A systematic approach to the bedside differentiation of cardiac murmurs and abnormal sounds.

Fortified by knowledge gained from cardiac catheterization studies, a more precise physiologic approach to cardiac auscultation has evolved in recent years. This system involves observing changes in the characteristics of murmurs and abnormal sounds during respiration, the Valsalva maneuver, exercise, changes in posture, after pharmacologic agents and during arrhythmias, These techniques will aid in the accurate identification of the origin of the murmur or abnormal sound but do not necessarily indicate the presence or severity of cardiac disease. The auscultatory results must be interpreted in the light of the complete clinical evaluation, which may include the ECG, chest x-ray and echocardiogram. Thus, the careful physiologic approach to the physical examination represents a powerful noninvasive tool that, when combined with other noninvasive studies, can accurately diagnose cardiac disease in many patients without the necessity for cardiac catheterization.