Had late tiffascan @27th week and everything is normal but 2d echo report mentioned, "efc noted in left ventricle", is it a problem if so how serious?

Ask questions: It's ok to ask questions and ask your doctor to clarify and explain the test results until you really understand ok.

Ask your doctor: Tiffascan is just a fancy name for a specialized ultrasound looking for fetal anomalies. While i don't know exactly what efc stands for (its a nonstandard acronym) but it probably refers to an "echobright intracardiac focus" (eif). Almost always, the finding of an eif on fetal ultrasound is not a concerning finding and if an echocardiogram is performed after birth, there are no abnormalities.