Strain echocardiography (global longitudinal strain)

What it measures. Ejection fraction, the percentage of blood the left ventricle pumps out, is the traditional yardstick for chemotherapy heart damage, but it falls late and varies by several points between scans. Speckle-tracking software follows natural acoustic markers in the ultrasound image and measures how much the muscle shortens along the heart's long axis, reported as global longitudinal strain, a negative percentage around minus 18 to minus 22 in healthy hearts. Anthracyclines and trastuzumab blunt this shortening early, while the ejection fraction is still normal.

Evidence and guidelines. Observational studies showed that a relative drop in strain of more than 15 per cent predicted later cardiotoxicity, and the 2022 European Society of Cardiology cardio-oncology guideline and the American Society of Echocardiography build strain into the definition of cancer therapy-related cardiac dysfunction and into surveillance schedules for anthracycline and HER2-targeted therapy. The SUCCOUR randomised trial compared strain-guided with ejection-fraction-guided starting of heart-protective drugs; the ejection fraction endpoint at one year did not differ between arms, but fewer patients in the strain-guided arm developed clinically significant dysfunction, and the trial supports using strain to start protection early rather than waiting for the ejection fraction to fall.

Who should have it and what changes. Patients starting anthracyclines, trastuzumab and related drugs, radiation to the chest, and survivors of childhood cancer under long-term follow-up. A significant strain fall prompts a cardiology review, starting an ACE inhibitor or beta blocker, and closer imaging; it rarely stops cancer treatment on its own, which is the point, because the aim is to complete curative treatment safely. Strain requires a modern echocardiography machine and trained sonographers; values differ between vendors, so serial scans should use the same system. Cardiac MRI is the reference when the ultrasound window is poor.