A heart attack can occur even when angiography shows no major blockage. This condition is called MINOCA (Myocardial Infarction with Non-Obstructive Coronary Arteries). Blood tests and heart tracings show a heart attack, but the arteries look clear. MINOCA accounts for a meaningful share of heart attacks, particularly in younger patients and women. Causes include a small plaque rupture whose clot partly dissolves before imaging, coronary artery spasm, microvascular dysfunction in the tiniest heart vessels, and, less commonly, spontaneous coronary artery dissection. A clear angiogram does not mean the heart is entirely safe, so patients may need further tests, ongoing treatment and monitoring. Accurate diagnosis matters because treatment differs by cause. Do not dismiss chest pain, breathlessness, unusual fatigue or palpitations just because initial tests look normal.
