title: Blood pressure and heart rate in young thalassemia major patients.
abstract: The analysis of blood pressure (BP) and heart rate (HR) variability is currently used to investigate the mechanisms responsible for cardiovascular control; therefore, we assessed whether an impairment of 24-h BP and HR profiles and sympathovagal interaction modulating cardiovascular function was present in patients with thalassemia major (TM) in preclinical phase of heart disease. Nine beta-thalassemic patients 18 years old without clinical signs of cardiac failure and 9 age- and sex-matched controls were studied. Twenty-four-hour-ambulatory BP and HR were measured using the SpaceLabs 90207 device. A truncated Fourier series with four harmonics was used to describe the diurnal blood pressure profile. Mean 24-h ambulatory systolic BP, diastolic BP, and mean arterial pressure were significantly lower in TM patients than in normal subjects (P < .05). A significantly higher nighttime HR value was found in TM patients (P < .05). More than 40% of the TM patients did not show a significant diurnal BP and HR rhythm. In TM patients, the overall amplitude of systolic BP, diastolic BP, and HR was significantly lower than in controls (P < .01). The night/day differences of systolic BP, diastolic BP, and HR were significantly lower in TM patients than in normals (P < .01). Furthermore, we performed power spectral analysis on short-term continuous finger BP and HR data in supine position and during passive head-up tilt. Total spectral power of systolic BP was significantly lower in patients than controls (P < .05). Low-frequency (LF) power of systolic BP and diastolic BP and LF/high-frequency (HF) ratio of HR were significantly lower during tilt in TM patients compared to controls (P < .05). High-frequency power of HR was significantly higher in patients than controls (P < .05). The baroreflex gain assessed by alpha-index was the same in supine position but was higher in TM patients during passive tilt (P < .05). An inverse relationship between LF/HF ratio of HR and hemoglobin levels in TM patients was found. Finally, plasma norepinephrine levels were significantly lower in thalassemics (P < .005). In young TM patients in a preclinical stage of heart disease, these findings demonstrated abnormal 24-h BP and HR rhythms and a decreased short-term variability of BP and HR, in particular in the LF range, showing a diminished sympathetic activity.
authors.affiliation: Department of Medicine and Experimental Oncology, University of Turin, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Veglio
authors.forename: R
authors.initials: R
authors.lastname: Melchio
authors.forename: F
authors.initials: F
authors.lastname: Rabbia
authors.forename: P
authors.initials: P
authors.lastname: Molino
authors.forename: G C
authors.initials: GC
authors.lastname: Genova
authors.forename: G
authors.initials: G
authors.lastname: Martini
authors.forename: D
authors.initials: D
authors.lastname: Schiavone
authors.forename: A
authors.initials: A
authors.lastname: Piga
authors.forename: L
authors.initials: L
authors.lastname: Chiandussi
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology*; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D003971:Diastole; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006728:Hormones / Q000097:blood; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic; D013599:Systole; D013997:Time Factors; D017086:beta-Thalassemia / Q000097:blood / Q000503:physiopathology*
chemical_list: D006728:Hormones