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ABSTRACT: Congestive heart failure is characterized by a sympathetic activation that is coupled with a baroreflex impairment. Whether these alterations are affected by clonidine is unknown. In 26 normotensive patients age 58.0+/-1.1 years (mean+/-SEM) affected by congestive heart failure (New York Heart Association functional class II or III) and treated with furosemide and enalapril, we measured mean arterial pressure, heart rate, venous plasma norepinephrine, and muscle sympathetic nerve traffic (microneurography) at rest and during baroreceptor stimulation and deactivation caused by stepwise intravenous infusions of phenylephrine and nitroprusside, respectively. Measurements were repeated after a 2-month administration of transdermal clonidine patch (14 patients) or placebo (12 patients) according to a double-blind, randomized sequence. Clonidine caused a slight, nonsignificant reduction in mean arterial pressure and heart rate without affecting exercise capacity and echocardiographically determined left ventricular ejection fraction. In contrast, both plasma norepinephrine and sympathetic nerve traffic were significantly reduced (-46.8% and -26.7%, respectively; P<0.01 for both). This reduction was coupled with no change in cardiac and sympathetic baroreflex responses. Transdermal placebo administration for a 2-month period did not affect any of the above-mentioned variables. Thus, in congestive heart failure patients who are undergoing conventional drug treatment, chronic clonidine administration exerts marked sympathoinhibitory effects without adversely affecting cardiac functions and clinical state. Whether this leads to further therapeutic benefits remains to be tested.
Hypertension 08/2001; 38(2):286-91. · 6.21 Impact Factor
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The American Journal of Cardiology 11/2000; 86(8):882-6. · 3.37 Impact Factor
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ABSTRACT: To assess whether the hypoxia associated with exposure to high altitude affects plasma endothelin-1 levels, and whether changes in endothelin-1 are related to those in systemic and pulmonary blood pressure.
Eight normal subjects ascended Mount Everest to an altitude of 5050 m within a period of 8 days (study 1) and 10 ascended Mount Rosa in the Italian Alps to an altitude of 4559 m within 2 days (study 2). In study 1 systemic blood pressure, heart rate, haematocrit, haemoglobin oxygen saturation (evaluated by percutaneous oximetry) and venous plasma endothelin-1 were measured several times during the ascent, and twice more during the time spent at high altitude. In study 2 the same parameters as well as systolic pulmonary pressure by echocardiography were evaluated on the second day of resting at 4559 m. In both studies, data obtained during the expeditions were compared with those collected from the same subjects at sea level.
In study 1 plasma endothelin-1 increased progressively up to 4240 m (from 1.8 +/- 0.1 pg/ml at sea level to 2.7 +/- 0.2 pg/ml) and decreased slightly thereafter; these increments were directly related to the decrements in percutaneous oxygen saturation, which, at that altitude, fell from 98.6 +/- 0.2% at sea level to 80.8 +/- 0.4%. Blood pressure and haematocrit also rose in response to exposure to high altitude but these changes were not related to changes in endothelin-1. In study 2 the increments in plasma endothelin-1 were similar to those observed in study 1 and the changes again correlated with changes in oxygen saturation as well as with those in systolic pulmonary pressure. On average, systolic pulmonary pressure increased from 19 +/- 1 to 26 +/- 1.9 mmHg, whereas systemic blood pressure and haematocrit were unchanged.
Exposure to high altitude is associated with consistent increases in plasma endothelin-1. This is probably the result of augmented secretion of the peptide in response to hypoxia and may contribute to the physiological adaptation of the pulmonary circulation to this condition.
Journal of Hypertension 09/1995; 13(8):859-65. · 4.02 Impact Factor
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ABSTRACT: To verify the applicability and the clinical significance of left ventricular wall stress determinations by intraoperative transesophageal echocardiography (TEE) during resections of abdominal aortic aneurysms.
Prospective comparison of changes in left ventricular wall stress between two groups of patients with and without coronary artery disease.
Operatory room of Universitary Institute.
Twenty-three patients with abdominal aortic aneurysms; 8 had clinically evident coronary artery disease (CAD+); 15 patients did not have clinical or electrocardiographic evidence of coronary artery disease (CAD-).
Resection of the aortic aneurysm and insertion of a synthetic prosthesis.
During operation transesophageal monitoring of left ventricular volumes and wall stress was performed during induction of anesthesia (T1), for two minutes after aortic clamping (T2), at the end of the proximal anastomosis (T3), for two minutes after aortic declamping (T4) and at the end of the procedure (T5). Circumpherential stress at end systole (sES) and end diastole (sED) was more sensitive than hemodynamic and volumetric parameters in detecting changes i function of the ischemic myocardium. In detail we observed: a significant increase of sES in CAD+versus CAD- at T2: 98 (sd 18) vs 83 (sd 14) 10(3) dyne/cm2. a significant increase of sED in CAD + versus CAD- at T2: 28.5 (sd 6) vs 22 (sd 4.5) 10(3) dyne/cm3. a similar trend of sES and sED at T4: 73 (sd 20.5) vs 46 (sd 15) 10(3) dyne/cm2 and 31 (sd 12) vs 16 (sd 7.7) 10(3) dyne/cm2 respectively. a significant increase of sED in CAD + at T5 (about 20' after T4): 26.5 (sd 9.5) vs 16 (sd 5.2) 10(3) dyne/cm2 which is expression of a persistent reduction of ventricular compliance in the ischemic patients.
Wall stress modifies MVO2 and subsequently is sensitive in detecting changes in myocardial performance. TEE could valuably integrate routine hemodynamic monitoring of patients with coronary heart disease who undergo surgical resection of abdominal aortic aneurysms.
Minerva anestesiologica 06/1994; 60(5):237-44. · 2.66 Impact Factor
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ABSTRACT: Endothelin-1 is a potent vasoconstrictive peptide which circulates in blood at very low concentrations. It is mostly released from endothelial cells towards the vascular smooth muscle cells. Therefore studies addressed at increasing endothelin-1 production using physical stimuli may easily fail to cause sizeable modifications in plasma endothelin levels. Upright posture and exposure to cold, the two maneuvers so far most commonly used in humans, often have inconsistent effects on plasma endothelin-1.
In recent studies we have found that exposure to high altitude (4500-5000 m) caused, in normal subjects, significant increases in endothelin-1 which were correlated with those of mean arterial pressure and of systolic pulmonary pressure.
Hypobaric hypoxia appears to stimulate the secretion of endothelin-1 and this response may contribute to the adaptation by the systemic and pulmonary circulation to the stress of altitude. If this can be confirmed, calcium antagonists, which are known to antagonize endothelin-1 mediated vasoconstriction, may be used to alleviate the pulmonary hypertension that occasionally occurs under these specific circumstances.
Journal of hypertension. Supplement: official journal of the International Society of Hypertension 02/1994; 12(1):S27-31.
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Journal of hypertension. Supplement: official journal of the International Society of Hypertension 01/1992; 9(6):S388-9.
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ABSTRACT: Echocardiography was used to explore the influence of independent variables (age, body surface area and heart rate) on the mean circumferential shortening velocity (MVCF) in 183 healthy subjects. Multiple stepwise regression analysis shows that heart rate is the only variable of the three just mentioned that influences MVCF. A regression equation is evolved and proposed as an index of MVCF correction for varying heart rates.
Cardiology 02/1986; 73(6):347-53. · 1.71 Impact Factor
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ABSTRACT: Systolic time intervals have been investigated in 26 subjects with severe liver cirrhosis. The patients were subdivided as follows: 15 with alcoholic cirrhosis; 11 with post-necrotic cirrhosis. Systolic time intervals were recorded and measured according to the Weissler's method. The left ventricular ejection time was significantly shortened due to the low systemic vascular resistance, while the pre-ejection period was unchanged, denoting preserved myocardial contractility. The isometric contraction time was also significantly shortened, thus confirming a good myocardial response to increased pre-load due to hyperdynamic state. The cardiac performance as assessed by systolic time intervals, is unchanged in hepatic cirrhosis.
Giornale italiano di cardiologia 08/1984; 14(7):525-9.
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Giornale italiano di cardiologia 02/1983; 13(3):163-9.
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Respiration 02/1982; 43(5):344-53. · 2.26 Impact Factor
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ABSTRACT: In order to improve the diagnostic procedure for patients with chest pain suspected of having acute ischemic heart disease we elaborated a mathematical model to predict ischemic risk and then compared its predictive capacity with that of the physician. From September 1989 to December 1992, 564 patients with a chief symptom of chest pain were seen at our Emergency Room (ER). Sixty-two percent of them were male, mean age was 58 +/- 13 years, and none had acute myocardial infarction or unstable angina. Clinical and historical data, serial sampling of enzymes and ECG patterns were collected for 4 hours after admission to the ER. At that point a decision was made to hospitalize or discharge that patient. Follow-up was completed within 2 months. At the end of follow-up, we observed that the physician's assessment resulted in 35% true positive, 55% true negative, 4.7% false positive, and 5.3% false negative judgments for acute ischemic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)
Annali italiani di medicina interna: organo ufficiale della Societa italiana di medicina interna 10(2):119-24.
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ABSTRACT: Platelet count and platelet function (circulating platelet aggregates, retention by glass beads and aggregation) were studied under basal conditions and after a cycloergometric exercise test in 10 subjects with stable angina pectoris and 10 normal subjects. There were no baseline differences between patients and controls in any of the tests of platelet function, nor did the values change after the exercise test. There was, however, a significant increase in the number of circulating platelets after the test in angina patients. Possible reasons for this phenomenon are discussed, with emphasis on the role of catecholamine hypersecretion induced by the physical exercise.
La Ricerca in Clinica e in Laboratorio 13(3):331-6.
