Biomedical subjects

Shaul Naschitz

Publications and source records attributed to Shaul Naschitz.

3 recordsLinked to original sources

PubMed2005

Search for disease-specific cardiovascular reactivity patterns: developing the methodology.

Aberrations of CVR (cardiovascular reactivity), an expression of autonomic function, lack specificity for a particular disorder. Recently, a CVR pattern particular to chronic fatigue syndrome has been observed. In the present study, we aimed to develop methodologies for assessing disease-specific CVR patterns. As a prototype, a population of 50 consecutive patients with FMF (familial Mediterranean fever) was studied and compared with control populations. A 10 min supine/30 min head-up tilt test with recording of the heart rate and blood pressure or the pulse transit time was performed. Five studies were conducted applying different methods. In each study, statistical analysis identified independent predictors of CVR in FMF. Based on regression coefficients of these predictors, a linear DS (discriminant score) was computed for every subject. Each study established an equation to assess CVR, calculate DS for FMF and determine the sensitivity and specificity of the DS cut-off. In each of the five studies, abnormal CVR was observed in FMF patients. The best accuracy (88% sensitivity and 90.1% specificity for FMF) was obtained by a method based on beat-to-beat heart rate and pulse transit time recordings. Data was processed by fractal and recurrence quantitative analysis with recordings in FMF patients compared with a mixed control population. Identification of disease-specific CVR patterns was possible with the methodologies described in the present study. In FMF, disease-specific CVR may be explained by the interplay between neuroendocrine loops specific to FMF with cardiovascular homoeostatic mechanisms. Recognition of disease-specific CVR patterns may advance the understanding of homoeostatic mechanisms and have implications in clinical practice.

Adult↗

PubMed2002

Fractal analysis and recurrence quantification analysis of heart rate and pulse transit time for diagnosing chronic fatigue syndrome.

This study aimed to develop a method to distinguish between the cardiovascular reactivity in chronic fatigue syndrome (CFS) and other patient populations. Patients with CFS (n = 23), familial Mediterranean fever (n = 15), psoriatic arthritis (n = 10), generalized anxiety disorder (n = 12), neurally mediated syncope (n = 20), and healthy subjects (n = 20) were evaluated with a shortened head-up tilt test (HUTT). A 10-minute supine phase of the HUTT was followed by recording 600 cardiac cycles on tilt, i. e., 5 to 10 minutes. Beat-to-beat heart rate (HR) and pulse transit time (PTT) were acquisitioned. Data were processed by recurrence plot and fractal analysis. Fifty-two variables were calculated in each subject. On multivariate analysis, the best predictors of CFS were HR-tilt-R/L, PTT-tilt-R/L, HR-supine-DET, PTT-tilt-WAVE, and HR-tilt-SD. Based on these predictors, the 'Fractal & Recurrence Analysis-based Score' (FRAS) was calculated: FRAS = 76.2 + 0.04*HR-supine-DET - 12.9*HR-tilt-R/L - 0.31*HR-tilt-SD - 19.27*PTT-tilt-R/L - 9.42* PTT-tilt-WAVE. The best cut-off differentiating CFS from the control population was FRAS = + 0.22. FRAS > + 0.22 was associated with CFS (sensitivity 70 % and specificity 88 %). The cardiovascular reactivity received mathematical expression with the aid of the FRAS. The shortened HUTT was well tolerated. The FRAS provides objective criteria which could become valuable in the assessment of CFS.

Anxiety Disorders↗

PubMed2002

Hemodynamics instability score in chronic fatigue syndrome and in non-chronic fatigue syndrome.

OBJECTIVE: In studying patients with chronic fatigue syndrome (CFS) we developed a method that confers numerical expression to the degree of blood pressure and heart rate lability, ie, the 'hemodynamic instability score' (HIS). The HIS in CFS patients differed significantly from healthy subjects. The present investigation compares the HIS in CFS, non-CFS chronic fatigue and patients with recurrent syncope. METHODS: Patients with CFS (n = 21), non-CFS chronic fatigue (n = 24), syncope of unknown cause (n = 44), and their age and sex-matched healthy controls (n = 21) were evaluated with a standardized head-up tilt test (HUTT). Abnormal reactions (endpoints) on HUTT were classified 'clinical outcomes' (cardioinhibitory or vasodepressor reaction, orthostatic hypotension, postural tachycardia syndrome) and 'HIS endpoint', i.e. HIS >-0.98. RESULTS: The highest incidence of endpoints was noted in patients with CFS (79%), followed by patients with syncope of unknown cause (46%), non-CFS chronic fatigue (35%), and healthy subjects (14%). Presyncope or syncope during tilt occurred in 38% of CFS patients, 21% of patients with non-CFS chronic fatigue, and 43% of patients with recurrent syncope. The average HIS values were: CFS = +2.02 (SD 4.07), non-CFS chronic fatigue = -2.89 (SD 3.64), syncope = -3.2 (SD 3.0), healthy = -2.48 (4.07). The odds ratios for CFS patients to have HIS >-0.98 was 8.8 compared with non-CFS chronic fatigue patients, 14.6 compared with recurrent syncope patients, and 34.8 compared with healthy subjects. CONCLUSION: The cardiovascular reactivity in patients with CFS has certain features in common with the reactivity in patients with recurrent syncope or non-CFS chronic fatigue, such as the frequent occurrence of vasodepressor reaction, cardioinhibitory reaction, and postural tachycardia syndrome. Apart from to these shared responses, the large majority of CFS patients exhibit a particular abnormality which is characterized by HIS values >-0.98. Thus, HIS >-0.98 lends objective criteria to the assessment of CFS.

Adult↗