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                 BioSignetics Corporation
                                                                    Digital Stethoscope Company                             




Study 1: Aortic Stenosis, pressure gradient 70 mm Hg

             diastole         beat1               diastole                  Beat 2        diastole  
Two consecutive heartbeats with Aortic Stenosis systolic murmur.

                                        S1  Systolic Murmur  S2              diastole         

Murmur is very strong, so it is already difficult to precisely
differentiate S1 and S2 from the murmur.

 Systolic Murmur Frequency Spectrum - note upper boundary
at around 150 Hz and lower at about 80 Hz.

Murmur intensity above 150% clearly differentiate it as abnormal.
Murmur duration spans almost the entire systole. Mean frequency
is low 118% (just 10Hz above the innocent level), but large
half-bandwidth brings it up to 140-150 Hz on the upper boundary.

Heart Energy Signature           S1  Murmur      S2

                                  S1 Murmur    S2    
Frequency and Power Plot


Very strong in intensity Systolic murmur spanning the entire
systole and diamond in shape is clearly visible. Abnormal
due to intensity. Longer in time then typical Still's or
Innocent Flow, frequency spectrum is wider than Still's.

Heart Energy SIgnature (HES) is distinctly abnormal.

Heart Sound was taken from the Ears On Auscultation Program
and Database, www.corsonics.com (D.L. Roy, MD; B. Holt)

                                                 #   #   #

Study 2 - Influence of the Pressure Gradient on the
Aortic Stenosis Intensity and Frequency Scores

Phonocardiogram Examples  Showing Normal Heart and
a Progression of the Systolic Murmur of Aortic Stenosis

Software provides tools to display heart signal and to estimate its
basic statistics that are presented in the format of Intensity Score (%);
Frequency Score (mean Frequency and Mean Half-Bandwidth) and
Time Duration Score (%).

                            S1                           S2 
Normal Heart Sound (some noise in the signal is present)

S1                                          S2
         Heart Energy Signature of Normal Heart

Aortic Stenosis (Gradient=25 mm Hg)


S1    Murmur                  S2                                            S1

            Heart Energy Signature of Aortic Stenosis (P=25mm Hg)


Aortic Stenosis (gradient = 70 mm Hg)

                                 S1    Murmur    S2                                           

        Heart Energy Signature of Aortic Stenosis (P=70mm Hg)


Aortic Stenosis (gradient = 95 mm Hg)


       S1            Murmur                  S2                                           

             Heart Energy Signature of Aortic Stenos is (P=95 mm Hg)

With the increase in the gradient from 25 mm Hg to 95 mm Hg we
detect a marked increase in Murmur Frequency ( 94 to 158 Hz)
matched by the increase in intensity from 85%  to 226 % and
murmur duration. At the highest pressure gradient (100 mm Hg)
frequency drops and murmur duration get reduced. Most likely
this is due to further flow restriction.

Data was collected on different patients.


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Copyright: 2004-2009 BioSignetics Corporation
Last modified: 02/02/09