TY - JOUR
T1 - Impaired baroreflex sensitivity and sympathovagal balance in syndrome X
AU - Adamopoulos, Stamatis
AU - Rosano, Giuseppe M C
AU - Ponikowski, Piotr
AU - Cerquetani, Elena
AU - Piepoli, Massimo
AU - Panagiota, Flevari
AU - Collins, Peter
AU - Poole-Wilson, Philip
AU - Kremastinos, Dimitrios
AU - Coats, Andrew J S
PY - 1998/10/1
Y1 - 1998/10/1
N2 - Alterations of autonomic nervous control of cardiac function have been described in syndrome X. The characteristics, however, of the autonomic control of the cardiovascular system in patients with syndrome X have not been adequately studied; thus, the aim of the present study was to investigate the role of baroreceptor sensitivity and sympathovagal balance in syndrome X. The study group included 12 patients with syndrome X, 12 age- and sex-matched control patients with coronary artery disease, and 12 age- and sex-matched controls with no evidence of heart disease. Baroreceptor sensitivity was evaluated by calculating the regression line relating phenylephrine-induced increases in systolic blood pressure to the attendant changes in the RR interval. Sympathovagal balance was assessed by using heart rate variability in the time and frequency domain and measuring plasma norepinephrine at rest and during incremental bicycle exercise. Baroreceptor sensitivity was significantly reduced in syndrome X compared with that in control normal subjects (7.4 ± 1.2 vs 16.8 ± 2.3 ms/mm Hg; p 50 ms, lower root-mean-square of the difference of adjacent RR intervals, and lower logarithmic value of the high-frequency component in patients with syndrome X compared with normal subjects. A nonsignificant trend toward lower baroreceptor sensitivity was found in patients with syndrome X compared with control ischemic patients (7.4 ± 2 vs 12.2 ± 1.3 ms/mm Hg). A nonsignificant trend toward a higher value of the low- to high-frequency ratio was also observed in patients with syndrome X than in both control groups. No difference was detected in norepinephrine levels either at rest or during exercise or in the exercise-induced norepinephrine increase between the 3 groups. No difference was also observed between ischemic patients and normal subjects in either baroreceptor sensitivity or heart rate variability measurements. A significant correlation (r = 0.80, p
AB - Alterations of autonomic nervous control of cardiac function have been described in syndrome X. The characteristics, however, of the autonomic control of the cardiovascular system in patients with syndrome X have not been adequately studied; thus, the aim of the present study was to investigate the role of baroreceptor sensitivity and sympathovagal balance in syndrome X. The study group included 12 patients with syndrome X, 12 age- and sex-matched control patients with coronary artery disease, and 12 age- and sex-matched controls with no evidence of heart disease. Baroreceptor sensitivity was evaluated by calculating the regression line relating phenylephrine-induced increases in systolic blood pressure to the attendant changes in the RR interval. Sympathovagal balance was assessed by using heart rate variability in the time and frequency domain and measuring plasma norepinephrine at rest and during incremental bicycle exercise. Baroreceptor sensitivity was significantly reduced in syndrome X compared with that in control normal subjects (7.4 ± 1.2 vs 16.8 ± 2.3 ms/mm Hg; p 50 ms, lower root-mean-square of the difference of adjacent RR intervals, and lower logarithmic value of the high-frequency component in patients with syndrome X compared with normal subjects. A nonsignificant trend toward lower baroreceptor sensitivity was found in patients with syndrome X compared with control ischemic patients (7.4 ± 2 vs 12.2 ± 1.3 ms/mm Hg). A nonsignificant trend toward a higher value of the low- to high-frequency ratio was also observed in patients with syndrome X than in both control groups. No difference was detected in norepinephrine levels either at rest or during exercise or in the exercise-induced norepinephrine increase between the 3 groups. No difference was also observed between ischemic patients and normal subjects in either baroreceptor sensitivity or heart rate variability measurements. A significant correlation (r = 0.80, p
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U2 - 10.1016/S0002-9149(98)00493-7
DO - 10.1016/S0002-9149(98)00493-7
M3 - Article
C2 - 9781968
AN - SCOPUS:0032189259
VL - 82
SP - 862
EP - 868
JO - American Journal of Cardiology
JF - American Journal of Cardiology
SN - 0002-9149
IS - 7
ER -