Immunotherapy and Heart Palpitations: What to Know

Short answer: Yes immunotherapy can, although uncommonly, cause heart palpitations. This may be due to heart rhythm changes (arrhythmias) or inflammation of the heart muscle (myocarditis), and it tends to occur early in treatment for some people. Prompt recognition and coordinated care with your oncology and cardiology teams are key. ^{[1] [2] [3]}

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Why palpitations can happen

• Immune activation effects: Immune checkpoint inhibitors (like nivolumab, pembrolizumab, ipilimumab, atezolizumab, durvalumab, avelumab) can trigger inflammation in heart tissue, leading to myocarditis and rhythm disturbances. These cardiac effects are rare but can be serious. ^{[4] [5]}
• Arrhythmias and myocarditis: Documented cardiovascular side effects include arrhythmias, myocarditis, pericarditis, heart failure, and conduction problems. Palpitations may be a sign of an abnormal heartbeat linked to these issues. ^{[2] [6] [7]}
• Timing: Symptoms often begin within the first three months of starting certain immunotherapies (e.g., nivolumab or combinations with ipilimumab). ^{[8] [9]}
• Combination regimens: When immunotherapy is given with chemotherapy (e.g., carboplatin/paclitaxel plus nivolumab), patient guides specifically list abnormal heartbeat among potential heart problems. ^[10]

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Red flags that need urgent care

• Chest pain or tightness, shortness of breath, swelling of ankles, fainting, or new/worsening palpitations should prompt immediate contact with your care team or emergency evaluation, because these can signal myocarditis or dangerous arrhythmias. Although uncommon, heart problems can be life‑threatening if not treated quickly. ^{[8] [9]}
• Cardio‑oncology programs emphasize that immunotherapies can cause myocarditis or rhythm disorders and require timely recognition and management. Rapid assessment reduces complications and mortality. ^{[3] [11]}

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How clinicians typically evaluate palpitations during immunotherapy

• Initial tests: Electrocardiogram (ECG) to check rhythm; blood tests for cardiac injury (troponin); and possibly echocardiogram to assess heart function. Some specialists obtain baseline ECG and troponin and may repeat them during the early treatment period. ^[12]
• Advanced imaging: If myocarditis is suspected, cardiac MRI and, in selected cases, endomyocardial biopsy may be considered. High‑dose steroids are started promptly when immune‑related myocarditis is suspected, and immunotherapy is withheld. ^{[5] [13]}
• Ongoing monitoring: For higher‑risk immunotherapy courses, structured monitoring schedules may be used early after initiation. Early collaboration between oncology and cardiology (cardio‑oncology) is advised. ^{[4] [14]}

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Practical coping steps for palpitations

• Act on new symptoms: Report any new palpitations, chest discomfort, shortness of breath, dizziness, or ankle swelling right away; do not wait for your next appointment. Early reporting allows safer and more effective management. ^{[8] [9]}
• Track episodes: Note timing, duration, triggers (e.g., exertion, caffeine), and associated symptoms; share with your team to guide testing and care. Structured symptom logs help identify patterns and urgency.
• Lifestyle measures:
  • Limit stimulants (caffeine, energy drinks, nicotine) that can worsen palpitations.
  • Hydrate well and avoid heavy alcohol use.
  • Practice stress‑reduction techniques (paced breathing).
  • Maintain gentle activity as tolerated; stop if symptoms intensify.
    These steps can reduce benign palpitations, though they do not replace medical evaluation when you’re on immunotherapy.
• Medication review: Ask your team to review other drugs that may affect heart rhythm (e.g., decongestants, certain antidepressants, thyroid medications). Adjustments may lower palpitation frequency.
• Thyroid checks: Immunotherapy can affect the thyroid, and both overactive and underactive thyroid states can cause palpitations; routine thyroid monitoring is common in many programs. Treating thyroid imbalance can resolve palpitations. ^{[15] [16]}

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When to seek emergency care

• Go to urgent care or the ER if palpitations come with chest pain, shortness of breath, fainting, severe dizziness, or if the heartbeat is extremely fast or irregular for more than a few minutes. These can indicate serious cardiac inflammation or dangerous arrhythmias requiring immediate treatment. ^{[8] [9] [3]}

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Outlook and care coordination

• Most people on immunotherapy do not develop heart issues, but because the potential problems can be serious, fast evaluation and coordinated cardio‑oncology care is recommended when symptoms arise. With timely management including holding immunotherapy and starting steroids for myocarditis many cases improve. ^{[1] [3] [5]}
• Ongoing collaboration between oncology and cardiology is increasingly standard, reflecting the evolving cardiac side‑effect profile of immune therapies. This team approach helps balance cancer control with heart safety. ^{[14] [17] [18]}