Heart Palpitations in Head and Neck Cancer: Links to Treatment and When to Seek Care

Heart palpitations feeling like your heart is racing, pounding, fluttering, or skipping beats can be associated with certain head and neck cancer treatments, particularly chemotherapy and immunotherapy, and more rarely as a late effect of neck radiation. ^[1] These symptoms can indicate a benign, temporary response or, in some cases, a sign of cardiotoxicity (treatment-related heart effects) that needs prompt medical attention. ^[2]

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How Treatments Can Cause Palpitations

• Chemotherapy (e.g., cisplatin, 5‑fluorouracil): These drugs can affect the heart and blood vessels, leading to chest discomfort, shortness of breath, and abnormal heart rhythms, which users may feel as palpitations. ^[1] Broader evidence shows chemotherapy can trigger arrhythmias, ischemia (reduced blood flow to the heart), hypertension, and heart failure, with risks that can occur during treatment or months to years later. ^[3]
  Key point: Palpitations during or after chemo can be part of a spectrum of cardiotoxic effects, even if uncommon. ^[4]

• Immunotherapy (e.g., pembrolizumab): Immune checkpoint inhibitors can rarely inflame the heart muscle (myocarditis), reduce pumping function, or trigger arrhythmias, any of which may present as palpitations; these effects are uncommon but potentially serious and may arise within the first three months or even after treatment ends. ^[5] Immune-related cardiotoxicity may include arrhythmia, myocarditis, pericarditis, and heart failure. ^[6]
  Key point: New palpitations with immunotherapy, especially if accompanied by chest pain or breathlessness, warrant urgent evaluation. ^[7]

• Radiation to the neck: Neck irradiation can injure autonomic nerves that control heart rate and blood pressure, leading to long‑term cardiovascular autonomic dysfunction; while this often presents as blood pressure instability, rhythm changes and palpitations may be noticed by some users. ^[8] Rarely, radiation can cause baroreflex failure years later, leading to severe blood pressure swings and symptoms that can include dizziness, syncope, and perceived heart pounding. ^[9]
  Key point: Radiation-related autonomic effects typically appear months to years after therapy and can progress over time. ^[8]

• Supportive medications (example: pilocarpine for dry mouth): In treated head and neck cancer populations, rare reports include bradycardia (slow heart rate), ECG abnormalities, palpitations, and syncope; causality is not always clear, but these side effects have been observed. ^[10]
  Key point: Even non-cancer drugs used during treatment can occasionally contribute to palpitations. ^[10]

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How Common and When They Occur

• Timing: Cardiac symptoms from chemo or immunotherapy may begin in days to weeks after starting treatment, and immune-related problems often appear within the first three months, but can occur at any time even after treatment has finished. ^{[1] [5]}
  Late effects: Some radiation-related autonomic issues and vascular changes (e.g., carotid stenosis) can emerge years later. ^{[8] [11]}

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Red Flags: When Palpitations Need Medical Evaluation

• Seek immediate care (Emergency Department): If palpitations are accompanied by chest pain or tightness, shortness of breath, dizziness, lightheadedness, fainting, unusual sweating, or if your heart feels like it is racing very fast or irregularly. ^{[7] [12] [13]}
  Why: These symptoms can signal arrhythmias, ischemia, myocarditis, or heart failure, which are rare but can be life‑threatening without prompt treatment. ^{[5] [6]}

• Contact your oncology or cardiology team promptly: If you develop new palpitations after starting chemotherapy or immunotherapy, or if you have a history of heart disease or high blood pressure and notice changes in heart rhythm. ^{[1] [5]}
  Monitoring: Your team may recommend heart function tests (e.g., ECG, echocardiogram) before or during treatment when risk is present. ^[5]

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Practical Steps You Can Take

• Track symptoms: Note onset, duration, triggers (rest vs. activity), associated symptoms (chest pain, shortness of breath), and heart rate if you can check it; share this with your care team. ^[13]
• Medication review: Ask whether your current cancer or supportive medications have heart rhythm risks, and whether dose adjustments or alternatives are appropriate. ^[2]
• Risk management: If you have cardiovascular risk factors (e.g., hypertension, diabetes, smoking), optimizing these may lower the chance of treatment‑related heart issues. ^[11]
• Follow recommendations: If advised, undergo baseline and periodic heart testing during treatment to detect early changes. ^{[5] [6]}

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Summary Table: Treatment Links to Palpitations and Action Thresholds

Treatment or Context	Possible Heart Effects Users May Feel as Palpitations	Typical Timing	Action Threshold
Cisplatin + 5‑FU regimens	Chest pain, shortness of breath, abnormal heartbeat (arrhythmia)	Days to weeks after start; can occur later	Urgent care for chest pain, breathlessness, racing or irregular heartbeat
Pembrolizumab (immunotherapy)	Arrhythmias, myocarditis, heart failure symptoms	Often within first 3 months; can occur anytime, even post‑therapy	Immediate evaluation for chest pain, dyspnea, ankle swelling, racing heartbeat
Neck radiation	Autonomic dysfunction; blood pressure swings; possible rhythm symptoms	Months to years after therapy; progressive	Report new palpitations, dizziness, syncope; consider autonomic and vascular assessment
Pilocarpine (supportive)	Rare bradycardia, ECG changes, palpitations, syncope	During use	Discuss with clinician; seek care if syncope, severe palpitations

Evidence for chemotherapy-associated chest pain, shortness of breath, and abnormal heartbeat comes from patient guidance for head and neck regimens. ^[1] Immune therapy guidance flags uncommon but potentially fatal heart problems with clear urgent-care triggers. ^{[5] [7]} Cardio-oncology resources describe treatment-related cardiotoxicity across modalities. ^[2] Radiation studies detail autonomic dysfunction and late vascular risks. ^{[8] [11]} Supportive medication labeling lists palpitations among rare events. ^[10]

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Bottom Line

Heart palpitations can be linked to head and neck cancer treatments most often chemotherapy and immunotherapy and, rarely, late effects of neck radiation and deserve attention, especially when new, persistent, or accompanied by chest pain, shortness of breath, dizziness, fainting, or ankle swelling. ^{[1] [5] [7]} Prompt evaluation helps rule out serious issues like arrhythmias or myocarditis and guides safe continuation or adjustment of cancer care. ^[6] If you have heart disease or risk factors, let your team know so they can monitor your heart during treatment. ^[1] Regular, proactive cardio-oncology follow‑up can reduce risks and catch problems early. ^[2]