Patients and Families

What are IHRC’s?

Inherited heart rhythm conditions, or IHRCs, are a group of heart problems that affect the electrical signals, and sometimes muscle function, of the heart.

There are several different conditions but they share some similar features. The most important common feature is the risk of the heart suddenly going in to a fast, abnormal rhythm that can cause fainting or blackouts or, in the most severe cases, a cardiac arrest. In many individuals there are no other symptoms and so the treatments are aimed at reducing the risk of dangerous heart rhythms and preventing sudden cardiac arrest.

Where do they come from?

Inherited heart rhythm conditions are generally caused by changes in a person’s genes and in particular the genetic code that programs the way the heart develops.

Although the genetic changes are present from birth, signs of the condition may not develop until later in life. As a person’s genes are inherited from their parents, these conditions can run in families. Sometimes, however, the genetic change arises in a person for the first time. Additional factors including other genes, use of certain medications, and levels of physical activity can affect the severity of the conditions so that, even within a single family, there may be a wide variation in the severity of an inherited heart rhythm condition.

To diagnose an inherited heart rhythm condition, individuals will undergo a series of tests to assess for the presence of the heart condition. Testing includes a number of clinical tests and also genetic testing (blood sample) to determine the likelihood of having the heart condition. No single test is all encompassing, and individuals will also receive a formal assessment from a heart rhythm physician to see if he or she is at risk.


Some inherited heart rhythm conditions can be managed with medication. Certain conditions require extra care when taking medication. Please refer to the links below for a list of drugs to avoid. These lists are always updated so be sure to check frequently.


These are some of the devices that can help to manage IHRCs

Implantable Cardioverter Defibrillator (ICD)

An ICD is a device that is placed permanently inside your body. An ICD monitors your heart rhythm (the speed and pattern of your heartbeat). If this rhythm becomes too fast or too slow, the ICD sends out electrical signals that help bring the rhythm back to normal. The ICD is put inside your body during a minor surgical procedure called implantation. In most cases, implantation takes 1 to 3 hours.



A metal electronic device which can regulate the rhythm of the heartbeat. It is usually implanted just under the skin at the left collarbone.


Loop Recorder

An implantable loop recorder (ILR) is a small thin device that is inserted under the skin to record the activity of your heart. The ILR monitors and records your hearts electrical activity in order to identify an irregular heart rhythm. The ILR can remain in place for up to 3 years.


Left Cardiac Sympathetic Denervation Surgery

Left cardiac sympathetic denervation surgery tries to minimize the risk of sudden death. In this procedure, a surgeon removes nerves that are part of the sympathetic nervous system and play a role in regulation of heart rhythm. Only some patients under this procedure – usually those who are not able to take their medication because of side effects, have serious symptoms even while on medication, or are at high risk of sudden death and have appropriate shocks from their implantable cardioverter defibrillator (ICD).