Tachycardia, a rapid heart rate, and cancer are distinct medical conditions that can significantly impact health. This article explores their relationship, examining how cancer itself, its treatments, and related complications can influence heart rate.
Understanding Tachycardia and Cancer
Tachycardia is a medical term for a heart rate exceeding the normal resting rate, generally over 100 beats per minute for adults. Cancer describes a group of diseases characterized by the uncontrolled growth and spread of abnormal cells. These cells can form tumors and disrupt normal bodily functions, affecting almost any body part and leading to various symptoms.
How Cancer Directly Causes Tachycardia
Cancer can directly influence heart rate through several physiological mechanisms. A tumor located near the heart, major blood vessels, or nerves regulating heart rhythm can physically interfere with the heart’s electrical signals. Tumors metastasizing to the heart muscle or pericardium can directly impair cardiac function, leading to arrhythmias, including tachycardia.
Certain cancers can also trigger paraneoplastic syndromes, where cancer cells produce substances like hormones or cytokines that affect distant organs. These substances, particularly inflammatory cytokines, can overstimulate the sympathetic nervous system, which controls the “fight or flight” response, thereby increasing heart rate. Elevated resting heart rate is observed in cancer patients, even in those who have not yet received chemotherapy, suggesting the cancer’s inherent influence.
How Cancer Treatment and Complications Can Cause Tachycardia
Tachycardia in cancer patients is frequently a result of indirect effects, side effects from treatments, or complications arising from the disease. Anemia, a common condition in cancer patients, occurs when there is a reduction in healthy red blood cells, often due to cancer itself or chemotherapy. When the body has fewer red blood cells to deliver oxygen, the heart must beat faster to compensate for the reduced oxygen supply to tissues.
Electrolyte imbalances, such as abnormal levels of potassium, sodium, magnesium, or calcium, can significantly impact heart function. Cancer or its treatments, especially those causing vomiting, diarrhea, or kidney issues, can lead to these imbalances, which are crucial for maintaining a stable heart rhythm.
Infections and fever are also common in cancer patients, particularly due to a weakened immune system from the disease or its therapies. Fever inherently causes an elevated heart rate as the body works to fight off the infection, and infections are the most frequent cause of fever in this population.
Many cancer treatments carry the risk of affecting heart function. Specific chemotherapies, including anthracyclines, fluoropyrimidines, and cyclophosphamide, as well as certain immunotherapies and targeted therapies, can have cardiotoxic effects or directly increase heart rate. Radiation therapy, especially to the chest area, can also damage heart structures and lead to arrhythmias, including tachycardia.
Dehydration, often caused by poor fluid intake or excessive fluid loss from vomiting, diarrhea, or fever, can reduce blood volume, forcing the heart to pump faster to circulate the remaining fluid. The psychological impact of a cancer diagnosis and its demanding treatments can also contribute to an elevated heart rate. Chronic pain, stress, and anxiety can activate the body’s sympathetic nervous system, leading to a physiological response that includes an increased heart rate.
When to Seek Medical Help
Experiencing a rapid heart rate during cancer treatment or recovery warrants medical attention. Report any new or worsening symptoms, including persistent feelings of a racing heart or palpitations, to your healthcare provider promptly. Seek immediate medical help if tachycardia is accompanied by chest pain, significant shortness of breath, dizziness, lightheadedness, or fainting. These symptoms could indicate a serious underlying issue requiring urgent evaluation, and timely medical assessment can help identify the cause and ensure appropriate management.