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1.
Braz J Med Biol Res ; 41(10): 849-53, 2008 Oct.
Article in English | MEDLINE | ID: mdl-19037531

ABSTRACT

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 +/- 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 +/- 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 +/- 10/81 +/- 5 mmHg) compared with ONT (99 +/- 13/67 +/- 5 mmHg). The increase in blood pressure was greater in OMH (Delta SBP = 17 +/- 2 vs Delta SBP = 9 +/- 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (Delta HR = 13 +/- 2 vs Delta HR = 20 +/- 3 bpm in ONT) during isometric exercise(handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 +/- 6 vs 11 +/- 4 burst/min in ONT) and exhibited a greater increase (Delta = 18 +/- 10 vs Delta = 8 +/- 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT.


Subject(s)
Exercise/physiology , Hypertension, Malignant/physiopathology , Stress, Physiological/physiology , Sympathetic Nervous System/physiopathology , Adult , Case-Control Studies , Female , Heart Rate/physiology , Humans , Hypertension, Malignant/blood , Hypertension, Malignant/genetics , Male , Parents
2.
Braz. j. med. biol. res ; 41(10): 849-853, Oct. 2008. graf, tab
Article in English | LILACS | ID: lil-496801

ABSTRACT

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 ± 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 ± 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 ± 10/81 ± 5 mmHg) compared with ONT (99 ± 13/67 ± 5 mmHg). The increase in blood pressure was greater in OMH (Ä SBP = 17 ± 2 vs Ä SBP = 9 ± 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (Ä HR = 13 ± 2 vs Ä HR = 20 ± 3 bpm in ONT) during isometric exercise (handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 ± 6 vs 11 ± 4 burst/min in ONT) and exhibited a greater increase (Ä = 18 ± 10 vs Ä = 8 ± 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT.


Subject(s)
Adult , Female , Humans , Male , Exercise/physiology , Hypertension, Malignant/physiopathology , Stress, Physiological/physiology , Sympathetic Nervous System/physiopathology , Case-Control Studies , Heart Rate/physiology , Hypertension, Malignant/blood , Hypertension, Malignant/genetics , Parents
3.
J Hum Hypertens ; 20(7): 523-8, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16543905

ABSTRACT

Obstructive sleep apnea (OSA) causes secondary hypertension. However, the reasons why the prevalence of hypertension among OSA patients varies widely (35-70%) are not clear. We sought to investigate the phenotypic characteristics of patients with and without hypertension among OSA patients who were matched for disease severity. We studied 152 OSA patients (76 normotensive and 76 hypertensive) diagnosed by polysomnography. Detailed phenotypic characteristics, including laboratorial analysis, were determined in all patients. Univariate analysis followed by multiple logistic regression analysis was used to identify variables that were independently associated with hypertension. The apnea-hypopnea index in normotensive and hypertensive patients was similar (48+/-26 and 48+/-26 events/h, respectively) as well as minimum arterial oxygen saturation (76+/-10 and 75+/-10%, respectively) and total sleep time with oxyhaemoglobin saturation <90% (25+/-25 and 28+/-26%, respectively). Hypertensive patients were older (57+/-11 vs 47+/-12 years; P<0.001), had a higher body mass index (BMI; 34+/-7 vs 30+/-5 kg/m(2); P<0.001), had a higher frequency of women (37 vs 8%; P<0.001), had a higher incidence of diabetes (25 vs 6%; P=0.002) and a higher family history of hypertension (75 vs 42%; P=0.01) than did the normotensive patients. Multiple logistic regression analysis indicated that age (P=0.004), familial history of hypertension (P=0.004), BMI (P=0.04) and female sex (P=0.03) were the independent variables associated with hypertension. We concluded that increasing age and BMI, familial history of hypertension as well as female gender are phenotypic characteristics associated with hypertension among OSA patients with similar disease severity.


Subject(s)
Hypertension/pathology , Sleep Apnea, Obstructive/pathology , Adult , Age Factors , Aged , Analysis of Variance , Body Mass Index , Female , Humans , Hypertension/blood , Hypertension/complications , Lipids/blood , Male , Middle Aged , Polysomnography/methods , Regression Analysis , Sleep Apnea, Obstructive/blood , Sleep Apnea, Obstructive/complications
4.
Circulation ; 104(15): 1792-8, 2001 Oct 09.
Article in English | MEDLINE | ID: mdl-11591616

ABSTRACT

BACKGROUND: The peripheral and central chemoreflexes are important autonomic mechanisms for regulating breathing and cardiovascular function. Although pathological inflammatory infiltration of the peripheral chemoreceptors and central nervous system has been reported in Chagas' disease, functional evaluation of chemoreflexes has not yet been performed. METHODS AND RESULTS: The hypothesis that chemoreflex function is altered in patients with Chagas' heart disease (CH) but normal left ventricle function was tested in 12 CH patients and 13 matched control subjects. The ventilatory rate, minute ventilation, heart rate, mean arterial pressure, forearm blood flow, forearm vascular resistance, and venous norepi-nephrine responses to hypoxia and hypercapnia were determined. During hypoxia, the decrease in oxygen saturation was smaller in CH patients, despite a similar ventilatory response between groups. Both groups showed an increase in heart rate during hypoxia, but this response was blunted in CH patients. Although the mean arterial pressure response to hypoxia was similar in both groups, forearm vascular resistance significantly decreased in control subjects while remaining unchanged in CH patients. Moreover, a significant increase in plasma norepinephrine levels elicited by stimulation of peripheral chemoreceptors was observed only in the CH group. During hypercapnia, the increase in minute ventilation was smaller in CH patients, who did not exhibit the increase in norepinephrine observed in control subjects. CONCLUSIONS: These data suggest that CH potentiates respiratory, cardiovascular, and autonomic responses to peripheral chemoreceptor activation by hypoxia in patients with normal left ventricular function. The ventilatory and sympathetic responses to central chemoreceptor activation by hypercapnia, however, are significantly blunted.


Subject(s)
Autonomic Nervous System Diseases/physiopathology , Chagas Cardiomyopathy/physiopathology , Chemoreceptor Cells/physiopathology , Peripheral Nervous System Diseases/physiopathology , Reflex, Abnormal , Adult , Autonomic Nervous System Diseases/complications , Autonomic Nervous System Diseases/diagnosis , Blood Flow Velocity , Blood Pressure , Capnography , Chagas Cardiomyopathy/complications , Female , Forearm/blood supply , Forearm/physiopathology , Heart Rate , Humans , Hypercapnia/physiopathology , Hyperoxia , Hypoxia/physiopathology , Male , Middle Aged , Norepinephrine/blood , Oximetry , Peripheral Nervous System Diseases/complications , Peripheral Nervous System Diseases/diagnosis , Pulmonary Ventilation , Vascular Resistance , Ventricular Function, Left
5.
Braz J Med Biol Res ; 33(1): 51-4, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10625874

ABSTRACT

Although a slightly elevated office blood pressure (BP) has been reported in several studies, little is known about the prolonged resting blood pressure, heart rate (HR) and baroreflex sensitivity (BRS) of prehypertensive subjects with a family history of hypertension. Office blood pressure, prolonged resting (1 h) BP and HR were measured in 25 young normotensives with a positive family history of hypertension (FH+) and 25 young normotensives with a negative family history of hypertension (FH-), matched for age, sex, and body mass index. After BP and HR measurements, blood samples were collected for the determination of norepinephrine, plasma renin activity and aldosterone levels, and baroreflex sensitivity was then tested. Casual BP, prolonged resting BP and heart rate were significantly higher in the FH+ group (119.9 +/- 11.7/78.5 +/- 8.6 mmHg, 137.3 +/- 12.3/74.4 +/- 7.9 mmHg, 68.5 +/- 8.4 bpm) compared to the FH- group (112.9 +/- 11.4/71.2 +/- 8.3 mmHg, 128.0 +/- 11. 8/66.5 +/- 7.4 mmHg, 62.1 +/- 6.0 bpm). Plasma norepinephrine level was significantly higher in the FH+ group (220.1 +/- 104.5 pg/ml) than in the FH- group (169.1 +/- 63.3 pg/ml). Baroreflex sensitivity to tachycardia (0.7 +/- 0.3 vs 1.0 +/- 0.5 bpm/mmHg) was depressed in the FH+ group (P<0.05). The FH+ group exhibited higher casual blood pressure, prolonged resting blood pressure, heart rate and plasma norepinephrine levels than the FH- group (P<0.05), suggesting an increased sympathetic tone in these subjects. The reflex tachycardia was depressed in the FH+ group.


Subject(s)
Blood Pressure/physiology , Heart Rate/physiology , Hypertension/genetics , Adolescent , Adult , Aldosterone/blood , Baroreflex , Body Mass Index , Chi-Square Distribution , Female , Humans , Hypertension/physiopathology , Male , Membrane Potentials , Norepinephrine/blood , Renin/blood , Sensitivity and Specificity , Sympathetic Nervous System/physiopathology
6.
Braz. j. med. biol. res ; 33(1): 51-4, Jan. 2000. tab
Article in English | LILACS | ID: lil-252256

ABSTRACT

Although a slightly elevated office blood pressure (BP) has been reported in several studies, little is known about the prolonged resting blood pressure, heart rate (HR) and baroreflex sensitivity (BRS) of prehypertensive subjects with a family history of hypertension. Office blood pressure, prolonged resting (1 h) BP and HR were measured in 25 young normotensives with a positive family history of hypertension (FH+) and 25 young normotensives with a negative family history of hypertension (FH-), matched for age, sex, and body mass index. After BP and HR measurements, blood samples were collected for the determination of norepinephrine, plasma renin activity and aldosterone levels, and baroreflex sensitivity was then tested. Casual BP, prolonged resting BP and heart rate were significantly higher in the FH+ group (119.9 + or - 11.7/78.5 + or - 8.6 mmHg, 137.3 + or - 12.3/74.4 + or - 7.9 mmHg, 68.5 + or - 8.4 bpm) compared to the FH- group (112.9 + or - 11.4/71.2 + or - 8.3 mmHg, 128.0 + or - 11.8/66.5 + or - 7.4 mmHg, 62.1 + or - 6.0 bpm). Plasma norepinephrine level was significantly higher in the FH+ group (220.1 + or - 104.5 pg/ml) than in the FH- group (169.1 + or - 63.3 pg/ml). Baroreflex sensitivity to tachycardia (0.7 + or - 0.3 vs 1.0 + or - 0.5 bpm/mmHg) was depressed in the FH+ group (P<0.05). The FH+ group exhibited higher casual blood pressure, prolonged resting blood pressure, heart rate and plasma norepinephrine levels than the FH- group (P<0.05), suggesting an increased sympathetic tone in these subjects. The reflex tachycardia was depressed in the FH+ group


Subject(s)
Female , Humans , Adult , Adolescent , Baroreflex , Blood Pressure/physiology , Heart Rate/physiology , Hypertension/genetics , Norepinephrine/blood , Sympathetic Nervous System/physiopathology , Aldosterone/blood , Body Mass Index , Chi-Square Distribution , Hypertension/diagnosis , Hypertension/physiopathology , Membrane Potentials , Renin/blood , Sensitivity and Specificity
7.
Arq Bras Cardiol ; 63(3): 203-5, 1994 Sep.
Article in Portuguese | MEDLINE | ID: mdl-7778992

ABSTRACT

We studied five patients with acquired ventricular septal defect during the course of an infective endocarditis. All patients were male and had a previous aortic valve disease associated with an aortic ring abscess. Clinical examination was useful for the diagnosis of 4 cases, emphasizing the following findings: systolic murmur and/or left paraesternal thrill and right-heart failure. Incidence of congestive heart failure was 60%, while 40% of all patients died during the in-hospital course. No specific etiologic agent was detected. Therefore, acquired ventricular septal defect should be suspected in patients with infective endocarditis of the aortic valve that evolve with a systolic murmur and/or paraesternal thrill and right-heart failure. Immediate surgical treatment is mandatory in these cases.


Subject(s)
Endocarditis, Bacterial/complications , Heart Septum , Adolescent , Adult , Aortic Valve Insufficiency/diagnosis , Aortic Valve Insufficiency/etiology , Cardiomyopathies/diagnosis , Cardiomyopathies/microbiology , Diagnosis, Differential , Echocardiography , Electrocardiography , Endocarditis, Bacterial/diagnosis , Heart Murmurs/diagnosis , Heart Murmurs/etiology , Humans , Male , Middle Aged , Radiography, Thoracic , Tricuspid Valve Insufficiency/diagnosis , Tricuspid Valve Insufficiency/etiology
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