Bradycardia is defined as a heart rate below 60 beats per minute. However, slow heart rates are often found in normal people, especially at rest or if very fit. Sinus bradycardia, junctional escape rhythm and Wenckebach block can also be seen in normal people and are usually asymptomatic.
Patients with asymptomatic bradycardia usually need no treatment.
Intermittent severe bradycardia can cause syncope. Chronic bradycardia can cause fatigue, shortness of breath on exertion and dizziness. Severe bradycardia can cause haemodynamic consequences of hypotension, altered conscious state, poor perfusion, ischaemic chest pain and cardiac failure. However, in the presence of bradycardia and haemodynamic compromise it is important to look for other factors such as myocardial infarction or poor ventricular function.
Patients with syncope, other symptoms or haemodynamic compromise due to bradycardia should be referred urgently for consideration of pacemaker implantation.
Transcutaneous pacing may be required in the emergency setting for acute severe bradycardia causing severe haemodynamic compromise. Temporary transvenous pacing may be required in patients with acute, symptomatic bradycardia. Patients with chronic symptomatic bradycardia and some patients with asymptomatic but significant bradyarrhythmias require permanent pacemaker implantation.
Revised February 2012. ©Therapeutic Guidelines Ltd (etg43demo November 2014)
