Heart palpitations, often described as a racing, pounding, or fluttering sensation in the chest, are a common and alarming symptom. The relationship between cancer and heart palpitations is well-documented, involving the disease itself and the side effects of its management. This connection is primarily mediated through systemic changes in the body and the direct effects of therapeutic interventions on the heart’s electrical system.
Systemic Effects of Cancer That Trigger Palpitations
The presence of a malignant tumor can disrupt the body’s internal environment, creating conditions that interfere with normal heart rhythm. This disruption results from substances released by the tumor or the body’s overall response to the disease. Tumors can alter the balance of electrolytes in the blood, which are necessary for regulating the heartbeat.
Specific electrolyte abnormalities, such as high calcium (hypercalcemia) or low potassium (hypokalemia), destabilize the heart muscle’s electrical activity and lead to irregular rhythms. Hypercalcemia is a recognized complication of certain cancers and directly influences the cardiac conduction system. These chemical shifts increase the likelihood of experiencing a skipped or rapid heartbeat.
Some tumors trigger paraneoplastic syndromes, where cancer cells secrete hormones that affect remote organs, including the heart. These substances can cause inflammation in the heart muscle (myocarditis), disrupting electrical pathways and resulting in arrhythmias. The body’s chronic inflammatory response to cancer, involving signaling molecules called cytokines, can also stress the cardiovascular system and contribute to rhythm disturbances.
Palpitations as a Side Effect of Cancer Treatment
Cancer treatments are a major source of cardiotoxicity, frequently manifesting as heart rhythm issues and palpitations. Certain conventional chemotherapy agents, particularly anthracyclines, risk damaging heart muscle cells, potentially leading to heart failure or arrhythmias. Anthracyclines, such as doxorubicin, generate harmful reactive oxygen species that cause acute and long-term damage to the heart’s structure.
Other chemotherapy drugs, including platinum-based agents like cisplatin, are linked to cardiotoxicity through direct cell toxicity and inflammation. Even newer targeted therapies and immunotherapies can provoke rhythm disturbances. Immune checkpoint inhibitors, for instance, may cause autoimmune-like inflammation (myocarditis), leading to severe rhythm abnormalities.
Radiation therapy directed at the chest for cancers like lymphoma, breast, or lung cancer also risks damaging the heart’s electrical system. Ionizing radiation causes scarring (fibrosis) in the heart muscle and surrounding tissues, including the conduction system. This damage can lead to abnormally fast (tachyarrhythmias) or slow (bradyarrhythmias) rhythms, sometimes years after treatment.
Indirect Factors That Mimic Cardiac Issues
Palpitations are often caused by factors related to the cancer experience that do not involve direct cardiotoxicity. Anemia, common due to the disease or treatment, forces the heart to work harder. Since fewer red blood cells carry oxygen, the heart must beat faster and more forcefully to maintain adequate oxygen delivery, which is perceived as a palpitation.
The psychological strain of a cancer diagnosis and treatment also contributes significantly. Anxiety, stress, and pain trigger the fight-or-flight response, releasing adrenaline and stress hormones. These hormones directly increase the heart rate and force of contraction, causing temporary but noticeable palpitations.
Infection and fever, common in patients with suppressed immune systems, increase the body’s metabolic demands. This requires the heart to pump more blood, resulting in an elevated heart rate (tachycardia) often felt as palpitations. Furthermore, many symptom management medications, such as anti-nausea drugs, can affect the heart’s electrical system, increasing the risk of abnormal rhythms.
When to Consult a Doctor
Any new or changing palpitations should be reported to the oncology team, as they may signal an underlying issue requiring investigation. Patients should note the frequency, duration, and potential triggers before speaking with a healthcare provider. Reporting these symptoms ensures that potential cardiovascular issues are addressed promptly and factored into the overall treatment plan.
Immediate medical attention is necessary if palpitations are accompanied by more severe symptoms, which may indicate a serious cardiac event. These warning signs include chest pain, severe shortness of breath, dizziness, lightheadedness, or fainting. If the heart is beating rapidly (over 100 beats per minute while resting) or feels irregularly erratic, a prompt emergency evaluation is warranted to assess for a dangerous arrhythmia.