Sinus Bradycardia (Nursing).


Sinus Bradycardia (Nursing).


Hafeez Y; Grossman SA; Pratt NJ






The sinoatrial node (SA) is the default pacemaker and therefore a crucial component of the heart's conduction system. It is located subepicardially and is crescent in shape. The sinoatrial node is innervated by vagus and sympathetic nerves. The sinoatrial nodal artery supplies blood to the sinoatrial node, it branches off the right coronary artery in 60% of cases, whereas in 40% of cases it comes off the left circumflex coronary artery. Sinus bradycardia is a cardiac rhythm with appropriate cardiac muscular depolarization initiating from the sinus node generating less than 60 beats per minute (bpm). Diagnosis of sinus bradycardia requires visualization of an electrocardiogram showing a normal sinus rhythm at a rate lower than 60 bpm. Where a normal sinus rhythm has the following criteria: Regular rhythm, with a P wave before every QRS. P wave is upright in leads 1 and 2, P wave is biphasic in V1. The maximum height of a P wave is less than or equal to 2.5 mm in leads 2 and 3. The rate of the rhythm is between 60 bpm and 100 bpm.



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Hafeez Y; Grossman SA; Pratt NJ, “Sinus Bradycardia (Nursing).,” NEOMED Bibliography Database, accessed October 2, 2023,