Cardiac toxicity . It is produced by chemotherapy drugs , toxins, and can damage your heart. As a consequence of this damage, the heart is unable to pump enough blood to supply the body with essential nutrients and oxygen. Although various chemotherapy drugs can cause cardiac toxicity, treatment with drugs called anthracyclines is the most common cause of cardiac toxicity in cancer patients .
Summary
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- 1 Cardiac toxicity
- 2 Causes of cardiac toxicity
- 3 Diagnosis
- 4 Symptoms
- 5 Prevent cardiac toxicity
- 6 Treatment
- 7 Sources
Cardiac toxicity
Damage to the heart muscle from a toxin is called cardiac toxicity. Cardiac toxicity can cause arrhythmias (changes in heart rhythm) or can progress to cause heart failure. Heart failure does not mean that your heart has stopped or is going to stop. It means that the heart muscle cannot pump hard enough to supply the body with blood that contains oxygen and essential nutrients. Heart failure occurs over time as the pumping action of the heart becomes weaker.
Causes of cardiac toxicity
There are many possible causes of cardiac toxicity. In cancer patients, cardiac toxicity can be caused by irradiation to the chest and by some chemotherapy drugs. The best-known cause of cardiac toxicity is the chemotherapy drug doxorubicin (Adriamycin®). the doxorubicinIt is a type of chemotherapy drug called anthracycline. Anthracyclines can be used to treat leukemia, lymphoma, multiple myeloma, and breast cancer. Other anthracyclines are: • Daunorubicin (Cerubidine®) • Epirubicin (Ellence®) • Idarubicin (Idamycin®) Other chemotherapy drugs that can produce cardiac toxicity are: • Cyclophosphamide (Cytoxan®) • Fluorouracil (5-FU) • Mitoxantrone (No ®) Among the cancer drugs that have been reported to cause abnormalities of heart rate or heart rhythm in more than 10% of patients are:
Diagnosis
Cardiac toxicity is diagnosed by various examinations and tests: Heart sounds: Your doctor will listen for abnormal heart sounds with a stethoscope. An extra sound in addition to the normal “tick tock” is called a murmur and may be a sign that your heart is injured. Chest x-ray: An x-ray provides a one-dimensional image of your heart and lungs. An enlarged heart on a chest x-ray may indicate that the heart muscle is injured. Electrocardiogram (ECG): An ECG machine records the electrical activity of your heart. This test is used to measure the rate and consistency of your heartbeat. Echocardiogram: This test uses sound waves to create an image of the heart. It shows whether the heart is filling with blood well and is pumping it well to the rest of the body. An echocardiogram is one of the most useful tests to diagnose heart failure. Multiple Synchronization Acquisition Study (MUGA): This procedure takes specialized pictures of the heart after a radioactive substance is injected into a vein. From the images, the contraction and relaxation of the heart and the blood supply to the heart can be visualized.
Symptoms
Cardiac toxicity is a serious problem. Tell your doctor immediately if you have any of the following symptoms: • Tiredness • Shortness of breath when exercising, worsening shortness of breath at rest • Discomfort when lying down • Ankle swelling
Prevent cardiac toxicity
Heart problems can be prevented by altering the amount of drug administered (dose), the form of administration, and the type of anthracycline. Some medications have also been developed that can prevent the damage caused by doxorubicin. Dosage: The main way to prevent cardiac toxicity is to limit the cumulative dose of drugs that harm the heart, especially anthracyclines. There is a defined amount of doxorubicin that can be given with a lower risk of complications: • If your total doxorubicin dose is less than 550 mg / m 2, there is less than a 1% chance that you will experience cardiac toxicity. • If your total doxorubicin dose is between 560 and 1155 mg / m 2, your risk increases to 30%. There also appear to be individual differences in the extent to which patients can tolerate doxorubicin. For example, some patients can receive high doses of doxorubicin without ever developing heart damage, while others have problems with relatively low doses (that is, less than 550 mg / m 2 of total dose). Route of administration: There is also some evidence that the method of administration of the drug may affect the risk of cardiac toxicity. Rapid administration of the drugs leads to elevated blood levels, which can cause more heart damage than the same amount of drug administered over a longer period of time. More frequent administration of smaller doses of the drug may also reduce toxicity compared to larger doses of drugs at longer intervals. Liposomal anthracyclines: The risk of cardiac toxicity from anthracyclines has been reduced by occurring differently. Liposomal anthracyclines have been encapsulated or encompassed in liposomes, tiny globule of fat. By “hiding” the drug in fat, it stays in the body longer, because the immune system does not target it for elimination and the liver does not break it down as quickly. Currently, there are studies indicating that the risk of heart problems is considerably lower with liposomal doxorubicin formulations than with conventional doxorubicin. Among the types of liposomal anthracyclines are: • Liposomal Daunorubicin (DaunoXorne®) • Pegylated Liposomal Doxorubicin (Doxil®) Pegylated liposomal doxorubicin is the most widely studied and has shown the most significant reductions in heart problems. Pegylated liposomal doxorubicin has shown an anticancer effect similar to conventional doxorubicin, but with less cardiac toxicity. Dexrazoxane (Zinecard®): This drug has been shown to prevent or reduce the intensity of heart damage caused by doxorubicin. Dexrazoxane is thought to protect the heart muscle by blocking the formation of free radicals from oxygen. One of the ways that radiation and chemotherapy damage cells is by forming free radicals. Free radicals are unstable molecules produced during many normal cellular processes that involve oxygen, such as burning fuel for energy. They are also formed by exposure to elements in the environment, such as tobacco smoke, radiation, and chemotherapy drugs. Dexrazoxane is thought to protect the heart muscle by blocking the formation of free radicals from oxygen. One of the ways that radiation and chemotherapy damage cells is by forming free radicals. Free radicals are unstable molecules produced during many normal cellular processes that involve oxygen, such as burning fuel for energy. They are also formed by exposure to elements in the environment, such as tobacco smoke, radiation, and chemotherapy drugs. Dexrazoxane is thought to protect the heart muscle by blocking the formation of free radicals from oxygen. One of the ways that radiation and chemotherapy damage cells is by forming free radicals. Free radicals are unstable molecules produced during many normal cellular processes that involve oxygen, such as burning fuel for energy. They are also formed by exposure to elements in the environment, such as tobacco smoke, radiation, and chemotherapy drugs. like burning fuel for energy. They are also formed by exposure to elements in the environment, such as tobacco smoke, radiation, and chemotherapy drugs. like burning fuel for energy. They are also formed by exposure to elements in the environment, such as tobacco smoke, radiation, and chemotherapy drugs.
Treatment
Initially, cardiac toxicity is treated by stopping or reducing the dose of the drug that damages your heart. After that, heart toxicity is treated the same as heart failure due to other causes. Your doctor may prescribe medications to make your blood more fluid and easier for your heart to move, and medications that help your heart beat more efficiently. Diuretics: Damage to your heart can cause you to retain water and have swelling in your ankles. Your doctor may prescribe a diuretic to increase the amount of water excreted in the urine. A frequently used diuretic is furosemide (Lasix®). Digitalis drugs: DigitalisThey are a whole group of drugs that make the heart beat more efficiently and increase the amount of blood pumped to the body. An example of a digitalis drug is digoxin(Lanoxin®). ACE inhibitors: These drugs also make it easier for your heart to pump blood to the body by opening your arteries and lowering your blood pressure. This improves blood flow to your kidneys, which don’t work properly with low blood flow. Some examples of ACE inhibitors are benazepril (Lotensin®), enalapril (Vasotec®) and fosinopril (Monopril®). Beta-blockers: These medications slow your heart rate and can be used if you have a heart attack (heart attack). Some examples are: metoprolol (Lopressor ®), propranolol (Inderal ®) and atenolol (Tenormin ®).