Cardiac Stress Test Misdiagnosis Malpractice

Published 2026-05-27 · John Mahoney · MedLegal AI

A patient with chest pain undergoes a stress test, gets reassured it was "negative," and dies of a heart attack two weeks later. Defense argument: the stress test was negative, the standard of care was met. Plaintiff argument: the wrong stress test was ordered, or the test was misinterpreted, or the test was inadequate for the pre-test probability. These are the cardiac stress test malpractice cases — well-defined by ACC/AHA guidelines and frequently winnable.

Modality Selection — The First Decision

Not all stress tests are equivalent. Modality selection matters:

• Exercise treadmill (Bruce protocol): appropriate for patients who can exercise, have interpretable resting EKG, low-to-intermediate pre-test probability
• Exercise stress with imaging (echo or nuclear): for patients who can exercise but have uninterpretable EKG (LBBB, paced rhythm, baseline ST changes) or intermediate-to-high pre-test probability
• Pharmacologic stress (dobutamine or vasodilator) with imaging: for patients who cannot exercise
• Coronary CT angiography (CCTA): increasingly first-line for intermediate-risk patients per 2021 ACC/AHA Chest Pain Guidelines
• Invasive coronary angiography: for high-risk patients or when non-invasive tests are inconclusive

Standard of care: select the appropriate modality based on patient characteristics and pre-test probability. Ordering an exercise treadmill in a patient who can't exercise (must use pharmacologic), or in a patient with LBBB (must use imaging), or in a high-risk patient where invasive angiography is indicated, is breach.

The Pre-Test Probability Trap

Stress test sensitivity and specificity depend on pre-test probability:

• Low pre-test probability: negative stress test reliable, positive may be false-positive
• Intermediate pre-test probability: stress test useful for risk-stratifying
• High pre-test probability: negative stress test is OFTEN A FALSE NEGATIVE. The standard of care often calls for coronary angiography rather than relying on a stress test.

This is the most common malpractice scenario: high-pre-test-probability patient (typical angina, multiple risk factors, abnormal EKG) gets a "reassuring" stress test, gets sent home, and has an MI. The stress test was the wrong test.

Misinterpretation Patterns

Stopping the test early

Patient symptoms or vital signs require stopping before adequate workload achieved. Test reported as "negative" but the patient never reached target heart rate (85% of age-predicted maximum). The test is non-diagnostic, NOT negative. Standard of care: any test that doesn't achieve adequate workload requires further evaluation.

ST changes ignored

EKG during stress shows ST depression but interpretation labels it "negative" or "non-specific." Patient subsequently has MI. The ST changes were significant.

Wall motion abnormality missed

Stress echocardiogram shows new wall motion abnormality with stress but report says "negative." Patient has MI. The abnormality was missed on read.

Perfusion defect misclassified

Nuclear stress shows a perfusion defect but labeled as "artifact" or "attenuation." Patient has MI. The defect was real.

Discovery Targets

• Complete cardiology consult note documenting pre-test probability assessment
• Stress test order specifying the modality requested
• Stress test protocol and actual workload achieved
• All EKG tracings from the test
• Stress imaging (echo or nuclear) and the interpreting cardiologist's read
• Any follow-up testing recommended
• The interpreting cardiologist's case volume and read history
• Hospital's stress lab quality assurance audits
• If MI occurred subsequently: catheterization images showing the lesion that was missed
• Time between stress test and MI (closer = stronger causation)

Causation Framework

Cardiac causation requires showing:

1. The patient had cardiac disease (atherosclerosis, plaque) at the time of the stress test
2. Appropriate testing would have identified the disease
3. Identification would have led to treatment (medical therapy, PCI, CABG)
4. Treatment would have prevented the subsequent MI

Your cardiologist expert constructs each step with reference to ACC/AHA guidelines and the patient's specific clinical picture.

Damages

• Death from MI: substantial wrongful death damages, especially for working-age patients
• Cardiac arrest with hypoxic brain injury: lifetime care, $5M-$15M
• Heart failure post-MI: ongoing cardiology care, possible transplant evaluation
• Coronary artery bypass after missed diagnosis vs PCI that could have been done earlier: differential of treatment cost + recovery time

Bottom Line

Cardiac stress test malpractice cases turn on modality selection and interpretation. The ACC/AHA guidelines (2021 Chest Pain Guidelines + ASNC nuclear cardiology guidelines) define the standard. When the wrong test was ordered for the patient's pre-test probability, or the test was misinterpreted, plaintiff attorneys have the foundation for substantial verdicts. The cases are technical but the standards are clear.

Related: PE/DVT malpractice, stroke / tPA malpractice.