Isabelle Magalhães Guedes Freitas1, Leonardo Barbosa de Almeida2, Natália Portela Pereira2, Pedro Augusto de Carvalho Mira2, Rogério Baumgratz de Paula3, Daniel Godoy Martinez2, Edgar Toschi-Dias4, Mateus Camaroti Laterza2. 1. Cardiovascular Research Unit and Exercise Physiology, University Hospital and Faculty of Physical Education and Sports, Federal University of Juiz de Fora University Campus, Juiz de Fora, MG, Brazil. isabelleguedes@yahoo.com.br. 2. Cardiovascular Research Unit and Exercise Physiology, University Hospital and Faculty of Physical Education and Sports, Federal University of Juiz de Fora University Campus, Juiz de Fora, MG, Brazil. 3. Interdisciplinary Center for Studies, Research and Treatment in Nephrology (NIEPEN), Federal University of Juiz de Fora, Juiz de Fora, MG, Brazil. 4. Heart Institute (Instituto do Coração), University of São Paulo Medical School, São Paulo, SP, Brazil.
Abstract
PURPOSE: The aim of this study was to determine the gain and latency of arterial baroreflex control of heart rate in patients with resistant hypertension compared to patients with essential hypertension and normotensive subjects. METHODS: Eighteen patients with resistant hypertension (56 ± 10 years, mean of four antihypertensive drugs), 17 patients with essential hypertension (56 ± 11 years, mean of two antihypertensive drugs), and 17 untreated normotensive controls (50 ± 15 years) were evaluated by spectral analysis of the spontaneous fluctuations of arterial pressure (beat-to-beat) and heart rate (ECG). This analysis estimated vasomotor and cardiac autonomic modulations, respectively. The transfer function analysis quantified the gain and latency of the response of output signal (RR interval) per unit of spontaneous change of input signal (systolic arterial pressure). RESULTS: The gain was similarly lower in patients with resistant hypertension and patients with essential hypertension in relation to normotensive subjects (4.67 ± 2.96 vs. 6.60 ± 3.30 vs. 12.56 ± 8.81 ms/mmHg; P < 0.01, respectively). However, the latency of arterial baroreflex control of heart rate was significantly higher only in patients with resistant hypertension when compared to patients with essential hypertension and normotensive subjects (-4.01 ± 3.19 vs. -2.91 ± 2.10 vs. -1.82 ± 1.09 s; P = 0.04, respectively). In addition, the index of vasomotor sympathetic modulation was significantly increased only in patients with resistant hypertension when compared to patients with essential hypertension and normotensive subjects (4.04 ± 2.86 vs. 2.65 ± 1.88 vs. 2.06 ± 1.70 mmHg2; P < 0.01, respectively). CONCLUSIONS: Patients with resistant hypertension have reduced gain and increased latency of arterial baroreflex control of heart rate. These patients also have increased vasomotor sympathetic modulation.
PURPOSE: The aim of this study was to determine the gain and latency of arterial baroreflex control of heart rate in patients with resistant hypertension compared to patients with essential hypertension and normotensive subjects. METHODS: Eighteen patients with resistant hypertension (56 ± 10 years, mean of four antihypertensive drugs), 17 patients with essential hypertension (56 ± 11 years, mean of two antihypertensive drugs), and 17 untreated normotensive controls (50 ± 15 years) were evaluated by spectral analysis of the spontaneous fluctuations of arterial pressure (beat-to-beat) and heart rate (ECG). This analysis estimated vasomotor and cardiac autonomic modulations, respectively. The transfer function analysis quantified the gain and latency of the response of output signal (RR interval) per unit of spontaneous change of input signal (systolic arterial pressure). RESULTS: The gain was similarly lower in patients with resistant hypertension and patients with essential hypertension in relation to normotensive subjects (4.67 ± 2.96 vs. 6.60 ± 3.30 vs. 12.56 ± 8.81 ms/mmHg; P < 0.01, respectively). However, the latency of arterial baroreflex control of heart rate was significantly higher only in patients with resistant hypertension when compared to patients with essential hypertension and normotensive subjects (-4.01 ± 3.19 vs. -2.91 ± 2.10 vs. -1.82 ± 1.09 s; P = 0.04, respectively). In addition, the index of vasomotor sympathetic modulation was significantly increased only in patients with resistant hypertension when compared to patients with essential hypertension and normotensive subjects (4.04 ± 2.86 vs. 2.65 ± 1.88 vs. 2.06 ± 1.70 mmHg2; P < 0.01, respectively). CONCLUSIONS:Patients with resistant hypertension have reduced gain and increased latency of arterial baroreflex control of heart rate. These patients also have increased vasomotor sympathetic modulation.
Entities:
Keywords:
Heart rate variability; Hypertension; Latency of baroreflex control
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