In patients with lung emphysema, heart sound is faint and sometimes is almost absent while performing auscultation on precordial area.  In fact, among many of such patients heart auscultation is useless.  Is there any solution?  
 
Sometimes some information could be obtained by auscultation just below the xiphoid process, above the sternum and clavicles on the base of the neck and on carotids.  If you suspect aortic stenosis, search for the diamond-shaped murmur on carotids.  
Moreover, vice versa, when heart sound is best heard below the xiphoid process, it is a sign of pulmonary emphysema.