International Journal of Scientific & Engineering Research, Volume 2, Issue 2, February-2011 1 ISSN 2229-5518 IJSER © 2011 http://www.ijser.org An Effiecient Modeling Technique for Heart Sounds and Murmurs Kiran Kumari Patil*, Dr.B.S Nagabhushan, Dr. Vijaya Kumar B.P (*Research Scholar Dr. MGR University, Chennai) Abstract— Cardiac auscultation is highly subjective and a cognitive process and the amount information that can be obtained by listening heart sounds largely depends on the expertise, experience and acuity of the ear of the physician. In general, the classification and interpretation of heart sounds and murmurs is based on a adjective 0-6/6 grade scale and described by using “faint”, “soft”, “loud”, “ high pitch”, “clear”, “thrill”, “tremor”, “musical” and others terms. These terms are not well-defined and suitable mathematical models are not available. Apart from that, the adjective scales vary among the doctors and difficult to derive a standard model for heart sound quality and correct clinical interpretation. In this research paper, we propose a novel framework based on psychoacoustic principles and derive psychoacoustic models for the heart sounds and murmurs. We discuss the theoretical foundations, psychoacoustic principles and derive the mathe- matical models for the psychoacoustic features such as loudness, sharpness, intensity, strength, roughness, tonality etc. for a set of heart sounds and murmurs. The proposed framework helps in deriving heart sound quality and also used for the com- parison and correlation with normal and pathologic murmurs and enhances clinical decisions. . Index Terms— psychoacoutic principles, psychoacoutic models, heart sounds, auscultation, phonocardiography . ——————————  —————————— 1 INTRODUCTION Heart sounds and murmurs are acoustic phenomenon caused by the mechnical events of cardiac system. Aus- cultation or hearing of heart sounds using conventional stethscope or electronic stehoscope is not purely a mech- nical phenomenon of sound wave propagation, but also auditory, sensory, cognative and perceptual event. Digital cardiac auscultation is an art and science of interpreating hearts sounds and murmurs used for clinical diagnostics. Congnitive process that paly significant role heart sound perception and clinical interpreatation. The phonocardio- graphy (PCG) — the art and science of recording and in- terpreting of heart sounds using latest digital technology has significantly helped to understand and interpret the complex heart sounds (normal, abnormal sounds includ- ing murmurs). The PCG is a display of the heart sound signal with respect time (time domain) and frequency components or spectral properties (frequency domain) and plotting the heart sounds and murmurs can provide useful information to the physician by complementing cardiac auscultation Phonocardiography techniques are used for the effective clinical investigations and corrective diagnostic heart related diseases and in particular valvu- lar heart diseases. When a heart valve is stenotic or dam- aged, the abnormal blood flow patterns produce a series of audible vibratory sounds known as murmurs [3]. Doc- tors and physicians detect these disorders by listening to heart sounds at different locations across the torso. Mur- murs heared during routine physical exminations offer important clues to the presence of undetected and asymp- tomatic cardiac disease. The process of interpreating heart sounds is called cardiac auscultation. It is a simple, non- invasive tec niques helps in early detection of cardiac dis- orders. Different cardiac ailments produce a potentially overwhelming set of acoustic pathological events and correctly identfying a disorder requires discrimination of subtle variations in the timing characteristics and spectral properties of heart sounds. The analysis and interpreta- tion is complicated by the natural variations in heart sounds introduced by factors such as the gender, age, habitus and dynamic state of the patients. Even in adults, anixiety, stress, fever, anemia etc. may also cause benign murmurs. Typically, these cases are distinguished by ex- amining the intensity of sounds, in addition to their tim- ing and frequency content. Sounds that are interesting from the perspective of auscultation are often short lived (less than 20 millseconds) and seperated from one another by less than 30 milliseconds. Pathological signals indica- tive of cardiac diseases are also often much quieter than other heart sounds and their audibility varies across su- cessive heart beats. Even with extensive experience, phy- sicians may often disagree about sounds, in particular with brief heart sounds. These inaccuracies are attributed