Biomedical subjects

Michael Rozenbaum

Publications and source records attributed to Michael Rozenbaum.

21 records · Page 2Linked to original sources

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↗

PubMed2002

Cardiovascular autonomic dysfunction in familial Mediterranean fever.

OBJECTIVE: To compare the hemodynamic responses to autonomic challenge evoked by upright tilt table testing in patients with familial Mediterranean fever (FMF). METHODS: Forty consecutive patients with FMF and 25 age and sex matched healthy controls were evaluated using the head-up tilt test (HUTT). The main outcome measures were the values of blood pressure (BP) and heart rate (HR) recorded during recumbence and tilt. The endpoints of vasodepressor and cardioinhibitory reactions, orthostatic tachycardia, and postural tachycardia syndrome were recorded. RESULTS: Patients with FMF exhibited significantly higher diastolic BP during supine and tilt measurements (p = 0.003 and 0.04, respectively). In response to tilt, patients showed significant increases in HR compared to healthy subjects (p = 0.02). Pathological endpoints on tilt were observed in the FMF group in 7 patients (17%) and in no controls. FMF severity, genotype, duration of illness, response to therapy, and associated amyloidosis did not correlate with pathological reactions on HUTT. CONCLUSION: FMF patients exhibit an abnormal cardiovascular reactivity, which is clinically occult, but can be detected on autonomic challenge. The abnormal autonomic activity in FMF is similar to dysautonomia described in a variety of rheumatic disorders.

Adolescent↗