Cardiac syndrome X
ICD-10 I20.9 · ICD-11 BA86

Treatment of Cardiac Syndrome X with Anginal Symptoms and Microvascular Spasm on Acetylcholine Testing

This protocol covers Cardiac syndrome X in patients whose acetylcholine (Ach) provocation test reveals microvascular spasm — presenting with anginal symptoms, ischaemic ECG changes, and an angiographic coronary lumen reduction of less than 90%.

Clinical Scenario
Microvascular spasm is identified on acetylcholine testing when anginal symptoms and ischaemic ECG changes occur alongside a coronary lumen reduction below the 90% threshold, distinguishing this pattern from macrovascular (epicardial) spasm. The combination of anginal symptoms, ischaemic ECG changes, and a sub-90% lumen reduction establishes the diagnosis.
Treatment Approach (partial)
Management of recurrent anginal episodes in this setting involves a nitrate-based approach — complete sequencing, selection criteria, and individualisation remain in the full structured protocol.
Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1093/eurheartj/ehae177

If the lumen reduction is <90%, the diagnosis of microvascular spasm is made.

The test is considered positive for macrovascular spasm if symptoms occur, accompanied by ischaemic ECG changes and an angiographic ≥90% reduction of the coronary lumen.

In patients with either epicardial or microvascular spasm following Ach testing, calcium antagonists should be considered as first-line therapy.

Nitrates should be considered to prevent recurrent episodes.

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