Based on PubMed | Can soft tissue sarcoma cause heart palpitations, and how common is this symptom?

Soft tissue sarcoma can be associated with heart palpitations, but this is uncommon and typically occurs through indirect mechanisms rather than the tumor itself causing palpitations directly. Most soft tissue sarcomas present with a lump, swelling, or pain, and only rarely involve the heart or trigger heart rhythm issues. ^{[1] [2]}

How palpitations can happen

• Cardiac metastases (spread to the heart): In rare cases, sarcoma cells spread to the heart muscle (myocardium) or the sac around the heart (pericardium). This can lead to symptoms such as arrhythmias (abnormal heart rhythms), conduction blocks, chest pain, shortness of breath, heart failure, or sudden death, any of which may be felt as palpitations. ^[3] In an autopsy series, cardiac involvement was found in a significant portion of cases, and arrhythmias were documented among the manifestations. ^[3]
• Intracardiac masses or local effects: When sarcoma grows inside heart chambers or involves valves, it can cause obstruction, rhythm disturbances, or heart failure symptoms, which some people experience as pounding or fluttering beats. ^{[4] [5]}
• Cancer treatments: Certain chemotherapies used for sarcomas can affect the heart’s electrical system or function, leading to palpitations during or after treatment. For example, anthracyclines (like doxorubicin) are known for late-onset cardiac issues including abnormal heartbeats, and patient information for sarcoma regimens warns about potential chest pain, shortness of breath, ankle swelling, and abnormal heartbeat months to years after therapy. Targeted therapies such as imatinib list palpitations among reported adverse effects. ^{[6] [7]}
• Paraneoplastic syndromes: Very rarely, cancers can trigger immune-mediated effects on the autonomic nervous system, causing irregular heartbeats or blood pressure changes, which may be felt as palpitations. ^[8]

How common are palpitations in soft tissue sarcoma?

• Direct tumor-related palpitations are rare. Typical soft tissue sarcoma symptoms involve a localized mass and sometimes pain or breathing trouble when a tumor compresses nearby structures, not heart rhythm symptoms. ^{[1] [2]}
• Cardiac metastasis frequency varies by series and setting. While clinical reports and case series suggest cardiac metastases are uncommon to diagnose during life, autopsy data in soft tissue sarcoma have shown heart involvement in a notable fraction of cases, with arrhythmias among reported symptoms when the heart is affected. ^[3] Prospective institutional reviews indicate many cardiac metastases are asymptomatic and discovered with echocardiography or CT rather than due to palpitations. ^{[9] [10]}
• Treatment-related palpitations are an established but infrequent side effect. Imatinib, used in certain sarcoma subtypes, includes palpitations among adverse events in the 1%–10% range across trials, and other serious rhythm problems are less common. ^[6] Anthracycline-based regimens may cause delayed cardiac problems, including abnormal heartbeat, though exact rates of palpitations specifically are not always quantified in patient summaries.

When to seek evaluation

• New or worsening palpitations deserve medical review, especially with cancer. Because palpitations can have many causes from anemia, dehydration, fever, thyroid issues, anxiety, to heart disease or medication effects evaluation helps identify and treat the root cause. If palpitations come with chest pain, shortness of breath, fainting, or swelling, this could indicate heart involvement and needs urgent care. ^[3] Cardiac imaging such as echocardiography can be particularly helpful when there is concern for cardiac metastasis or treatment-related cardiotoxicity. ^{[3] [9] [10]}

Practical takeaways

• Soft tissue sarcoma itself does not commonly cause palpitations; when palpitations occur, they are more likely due to heart spread, treatment effects, or other non-cancer causes. ^{[1] [2] [3]}
• Cardiac involvement is uncommon in routine practice but can occur, and arrhythmias have been reported when the heart is affected by metastases or intracardiac tumors. ^{[3] [4] [5]}
• Medications used in sarcoma can cause palpitations, so reporting symptoms to your oncology team is important for dose adjustments or cardiology referral. ^[6]

Summary table: Potential pathways to palpitations in soft tissue sarcoma

Pathway	How it may cause palpitations	How common	Key notes
Cardiac metastases (myocardium/pericardium)	Arrhythmias, conduction block, heart failure symptoms	Uncommon clinically; seen in a notable fraction at autopsy	Echocardiography often diagnostic; symptoms include chest pain, dyspnea, arrhythmias
Intracardiac mass/valvular involvement	Flow obstruction and rhythm disturbance	Rare	May present with acute heart symptoms; surgery/radiation sometimes considered
Chemotherapy (e.g., anthracyclines)	Electrical/structural cardiac effects leading to abnormal heartbeat	Variable; delayed onset possible	Monitor during/after therapy; report symptoms
Targeted therapy (e.g., imatinib)	Drug-related palpitations	Reported 1%–10%	Check for concurrent pericardial effusion or other cardiac effects
Paraneoplastic autonomic effects	Irregular heart rate, blood pressure swings	Very rare	Consider if other autonomic symptoms present

If you’re experiencing palpitations and have soft tissue sarcoma, it would be reasonable to discuss them with your care team so they can check for common causes and, if needed, arrange heart testing such as an ECG or echocardiogram. ^{[3] [9] [10]}