What is Cardiotoxicity?

Cardiotoxicity is damage to the heart muscle. Chemotherapy drugs that are used to treat blood cancer can cause damage to the heart tissue. This is especially true for anthracycline chemotherapy drugs, and potentially cyclophosphamide chemotherapy drugs.¹

Different conditions may occur with cardiotoxicity. They include:²

• Cardiomyopathy – This occurs when the heart muscle is weakened or hardened. This may change the rhythm of the heart or lead to heart failure.
• Myocarditis – This is an inflammation of the heart that makes it harder for the heart to pump. This may change the rhythm of the heart or lead to heart failure.
• Pericarditis – This is an inflammation of the sac around the heart. It may cause chest pain or heart failure.
• Acute coronary syndrome – This is caused by damage or blockage to the blood vessels that supply the heart. It can cause chest pain or a heart attack.
• Congestive heart failure – This occurs when the heart is unable to fully pump blood throughout the body. It can become severe, potentially requiring a heart transplant.

Symptoms

Symptoms relate to damage to the heart muscle and vessels that supply nutrients to the heart. Symptoms of cardiotoxicity may include:¹

• Shortness of breath
• Chest pain
• Sensation of heart pounding or fluttering
• Swelling in the legs
• Bloating and swelling of the belly
• Dizziness

Diagnosis

Not everyone who receives chemotherapy will experience cardiotoxicity. However, if you or your loved one are faced with this complication, many advanced treatment centers focus on diagnosing and treating this condition. Diagnosis may include:³

• Physical exam
• Echocardiogram (ultrasound of the heart)
• MRI, which takes images of your heart using a magnetic field
• Blood work that shows damage to the heart muscle

Treatment

To treat cardiotoxicity, your doctor may prescribe drugs that make your heart pump stronger or work more effectively. Some of these drugs may include:⁴

• Beta-blockers – These slow down your heart rate, lower your blood pressure, and strengthen your heart muscle. These drugs can help reduce rhythm problems, high blood pressure, or heart failure.
• ACE inhibitors and angiotensin system inhibitors (ARBs) – These decrease your blood pressure and strengthen your heart muscle. They may also help to decrease blood pressure and heart failure.
• Diuretics – Sometimes called water pills, these drugs rid the body of extra fluid by increasing urination. This helps decrease symptoms of heart failure, such as shortness of breath and swelling in the feet. By eliminating extra fluid, the heart is able to pump better and more efficiently.

Outcome

The outcome of cardiotoxicity as a result of heart damage due to cancer treatment is highly variable. Each cancer drug is different and causes different effects within the body. As a result, the effect on the heart differs as well. Damage to the heart can range from mild to severe.

More studies are needed to help inform doctors about cancer treatments and heart side effects. Large trials that follow participants over time would allow doctors to understand how a drug might affect the heart over time. Cancer drug discovery is happening very quickly, with increasing survival rates. The more research and clinical studies performed on the effects of cancer treatment on the heart, the better we will understand the long-term impact and survival.

Prevention

Early diagnosis and treatment of heart damage is important to prevent serious, life-threatening complications. People who are receiving treatment or have previously received treatment for blood cancer should tell their doctor if they experience:¹

• Chest pain
• Changes in the rhythm of the heart, like skipped beats
• Feeling short of breath

Cardiotoxicity may also be prevented by limiting the amount of the potentially damaging drug a person receives and how the drug is given.

Limiting doses

Limiting the dose of the damaging drug over time is the best prevention. Doctors do not know the exact amount of chemotherapy that will damage the heart of each person. Exploring your risks and benefits of treatment is important.⁵

How you receive the drug

The way you take the drug matters when preventing heart damage due to cancer treatment. Drugs given quickly result in high blood levels. This may damage the heart more than the same amount given over a longer period of time. Taking smaller doses more often may decrease the toxicity compared to larger doses less often. Do not attempt to change your drug regimen without talking to your doctor.⁵

Monitoring for cardiotoxicity after cancer treatment is an important part of cancer survivorship. Coordinated treatment programs will include care from your oncologist and cardiologist (heart doctor). You may also receive long-term nutrition counseling and other supportive care. Together, these services can help you tackle any complications you may encounter. They can also help improve your overall treatment outcome and quality of life.⁵