This protocol covers Cardiac syndrome X in the specific setting of vasospastic angina confirmed by epicardial (macrovascular) coronary spasm on acetylcholine testing — characterised by anginal symptoms, ischaemic ECG changes, and marked coronary lumen reduction on provocation.
Acetylcholine (Ach) provocation testing establishes the diagnosis when it reproduces anginal symptoms together with ischaemic ECG changes and an angiographic coronary lumen reduction of ≥90%, confirming epicardial macrovascular spasm. This subset of Cardiac syndrome X carries specific treatment implications distinct from microvascular disease.
First-line therapy is directed at calcium channel blockers (calcium antagonists) to control anginal symptoms and prevent ischaemia. The complete regimen — including escalation strategies for severe or refractory vasospastic angina — is set out in the full structured protocol.
DOI: 10.1093/eurheartj/ehae177
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.
Calcium channel blockers are recommended to control symptoms and to prevent ischaemia and potentially fatal complications.
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