ABSTRACT
Heart sounds and murmurs can signal many pathological conditions before they manifest themselves as changes in other physiological signals such as the electrocardiogram (ECG) or blood pressure (BP); therefore, auscultation (listening to heart sounds and murmurs) has become a primary test performed by the physician to assess the functional integrity of the heart. As such, auscultation is a fundamental component in cardiac diagnosis. It is the most commonly used technique for screening and diagnosis in primary health care. In some circumstances, particularly in remote areas or some developing countries, auscultation may be the only means available to the clinician for this purpose. However, it should be recognized that due to the subjectivity of the auscultation method, namely, the limitations of the human ear in listening to the heart sounds to detect relevant symptoms, forming a diagnosis based on sounds heard through a stethoscope is a clinical skill that can take years to acquire and rene. Additionally, due to the lack of a solid theory on the genesis of heart sounds, the objectivity of any cardiac diagnosis based solely on auscultation may be questionable. For a reliable and accurate diagnosis, physicians require more information to correlate the temporal relationships between the heart sounds, the atrial and ventricular BP waveforms (mechanical events), and the ECG signal ( electrical events) during the cardiac cycle. Phonocardiography (PCG), which is the method of graphical recording of heart sounds and murmurs, constitutes an integral component of this cardiovascular prole.
