Four international cardiac societies have issued updated heart attack guidelines that finally recognise how symptoms differ in women.

The key change: emergency departments must now use sex-specific troponin thresholds. Women have naturally lower troponin levels than men, so the old single threshold systematically missed heart attacks in women. Professor Nicholas Mills of the University of Edinburgh, who led the task force, called it "unintended systematic bias against women."

The guidelines also formally recognise atypical symptoms like nausea and indigestion as indicators of cardiac distress in women, and conditions like spontaneous coronary artery dissection, a stress-linked tear in the heart's artery that disproportionately affects women.

The framework is the Fifth Universal Definition of Myocardial Infarction, developed by the ESC, American College of Cardiology, American Heart Association and World Heart Federation, published in the European Heart Journal.

If hospitals adopt the standards, fewer women should face the delayed or missed diagnoses that have persisted for decades.