Loud S1 is caused by-
Loud S1: Tachycardia Sho PR Interval. Mitral stenosis Tricuspid stenosis Soft S1: Bradycardia Prolonged PR Interval Aoic regurgitation Pulmonary regurgitation. Ref : Harrison's 20th edition pg 1563
Calcified mitral valve
Mitral Regurgitation
Sho PR interval
Bradycardia
C.V.S