Bradycardia is usually associated with sinus arrhythmias, where the difference between PP intervals can be greater than 0.12s in addition to the bradycardia on the ECG.
Bradycardia with sinus arrhythmia usually occurs in healthy young people and athletes and is usually not harmful to health and should be followed up. Intracranial disease, severe hypoxia, hypothermia, hypothyroidism, obstructive jaundice and vasovagal syncope, and the application of drugs such as cholinomimetics, amiodarone, beta-blockers or digitalis. Sinus node lesions and acute inferior wall myocardial infarction also commonly occur with sinus bradycardia with arrhythmias.