Possible Heart Effects

Immune checkpoint inhibitors help our own immune system fight cancer. Patients may also have side effects from this activated immune system. Heart side effects include:  

• Myocarditis (inflammation of the heart muscle): This can lead to impaired heart function, heart failure, and abnormal heart rhythms. This is the most serious heart complication associated with immune checkpoint inhibitors. The most severe cases are life-threatening. Overall, this is a rare complication, affecting about 1 out of 100 individuals in some reports (a rate of about 1%). It usually occurs within the first three months of treatment.
• Arrhythmias (problems in the electrical system of the heart): Immune checkpoint inhibitors have been associated with irregular rhythms, fast rhythms, slow rhythms, and heart block.
• Pericarditis (inflammation of the heart sac): This can lead to fluid collecting in the heart sac called a pericardial effusion. In some cases the fluid has to be removed.
• Vasculitis (inflammation of blood vessels): This can affect any size blood vessel but more commonly affects larger blood vessels.
• Other cardiovascular side effects include accelerated plaque formation in blood vessels throughout your body (atherosclerosis).
• Common symptoms of these heart problems include shortness of breath, chest pain, passing out, heart racing or skipping, and muscle weakness.

When Do Heart Effects Typically Occur?  

Immune checkpoint inhibitors can have long-lasting effects on the body up to one year after the last dose. However, side effects typically occur within the first three months of treatment.