Both the Mitral Valve and the Tricuspid Valves each have long elastic stringy chordeneae tindinea that attach each of the respective valves to the papillary muscles in to each of the respective right and left ventricles. If the cordinea tindinea become damaged and elongated, full valve closure may not occur and regurgitation into the respective atria's can occur. These failures of full closure in either of the Mitral or Tricuspid valves can lead to the production of midsystolic murmurs. This ejection click occurs between S1 and S2 heart sounds, it is generated as the cordinea tindinea snap back to hold the Mitral Valves leaflet from ballooning retrograde during the maximum ventricular ejection.
Inspiration increases the intensity of the ejection click.
Also, ventricular blood volume effects the location of the midsystolic click. Deceased right ventricular volume will move the ejection click closer to the S1 heart sound, while increased right ventricular volume will move to ejection sound closer to the S2 heart sound. This murmur is best heard at the Apex, but can be detected during normal physical examination at the left 5th intercostal space close to the sternal boarder. Both the midsystolic murmur and the mitral valve ejection click are high frequency and are best heard with the Diaphragm of the stethoscope. Click here to hear the Mitral Valve Prolapse Sound File.