Multistructure index characterization of heart rate and systolic blood pressure reveals precursory signs of syncope

Abstract

Recurrent syncope — abrupt loss of consciousness — can have a serious impact on patients’ quality of life, comparable with chronic illnesses. Vasovagal syncope (VVS) is a specific reflex syncope, in which an inappropriate reaction of the autonomic nervous system (ANS) plays a key role in the pathophysiology. In syncope diagnosis, an ideal diagnostic method should positively identify vasovagal sensitive patients, without the need to perform a specialised head-up tilt table (HUTT) test. We apply a novel methodology of multistructure index (MI) statistics for seamlessly evaluating the size spectrum of the asymmetry properties of magnitudes of neural reflexes responsible for maintaining the homeostatic dynamics of autonomic control. Simultaneous evaluation using the MI of the effects on heart rate and blood pressure involved in achieving homeostasis of contrasting properties of the dynamics of slow and fast neural regulation reveals a clear distinction between vasovagal patients and healthy subjects, who are/are not susceptible to spontaneous fainting. Remarkably, a healthy cardiovascular response to the HUTT test is indeed evident prior to the test, making the MI a robust novel indicator, clearly distinguishing the cardiovascular autonomic regulation of healthy people from that of vasovagal patients without the need to perform an actual HUTT test.

Development and evaluation of a novel system for inducing orthostatic challenge by tilt tests and lower body negative pressure

“…The latest literature reports show that the analysis of basic physiological parameters, e.g. heart rhythm and blood pressure, enables for predicting orthostatic hypotension 21 and reveals precursory signs of syncope 22 . Our intention was to verify, in relation to specialist literature, the behaviour of a group of cadets experiencing accelerations on a regular basis who were subjected to tests in a device of a novel design.…”

An assessment of heart rate and blood pressure asymmetry in the diagnosis of vasovagal syncope in females

“…The multistructure index (a generalization of asymmetry indices) derived by Makowiec et al (2017) gives promising perspectives of HRA and BPA estimations as a diagnostic tool in vasovagal syndrome; TABLE 5 Asymmetry proportion comparisons in the analyzed biosignals: the asymmetry occurrence between supine (S1), the initial part of tilt (T1), and the pre-syncope phase of tilt (T2) in the head-up tilt test in vasovagal patients obtained by Porta's Index (PI > 50) and Guzik's Index (GI > 50 and GI S < 50).…”

“…Recent studies show promising results in diagnosing VVS using various HRA methods—the multistructure index (generalization of HRA indices) and the deceleration capacity (obtained from phase-rectified signal averaging) may serve as good discriminators of VVS ( Makowiec et al, 2017 ; Zheng et al, 2020 ). We decided to further explore the physiology of VVS by analyzing HRV, BPV, and their asymmetries in order to better understand what is happening in people who are more sensitive to orthostatic stress.…”

Autonomic Neuropathy and Cardiovascular Disease in Aging

“…Head-up tilt test is the widely used test to evaluate a patient for vasovagal syncope (94). According to the American College of Cardiology/American Heart Association guidelines published on 2017 for treatment of vasovagal syncope in patients with prolonged prodromal period, patient's education to practice physical counter-maneuvers such as limb and/or abdominal contraction, squatting, or leg crossing could be significantly effective (95).…”