Cardiac Imaging

Which Imaging Study Is Best for New Cardiac Symptoms During Cancer Therapy?

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Which Imaging Study Is Best for New Cardiac Symptoms During Cancer Therapy?

A 62-year-old woman with HER2-positive breast cancer, four months into her trastuzumab regimen, reports new-onset dyspnea on exertion and vague chest tightness during her follow-up visit. Her oncologist is now faced with a critical decision: are these symptoms the first sign of treatment-related cardiotoxicity, an unmasking of underlying coronary artery disease, or another complication? Choosing the right initial imaging study is essential to protect her heart without delaying her cancer treatment unnecessarily. This article details the clinical workflow for this specific scenario—an adult patient developing cardiac symptoms during oncologic therapy where ischemia cannot be excluded. For this presentation, the American College of Radiology (ACR) Appropriateness Criteria rate a resting transthoracic echocardiogram as Usually Appropriate as the initial imaging step.

## Who Fits This Clinical Scenario for Cardiac Assessment During Cancer Therapy?

This guidance applies specifically to adult patients who are actively undergoing oncologic therapy and develop new or worsening cardiac symptoms. These symptoms can include dyspnea, chest pain, fatigue, palpitations, or new-onset edema. A key feature of this scenario is that ischemia has not been excluded, meaning coronary artery disease is a reasonable consideration in the differential diagnosis. This article addresses the choice of the initial imaging study in this workup.

This workflow is NOT intended for:

  • Asymptomatic patients needing baseline screening: If a patient has no cardiac symptoms and requires risk stratification before starting a potentially cardiotoxic therapy, that represents a different clinical question. That scenario focuses on establishing a baseline Left Ventricular Ejection Fraction (LVEF) and overall risk profile.
  • Patients with acute, unstable cardiac emergencies: A patient presenting with signs of an acute coronary syndrome (e.g., ST-elevation myocardial infarction) requires an emergent cardiology consultation and likely proceeds directly to an electrocardiogram (ECG) and cardiac catheterization, bypassing the elective imaging decisions discussed here.
  • Patients with a clear non-cardiac cause: If symptoms are definitively attributed to another cause, such as severe anemia or a large pleural effusion seen on a staging scan, the cardiac imaging workup may be deferred or tailored differently.

## What Diagnoses Are You Working Up in This Scenario?

When a patient on cancer therapy develops cardiac symptoms, the differential is broad, spanning direct effects of the treatment and exacerbations of underlying conditions. The initial imaging choice must be sensitive enough to evaluate the most common and consequential possibilities.

Chemotherapy-Induced Cardiotoxicity: This is often the primary concern. Many antineoplastic agents, including anthracyclines (e.g., doxorubicin), HER2-targeted therapies (e.g., trastuzumab), and some tyrosine kinase inhibitors, can impair myocardial function. This typically manifests as a reduction in LVEF, which can be symptomatic (heart failure) or asymptomatic. The goal is to detect this early to allow for cardioprotective interventions and modification of the cancer regimen.

Coronary Artery Disease (CAD) and Ischemia: Cancer and its treatments create a pro-inflammatory and pro-thrombotic state that can accelerate atherosclerosis or destabilize pre-existing plaques. Furthermore, certain agents like 5-fluorouracil (5-FU) and capecitabine can induce coronary vasospasm. The patient’s new symptoms may represent the first clinical manifestation of significant, previously subclinical CAD.

Pericardial Disease: Both radiation therapy to the chest and certain chemotherapies can cause pericarditis or pericardial effusions. These conditions can present with chest pain, dyspnea, and on examination, a pericardial friction rub or signs of tamponade in severe cases.

Thromboembolic Disease: Malignancy is a significant risk factor for venous thromboembolism, including pulmonary embolism (PE). While a dedicated CT angiogram of the pulmonary arteries is the definitive test for PE, initial cardiac imaging can reveal secondary signs, such as right ventricular strain or dilation, that raise suspicion and prompt further investigation.

## Why Is a Resting Transthoracic Echocardiogram the Recommended First Step?

For an initial assessment of an oncology patient with new cardiac symptoms, a resting transthoracic echocardiogram (TTE) is rated Usually Appropriate by the ACR. It provides a comprehensive, non-invasive evaluation that directly addresses the most pressing clinical questions in this scenario.

The primary strength of a TTE is its ability to directly visualize and quantify cardiac structure and function. It provides a reliable measurement of LVEF and allows for the assessment of global longitudinal strain (GLS), a more sensitive marker for detecting early, subclinical myocardial dysfunction before the LVEF drops. This is critical for monitoring cardiotoxicity. The TTE can also identify regional wall motion abnormalities that would suggest underlying ischemia or prior infarction.

Furthermore, TTE is excellent for evaluating other potential causes on the differential. It can readily detect pericardial effusions, assess valvular function, and estimate pulmonary artery pressures, which may be elevated in the setting of a significant pulmonary embolism. As a radiation-free modality (0 mSv), it is safe for repeated use, a crucial feature for serial monitoring throughout a patient’s cancer treatment.

Comparison to Other Modalities:

  • CTA Coronary Arteries with IV Contrast: While also rated Usually Appropriate, this study serves a different primary purpose. It is excellent for non-invasively ruling out obstructive CAD but provides less robust functional data than an echocardiogram. It also involves radiation (☢☢☢ 1-10 mSv) and iodinated contrast. It is often considered a second-line or problem-solving tool if the TTE is inconclusive or if suspicion for CAD remains high despite a normal functional assessment.
  • Invasive Coronary Arteriography: Rated May be appropriate, this is the gold standard for diagnosing CAD but is an invasive procedure with associated risks. It is not an appropriate initial screening tool for this broad differential. It is reserved for patients with a high pre-test probability of severe CAD or those with objective evidence of significant ischemia on non-invasive testing.

## What’s Next After a Resting Transthoracic Echocardiogram? Downstream Workflow

The results of the initial TTE will guide the subsequent management and diagnostic pathway. The goal is to arrive at a diagnosis that allows for collaboration between the oncology and cardiology teams (a cardio-oncology approach).

  • If the TTE shows a significant drop in LVEF or abnormal strain: This is highly suggestive of cardiotoxicity. The next step involves a cardiology consultation to initiate or optimize cardioprotective medications (e.g., ACE inhibitors, beta-blockers). The oncology team will need to weigh the risks and benefits of continuing, modifying, or pausing the current cancer therapy.
  • If the TTE is normal (preserved LVEF, no wall motion abnormalities): Cardiotoxicity is less likely to be the primary cause of symptoms. If clinical suspicion for ischemia remains high based on risk factors and symptom character, a functional stress test is the logical next step. A US echocardiography transthoracic stress study is rated Usually Appropriate and can unmask ischemia not present at rest. Alternatively, if anatomical definition is needed, a CTA coronary arteries may be pursued.
  • If the TTE shows regional wall motion abnormalities: This finding points toward an ischemic etiology. The patient should be managed for coronary artery disease, typically involving a cardiology consult for further risk stratification, which may include a stress test or coronary angiography.
  • If the TTE is indeterminate or shows other findings: An indeterminate study due to poor acoustic windows may prompt consideration of an alternative modality like cardiac MRI. If a significant pericardial effusion is found, a pericardiocentesis may be both diagnostic and therapeutic. If signs of right heart strain are present, a workup for pulmonary embolism should be initiated immediately.

## Pitfalls to Avoid (and When to Get Help)

Navigating the workup of cardiac symptoms in a cancer patient requires careful consideration to avoid common pitfalls that can delay diagnosis or expose the patient to unnecessary risk.

  • Attributing all symptoms to “deconditioning”: While cancer-related fatigue is real, new-onset dyspnea or chest pain should always be investigated thoroughly and not dismissed.
  • Ignoring baseline studies: Always compare the current TTE findings, particularly the LVEF, to any pre-treatment baseline studies. A “normal” LVEF of 55% may represent a significant decline from a baseline of 70%.
  • Over-reliance on a single test: A normal resting TTE does not completely rule out demand ischemia. If symptoms are exertional and the clinical story is compelling for angina, a stress test is warranted.
  • Delaying cardiology involvement: In any case of suspected cardiotoxicity or new-onset heart failure, early collaboration with a cardiologist or a dedicated cardio-oncology service is crucial for optimal management.

If a patient presents with hemodynamic instability, severe chest pain with ECG changes, or worsening respiratory distress, escalate immediately to cardiology and consider inpatient admission for urgent management.

## Related ACR Topics and Tools

This article covers one specific variant within a broader ACR topic. For a comprehensive overview of all clinical scenarios related to cardiac assessment in oncology patients, please see our parent guide. The following GigHz tools can also support your clinical decision-making:

Frequently Asked Questions

Why not order a stress test as the very first imaging study?

While a stress test (like stress echo or nuclear MPI) is rated ‘Usually Appropriate’, a resting TTE is often preferred as the initial step because it directly assesses the primary concern of cardiotoxicity (via LVEF and strain) and evaluates for structural causes like pericardial effusion, which a stress test does not. If the resting study is normal and ischemic symptoms are the main concern, a stress test is an excellent next step.

What if my patient cannot undergo a stress test due to poor functional status?

If a patient cannot exercise, a pharmacologic stress test (e.g., dobutamine stress echo or vasodilator nuclear perfusion imaging) is an alternative. If the primary question is anatomical (ruling out obstructive coronary disease), a CTA of the coronary arteries is another excellent, radiation-free option (in the case of cardiac MRI) or a low-radiation CT option that does not require exercise.

Is a cardiac MRI (CMR) a good first choice in this scenario?

Cardiac MRI is rated ‘Usually Appropriate’ and is considered the gold standard for quantifying ventricular volumes and function. However, it is less available, more time-consuming, and more expensive than echocardiography. TTE is generally sufficient and more practical for the initial assessment. CMR is an outstanding problem-solving tool for cases with poor acoustic windows on echo or when myocardial tissue characterization (e.g., for suspected myocarditis or infiltration) is needed.

Should I order a chest radiograph for new dyspnea in this patient?

A chest radiograph is rated ‘May be appropriate (Disagreement)’ by the ACR for this specific cardiac workup. While it is not the primary tool for assessing cardiac function, it is often obtained in the workup of dyspnea to evaluate for other causes like pneumonia, pleural effusions, or pulmonary edema. It can provide complementary information but does not replace the need for a dedicated cardiac imaging study like an echocardiogram.

How do biomarkers like troponin and BNP/NT-proBNP fit into this workflow?

Biomarkers are a crucial part of the cardio-oncology toolkit. An elevated troponin may indicate myocardial injury from ischemia or myocarditis. An elevated B-type natriuretic peptide (BNP) or N-terminal pro-BNP (NT-proBNP) is a sensitive marker for ventricular wall stress and heart failure. These lab tests should be obtained alongside imaging to provide a more complete clinical picture and can help guide the urgency and direction of the imaging workup.

Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 30, 2026