Evaluating arterial pressure, vasomotor activity and their response to diagnostic tests

• US 9,801,607 B2
• Filed: 03/04/2014
• Issued: 10/31/2017
• Est. Priority Date: 01/31/2010
• Status: Active Grant

• Current Assignee: Vladimir Shusterman
• Original Assignee: Vladimir Shusterman
• Inventors: Shusterman, Vladimir
• Primary Examiner(s): Lin, Jerry
• Application Number:
  US14/196,738
• Publication Number:
  US 20140187941A1
• Time in Patent Office: 1,337 Days
• Field of Search: 702 19
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02014 Determining aneurysm
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 8/04 Measuring blood pressure

Abstract

Method and system for evaluating arterial pressure waves, vascular properties, as well as for diagnostic, physiological and pharmacological testing using various combinations of the following data acquisition and processing steps (some of the steps are optional): 1. Perturbing arterial pressure from its steady state. 2. Measuring the dynamics of at least one parameter related to the passage of arterial pressure waves along blood vessels. 3. Characterizing the magnitude and functional relation of changes in parameters described above in relation to changes in blood pressure during its displacement from and/or return to the steady state. 4. Classifying (comparing) the individual functional relation described above with a databank of parameters/functional relations for different states of vasomotor activity.

Claims

1. A method for dynamical evaluation of at least one indicator selected from arterial pressure, cardiac output, and vascular properties, said method comprising:

placing at least two sensors, at least one of which contains an accelerometer adapted for placement on the surface of an individual'"'"'s torso and is adapted for registering at least one torso-surface movement related to cardiovascular mechanical activity,

collecting data from said at least two sensors over multiple cardiac cycles; and

processing said data, wherein said processing is adapted to determine at least two parameters of cardiovascular activity and is further adapted to derive at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries.

2. A method as set forth in claim 1 that includes preprocessing said physiological signals to separate said signals from noise and interference using at least one method selected from filtering using fixed filters, filtering using adaptive filters, pattern recognition, orthogonal linear decomposition, and wavelet decomposition.

3. A method as set forth in claim 1 in which said processing further includes calibrating said parameters with respect to at least one reference value selected from:

i. systolic pressure;

ii. diastolic pressure;

iii. mean arterial pressure;

iv. hear rate;

v. vascular properties;

vi. arterial-pressure-wave (pulse) transit time (PTT);

vii. arterial-pressure-wave velocity;

viii. an individual'"'"'s baseline values of said parameters;

ix. characteristics of displacement of said parameters from baseline values;

x. the magnitude, range, speed, time length, and pattern of temporal changes in said parameters;

xi. the magnitude, range, speed, time length, and pattern of spatial changes in said parameters with respect to different anatomical locations;

xii. augmentation index (AI);

xiii. a functional relationship between at least two reference values;

xiv. at least one measure of similarity with at least one typical value for an individual;

xv. at least one measure of difference with an individual'"'"'s baseline (typical) values;

xvi. at least one measure of similarity with at least one typical pattern for an individual;

xvii. at least one measure of similarity with at least one typical value for a population;

xviii. at least one measure of difference with at least one typical pattern for a population;

xix. at least one measure of similarity with at least one typical pattern for a population;

xx. a functional relationship between said parameters and at least two reference points within at least one reference signal selected from;

a. systolic pressure;

b. diastolic pressure;

c. mean arterial pressure;

d. heart rate;

e. arterial-pressure-wave (pulse) transit time;

f. arterial-pressure-wave velocity; and

g. vascular properties;

xxi. a functional relationship between said parameters and at least two reference values within at least two said reference signals.

4. A method as set forth in claim 1 which includes tracking the passage of pressure waves in at least one central artery selected from:

the aorta, ascending aorta, thoracic aorta, abdominal aorta, pulmonary artery, renal arteries, carotid arteries, and subclavian arteries.

5. A method as set forth in claim 1 in which at least one sensor is placed in the vicinity of a non-central artery to obtain a signal related to the blood-pressure wave in the non-central artery in order to compare said signal with that registered in the vicinity of a central artery, and to separate peripheral vascular activity from the systemic blood pressure.

6. A method as set forth in claim 1 in which said at least two sensors include at least one sensor selected from:

a MEMS sensor, a three-axial MEMS accelerometer sensor, electrocardiographic sensor, photoplethysmographic sensor, impedance plethysmography sensor, ultrasound sensor, and volume-clamp sensor and

in which said processing includes determining said at least two parameters of cardiovascular activity in at least one data type selected from;

A. Electrocardiogram (ECG);

B. Accelerations of the torso surface registered by said at least one sensor, which contains an accelerometer;

C. Pressure-wave signal;

D. The 1^st derivative (acceleration) of the pressure wave registered by said at least one sensor, which contains an accelerometer; and

E. The 2^nd derivative of the pressure wave signal registered by said at least one sensor, which contains an accelerometer;

wherein said at least two parameters of cardiovascular activity are selected from;

i. the amplitude of the specific peaks,

ii. the area of the specific peaks,

iii. the duration of the specific peaks,

iv. the time of occurrence of the specific peaks,

v. the median, mode, standard deviation, variance, and range of temporal variation of the systolic, diastolic, and mean arterial pressure;

vi. space-time maps of at least one distribution of the signal parameters listed above in at least two said signals;

vii. the time of the fiducial points, including at least one parameter selected from;

the peak of the ECG R, P, O, S, T, and U wave;

the beginning, peak, and end of the pressure wave;

the beginning, peak, and end of the pressure-wave acceleration; and

the beginning, peak, and end of the pressure-wave 2^nd derivative;

and further includes determining said at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries, wherein said at least one parameter is selected from;

i. the time interval between the specific peaks in at least one said signal;

ii. the time interval between the time of occurrence of at least one specific peak in at least two said signals;

iii. pressure-wave velocity;

iv. arterial-pressure-wave (pulse) transit time;

v. systolic pressure;

vi. diastolic pressure;

vii. mean arterial pressure;

viii. heart rate;

ix. vascular properties;

x. the augmentation index.

7. A method as set forth in claim 1 in which at least one of said at least two sensors is placed on at least one site selected from a limb, the torso, the neck, and the head of said subject.

8. A method as set forth in claim 1 which includes:

placing at least two accelerometer-containing sensors adapted for measuring at least one movement related to cardiovascular mechanical activity, at specific locations on the surface of an individual'"'"'s torso;

monitoring physiological signals;

preprocessing said physiological signals respecting the heart'"'"'s mechanical activity to separate signals from noise and interference; and

processing said physiological signals to determine at least one parameter value and to track the passage of the arterial blood-pressure wave through said at least two sensors'"'"' locations.

9. A system for dynamic evaluation of at least one indicator selected from arterial pressure, cardiac output, and vascular properties, said system comprising:

at least two sensors, at least one of which is adapted for placement on the surface of an individual'"'"'s torso, contains an accelerometer, and is further adapted for registering torso-surface movement related to cardiovascular mechanical activity;

an acquisition module for acquiring information from said at least two sensors; and

a processing module for processing said information (signal) from said at least two sensors wherein said processing module is adapted to determine at least two parameters of cardiovascular activity and is further adapted to derive at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries.

10. A system as set forth in claim 9 in which said sensors include at least two MEMS sensors.

11. A system as set forth in claim 9 which includes filters to improve the signal-to-noise ratio with respect to the arterial pressure-wave signal and to reduce the impact of at least one type of interference selected from:

power-line interference, noise, artifacts, and electromagnetic interference, using at least one component selected from;

a fixed filter, adaptive filter, pattern-recognition component, orthogonal linear decomposition component, and wavelet decomposition component.

12. A system as set forth in claim 9 which further includes a communication module for communicating with at least one of the following devices:

external computer, computer tablet, smart phone, and Internet cloud.

13. A system as set forth in claim 9 which includes an output/display module.

14. A system as set forth in claim 9 in which said at least two sensors include at least one sensor-is-selected from an electrocardiographic sensor, accelerometer, photoplethysmographic sensor, impedance plethysmography sensor, MEMS sensor, three-axial MEMS sensor, ultrasound sensor, and volume-clamp sensor;

and in which said processing module performs at least one of the following processing steps;

determining said at least two parameters of cardiovascular activity in at least one said signal selected from;

A. Electrocardiogram (ECG);

B. Acceleration of the torso surface registered by said at least one sensor, which contains an accelerometer;

C. Pressure-wave signal;

D. The 1^st derivative (acceleration) of the pressure wave registered by said at least one sensor, which contains an accelerometer; and

E. The 2^nd derivative of the pressure wave registered by said at least one sensor, which contains an accelerometer;

wherein said at least two parameters of cardiovascular activity are selected from;

i. the amplitude of the specific peaks;

ii. the area of the specific peaks;

iii. the duration of the specific peaks;

iv. the time of occurrence of the specific peaks;

v. the median, mode, standard deviation, variance, and range of temporal variation of the systolic, diastolic, and mean arterial pressure;

vi. space-time maps of at least one distribution of the signal parameters listed above in at least two said signals;

vii. the time of the fiducial points, including at least one parameter selected from;

the peak of the ECG R, P, O, S, T, and U wave;

the beginning, peak, and end of the pressure wave;

the beginning, peak, and end of the pressure-wave acceleration; and

the beginning, peak, and end of the pressure-wave 2^nd derivative;

and further determining said at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries, wherein said at least one parameter is selected from;

i. the time intervals between the specific peaks in at least one said signal;

ii. the time intervals between the time of occurrence of at least one specific peak in at least two said signals;

iii. pressure-wave velocity;

iv. arterial-pressure-wave (pulse) transit time

v. systolic pressure;

vi. diastolic pressure;

vii. mean arterial pressure;

viii. heart rate;

ix. vascular properties;

x. the augmentation index.

15. A system as set forth in claim 12, in which said communication module is wireless.

16. A system as set forth in claim 9 in which said at least one sensor includes a combination of at least one accelerometer and at least one electrocardiographic sensor.

17. A system as set forth in claim 9 in which said processing module is further adapted to perform calibration of said information using at least one reference selected from:

i. systolic pressure;

ii. diastolic pressure;

iii. mean arterial pressure;

iv. heart rate;

v. vascular properties;

vi. arterial-pressure-wave (pulse) transit time;

vii. arterial-pressure-wave velocity;

viii. an individual'"'"'s baseline values;

ix. characteristics of displacement from baseline values;

x. the magnitude, range, speed, time length, and pattern of temporal changes;

xi. the magnitude, range, speed, time length, and pattern of spatial changes with respect to different anatomical locations;

xii. augmentation index;

xiii. a functional relationship between at least two reference values;

xiv. at least one measure of similarity with an individual'"'"'s baseline (typical) values;

xv. at least one measure of difference with an individual'"'"'s baseline values;

xvi. at least one measure of similarity with at least one typical pattern for an individual;

xvii. at least one measure of similarity with at least one baseline value in a group of subjects;

xviii. at least one measure of difference with group baseline values in a group of subjects;

xix. at least one measure of similarity with at least one typical pattern for a group of subjects;

xx. a functional relationship between said parameters and at least two reference points within at least one reference signal selected from;

a. systolic pressure;

b. diastolic pressure;

c. mean arterial pressure;

d. heart rate;

e. arterial-pressure-wave (pulse) transit time;

f. arterial-pressure-wave velocity;

g. vascular properties;

xxi. a functional relationship between said parameters and at least two reference points in at least two said reference signals.

18. A system as set forth in claim 9, which includes:

(i) at least two accelerometer-containing sensors, which are adapted for placement on the surface of an individual'"'"'s torso and for measuring mechanical movement related to cardiovascular mechanical activity;

(ii) at least one acquisition module for receiving information from said at least two sensors; and

(iii) at least one processing module for processing said at least two signals obtained from said two sensors, with said processing adapted for determining at least one parameter value related to cardiovascular activity and further adapted for tracking at least one parameter of cardiovascular mechanical activity measured by at least two said sensors containing accelerometers.

19. A system for dynamic evaluation of at least one indicator selected from arterial pressure, cardiac output, and vascular properties, said system comprising:

at least two accelerometer-containing MEMS sensors adapted for placement on the surface of an individual'"'"'s torso and further adapted for measuring torso-surface movement related to cardiovascular mechanical activity;

at least one acquisition module for receiving information (data) from said at least two sensors; and

at least one processing module for processing said information from said at least two sensors wherein said processing module is adapted to determine at least two parameters of cardiovascular activity and is further adapted to derive at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries.

20. A system as set forth in claim 19 which further includes a communication module for communicating with at least one of the following devices:

external computer, computer tablet, smart phone, and Internet cloud.

21. A system as set forth in claim 20 in which said communication module is wireless.

22. A system as set forth in claim 19 which further includes at least one sensor selected from:

an electrocardiographic sensor, photoplethysmographic sensor, impedance plethysmography sensor, accelerometer sensor, a MEMS sensor, a three-axial MEMS accelerometer sensor, ultrasound sensor, and volume-clamp sensor; and

in which said processing module contains at least one functional element that performs at least one of the following operations;

(i) determining said at least two parameters of cardiovascular activity from at least one data type selected from;

A. Electrocardiogram (ECG);

B. Acceleration of the torso surface registered by said at least one sensor, which contains an accelerometer;

C. Pressure-wave signal;

D. The 1^st derivative (acceleration) of the pressure wave registered by said at least one sensor, which contains an accelerometer; and

E. The 2^nd derivative of the pressure wave registered by said at least one sensor, which contains an accelerometer;

wherein said at least two parameters of cardiovascular activity are selected from;

i. the amplitude of the specific peaks;

ii. the area of the specific peaks;

iii. the duration of the specific peaks;

iv. the time of occurrence of the specific peaks;

v. the median, mode, standard deviation, variance, and range of temporal variation of the systolic, diastolic, and mean arterial pressure;

vi. space-time maps of at least one distribution of the signal parameters listed above in at least two said signals;

vii. the time of the fiducial points, including at least one parameter selected from;

the peak of the ECG R, P, Q, S, T, and U wave;

the beginning, peak, and end of the pressure wave;

the beginning, peak, and end of the pressure-wave acceleration; and

the beginning, peak, and end of the pressure-wave 2^nd derivative;

and further determining said at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries, wherein said at least one parameter is selected from;

i. the time intervals between the specific peaks in at least one said signal;

ii. the time intervals between the time of occurrence of at least one specific peak in at least two said signals;

iii. pressure-wave velocity;

iv. arterial-pressure-wave (pulse) transit time;

v. systolic pressure;

vi. diastolic pressure;

vii. mean arterial pressure;

viii. heart rate;

ix. vascular properties;

x. the augmentation index;

(ii) calibrating said parameters with respect to at least one reference value selected from;

i. systolic pressure;

ii. diastolic pressure;

iii. mean arterial pressure;

iv. heart rate;

v. vascular properties;

vi. arterial-pressure-wave (pulse) transit time;

vii. arterial-pressure-wave velocity;

viii. an individual'"'"'s baseline values;

ix. characteristics of displacement from baseline values;

x. the magnitude, range, speed, time length, and pattern of temporal changes;

xi. the magnitude, range, speed, time length, and pattern of spatial changes with respect to different anatomical locations;

xii. augmentation index;

xiii. a functional relationship between at least two reference values;

xiv. at least one measure of similarity with an individual'"'"'s baseline (typical) values;

xv. at least one measure of difference with an individual'"'"'s baseline values;

xvi. at least one measure of similarity with at least one typical pattern for an individual;

xvii. at least one measure of similarity with at least one baseline value in a group of subjects;

xviii. at least one measure of difference with group baseline values in a group of subjects;

xix. at least one measure of similarity with at least one typical pattern for a group of subjects;

xx. a functional relationship between said parameters and at least two reference points within at least one reference signal selected from;

a. systolic pressure;

b. diastolic pressure;

c. mean arterial pressure;

d. heart rate;

e. arterial-pressure-wave (pulse) transit time;

f. arterial-pressure-wave velocity;

g. vascular properties;

xxi. a functional relationship between said parameters and at least two reference points in at least two said reference signals.

23. A system as set forth in claim 19 in which at least one of said at least two sensors is placed on at least one site selected from a limb, the torso, the neck, and the head of said subject.

24. A system for monitoring at least one vital sign selected from blood pressure, cardiac output, and vascular activity, said system comprising:

at least one accelerometer-containing sensor adapted for registering at least one mechanical movement of the surface of the torso;

at least one acquisition module for acquiring information (data) from said at least one sensor over multiple cardiac cycles; and

at least one processing module adapted to process said information respecting the features that originate from at least two anatomical locations using at least one processing step selected from;

(i) determining said at least two parameters of cardiovascular activity in at least one data type selected from;

A. Electrocardiogram (ECG);

B. Accelerations of the torso surface registered by said at least one sensor, which contains an accelerometer;

C. Pressure-wave signal;

D. The 1^st derivative (acceleration) of the pressure wave registered by said at least one sensor, which contains an accelerometer; and

E. The 2^nd derivative of the pressure wave registered by said at least one sensor, which contains an accelerometer;

wherein said at least two parameters of cardiovascular activity are selected from;

i. the amplitude of the specific peaks;

ii. the area of the specific peaks;

iii. the duration of the specific peaks;

iv. the time of occurrence of the specific peaks;

v. the median, mode, standard deviation, variance, and range of temporal variation of the systolic, diastolic, and mean arterial pressure;

vi. space-time maps of at least one distribution of the signal parameters listed above in at least two said signals;

vii. the time of the fiducial points, including at least one parameter selected from;

the peak of the ECG R, P, Q, S, T,

and U wave;

the beginning, peak, and end of the pressure wave;

the beginning, peak, and end of the pressure-wave acceleration; and

the beginning, peak, and end of the pressure-wave 2^nd derivative;

and further determining said at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries, wherein said at least one parameter is selected from;

i. the time intervals between the specific peaks in at least one said signal,

ii. the time intervals between the time of occurrence of at least one specific peak in at least two said signals;

iii. pressure-wave velocity;

iv. arterial-pressure-wave (pulse) transit time;

v. systolic pressure;

vi. diastolic pressure;

vii. mean arterial pressure;

viii. heart rate;

ix. vascular properties;

x. the augmentation index;

(ii) calibrating said parameters with respect to at least one reference selected from;

i. systolic pressure;

ii. diastolic pressure;

iii. mean arterial pressure;

iv. heart rate;

v. vascular properties;

vi. arterial-pressure-wave (pulse) transit time;

vii. arterial-pressure-wave velocity;

viii. an individual'"'"'s baseline values;

ix. characteristics of displacement from baseline values;

x. the magnitude, range, speed, time length, and pattern of temporal changes;

xi. the magnitude, range, speed, time length, and pattern of spatial changes with respect to different anatomical locations;

xii. augmentation index;

xiii. a functional relationship between at least two reference values;

xiv. at least one measure of similarity with an individual'"'"'s baseline (typical) values;

xv. at least one measure of difference with an individual'"'"'s baseline values;

xvi. at least one measure of similarity with at least one typical pattern for an individual;

xvii. at least one measure of similarity with at least one baseline value in a group of subjects;

xviii. at least one measure of difference with group baseline values in a group of subjects;

xix. at least one measure of similarity with at least one typical pattern for a group of subjects;

xx. a functional relationship between said parameters and at least two reference points within at least one reference signal selected from;

a. systolic pressure;

b. diastolic pressure;

c. mean arterial pressure;

d. heart rate;

e. arterial-pressure-wave (pulse) transit time;

f. arterial-pressure-wave velocity;

g. vascular properties;

xxi. a functional relationship between said parameters and at least two reference points in at least two said reference signals.

25. A system as set forth in claim 24 which further includes at least one sensor which is placed on at least one site selected from a limb, the torso, the neck, and the head of said subject.

26. A system as set forth in claim 24 which further includes at least one sensor selected from:

an electrocardiographic sensor, photoplethysmographic sensor, impedance plethysmography sensor, accelerometer sensor, a MEMS sensor, a three-axial MEMS accelerometer sensor, ultrasound sensor, and volume-clamp sensor.

27. A device for monitoring at least one vital sign selected from blood pressure, cardiac output, and vascular activity, said device comprising:

at least two sensors, at least one of which is adapted for placement on the surface of an individual'"'"'s torso, contains an accelerometer, and is further adapted for measuring torso-surface movement related to cardiovascular mechanical activity;

at least one acquisition module for acquiring information (data) from said at least two sensors over multiple cardiac cycles;

at least one module selected from communication module and data-storage (memory) module for transferring said information to an external processing module wherein said processing module is adapted to determine at least two parameters of cardiovascular activity and is further adapted to derive at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries.

28. A portable device as set forth in claim 27 which further includes at least one sensor selected from:

an electrocardiographic sensor, photoplethysmographic sensor, impedance plethysmography sensor, accelerometer sensor, a MEMS sensor, a three-axial MEMS accelerometer sensor, ultrasound sensor, and volume-clamp sensor.

29. A portable device as set forth in claim 27, in which said processing module is further adapted to include at least one functional element that performs at least one of the following operations:

(i) determining said at least two parameters of cardiovascular activity in at least one data type selected from;

A. Electrocardiogram (ECG);

B. Acceleration of the torso surface registered by said at least one sensor, which contains an accelerometer;

C. Pressure-wave signal;

D. The 1^st derivative (acceleration) of the pressure wave registered by said at least one sensor, which contains an accelerometer; and

E. The 2^nd derivative of the pressure wave registered by said at least one sensor, which contains an accelerometer;

wherein said at least two parameters of cardiovascular activity are selected from;

i. the amplitude of the specific peaks;

ii. the area of the specific peaks;

iii. the duration of the specific peaks;

iv. the time of occurrence of the specific peaks;

v. the median, mode, standard deviation, variance, and range of temporal variation of the systolic, diastolic, and mean arterial pressure;

vi. space-time maps of at least one distribution of the signal parameters listed above in at least two said signals;

vii. the time of the fiducial points, including at least one parameter selected from;

the peak of the ECG R, P, Q, S, T, and U wave;

the beginning, peak, and end of the pressure wave;

the beginning, peak, and end of the pressure-wave acceleration; and

the beginning, peak, and end of the pressure-wave 2^nd derivative;

and further determining said at least one parameter of cardiovascular mechanical activity related to the arterial pressure in the central arteries, wherein said at least one parameter is selected from;

i. the time intervals between the specific peaks in at least one said signal;

ii. the time intervals between the time of occurrence of at least one specific peak in at least two said signals;

iii. pressure-wave velocity;

iv. arterial-pressure-wave (pulse) transit time;

v. systolic pressure;

vi. diastolic pressure;

vii. mean arterial pressure;

viii. heart rate;

ix. vascular properties;

x. the augmentation index;

(ii) calibrating said parameters with respect to at least one reference selected from;

i. systolic pressure;

ii. diastolic pressure;

iii. mean arterial pressure;

iv. heart rate;

v. vascular properties;

vi. arterial-pressure-wave (pulse) transit time;

vii. arterial-pressure-wave velocity;

viii. an individual'"'"'s baseline values;

ix. characteristics of displacement from baseline values;

x. the magnitude, range, speed, time length, and pattern of temporal changes;

xi. the magnitude, range, speed, time length, and pattern of spatial changes with respect to different anatomical locations;

xii. augmentation index;

xiii. a functional relationship between at least two reference values;

xiv. at least one measure of similarity with an individual'"'"'s baseline (typical) values;

xv. at least one measure of difference with an individual'"'"'s baseline values;

xvi. at least one measure of similarity with at least one typical pattern for an individual;

xvii. at least one measure of similarity with at least one baseline value in a group of subjects;

xviii. at least one measure of difference with group baseline values in a group of subjects;

xix. at least one measure of similarity with at least one typical pattern for a group of subjects;

xx. a functional relationship between said parameters and at least two reference points within at least one reference signal selected from;

a. systolic pressure;

b. diastolic pressure;

c. mean arterial pressure;

d. heart rate;

e. arterial-pressure-wave (pulse) transit time;

f. arterial-pressure-wave velocity;

g. vascular properties;

xxi. a functional relationship between said parameters and at least two reference points in at least two said reference signals.

30. A portable device as set forth in claim 27 in which at least one of said at least two sensors is placed on at least one site selected from a limb, the torso, the neck, and the head of said subject.

31. A portable device as set forth in claim 27 in which said communication module is adapted for communicating with at least one of the following devices:

external computer, computer tablet, smart phone, and Internet cloud.

32. A portable device as set forth in claim 31 in which said communication module is wireless.

33. A portable device as set forth in claim 27, which includes:

(i) at least two accelerometer-containing sensors, which are adapted for placement on the surface of an individual'"'"'s torso and for registering mechanical movement related to cardiovascular mechanical activity;

(ii) an acquisition module for receiving information from said at least two sensors over multiple cardiac cycles; and

(iii) at least one module selected from communication module and data-storage (memory) module for transferring said information to an external processing module wherein said processing module is adapted to determine at least two parameter values of cardiovascular activity registered by at least two said sensors containing accelerometers.

34. A device as set forth in claim 27, which is adapted for incorporation into a patch for attachment on the skin surface of an individual'"'"'s torso.

35. A device as set forth in claim 34, said device further adapted to have an adhesive substance on its cover to provide good attachment to the skin surface.

36. A device as set forth in claim 27, which is adapted for incorporation into at least one portable unit selected from:

a Holter ECG monitor, body-surface patch, bag, pack, wristband, belt, vest, t-shirt, necklace, headband, armchair, car seat, bed, and mattress.