Simpson’s Biplane EF Calculator

Simpson’s biplane method: explanation, clinical context and references The biplane method of disks (the modified Simpson’s rule) estimates left ventricular end-diastolic and end-systolic volumes from apical 4-chamber and apical 2-ch views; the ejection fraction (LVEF) is then calculated as EF = [(EDV − ESV) / EDV] × 100%. In routine practice the machine may report volumes from each apical view and clinicians commonly average the two view-derived volumes to obtain a biplane estimate; alternatively, if a single, validated EDV and ESV are provided by the lab (already derived by biplane disk summation), those direct values can be used. Stroke volume equals EDV − ESV; cardiac output can be estimated as SV × heart rate, and cardiac index as CO divided by body surface area (BSA).

LVEF thresholds used for clinical categorization commonly follow guideline conventions (HFrEF <40%, HFmrEF 41–49%, HFpEF >50%), but LVEF should always be interpreted in the clinical context, taking into account image quality, geometric assumptions and additional measures (volumes indexed to BSA, strain imaging, natriuretic peptides, clinical status).