Progressive cardiac conduction defect (PCCD)


This condition, also known as PCCD, is a rare inherited heart rhythm disturbance where the heart’s electrical impulses are conducted very slowly. 

Over time, this can lead to a complete heart block – also known as third degree heart block.

PCCD can also cause fast, life-threatening rhythm disturbances from electrical impulses that originate from the wrong areas of the heart rather than the heart's natural pacemaker, the SA node (sino-atrial node).

For some people with PCCD, the changes are caused by the action of sodium channels in the heart’s cells, similarly to those who suffer from Brugada Syndrome.

Symptoms of PCCD

The most common symptoms are unexplained dizziness and blackouts. There is also a small risk of sudden death in PCCD. If your heart rate becomes so slow that the heart doesn’t pump enough blood over a period of time, your heart could stop. This is a cardiac arrest and is a medical emergency.

If you or a family member has PCCD and suddenly collapses, it is imperative to call 999 and try to perform cardio-pulmonary resuscitation (CPR) until an ambulance or medical help arrives. If you are untrained in CPR, the 999 operator will be able to talk you through the process.

How is PCCD diagnosed?

Your doctor will do an ECG, which should show any abnormalities in the heart’s rhythm. You may also be asked to have an ECG recording for a longer period such as a 24-hour ECG. Your doctor may refer you to a specialist to have an electrophysiological (EP) study.

If a member of your family already has PCCD and a genetic mutation has been found, you will be able to ask about genetic screening for yourself.

What treatments are available for PCCD?

If you have PCCD, you will need to have a pacemaker fitted to stop a dangerously slow heart rate (bradycardia). However, your pacemaker may not prevent escape tachycardias, which is a type of fast heart rhythm, so you may also be prescribed medicines to stop this from happening.

For some people, your doctor may suggest that you have a special type of ICD fitted, which also acts as a  pacemaker. ICD’s are designed to deliver a shock when your heart goes into a fast, life-threatening rhythm. This shock is intended to revert the heart back into a normal rhythm.

Can I live a normal life with PCCD?

There are very few things you need to change about the way you live if you have PCCD. However, you should be aware that: 

  • If you have a pacemaker or ICD fitted you will not be able to play contact sports.
  • It may also affect the type of work you do – particularly if you work with magnetic or power tools. 
  • You may be told to restrict or avoid strenuous exercise if you suffer from tachycardias (a fast heart rhythm).

Want to find out more?

Inherited heart conditions: Inherited heart rhythm disturbances booklet

This booklet explains what an inherited heart rhythm disturbance means. It covers screening, testing and implications for the family and future generations.



If you have further questions about inherited heart conditions, our Genetic Information Service can help you. Call 0300 456 8383. Lines are open from 9am to 5pm Monday to Friday (charged at a rate similar to 01 or 02 calls).

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