Bradyarrhythmias

A bradyarrhythmia is defined as a rhythm disturbance that results in a heart rate of less than 60 bpm. It is important to note that many healthy people have a resting heart rate that is less than 60 bpm, most commonly due to sinus bradycardia (i.e. a rhythm arising from the sinus node but with a ventricular rate less than 60 bpm). Other forms of bradyarrhythmia are sinus node disease, sick sinus syndrome, first-degree atrioventricular (AV) block, second-degree AV block (which can be characterized as Möbitz type I (Wenckebach phenomenon) or Möbitz type II), and third-degree AV block (also known as complete heart block). This chapter discusses the bradyarrhythmias, focusing on their etiology, symptoms, demographics, diagnosis, prognosis, and treatment.