Heart block

What is heart block?

Heart block is a type of arrhythmia called bradycardia. It is the slowing down or interruption of the electrical signal to the lower chambers of the heart (the ventricles) that cause the heart muscle to contract. It may also develop as a side effect of certain heart medications. In some cases, no cause can be identified. An uncommon form can also occur in infants (congenital heart block).

Heart block is most likely to occur in the elderly, especially those who have other forms of circulatory diseases such as:

  • Coronary artery disease
  • Cardiomyopathy
  • Rheumatic heart disease
  • Uncontrolled or untreated high blood pressure

Third degree heart block (complete atrioventricular block) is usually a complication of a heart attack, but may also result from heart surgery or infections of the heart muscle.


Symptoms range from lightheadedness to fatigue or fainting.


Heart block is usually diagnosed using an electrocardiogram (ECG/EKG), a printed record of your heart’s electrical activity that gives information about its rhythm, size and any possible damage.


If necessary, heart block is treated by implanting a pacemaker to take over the job of providing regular electrical heart stimulation and helps the heart to beat in a regular rhythm.