Cardiac syndrome X, also known as microvascular angina, is a condition characterized by angina (chest pain) and evidence of myocardial ischemia (reduced blood flow to the heart muscle) despite having normal coronary arteries on angiography. This means that the larger coronary arteries, typically examined during a cardiac catheterization, do not show significant blockages or narrowings that would usually explain the symptoms or the ischemia.

The exact cause of Cardiac syndrome X is not fully understood, but it is thought to involve the smaller coronary microvessels, which are not visible on standard angiography. These microvessels may not function properly, leading to reduced blood flow to the heart muscle, especially during stress or exertion.

Symptoms of Cardiac syndrome X are similar to those of traditional angina, including chest pain or discomfort, typically triggered by physical exertion or emotional stress and relieved by rest or medication such as nitroglycerin. However, unlike typical angina caused by coronary artery disease, Cardiac syndrome X is not usually associated with an increased risk of heart attacks, and the prognosis is generally better.

The diagnosis is often made after excluding other causes of chest pain and ischemia. Treatment focuses on symptom relief and may include lifestyle changes, medications to improve blood flow and reduce pain, and sometimes interventions to manage risk factors and improve cardiovascular health. Management of stress and psychological factors is also important, as these can contribute to the condition.

Because Cardiac syndrome X can be challenging to diagnose and manage, patients may require a comprehensive evaluation and a tailored treatment approach.