| REF | ejection fraction at rest; referred; refused; renal erythropoietic factor |
|---|---|
| REFI | regional ejection fraction image |
| RF | radial fiber; radio frequency; receptive field; regurgitant fraction; Reitland-Franklin [unit]; rela... |
| rOEF | regional oxygen extraction fraction |
| RVEF | right ventricular ejection fraction; right ventricular end-flow |