How to recognize INOCA on exercise stress ECG and report your findings

Some patients present with convincing angina, an abnormal cardiac stress test, and clean coronaries on angiography—a pattern known as INOCA (ischemia with nonobstructive coronary arteries), or ANOCA (angina with nonobstructive coronary arteries). It's not low risk, and it isn't rare, especially in women. On exercise stress ECG, the changes can look very similar to ischemia from obstructive disease—and if the pattern goes unrecognized, these patients may leave thinking nothing is wrong.

In this lesson from our Exercise Stress ECG Essentials course you'll learn how to:

• Recognize the INOCA / ANOCA pattern
• Identify ST-segment depression in ECG tracings consistent with INOCA
• Interpret recovery ECG tracings to detect ischemia
• Spot symptom clues during exercise that point toward INOCA
• Report INOCA findings accurately

INOCA (ANOCA): ischemia (angina) with nonobstructive coronary arteries

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You'll often meet patients who have convincing angina, abnormal stress results, and clean coronary arteries on angiography or coronary CT. That pattern points to ischemia, or angina, with nonobstructive coronary artery, abbreviated INOCA or ANOCA. It's common, especially in women, and it carries real risk.
In these patients, the problem isn't a major blockage in a large coronary artery. Instead, the issue often lies in the small vessels, in abnormal vasomotor tone, or in a combination of the two.

ECG findings in INOCA

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What matters for us during an exercise stress ECG is recognizing the electrical and symptomatic clues that point toward this pattern. On the ECG, the changes can look very similar to ischemia from obstructive coronary disease.

ECG ST-segment depression

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You may see horizontal or downsloping ST-segment depression of one millimeter or more in two contiguous leads. These changes may appear at lower workloads than expected, and they may persist into recovery, which can be especially informative.

Recovery phase clues

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Sometimes the clearest evidence of ischemia in these patients shows up on the one- or two-minute recovery tracings, when motion artifact settles and the ST segment becomes easier to evaluate.

Symptoms of INOCA 

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Symptoms provide another important clue. Patients with ANOCA often experience classic angina during exercise, pressure tightness, shortness of breath, or symptoms that feel similar to their prior episodes, even though their arteries appear free of major stenosis.
Their symptoms may begin earlier in exercise or may feel out of proportion to the workload. Some may also describe angina that continues briefly into early recovery rather than resolving immediately.

Physiological clues in INOCA during exercise stress testing

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Their overall physiological response during the test can offer hints as well. They may have lower exercise capacity than expected for their age and sex, or they may show an exaggerated blood pressure response or unusually slow heart rate recovery.
These findings don't diagnose INOCA on their own, but they support the overall pattern when paired with symptoms and ST-segment changes.

How to report INOCA findings

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In your report, it's important to name what you see. Instead of calling the test normal, describe it accurately. For example, exercise ECG demonstrated horizontal ST-segment depression in the lateral leads with typical angina symptoms in the setting of nonobstructive coronary arteries. Findings are consistent with ischemia with nonobstructive coronary arteries.

Why recognizing INOCA matters

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Recognizing this pattern matters because these patients are not low risk just because their arteries look normal. Identifying ANOCA or INOCA during stress testing helps guide appropriate follow up and prevents these patients from being told nothing is wrong.