Suggest Treatment For Shortness Of Breath, Fatigue And Fast Heart Beat

hi doctor, i m 37 yr old women. i have shortness of breath,fatigue and race heart beat while working. i saw a cardiologist. my tmt is normal,ecg normal, in echo,lv is dilated to 5.4 cm.i sought for second opinion .according to him i have no heart problem .he says i have trivial MR,and thats not a problem.which is correct?