Let us focus on the apical acoustic events using the diaphragm of the stethoscope, again, the carotid vessel, you can determine systole by the movement of the cotton swab, and then we place our stethoscope at the apex and we focus on both systole and diastole using the diaphragm. [Cut-away]
What we heard at the apex in systole was a high frequency murmur, a holosystolic murmur at the apex. Then, one must ask, but what is the significance of a systolic murmur at the apex of that description? And one must, of course, think mitral regurgitation. What would be the significance of mitral regurgitation occurring in our patient? We must define that and integrate it with the rest of our evaluation. Now, of course, we also heard in diastole the third and fourth sounds. They were expected, after all, we palpated them on the chest wall, but the systolic murmur of mitral regurgitation we must now consider it and integrate it with our entire diagnosis.
Oscilloscope
By viewing an oscilloscopic imaging and simultaneously listening, we can further appreciate this auscultatory events.
MR
The systolic murmur of mitral regurgitation heard in our patient is likely due to mitral valve apparatus dysfunction. The dilated, failing ventricle alters the geometry of the papillary muscles and leads to mitral incompetence. Mitral annulus dilatation may contribute to dysfunctional mitral regurgitation. Although not the primary cause of heart failure in this setting, mitral regurgitation may increase pulmonary venous congestion. The degree of mitral regurgitation may also improve with the decrease in size of the dilated left ventricle.
Moving heart
This is a graphic example of the heart in a patient with mitral regurgitation. In the animation that follows, we can appreciate that the murmur is generated across the regurgitant mitral valve during left ventricular systole.
Murmur descriptors
Murmurs may be characterized by descriptors that include location, timing, contour and frequency.
Pressure curves
These simultaneous left atrial, left ventricular and aortic pressure curves illustrate the relationship of the hemodynamic events to the timing, contour and frequency of the systolic murmur. The murmur begins with mitral closure obscuring the first heart sound. It continues up to and through aortic closure, as left ventricular pressure exceeds left atrial pressure throughout this period. The murmur is plateau shaped because there is a significant pressure gradient between the left ventricle and left atrium throughout all of systole. The murmur is high in frequency primarily because blood is flowing from the high pressure left ventricle to the low pressure left atrium.
S3 and S4
Third and fourth heart sounds are also heard at the apex. There was no respiratory variation that may occur when right sided in origin. They further reflect left ventricular failure and volume overload.