Sinus Rhythms

Normal sinus rhythm: HR 60 to 100, regular rhythm, normal P wave, normal PR interval and normal QRS complexes

Sinus bradycardia: HR < 60, regular rhythm, normal P wave, normal PR interval and normal QRS complexes

Sinus tachycardia: HR 100 to 150, regular rhythm, normal P wave, normal PR interval and normal QRS complexes

Sinus arrhythmia: HR 60 to 100, irregular rhythm, normal P wave, normal PR interval and normal QRS complexes

Sinus pause/arrest: Transient absence of sinus P waves lasting from 2 seconds to several minutes; otherwise normal rate, rhythm, P wave, PR interval and QRS complexes