cardiolab logocardiolab

Normal Sinus Rhythm

normal
Lead II
25 mm/s10 mm/mV
Heart rate
72bpm
RR
833ms
QT
338ms

Controls

72 BPM
0.03 mV

Normal Sinus Rhythm

The heart's normal electrical rhythm. The SA node fires at 60–100 bpm, impulses conduct normally through the atria, AV node, and ventricles.

Recognition· 4
  • Regular rhythm
  • P wave before every QRS
  • PR interval 120–200 ms
  • Narrow QRS (<120 ms)
Mechanism

SA node fires normally at 60–100 bpm, impulses conduct through normal pathways

The sinoatrial (SA) node in the right atrium acts as the heart's natural pacemaker. It generates electrical impulses that spread through the atria, pause briefly at the AV node, then rapidly conduct through the ventricles via the His-Purkinje system.

Findings· 5
  • Regular rhythm.
  • Upright P wave before every QRS.
  • PR interval 120–200 ms.
  • Narrow QRS (<120 ms).
  • Each P followed by a QRS.
Clinical Impact

Normal finding — no treatment needed