First Heart Sounds First Heart Sound (Minimally Split) On occasion the first heart sound can be made up of two separate sounds separated by a very small interval (20-30 milliseconds).The Mitral component (caused by closure of the Mitral valve) comes first and is louder than the Tricuspid component (caused by closure of the Tricuspid valve).A minimally split first heart sound is a normal variation of the first heart sound. play pause Position: Tricuspid Chestpiece: Diaphragm Maneuver: Supine Phonocardiogram Heart Animation Table of Contents 1First Heart Sound - Loud 2First Heart Sound (Minimally Split) 3First Heart Sound (Markedly Split) 4First Heart Sound - Decreased Intensity 5Fourth Heart Sound Plus First Heart Sound 6First Heart Sound plus Aortic Ejection Click Practice Drill