Diagnostic criteria

  Heart rate < 50/minute.

  P wave is positive in D1 and D2.

  Every P wave is followed by a QRS complex.

Causes of sinus bradycardia

  During sleep

  Medications: beta blockers, verapamil, diltiazem, amiodarone, digoxine, ivabradine, clonidine,

      lithium, pyridostigmine

  Myocardial ischemia or infarction


  Increased vagal tone

  Athlete's heart


  Increased intracranial pressure


  Advanced age

ECG 1. Sinus bradycardia.

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ECG 2. Sinus bradycardia due to concomitant ingestion of bisoprolol and diltiazem.

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ECG 3. Sinus bradycardia during acute inferior myocardial infarction. The heart rate is approximately 25/minute.
Inferior leads show ST segment elevation.
Immediately after recording of the above ECG, the patient underwent coronary angiography which revealed 99% stenosis of
the proximal Right Coronary Artery (RCA).

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