Ambulatory ventricular function monitor

• US 4,633,881 A
• Filed: 07/01/1982
• Issued: 01/06/1987
• Est. Priority Date: 07/01/1982
• Status: Expired due to Term

• Current Assignee: General Hospital Corporation The Boston MA
• Original Assignee: The General Hospital Corporation (Mass General Brigham, Inc.)
• Inventors: Alpert, Nathaniel M., Moore, Richard H., Strauss, H. William
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/394,465
• Time in Patent Office: 1,650 Days
• Field of Search: 128/653, 128/654, 128/659, 128/644, 128/708
• US Class Current: 600/436
• CPC Class Codes: A61B 5/02755 Radioactive tracers
• CPC Class Codes: A61B 5/6805 Vests
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G01T 1/161 Applications in the field of nuclear medicine, e.g. in vivo counting apparatus for radiation diagnosis A61B6/00
• CPC Class Codes: G01T 1/20183 Arrangements for preventing or correcting crosstalk, e.g. optical or electrical arrangements for correcting crosstalk
• CPC Class Codes: G01T 1/2019 Shielding against direct hits

Abstract

An ambulatory ventricular function anaylzer system is provided. The ambulatory ventricular function analyzer system is carried by a garment worn by a cardiac patient and includes ECG electrodes, a main left ventricular probe detector, and a background lung probe detector for providing diagnostically useful information while the patient goes about the normal activities of daily life. An information processing sub-system including a microprocessor responds to the electrode signal and to the probe signals and provides composite data representative of the ECG activity, the background lung time-activity, the left ventricular time-activity, and an R-wave histogram averaged over multiple cardiac cycles. The averaged data is sequentially sotred over a long time interval on magnetic tape in plural categories representing premature ventricular contraction, postpremature ventricular contraction, and normal ventricular contraction for subsequent display on a computer-based graphics display for study by a cardiac specialist. The main left ventricular function probe detector includes an array of cadmium telluride crystals mounted in a Pb housing having a parallel hole Pb collimator. The detector is substantially insensitive to position changes that arise during ambulatory monitoring.

Claims

1. An ambulatory ventricular function recorder, comprising:

a vest garment including means for removably supporting it about the human body;

nuclear radiation detection first means, connected to and wholly supported in a body ambulatory manner by said garment, and adapted to respond to nuclear radiation from the region of the ventricle for repetitively providing an analog signal the amplitude of which cyclically represents the nuclear ventricular time-activity of the heart;

second means, wholly suported in a body ambulatory manner by said garment and responsive to said analog signal, for repetitively providing a digital representation of said analog signal;

third means, wholly supported in a body ambulatory manner by said garment and responsive to said digital representation, for accumulating said digital representation in storage so as to repetitively provide composite data that represents an average of said repetitively provided digital representation over successive time intervals that each correspond to a predetermined plurality of heart beats; and

said third means including means for accumulating said digital representation in categories corresponding to premature, normal and post-premature ventricular contraction.

2. An ambulatory ventricular function recorder according to claim 1, wherein said removable supporting means of said garment includes means for removably supporting it about the torso of the human body.

3. An ambulatory ventricular function recorder according to claim 1, wherein said first means includes a main nuclear probe detector;

and further including a separate background nuclear probe detector connected to said garment for providing a signal representing the nuclear time-activity of a preselected lung.

4. An ambulatory ventricular function recorder according to claim 3, wherein said main nuclear probe includes a housing having a mouth, a collimator positioned in said mouth, and a planar array of gamma photon radiation-sensitive crystals positioned in said housing and behind said collimator.

5. An ambulatory ventricular function recorder according to claim 4, wherein said housing and said collimator are made of lead, said lead collimator is provided with a plurality of parallel holes therethrough, and said crystals are CdTe radiation-sensitive detectors.

6. An ambulatory ventricular function recorder according to claim 4, further including a summer discriminator amplifier including a comparator having a preselected threshold responsive to the output signals of said radiation-sensitive crystals and operative to sum those output signals that exceed said preselected threshold to provide said analog signal.

7. An ambulatory ventricular function monitor according to claim 1, wherein said second means includes an analog-to-digital converter responsive to said analog signal and operative to provide a first digital pulse stream the frequency of which depends upon the magnitude of said analog signal, and said third means includes a microprocessor and associated memories responsive to said first digital pulse stream and operative to provide said data averaged over a plurality of cardiac cycles.

8. An ambulatory ventricular function monitor according to claim 7, wherein said microprocessor is operative for successive data collection intervals of said averaging time interval to sample said first pulse stream, to count the number of pulses which occur during respective sampling intervals of each data collection interval, and to accumulate the counts for successive sampling intervals in memory the address location of which depends on the phase of the particular sampling interval relative to the data collection interval.

9. An ambulatory ventriclar function monitor according to claim 8, further including fourth means coupled to said third means for separating said averaged data in plural categories representing PVC, NVC, and PPVC.

10. An ambulatory ventricular function monitor according to claim 9, wherein said fourth means includes separately addressable accumulating registers respectively dedicated to PVC, NVC, and PPVC.

11. An ambulatory ventricular function monitor according to claim 10, wherein said fourth means further include means for providing an electrocardiographic analog signal, an analog-to-digital converter responsive to said electrocardiographic analog signal and operative to provide a second digital pulse stream the frequency of which depends upon the magnitude of said analog electrocardiographic signal, and wherein said microprocessor is responsive to said first and said second digital pulse streams and operative to provide said averaged data in said separately addressable accumulating registers respectively dedicated to PVC, NVC, and PPVC.

12. An ambulatory ventricular function monitor according to claim 11, wherein said averaging time interval is two minutes.

13. An ambulatory ventricular function monitor according to claim 11, wherein said averaging time interval is sixteen minutes.

14. An ambulatory ventricular function monitor according to claim 1 or 11, further including a programmable oscilloscope operative to read and display said data and calculate and display selected cardiac ventricular parameters.

15. An ambulatory ventricular function monitor according to claim 1, wherein said third means includes a magnetic tape.

16. An ambulatory ventricular function monitor according to claim 1, wherein said third means includes a tiny disc.

17. An ambulatory ventricular function monitor according to claim 1, whereinsaid third means includes a bubble memory device.

18. A small, lightweight, and rugged nuclear probe detector assembly and ambulatory ventricular function monitor responsive thereto, comprising:

a vest garment including means for removably supporting it about the human body;

nuclear radiation detection first means, connected to and wholly supported in a body ambulatory manner by said garment, and adapted to respond to nuclear radiation from the region of the ventricle for repetitively providing an analog signal the amplitude of which cyclically represents the nuclear ventricular time-activity of the heart;

second means, wholly supported in a body ambulatory manner by said garment and responsive to said analog signal, for repetitively providing a digital representation of said analog signal;

third means, wholly supported in a body ambulatory manner by said garment and responsive to said digital representation, for accumulating said digital representation in storage so as to repetitively provide composite data that represents an average of said repetitively provided digital representation over successive time intervals that each correspond to a predetermined plurality of heartbeats;

said third means including means for accumulating said digital representation in categories corresponding to premature, normal and post-premature ventricular contraction;

said nuclear radiation detection first means including;

a radiation shield defining an enclosure having a mouth;

a plurality of gamma photon radiation-sensitive detectors arranged in a plane and mounted in said enclosure interiorly of said mouth; and

a collimator provided with an aperture pattern mounted to said mouth of said radiation shield extends over all of said plurality of gamma photon radiation-sensitive detectors.

19. A small, lightweight, and rugged nuclear probe detector assembly according to claim 18, wherein said collimator and said shield are made of lead.

20. A small, lightweight, and rugged nuclear probe detector assembly according to claim 19, wherein said lead collimator pattern includes a plurality of parallel hole apertures.

21. A small, lightweight, and rugged nuclear probe detector assembly according to claim 18, wherein said gamma photon radiation-sensitive detectors are CdTe crystals.

22. A small, lightweight, and rugged nuclear probe detector assembly according to claim 18, wherein said gamma photon radiation-sensitive detectors are germanium.

23. A small, lightweight, and rugged nuclear probe detector assembly according to claim 18, wherein said gamma photon radiation-sensitive detectors are sodium iodide crystals having an avalanche photodiode readout.

24. A small, lightweight, and rugged nuclear probe detector assembly according to claim 18, wherein said gamma photon radiation-sensitive detectors are plastic scintillation detectors having an avalanche photodiode readout.

25. A small, lightweight, and rugged nuclear probe detector assembly according to claim 18, wherein said gamma photon radiation-sensitive detectors are mercury cadmium telluride crystals.

26. A small, lightweight, and rugged nuclear probe detector assembly according to claim 18, wherein said gamma photon radiation-sensitive detectors are bismuth germanate crystals having an avalanche photodiode readout.