycardia”). Continue reading
