Laura Stefani

Effects of exercise on natriuretic peptides and cardiac function in man

We evaluated cardiac function and the plasma levels of atrial (ANP) and brain (BNP) natriuretic peptides during bicycle (B) and hand-grip (HG) exercises in eight healthy males. Each test was preceded by a control protocol in resting conditions. Left ventricular (LV) function (echocardiography) was evaluated during both exercises. Atrial function was assessed only during HG. Plasma ANP significantly increased during B (+236%) and HG (+77%), while there was a significant trend towards higher plasma BNP levels during B (+41%) and HG (+30%) than during the corresponding control tests. Plasma ANP correlated with heart rate in both tests, with left atrial volume, pulmonary vein flow systolic fraction and mitral flow E/A ratio in HG; BNP in both test correlated with LV dimensions and function. These data suggest that during exercise the cardiac release of ANP and BNP is differently regulated and related to changes in left atrial and LV function, respectively.

Acute Effects of Physiological Increments of Brain Natriuretic Peptide in Humans

To investigate the effects of physiological increases in plasma brain natriuretic peptide concentration in humans, we studied six healthy volunteers who received incremental infusions (0.25 pmol/kg per minute in the first hour and 0.50 pmol/kg per minute in the second) of synthetic human brain natriuretic peptide-32 in a placebo-controlled, crossover study. Peptide plasma levels were 1.69 +/- 0.39 pmol/L at baseline and rose 1.5- and 3-fold with the lower and higher doses, respectively. These values were within the normal range and also comparable to those reported in patients with mild essential hypertension. The urinary excretion rate of cGMP also increased during brain natriuretic peptide infusion, indicating stimulation of natriuretic peptide receptors. Peptide administration induced a significant 1.7-fold increase in urinary sodium excretion without affecting renal plasma flow (para-aminohippurate clearance), glomerular filtration rate (creatinine clearance), and urine flow rate. Fractional proximal sodium reabsorption (lithium clearance method) was unchanged, and fractional distal sodium reabsorption significantly decreased. Brain natriuretic peptide caused no changes in arterial pressure, heart rate, hematocrit, and serum proteins, but it exerted an inhibitory effect on the renin-aldosterone axis, as indicated by the significant 50% or more decrease of plasma renin activity and urinary excretion rate of aldosterone. These results suggest that brain natriuretic peptide may be involved in the overall regulation of body fluid and cardiovascular homeostasis in humans, mainly through its natriuretic and endocrine effects.

Real-time evaluation of longitudinal peak systolic strain (speckle tracking measurement) in left and right ventricles of athletes

BackgroundStrain, and particularly Longitudinal Peak Systolic Strain (LPSS), plays a role in investigating the segmental and overall contractility of the heart which is a particularly interesting feature in athletes in whom regular training determines several morphological and functional modifications in both the ventricles, that normally work at different loads. Speckle tracking techniques assess the LPSS of LV and RV from B-mode imaging in real time, with uniform accuracy in all segments, and can verify the possible dissimilar segmental contributions of the two chambers to overall myocardial contraction. The aim of the study is to quantify the LPSS in real time in both the ventricles in order to estimate any possible different deformation properties in them during a systolic period.Methods32 subjects (20 athletes and 18 controls) were submitted to a standard echocardiographic examination at rest and after a Hand Grip (HG) stress. From a four-chamber-view image, the LPSS parameter was measured with Speckle Tracking analysis in the basal and medium-apical segments of the two ventricles, at rest and after HG.ResultsIn both athletes and controls, LPSS values were significantly higher in the RV of athletes (RV LPSS medium-apical -23.87 ± 4.94; basalfreewall -25.04 ± 4.12 at rest) and controls (RV LPSSmedium-apical -25.21 ± 4.97; basalfreewall -28.69 ± 4.62 at rest) than in the LV of both (athletes LV LPSS medium-apical -18.14 ± 4.16; basallateralwall -16.05 ± 12.32; controls medium-apical -18.81 ± 2.64; basallateralwall -19.74 ± 3.84) With the HG test a significant enhancement of the LPSS(with P < .05) in the medium-apical segments of LV and RV was evident, but only in athletes; there was no modification of the standard echo-parameters in either group.ConclusionST analysis is an easy method for investigating the contractility of the RV through deformation parameters, showing greater involvement of the RV than LV at rest. In athletes only, after isometric stress the two ventricles show particular myocardial deformation properties of the regions around the apex where the curvature of the wall is more marked. The clinical application of this new approach in athletes and normal subjects requires further investigation.

Speckle tracking for left ventricle performance in young athletes with bicuspid aortic valve and mild aortic regurgitation.

AIMS Longitudinal peak systolic strain (LPSS) quantifies regional and global heart function. Few data are available on left ventricle (LV) performance in young athletes with bicuspid aortic valve (BAV), where a pattern of mild aortic insufficiency is relatively frequent, and the ejection fraction (EF) is often normal for a long time. We report the measurement of LV strain in young BAV athletes. METHODS AND RESULTS Three groups (20 athletes with BAV, 20 healthy athletes, and 20 sedentary healthy subjects, all aged 25 +/- 3 years) underwent standard echo examination to evaluate LPSS at the basal and medium-apical segments of the lateral wall (LW) and interventricular septum (IVS) of the LV. LPSS was within the normal range; however, in BAV athletes, the LPSS of the basal segments tended to be lower (S%IVS(basal), -17.7 +/- 2.7; S%LW(basal), -14.2 +/- 2.2; S%IVS(med-apic), -21 +/- 3.5; S%LW(med-apic), -18.8 +/- 4.2), producing a gradient from basal to apical regions. The EF was normal in all subjects. CONCLUSION Young trained BAV athletes have normal LV performance. Nevertheless, these athletes tend to have lower strain than healthy subjects in the LV basal segments. The clinical implications of this finding are uncertain and require further investigation.

Bicuspid aortic valve in competitive athletes

Aim: Bicuspid aortic valve (BAV) is a common congenital cardiac condition. The presence of BAV in non-elite athletes has been poorly investigated; it is usually asymptomatic until valvular stenosis, regurgitation or other vascular alterations are evident. Design: Over a three-year period, 2273 competitive athletes were consecutively investigated with transthoracic echocardiography. The traditional parameters, the aortic root dimensions at four levels and the systolic and diastolic flow of aortic valve, were studied with continuous Doppler according to the echo guidelines. Setting: The study protocol included all the non-elite athletes investigated for the first evaluation to obtain eligibility. Patients: 2273 competitive athletes aged 8–60 years from several sports and regularly trained were evaluated with anamnesis, clinical check-up and echocardiography in order to exclude subjects with systemic or congenital heart disease. Results: BAV was diagnosed in 58 athletes (2.5%). Of these, nine had normal valvular function, 47 had abnormal valvular function with mild–moderate aortic regurgitation, and two had moderate stenosis. Aortic root dimensions at all levels were significantly greater in athletes with BAV than in athletes with a normal tricuspid valve. No relation was found with age, body surface area, aortic regurgitation or years of training. Conclusions: BAV is a relatively common congenital cardiac disease in athletes and commonly asymptomatic for a long time. This study suggests the usefulness of evaluating young athletes using echocardiography at least once when they start their sporting activity.

Supernormal functional reserve of apical segments in elite soccer players: an ultrasound speckle tracking handgrip stress study

BackgroundUltrasound speckle tracking from grey scale images allows the assessment of regional strain derived from 2D regardless of angle intonation, and it is highly reproducible. The study aimed to evaluate regional left ventricular functional reserve in elite soccer players.Methods50 subjects (25 elite athletes and 25 sedentary controls), aged 26 ± 3.5, were submitted to an echo exam, at rest and after the Hand Grip (HG) test. Both standard echo parameters and strain were evaluated.ResultsEjection fraction was similar in athletes and controls both at rest (athletes 58 ± 2 vs controls 57 ± 4 p ns) and after HG (athletes 60 ± 2 vs controls 58 ± 3 p ns). Basal (septal and anterior) segments showed similar strain values in athletes and controls both at rest (athletes S% -19.9 ± 4.2; controls S% -18.8 ± 4.9 p = ns) and after HG (athletes S% -20.99 ± 2.8; controls S% -19.46 ± 4.4 p = ns). Medium-apical segments showed similar strain values at rest (athletes S% -17.31 ± 2.3; controls S% -20.00 ± 5.3 p = ns), but higher values in athletes after HG (athletes S% -24.47 ± 2.8; controls S% -20.47 ± 5.4 p < 0.05)ConclusionIn athletes with physiological myocardial hypertrophy, a brief isometric effort produces enhancement of the strain in medium-apical left ventricular segments, suggesting the presence of a higher regional function reserve which can be elicited with an inotropic challenge and suitable methods of radial function quantification such as 2D-derived strain.

Adaptative or maladaptative hypertrophy, different spatial distribution of myocardial contraction.

Background:  Left ventricular hypertrophy (LVH) may be an adaptative remodelling process induced by physical training, or result from pathological stimuli. We hypothesized that different LVH aetiology could lead to dissimilar spatial distribution left ventricular (LV) contraction, and compared different components of LV contraction using 2‐dimensional (2‐D) speckle tracking derived strain in subjects with adaptative hypertrophy (endurance athletes), maladaptative hypertrophy (hypertensive patients) and healthy controls.

Cardiovascular Effects of Brain Natriuretic Peptide in Essential Hypertension

We evaluated the cardiovascular effects of pathophysiological plasma levels of brain natriuretic peptide in seven patients with mild to moderate essential hypertension by performing equilibrium radionuclide angiocardiography at baseline and during brain natriuretic peptide infusion at increasing doses (4, 8, 10, and 12 pmol/kg per minute for 20 minutes each). Brain natriuretic peptide induced a progressive reduction of left ventricular end-diastolic volume (from 107.5 +/- 10.3 to 89.0 +/- 11.0 mL at the end of all infusion periods) and end-systolic volume, whereas stroke volume did not show any significant change (from 64.9 +/- 5.9 to 62.7 +/- 7.8 mL). Cardiac output, arterial pressure, and peripheral vascular resistance did not change significantly. The lack of effects on systemic hemodynamics was probably due to compensatory activation of the sympathetic nervous system, as indicated by the significant increase in plasma norepinephrine levels (from 1.75 +/- 0.18 to 2.19 +/- 0.21 nmol/L), heart rate (from 68 +/- 6 to 81 +/- 6 beats per minute), peak ejection rate, and peak filling rate. These results indicate that brain natriuretic peptide, at the pathophysiological plasma concentrations reached in this study, influences cardiovascular homeostasis mainly by reducing cardiac preload.

The cardiovascular profile of soccer referees: an echocardiographic study

BackgroundDuring a soccer game, the cardiovascular system is severely taxed The referees must be alert and their level of fitness must be such that fatigue will not impair their decision-making. Referees peak overall performance is usually after 40 when the performance starts to decline. We evaluated the morphological and functional cardiac profile of professional soccer referees.Materials and methodsWe submitted to a clinical and echocardiographic exam a group of 120 professional soccer referees aged 25 – 45 years, including the first division of the Italian Championship, matched with 120 soccer players, including élite soccer players. Data were compared using an unpaired Students t test. Statistical significance was with p < 0.05.ResultsRight ventricle dimensions (22.2 ± 3.8 vs 25.9 ± 2.4 mm) and Left Ventricular Mass Index (LVMi) (100.5 ± 45.2 vs 105.4 ± 17.3) were significantly greater in referees than in active soccer players. Left atrium dimensions (33.7 ± 8.9 vs 36.2 ± 3.1 mm), aortic root (29.7 ± 7.9 vs 32.1 ± 3 mm) and LVMi (115.1 ± 16.7 vs 134.1 ± 19.9 g/m2) were significantly greater in élite soccer players than in first-division referees.ConclusionOur investigation shows that right ventricle is greater in referees than in soccer players. The differences (left atrium, aortic root and LVMi) between first division referees and élite soccer players may derive from the different training workloads.

Exercise as a prescription therapy for breast and colon cancer survivors

Background Breast and colon tumors are the most common types of cancer in the general population. As a result of improved diagnosis and treatment, more people are now surviving cancer. Lifestyle has been identified as one of the potential risk factors for cancer, and it has been demonstrated recently that physical activity reduces the physiological and psychological symptoms and side effects of chemotherapy. Muscular atrophy, weight changes, decreased aerobic capacity, fatigue, and depression are the most common symptoms in cancer patients. The exact amount of moderate to vigorous physical activity needed to overcome these effects has not yet been established, but an individualized and variable exercise program as prescription therapy could be considered a helpful tool for improving quality of life. This paper proposes a model of lifestyle analysis and dedicated individualized exercise programs for the treatment of cancer patients. The program starts with a preliminary evaluation of the patient’s lifestyle using a questionnaire and accelerometer, which provides information on the amount of daily physical activity and number of steps taken, as well as an assessment of aerobic capacity, cardiovascular response, muscle strength, and resistance. Two different levels of aerobic exercise, ie, low-to-moderate (40% of maximal heart rate) to moderate (60% of maximal heart rate) can be prescribed. This model of exercise prescription in patients with cancer offers a flexible program for assisting in the management of this complex disease. It is projected to ensure easier management of medical problems related to cancer, and to attract a greater number of participants over time.