Methods of observing autonomic neural stimulation and diagnosing cardiac dynamical dysfunction using heartbeat interval data to analyze cardioventilatory interactions
First Claim
1. A method of determining the occurrence of a neural stimulus to a cyclic physiological function which occurs in a subject, comprising the steps of:
- (a) determining the time interval between successive heartbeats of said subject and generating data representative of said time intervals;
(b) determining the phase of said cyclic physiological function over a predetermined interval concurrent with said time interval determination, said interval having a duration of more than one heartbeat, and generating data representative of said phase;
(c) combining said heartbeat interval and physiological phase data as a data set;
(d) processing said data set to identify pronounced variations in said heartbeat interval data within a portion of said cycle of said physiological function;
whereby the presence of said repetitive pronounced variation is indicative of the occurrence of neural stimulus.
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Abstract
Methods of isolating individual neural impulses are disclosed. In a preferred embodiment, methods of observing the response of the heart to autonomic neural control are presented. The present invention is used to observe cardioventilatory phase-locking. The noninvasive technique disclosed are a useful clinical tool for observing phase locking as diagnostic of physiological disorders which result from autonomic neural dysfunction. The methods of observation disclosed also are applicable to the isolation of other neural impulses. An understanding of cardioventilatory interaction is obtained by plotting highly accurate heartbeat-interval (hbi) time series data versus ventilator phase. The data displays created by the methods of the present invention show structure whose features are reproducible over time and across subjects. These structures are attributable to the effect of individual neural impulses from the autonomic nervous system which influence the cardiac pacemaker. The absence of neural function has been correlated to various physiological dysfunctions.
127 Citations
20 Claims
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1. A method of determining the occurrence of a neural stimulus to a cyclic physiological function which occurs in a subject, comprising the steps of:
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(a) determining the time interval between successive heartbeats of said subject and generating data representative of said time intervals; (b) determining the phase of said cyclic physiological function over a predetermined interval concurrent with said time interval determination, said interval having a duration of more than one heartbeat, and generating data representative of said phase; (c) combining said heartbeat interval and physiological phase data as a data set; (d) processing said data set to identify pronounced variations in said heartbeat interval data within a portion of said cycle of said physiological function; whereby the presence of said repetitive pronounced variation is indicative of the occurrence of neural stimulus. - View Dependent Claims (2, 3, 4)
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5. A method of observing cardiac neural stimulus in a subject, comprising the steps of:
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(a) determining the time interval between successive heartbeats of said subject and generating data representative of said time intervals; (b) determining the frequency of a cycle of a physiological function of said subject over a predetermined interval concurrent with said time interval determination, said interval having a duration of more than one heartbeat, and generating data representative of said frequency; (c) combining said heartbeat interval and physiological frequency data as a data set; (d) processing said data set through a band pass filter, wherein said band pass filter is designed to operate at frequencies between about 1/20 and about 1/100 of said physiological cycle to obtain a final data set; (e) collecting a plurality of said final data sets, taken successively in time from said subject; and (f) displaying said plurality of final data sets in a manner to indicate the presence of a repetitive pronounced variation within a particular portion of said physiological cycle. - View Dependent Claims (6)
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7. A method of identifying cardiac neurological dysfunction in a subject, comprising the steps of:
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(a) determining the time interval between successive heartbeats of said subject and generating data representative of said time intervals; (b) determining the frequency of ventilation of said subject over a predetermined interval concurrent with said time interval determination which coincides with a plurality of said heartbeats, and generating data representative of said frequency; (c) combining said heartbeat interval and ventilatory frequency data as a data set; (d) processing said data set to determine the presence or absence of cardioventilatory phase locking; and (e) displaying said data in a manner to indicate the presence or absence of said phase locking, the presence of phase locking being indicative of neural dysfunction. - View Dependent Claims (8, 9, 10)
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11. A method for determining the presence of cardioventilatory phase locking in a subject, comprising the steps of:
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(a) acquiring data representing the respective time intervals between successive heartbeats of said subject; (b) concurrently acquiring data representing the phase of the ventilatory cycle of said subject related to said heartbeat interval data; (c) determining whether said data acquired in steps (a) and (b) are substantially linearly correlated at substantially the same point in the ventilatory cycle of said subject over a discrete period of time; whereby the existence of said substantial linear correlation is indicative of cardioventilatory phase locking. - View Dependent Claims (12)
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13. In a patient having a heart and at least one other organ exhibiting a regularly recurring physiological cycle, apparatus for observing cardiac neural stimulus in the patient comprising:
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(a) means for determining heartbeat data representative of the time interval between successive heartbeats of said patient; (b) means for determining frequency data representative of the frequency of said regularly recurring physiological cycle of said at least one other organ of said patient over a period of time concurrent with said successive heartbeats; and (c) computing means for combining said heartbeat data and said frequency data and for processing said combined data to determine the presence of a repetitive pronounced variation of said regularly recurring physiological cycle and identify the a particular portion of said physiological cycle said pronounced variation occurs. - View Dependent Claims (14)
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15. Apparatus for cardiac and ventilatory monitoring of a patient, comprising:
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(a) means for determining data representative of the time interval between successive heartbeats of said patient; (b) means for determining data representative of the frequency of ventilation of said patient over a period of time including said successive heartbeats; and (c) computing means for combining said heartbeat data and said ventilation data to create a combined data set and means for processing said combined data set to determine the presence and/or absence of cardioventilatory phase locking. - View Dependent Claims (16)
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17. A method of analyzing data collected from rhythmic systems, comprising the steps of:
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(a) collecting first data representative of a first non-periodic rhythmic activity; (b) collecting second data representative of a second rhythmic activity concurrently with said first data;
said second activity having an interrelationship with said first activity;(c) processing said first and second data to relate said first activity to the phase of said second activity; and (d) determining the existence of ordered data structures indicative of the interrelationship between said first and second activities. - View Dependent Claims (18, 19, 20)
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Specification