Cardiotoxicity Monitoring: Clinical Significance and Implications

Introduction

The heart plays a pivotal role by distributing blood to other organs by constantly pumping blood from it. Any damage to the heart muscles or the valves may affect the heart's efficiency in performing its daily tasks. Severe damage to the heart may result in cardiotoxicity, which is a serious condition. Hence, it is vital to monitor the heart to distinguish normal and abnormal functioning and help restore normal activities of the heart.

What Is Cardiotoxicity?

The drugs for cancer treatment may have an adverse influence on the heart. It usually develops after years of cancer treatment, specifically in adults who have undergone cancer treatment in childhood. The damage occurred in the heart due to chemotherapy (drugs used for cancer) is called cardiotoxicity. It is the occurrence of heart dysfunction or muscle damage. As a result, the heart becomes weaker and is inefficient in pumping blood, resulting in poor blood circulation.

Cardiotoxicity causes difficulty in pumping blood from the heart. The heart muscles are affected in severe conditions, resulting in poor blood output and cardiomyopathy. Cardiotoxicity specifically affects individuals who have undergone radiation therapy in the chest. However, the exact rate of cardiotoxicity affecting individuals with cancer treatment is yet to be known.

Who Is at Risk of Cardiotoxicity?

The following individuals are at risk of cardiotoxicity:

• Hypertension.

• Diabetes.

• Obese individuals.

The severe form of cardiotoxicity results in cardiomyopathy, in which the heart muscles are inflamed and do not function properly. It could also be caused due to viral infections.

How Does Cardiotoxicity Affect the Body?

Cardiotoxicity affects the body in many ways; it predominantly affects the heart.

• Cardiomyopathy.

• Heart failure.

• Heart valve disease.

• Arrhythmia (irregular heart rhythms).

• Slow heart rate.

• Heart attacks (myocardial infarction).

• Coronary artery disease.

• Fluid buildup around the heart.

• Low or high blood pressure.

• Constrictive pericarditis (thickening of the heart lining).

What Are the Symptoms of Cardiotoxicity?

Some of the common symptoms of cardiotoxicity are:

• Chest pain.

• Dizziness.

• Heart palpitations.

• Dyspnea (shortness of breath).

• Edema (swelling and fluid retention).

• Abdomen enlargement.

What Causes Cardiotoxicity?

Some of the drugs causing cardiotoxicity are mentioned below:

• Anthracyclines.

• Trastuzumab.

• Radiation therapy.

• Chemotherapy treatment.

• Anorexia nervosa.

• Intake of heavy metals.

• Incorrect drug administration like Bupivacaine.

Can Cardiotoxicity Be Reversed?

Cardiotoxicity is a reversible condition that can be treated with medications if diagnosed at the right time. However, the treatment and prognosis are comparatively less successful in cases of severe symptoms and pre-existing medical conditions.

How to Manage Cardiotoxicity?

Cardiotoxicity is managed in different ways. The administration of drugs like beta blockers helps improve heart functions. Certain cardiotoxicity may require intervention by the doctor or surgery to stabilize heart functions. Once the heart is stabilized, the blood flow to the heart and the amount of blood pumped out in each beat are evaluated.

What Is Cardiotoxicity Monitoring?

Cardiotoxicity is monitored with the help of additional diagnostic tests and imaging techniques that measure the functions of the heart. Some of the tests to measure cardiotoxicity are:

1. Echocardiogram - It is a test to evaluate the heartbeat and the blood flow through the heart. It is the most commonly used imaging tool in cardiotoxicity monitoring. The recent advances in electrocardiogram help identify ischemia (poor blood supply) and infarction. It also helps localize the origin and pathways of arrhythmias. Assessing the therapeutic options for patients with heart failure is extremely crucial. It is also helpful in identifying patients with genetic diseases who have high chances of arrhythmias. It comprises electrodes that are placed on the chest, through which current is passed for heart evaluation. It helps to diagnose heart conditions like

• Arrhythmias (irregular heartbeat).

• Pericarditis (inflammation surrounding the heart).

• Chamber hypertrophy (thickening of walls in the lower heart chamber).

• Hyperkalemia (high potassium).

2. Cardiac MRI - MRI refers to magnetic resonance imaging, the gold standard method for cardiotoxicity. It uses magnetic and radio waves with a special computer that creates detailed images of the heart's structures. Before undergoing any scan, it is important to remove any metals from the body as they may affect the individual during the procedure. Although the magnetic field is not harmful, it may affect the functions of certain medical devices in the body. The doctor may advise the patient to follow a specific diet and water intake before the procedure. It is better to leave the regularly worn jewelry at home, and wearing comfortable clothes is helpful. In the case of claustrophobic patients (fear of closed spaces), it is better to inform the doctor priorly. In such patients, a mild sedative is administered.

3. Cardiac Stress Test - It measures the heart’s response to intense activities like riding a stationary bike and treadmill. The machine is connected to the body to evaluate the heart rate and blood pressure. The test is also known as a stress exercise test. Generally, exercises help the heart pump faster. As the heart pumps fast, more blood is ejaculated. It helps identify conditions like coronary artery disease and heart rhythm problems. A stress test acts as a guide to treat heart disorders. The test helps the healthcare professional to decide the suitable treatment for better results.

• Cardiac CT Scan - It is an imaging technique that views the heart from multiple angles. It helps to completely understand the improper functioning of the heart and treat it accordingly. The patient undergoing the test is asked to lie on a table. A small electrode is connected to the chest, and the heart's electrical activity is recorded. Sometimes, a few medications are prescribed to slow the heart rate. The scan helps to create three-dimensional images of the heart. The doctor may ask the patients to hold their breath for a short while. Usually, the scan takes about ten minutes. In a CT (computed tomography) scan, slices of the body area are created as separate images. This gives a proper understanding of the poor heart functions at each level, which helps to repair them if diagnosed on time.

Conclusion

Cardiotoxicity monitoring is performed to understand abnormal blood pressure and heart rhythms. Examining the heart helps provide proper insight into heart conditions and treat them appropriately. Various monitoring methods include electrocardiogram (ECG), computed tomography (CT), cardiac stress test, and magnetic resonance imaging (MRI). Early detection of heart conditions helps to treat the root cause of the disease and restore functions, resulting in a quality life.