Myocardial contraction fraction: an underused imaging biomarker

Abstract Funding Acknowledgements Type of funding sources: None. Background The Myocardial contraction fraction (MCF% – stroke volume over myocardial volume) is an alternative/complementary measure cardiac function to the ejection (EF% end diastolic volume), (1–2). It dimensionless, does not need allometric scaling, easy compute and intuitive: produced per unit myocardium, with some data for its utility in different forms hypertrophy, (3–5). EF limitations (eg HFpEF) are well known. We explored potential MCF a variety diseases. Purpose To define reference ranges normal disease using large dataset, exploring sex age-related differences. evaluate compare use as prognostic biomarker compared more commonly used LVEF. Methods 3 cohorts were used: 1. Health: 3,541 subjects from UK biobank, supplemented by 72 local healthy volunteers (UKB lower age limit 45) normality age/sex 2. Disease: n=380 range diseases : 125 HCM, 157 Fabry (FD) 26 Transthyretin (TTR) Amyloid. 3. Prognostic cohort: n=1500 patients single centre outcomes (26% death or hospitalisation heart failure median 5.5years follow-up) All CMR images analysed clinically validated artificial intelligence (AI) algorithm convenience large-scale analysis (6) determine Results There was no significant changes but there difference (male 0.94, 0.68–1.2; female 1.10, 0.82–1.37 p<0.05)—see figure values each cohort shown 2, all reduction controls. Values ranged 0.47 Amyloid 0.94 Fabrys. Outcome: strongly predicted patient powerful predictor than LVEF (LVEF chi-squared=84 vs chi-squared=160). Conclusion complementary performance equally logical, intuitive calculate. frequently reduced even when normal, much stronger outcome