Tell the patient what you are doing and warm up the stethoscope before placing it on the patient's chest. Traditionally, the precordium is divided up into four areas where the sounds or murmurs from each valve can be heard. However, the sounds related to these valves are not always loudest at their respective areas and auscultation should not be limited to these sites alone. Begin your examination at the apex beat, where the first heart sound is usually loudest, and move up the left sternal edge ending with the aortic area and carotid arteries. The diaphragm and bell should be used alternately during the examination.
Inspiration increases right heart flow and accentuates right heart sounds and murmurs.
During expiration there is increased flow to the left heart which increases left heart murmurs. The first heart sound is easiest to hear with the diaphragm medial to the apex at the lower sternal border. It is often accentuated in mitral stenosis, short P-R tachycardias, left atrial myxoma, and mitral valve prolapse. It may be diminished in P-R prolongation, calcification of the mitral valve, severe left ventricular failure, left bundle branch block, and mitral regurgitation. The mitral valve closes slightly before the tricuspid valve but the interval is short and difficult to detect.