An intercalated disc forms connections between neighboring cells in the heart. These structures are highly specialized and enable the coordinated function of the heart cells, known as myocytes, to allow the heart to beat. These are found only in cardiac tissue. Pathologists can quickly identify samples from the heart by spotting the intercalated discs and distinctive myocytes. Thanks to these connections, the heart can beat almost as a single unit, rather than firing cells separately as in other muscle types.

Two types of connections are formed at each intercalated disc, which intertwines the cell membranes of two myocytes. The first is a physical link with tiny connective tissues that effectively tie the cells together. Much like a harness, the joint at each intercalated disc allows the cells to work together in unison, making them stronger and more efficient. The network of tiny connections joining heart cells effectively gives the heart a high degree of coordination.

A chemical link is also present at each intercalated disc. This allows cells to rapidly exchange chemical and electrical information, key to cardiac function. When the heart's internal pacemaker sends electrical signals to trigger contraction and relaxation, they leap across the intercalated discs to control the myocytes. This complex interconnected network allows for a high degree of control over the heart muscle, and makes it extremely strong.

When samples of tissue from the heart are viewed under a microscope, the intercalated discs can be clearly visible. A pathologist examining a specimen from a diseased or ill patient may take note of any abnormalities in the tissue. These could include dead cells, evidence of oxygen deprivation or other issues that kill sections of the heart, along with discoloured or enlarged cells. Some researchers believe that intercalated discs can play a role in some heart conditions, such as cardiomyopathy.

Disorders of heart function, including those involving problems at the intercalated disc, can be difficult for care providers to treat. Widespread problems with the heart may necessitate a transplant to address the situation. Others may be controllable with medication and surgical treatment. Researchers study structures like the intercalated discs to learn more about how the heart functions in healthy individuals so they can more easily identify the source of the problem when something goes wrong. This information can help with the development of new medications and other treatment options for patients with heart disorders.