Walter X Welkowitz

US Patent:

49934201, Feb 19, 1991

Filed:

Mar 30, 1990

Appl. No.:

7/502409

Inventors:

Walter Welkowitz - Metuchen NJ
Oing Cui - Highland Park NJ
Yun Qi - Piscataway NJ

Assignee:

Rutgers University - Piscataway NJ

International Classification:

A61B 502

US Classification:

128668

Abstract:

A method and apparatus for monitoring the cardiac output of living subjects. Carotid pulse waveforms and femoral pulse waveforms are measured and converted to digitized signals. The carotid pulse signal or waveform is applied as a voltage to the simulated aorta circuit and the circuit component values varied to develop a waveform output best matching the femoral pulse electrical waveform.

US Patent:

51018284, Apr 7, 1992

Filed:

Apr 11, 1991

Appl. No.:

7/685591

Inventors:

Walter Welkowitz - Metuchen NJ
Qing Cui - Highland Park NJ
Yun Qi - Piscataway NJ

Assignee:

Rutgers, The State University of NJ - New Brunswick NJ

International Classification:

A61B 502

US Classification:

128668

Abstract:

Apparatus for noninvasively monitoring cardiovascular system parameters of a living subject comprises means for sensing waveforms externally of the body of the subject above the carotid and femoral arteries, means for non-invasively calibrating and digitizing the pulse waveforms, and a digital signal processor having means for converting the digitized, calibrated pulse information by Fast Fourier Transform to first and second sets of harmonically related blood pressure components in the frequency domain, means for comparing corresponding ones of the components in the first and second harmonically related sets to determine amplitude and phase transfer function components of the portion of the cardiovascular system between the carotid and femoral arteries, means for simulating the portion of the system by a hybrid electrical circuit model having at least three variable parameters, means for determining corresponding amplitude and phase transfer function components of the hybrid model and for adjusting the variable parameters so as to substantially match the transfer functions of the model and the portion of the cardiovascular system, and means for determining cardiac output utilizing the adjusted parameters of the hybrid model and the calibrated pulse information.

US Patent:

56473699, Jul 15, 1997

Filed:

Apr 19, 1996

Appl. No.:

8/634974

Inventors:

Steven P. Petrucelli - Cranbury NJ
Walter Welkowitz - Metuchen NJ
Lisa K. Liss - Dunellen NJ
Alan M. Smith - East Brunswick NJ
Stephen A. Orbine - Bernardsville NJ

Assignee:

Rutgers University - New Brunswick NJ

International Classification:

A61B 500

US Classification:

128672

Abstract:

Apparatus and methods for noninvasively measuring cardiovascular system parameters. According to a first preferred embodiment, the apparatus generates a time varying electrical voltage waveform having voltages corresponding to systolic and diastolic arterial pressures of the subject, the parameters being modelled by a lumped element electric circuit model analogous to the living subject's cardiovascular system, said circuit model including a systolic capacitor analogous to arterial compliance during systole, said apparatus comprising means for computing the value of said systolic capacitor from a measurement of an elapsed time between two voltage levels within a portion of said voltage waveform corresponding to systole, according to a predetermined criteria; and means for computing at least one said cardiovascular system parameter from said capacitor value. According to a second embodiment, a time-varying systolic arterial compliance is measured by measuring an arterial pulse pressure waveform. A third embodiment discloses a method of measuring cardiac output noninvasively from a cuff measurement of a patient's systolic minus diastolic blood pressure and a heart rate measurement.

US Patent:

55357539, Jul 16, 1996

Filed:

Oct 4, 1994

Appl. No.:

8/317927

Inventors:

Steven P. Petrucelli - Cranbury NJ
Walter Welkowitz - Metuchen NJ
Lisa K. Liss - Dunellen NJ
Alan M. Smith - East Brunswick NJ
Stephen A. Orbine - Bernardsville NJ

Assignee:

Rutgers University - New Brunswick NJ

International Classification:

A61B 500

US Classification:

128672

Abstract:

Apparatus and methods for noninvasively measuring cardiovascular system parameters. According to a first preferred embodiment, the apparatus generates a time varying electrical voltage waveform having voltages corresponding to systolic and diastolic arterial pressures of the subject, the parameters being modelled by a lumped element electric circuit model analogous to the living subject's cardiovascular system, said circuit model including a systolic capacitor analogous to arterial compliance during systole, said apparatus comprising means for computing the value of said systolic capacitor from a measurement of an elapsed time between two voltage levels within a portion of said voltage waveform corresponding to systole, according to a predetermined criteria; and means for computing at least one said cardiovascular system parameter from said capacitor value. According to a second embodiment, a time-varying systolic arterial compliance is measured by measuring an arterial pulse pressure waveform. A third embodiment discloses a method of measuring cardiac output noninvasively from a cuff measurement of a patient's systolic minus diastolic blood pressure and a heart rate measurement.

US Patent:

50368575, Aug 6, 1991

Filed:

Oct 26, 1989

Appl. No.:

7/426770

Inventors:

John L. Semmlow - New Brunswick NJ
Walter Welkowitz - Metuchen NJ
John Kostis - Warren NJ
Metin Akay - Piscataway NJ

Assignee:

Rutgers, The State University of New Jersey - New Brunswick NJ

International Classification:

A61B 502

US Classification:

128715

Abstract:

A method and system for non-invasively detecting Coronary Artery Disease. The method comprises analyzing the diastolic heart sounds detected from a patient's chest cavity during the diastolic portion of the heart cycle in order to identify a low level auditory component associated with turbulent blood flow in partially occluded coronary arteries. These diastolic heart sounds are modeled using advanced signal processing techniques such as Autoregressive (AR), Autoregressive Moving Averaging (ARMA) and Eigenvector methods, so that the presence of such an auditory component may be reliably indicated even under high noise conditions. The system includes an acoustic transducer, pulse sensor device, signal processor means and a diagnostic display. Additionally, the system includes a controller for automatically sequencing data collection, analysis and display stages, therefore requiring a minimum of operator interaction. The system further discloses a piezoelectric type low mass accelerometer for use as an acoustic transducer providing higher sensitivity at the high frequencies necessary for detecting coronary artery disease, specifically between 300 to 1200 Hz.

US Patent:

51098636, May 5, 1992

Filed:

May 6, 1991

Appl. No.:

7/696185

Inventors:

John L. Semmlow - New Brunswick NJ
Walter Welkowitz - Metuchen NJ
John B. Kostis - Warren NJ
Vasant Padmanabhan - Piscataway NJ

Assignee:

Rutgers, The State University of New Jersey - New Brunswick NJ
University of Medicine and Dentistry of New Jersey - Newark NJ

International Classification:

A61B 502

US Classification:

128715

Abstract:

A method and system for non-invasively detecting Coronary Artery Disease. The method comprises analyzing the diastolic heart sounds detected from a patient's chest cavity during the diastolic portion of the heart cycle in order to identify a low level auditory component associated with turbulent blood flow in partially occluded coronary arteries. These diastolic heart sounds are modeled using advanced signal processing techniques such as Autoregressive (AR), Autoregressive Moving Averaging (ARMA) and Eigenvector methods, so that the presence of such an auditory component may be reliably indicated even under high noise conditions. The system includes an acoustic transducer, pulse sensor device, signal processor means and a diagnostic display. Additionally, the system includes a controller for automatically sequencing data collection, analysis and display stages, therefore requiring a minimum of operator interaction. The system further discloses a piezoelectric type low mass accelerometer for use as an acoustic transducer providing high sensitivity at the high frequencies necessary for detecting coronary artery disease, specifically between 300 to 1200 Hz.