cardiolab logocardiolab

Sinus Bradycardia

normal
Lead II
25 mm/s10 mm/mV
Heart rate
72bpm
RR
833ms
QT
368ms

Sinus Bradycardia

The SA node fires at a normal pattern but at a rate below 60 bpm. Common in athletes, during sleep, and with certain medications (beta-blockers, calcium channel blockers).

Mechanism

The SA node fires at a normal pattern but at a rate below 60 bpm. Common in athletes, during sleep, and with certain medications (beta-blockers, calcium channel blockers).

Findings· 3
  • Regular rhythm, rate <60 bpm.
  • Normal P waves, normal PR interval, narrow QRS.
  • Identical morphology to NSR, just slower.
Clinical Impact

Often benign. Symptomatic bradycardia (dizziness, syncope, hypotension) may require atropine or pacing.

Differential· 2
Junctional Escape

Both have slow regular rates. Junctional has absent or inverted P waves.

Complete Heart Block

Slow ventricular rate but with AV dissociation — P waves march through independently.