True in mitral regurgitation (MR) is
S1 is soft in MR unlike MS. 
Functional or Secondary MR is caused by dilation of the left ventricle causing leakage at the mitral annulus. 
ECG in MR shows 'P' mitrale due to dilation of the Left atrium.
Pansystolic murmur at the apex
Loud S1
Functional or Secondary MR is caused by papillary muscle rupture after myocardial infarction
ECG commonly reveals 'P' pulmonale