Time course of strength adaptations following high-intensity resistance training in individuals with multiple sclerosis.

PURPOSE: No evidence exists regarding the time course and clinical relevance of muscle strength improvements following resistance training in people with multiple sclerosis (PwMS). The purpose of this study was to investigate the temporal course and the clinical meaningfulness of the changes in strength induced by high-intensity resistance training and whether these changes impact on muscle endurance to fatigue and functional outcomes. METHODS: PwMS with predominantly unilateral hyposthenia of the ankle dorsiflexors underwent a 6-week isokinetic training of the more affected ankle dorsiflexion muscles. Maximal strength was measured at baseline, during the training on a weekly basis, at the end of the intervention (POST) and at the 12-week follow-up. Muscle endurance to fatigue, mobility and walking outcomes were assessed at baseline, POST and follow-up. Reproducibility and responsiveness analyses were performed. RESULTS: Significant gains in muscle strength were already detected after 3 weeks of training with no further improvements in the following weeks. These improvements exceeded the cutoff values for relevant changes and were also positively correlated to improved muscle endurance to fatigue and mobility measures. None of the observed changes in muscle performance and functional outcomes was retained at the follow-up. CONCLUSIONS: Preliminary evidence showed that 3 weeks of high-intensity resistance training induces consistent and meaningful improvements in muscle performance of the ankle dorsiflexors in PwMS. These findings may have practical dose-response and cost-effectiveness implications in the management of MS-induced muscle weakness, potentially enhancing the understanding of the response to training exhibited by PwMS. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier NCT02010398; December 2013.

The fibroblast growth factor-23 and Vitamin D emerge as nontraditional risk factors and may affect cardiovascular risk.

OBJECTIVES: Fibroblast growth factor-23 (FGF-23) and vitamin D are hormones involved in phosphate homoeostasis. They also directly influence cardiomyocyte hypertrophy. We examined whether the relationships between levels of vitamin D or FGF-23, cardiac phenotype and outcome were independent of established cardiac biomarkers in a large cohort of community-dwelling elderly subjects. DESIGN AND SETTING: Plasma levels of FGF-23 and vitamin D were measured in 1851 men and women (65-84 years) resident in the Lazio region of Italy. Participants were referred to eight cardiology centres for clinical examination, electrocardiography, comprehensive Doppler echocardiography and blood sampling. All-cause mortality or hospitalizations were available after a median follow-up of 47 months with record linkage of administrative data. RESULTS: Vitamin D deficiency (<20 ng mL(-1) ) was found in 72.3% of subjects, but FGF-23 levels were normal [74 (58-97) RU per mL]. After adjustment for cardiovascular risk factors and morbidities, low concentrations of vitamin D and high levels of FGF-23 were associated with a higher left ventricular (LV) mass index. Levels of FGF-23 [hazard ratio (HR) (95% confidence interval (CI)) 1.71 (1.28-2.28), P < 0.0001] but not vitamin D [0.76 (0.57-1.01), P = 0.08] were independently associated with mortality after adjustment for clinical risk factors and two cardiac markers together (N-terminal pro-brain natriuretic peptide and high-sensitivity cardiac troponin T), but did not predict hospital admission. People with above median values of FGF-23 and below median values of vitamin D had greater LV hypertrophy and higher mortality. CONCLUSIONS: In community-dwelling elderly individuals with highly prevalent vitamin D deficiency, FGF-23 levels were associated with LV hypertrophy and predicted mortality independently of two robust cardiac biomarkers. A causal relationship was not demonstrated, but the hormones involved in mineral metabolism emerged as nontraditional risk factors and may affect cardiovascular risk.

High-sensitivity cardiac troponin T for detection of subtle abnormalities of cardiac phenotype in a general population of elderly individuals.

OBJECTIVE: To investigate the association between circulating cardiac biomarkers and minor abnormalities in cardiac phenotype [left ventricular (LV) mass and midwall fractional shortening (MFS)] in elderly individuals in a general population sample. DESIGN AND SETTING: We examined the relationship between plasma concentrations of high-sensitivity cardiac troponin T (hs-cTnT) or N-terminal probrain natriuretic peptide (NT-proBNP) and elevated LV mass (LV mass/body surface area >95 g m(-2) for women and 115 g m(-2) for men), reduced MFS (<15%) or isolated LV diastolic dysfunction in 1973 elderly subjects (mean age 73 ± 5 years, range 65-84) resident in the Lazio region of Italy and enrolled in the PREDICTOR study. RESULTS: Overall, 24.8% of subjects had elevated LV mass, and 30.4% had reduced MFS. Median [quartile 1-3] plasma concentrations of hs-cTnT and NT-proBNP were higher in individuals with elevated than those with normal LV mass: 6.6 [3.5-11.6] and 147 [64-296] ng L(-1) vs. 4.6 [3.0-8.1] and 79 [41-151] ng L(-1) respectively (P < 0.001). There was a graded increase in median hs-cTnT concentrations across clinical categories of LV hypertrophy: 4.6 [3.0-8.1], 5.8 [3.1-10.2], 7.6 [3.8-13.7] and 8.4 [3.8-17.6] ng L(-1) for subjects with normal LV mass and mild, moderate or severe LV hypertrophy respectively (P < 0.0001); hs-cTnT also increased with increasing quartiles of MFS or grades of isolated LV diastolic dysfunction. CONCLUSIONS: Within an extremely low range of concentrations, increased hs-cTnT amongst community-dwelling elderly subjects is associated with subtle alterations in cardiac phenotype, suggesting that minor injury to cardiac myocytes and subsequent release of troponin reflect subclinical pathophysiological LV deterioration in this population.

Papillary muscle rupture: small life-threatening myocardial infarction.

We report the case of a 70 years old man admitted to our coronary care unit because of atrial fibrillation, non-ST-elevation myocardial infarction and cardiogenic shock. Emergency coronary angiography showed a 99 % stenosis of the circumflex coronary that was successfully treated with a bare metal stent. Atrial fibrillation was cardioverted to sinus rhythm. Nevertheless, no hemodynamic benefit was observed. Transesophageal echocardiography (TEE) showed rupture of the papillary muscle (PM). The patient underwent emergent mitral valve replacement. Surgical visualization of the mitral valve confirmed the rupture of the antero-lateral PM. The postoperative course was uneventful and the patient recovered fully. This case highlights that even small myocardial infarction may have dramatic clinical presentations such as PM rupture with cardiogenic shock. Clinical suspicion and rapid confirmation of the diagnosis by TEE are essential requirements for successful treatment.

Global cardiovascular risk management in different Italian regions: an analysis of the Evaluation of Final Feasible Effect of Control Training and Ultra Sensitisation (EFFECTUS) educational program.

BACKGROUND AND AIM: The Final Evaluation Feasible Effect of Ultra Control Training and Sensitization (EFFECTUS) is an educational program, aimed at improving global CV risk stratification and management in Italy. The present study evaluates differences on clinical approach to global CV risk among physicians involved in the EFFECTUS program and stratified in three geographical macro-areas (North, Center, South) of our Country. METHODS AND RESULTS: Physicians were asked to submit data already available in their medical records, covering the first 10 adult outpatients, consecutively seen in the month of May 2006. Overall, 1.078 physicians (27% females, aged 50 ± 7 years) collected data of 9.904 outpatients (46.5% females, aged 67 ± 9 years), among which 3.219 (32.5%) were residents in Northern, 3.652 (36.9%) in Central and 3.033 (30.6%) in Southern Italy. A significantly higher prevalence of major CV risk factors, including obesity, physical inactivity, hypertension and diabetes, was recorded in Southern than in other areas. Accordingly, Southern physicians more frequently prescribed antihypertensive, glucose and lipid lowering agents than other physicians, who paid significantly more attention to life-style changes in their clinical practice. CONCLUSIONS: This analysis of the EFFECTUS study demonstrates a high prevalence of CV risk factors in Italy, particularly in Southern areas, and indicates some important discrepancies in the clinical management of global CV risk among physcians working in different Italian regions.

Effect of canrenone on left ventricular mechanics in patients with mild systolic heart failure and metabolic syndrome: the AREA-in-CHF study.

BACKGROUND AND AIM: We analyzed the effect of the mineralocorticoid receptor antagonist canrenone on LV mechanics in patients with or without metabolic syndrome (MetS) and compensated (Class II NYHA) heart failure (HF) with reduced ejection fraction (EF≤45%) on optimal therapy (including ACE-i or ARB, and ß-blockers). METHODS AND RESULTS: From a randomized, double-blind placebo-controlled trial (AREA-in-CHF), patients with (73 on canrenone [Can] and 77 on placebo [Pla]), based on modified ATPIII definition (BMI≥30kg/m(2) instead of waist girth) or without MetS (146 by arm). In addition to traditional echocardiographic parameters, we also evaluated myocardial mechano-energetic efficiency (MME) based on a previously reported method. At baseline, Can and Pla did not differ in age, BMI, blood pressure (BP), metabolic profile, BNP, and PIIINP. Compared with MetS-Pla, and controlling for age, sex and diabetes, at the final control MetS-Can exhibited increased MME, preserved E/A ratio, and decreased atrial dimensions (0.04

Impact of physicians' age on the clinical management of global cardiovascular risk: analysis of the results of the Evaluation of Final Feasible Effect of Control Training and Ultra Sensitisation Educational Programme.

AIM: To evaluate the potential impact of physicians' age on global cardiovascular (CV) risk management in the population of the Evaluation of Final Feasible Effect of Ultra Control Training and Sensitisation (EFFECTUS) study. METHODS: Involved physicians were stratified into three age groups (≤ 45, 46-55 and > 55 years), and asked to provide clinical data covering the first 10 adult outpatients, consecutively seen in May 2006. RESULTS: Overall 1078 physicians, among whom 219 (20%) were aged ≤ 45, 658 (61%) between 46 and 55, and 201 (19%) > 55 years, collected data of 9904 outpatients (46.5% female patients, aged 67 ± 9 years), who were distributed into three corresponding groups: 2010 (20%), 6111 (62%) and 1783 (18%), respectively. A higher prevalence of myocardial infarction and stroke was recorded by younger physicians rather than those aged > 46 years. Older physicians frequently recommended life-style changes, whereas a higher number of antihypertensive, antiplatelet, glucose and lipid-lowering prescriptions was prescribed by physicians aged ≤ 45 years. CONCLUSIONS: This analysis of the EFFECTUS study indicates a higher prevalence of vascular diseases among outpatients who were followed by younger physicians, who prescribed a higher number of CV drugs than older physicians. These older physicians have more attitude for prescribing favourable life-style changes than younger physicians.

[Arterial hypertension and heart failure]. / L'ipertensione arteriosa nella genesi dello scompenso cardiaco.

Systemic hypertension is a condition that frequently occurs before the onset of heart failure; furthermore, left ventricular hypertrophy (LVH) is an important risk factor for the development of heart failure (HF). Many studies have demonstrated that a linear relationship exists between increasing values of LV mass and the relative risk of the development of congestive HF. Hypertrophy-hyperplasy of cardiomyocytes and endothelial cells leads to a reduction in coronary reserve and to cell death due to apoptosis or focal necrosis. This characteristic has been defined as 'load dependent myocyte dysfunction' and it is characterized both by structural dysfunctions with cell death and by functional alterations that are detectable early with the evaluation of myocardial function measuring the mid-wall shortening. The detection of extremely high myocardial growth is another factor that could help to make an early diagnosis of HF. The presence of 'load geometrical adaptation' markers, together with an early detection of systolic function anomalies that are often accompanied by diastolic modifications, could help to identify, in an early phase, patients who will develop symptomatic LV dysfunction; therefore, these patients can be intensively treated and undergo a specific follow-up.

Characterization of post-discharge atrial fibrillation following open-heart surgery in uncomplicated patients referred to an early rehabilitation program.

BACKGROUND: Atrial fibrillation (AF) is frequently observed after open-heart surgery, following discharge from the cardiac surgery clinic. Compared to those usually reported in the early postoperative period, this arrhythmia is delayed in onset and is often a cause of re-hospitalization. Post-discharge AF has never been characterized in the literature. METHODS: We retrospectively analyzed post-discharge AF occurring within 30 days of coronary artery bypass graft or of valvular procedures in 376 patients referred to an early postoperative rehabilitation program. To investigate the probability of the persistence of post-discharge AF, we prospectively examined 232 patients who had undergone valvular procedures. RESULTS: An arrhythmia was recognized in 61/376 patients (16%), resulted in worsening of the NYHA functional class in 27 (44%) and in life-threatening hemodynamic effects requiring urgent cardioversion in 5 (8%). Events were predicted by the occurrence of postoperative AF (6-fold higher risk), left ventricular hypertrophy, an enlarged left atrium and valvular pathology (3-fold) and by the lack of beta-blocker protection (5-fold). AF persisted in 20/232 (9% of the study population, 18% of patients who had post-discharge AF) and had a relevant impact on the patient's clinical status. Predictors of events were older age, an enlarged left atrium and a lower left ventricular ejection fraction. CONCLUSIONS: Post-discharge AF following open-heart surgery is frequent in patients undergoing valvular procedures and often persists over time. The clinical impact of the arrhythmia is relevant, it might cause re-hospitalizations in many circumstances and, consequently, may have an impact on hospital resources. Events are much less frequent in patients taking beta-blockers than in those who do not, and they can be predicted by simple variables observed in the early stages after surgery.

Appropriate or inappropriate left ventricular mass in the presence or absence of prognostically adverse left ventricular hypertrophy.

OBJECTIVES: To evaluate whether assessment of appropriateness of left ventricular mass (LVM) adds to the traditional definition of left ventricular hypertrophy (LVH). DESIGN: Cross-sectional, relational. METHODS: Echocardiographic LVH and appropriateness of LVM were studied in 562 subjects (231 normotensive controls, aged 35+/-11 years, 142 women; 331 hypertensive patients, aged 47+/-11 years, 135 women) classified on the basis of either the presence or the absence of both LVH (LVM index > or = 51 g/m2.7) and inappropriate LVM (LVM > 128% of the value predicted by an equation including age, sex and stroke work). RESULTS: Body mass index was comparable in hypertensive patients and controls. Hypertensive patients without LVH but with inappropriate LVM (n = 21) had higher relative wall thickness and total peripheral resistance than all other groups, whereas cardiac output was lower (all P < 0.001). Midwall mechanics was normal with appropriate LVM, independently of presence of LVH, whereas it was depressed in inappropriate LVM, either with or without LVH (both P < 0.0001). There was no substantial difference in ejection fraction among controls and hypertensive groups. Stress-corrected midwall shortening was more closely related to deviation of LVM from the value appropriate for stroke work, body size and gender (r = -0.56, P < 0.0001) than to LVM index (r = -0.26). CONCLUSIONS: Inappropriate LVM is associated with concentric geometry, high peripheral resistance and depressed wall mechanics. The deviation of LVM from the value appropriate for stroke work, body size and sex correlates with measures of myocardial function better than LVM.

Inappropriate left ventricular mass in normotensive and hypertensive patients.

We evaluated cardiovascular features of normotensive and hypertensive adults with left ventricular (LV) mass values exceeding levels predicted for given stroke work, gender, and height, termed "inappropriate" LV mass. Inappropriate LV mass is associated with overweight, concentric LV geometry, and low myocardial systolic function not only in hypertensive subjects, but also in normotensive subjects.

Cardiac abnormalities in type 1 diabetes.

BACKGROUND: Left ventricular (LV) structural and hemodynamic consequences of type 1 diabetes mellitus are not fully understood. METHODS: To evaluate LV geometry, systolic and diastolic function in type 1 diabetes, Doppler echocardiograms were performed in 40 normotensive, type 1 diabetic patients without coronary heart disease or valvular lesions (22 men, 18 women, mean age 43 +/- 6 years, body mass index 24.7 +/- 2.8 kg/m2) and in 40 age and sex-matched non-diabetic normotensive controls (22 men, 18 women, mean age 43 +/- 5 years, body mass index 23.2 +/- 2.8 kg/m2), in a case-control design. RESULTS: Patients had higher systolic blood pressure than controls (p < 0.03) and comparable diastolic blood pressure and heart rate. LV dimension and mass were higher in patients than in controls (both p < 0.0001) whereas relative wall thickness did not differ. For comparable levels of end-systolic stress, patients exhibited a higher ejection fraction than controls (p < 0.01) and normal midwall shortening. Cardiac output was also higher (p < 0.001), whereas total peripheral resistance was lower in patients than in controls (p < 0.0001). Isovolumic relaxation time and E deceleration were prolonged in patients and peak A velocity was greater than in controls (all p < 0.01), whereas the difference in duration between A and pulmonary vein peak reverse flow at atrial contraction was comparable. In subgroup analyses, all reported features were independent of a) presence of target organ damage; b) duration of disease; c) levels of glycosylated hemoglobin. CONCLUSIONS: In normotensive patients with type 1 diabetes: 1) there was a moderate increase in LV mass; 2) LV chamber function was supernormal and wall mechanics was normal; 3) LV active relaxation was impaired but chamber stiffness was normal.

Pulmonary venous flow and mitral inflow velocity pattern in uncomplicated obesity: evidence for late diastolic dysfunction.

BACKGROUND: Active left ventricular relaxation, assessed by Doppler isovolumic relaxation time, is impaired in obesity. There is little information on left ventricular passive properties during filling. METHODS: To evaluate left ventricular late diastolic stiffness in obesity, Doppler echocardiographic interrogation of mitral inflow tract and pulmonary vein flow velocities were obtained from 47 normotensive, young obese subjects (11 males, 36 females) and 43 normotensive, young normal-weight volunteers (13 males, 30 females) of comparable age. RESULTS: After controlling the effect of blood pressure and left ventricular mass, isovolumic relaxation time was prolonged in obese subjects (p < 0.0001 vs normal-weight controls). No difference was found in transmitral peak early and late flow velocities. Obese subjects exhibited prolonged pulmonary vein reverse flow velocity during atrial contraction (p < 0.004), and a higher difference or ratio between duration of pulmonary reverse flow and duration of transmitral forward late flow (6 +/- 31 vs -20 +/- 39 ms or 1.06 +/- 0.3 vs 0.84 +/- 0.3, p < 0.002 and p < 0.001, respectively). These differences were also confirmed after controlling blood pressure and left ventricular mass. Non-invasively estimated left ventricular end-diastolic pressure was higher in obese subjects than in controls (p < 0.002). At multivariate analysis a higher body mass index was the sole predictor of prolonged difference between duration of pulmonary reverse flow and duration of transmitral forward late flow (beta = 0.38, p < 0.001). CONCLUSIONS: Obesity is associated with prolonged left ventricular active relaxation and abnormalities of filling pressure not detectable by the sole mitral inflow velocity pattern. These latter abnormalities are consistent with the presence of early increased left ventricular passive stiffness.

Relation of left ventricular diastolic properties to systolic function in arterial hypertension.

BACKGROUND: It is unclear whether impairment of left ventricular (LV) diastolic characteristics is independent of systolic dysfunction. METHODS AND RESULTS: To address this issue, 159 consecutive hypertensive patients (44+/-11 years, 78 obese, 96 women) and 165 normotensive subjects (32+/-11 years, 84 obese, 110 women) were studied with the use of Doppler echocardiography. After adjustment for age, body mass index (BMI), and sex, we found that ejection fraction (EF; M-mode, z-derived) was higher in hypertensive (66. 6+/-5.2%) than in normotensive (63.9+/-4.4%, P<0.0001) subjects, whereas midwall shortening (MS) was lower (hypertensive patients 16. 9+/-2.0%, normotensive subjects 17.8+/-2.2%, P<0.02), even after correction for end-systolic wall stress (P<0.05). Isovolumic relaxation time (IVRT) was greater in hypertensive patients (103+/-14 ms) than in normotensive subjects (78+/-19 ms), as was deceleration time of E velocity and peak A velocity (all P<0.0001). In multivariate analysis, IVRT was unrelated to EF, but a negative relation was found with MS (P<0.001), independent of age, BMI, presence of arterial hypertension, LV geometry, and load (multiple R(2)=0.58). For comparable age, sex distribution, BMI, and blood pressure values, hypertensive patients with lower afterload-adjusted MS exhibited longer IVRT than patients with normal MS (P<0.005). However, IVRT remained higher than in normotensive control subjects after control for LV geometry and load. CONCLUSIONS: Doppler indices of delayed LV relaxation can be detected in the presence of normal or supranormal EF but are independently related to impaired MS. A less severely abnormal relaxation, however, can be also detected in the presence of normal midwall function, independent of LV geometry and load. Thus, diastolic abnormalities may occur before systolic dysfunction even when it is measured at the midwall.

Relation of insulin resistance to left ventricular hypertrophy and diastolic dysfunction in obesity.

OBJECTIVE: To assess relations of left ventricular (LV) geometry and function to insulin resistance in obesity-a condition associated with volume overload and abnormal LV relaxation. DESIGN: Cross-sectional relational study. SUBJECTS: 27 healthy overweight-obese subjects (18 women, body mass index (BMI) = 35.0+/-4.0 kg/m2) and 31 age-matched normal-weight controls (21 women, BMI = 22.6+/-2.4 kg/m2). MEASUREMENTS: Subjects were studied by Doppler-echocardiography the same day and hour (08.00 h) as measurements of fasting insulin and blood glucose were made. Insulin resistance was determined by the 'Homeostasis Assessment Model'. RESULTS: Twelve obese subjects with insulin resistance (IR) had higher body size than 15 patients without IR and higher blood pressure than normal-weight controls (all P < 0.01). Relative IR was related to isovolumic relaxation time. This relation was not maintained after controlling for age, blood pressure, weight and height. Isovolumic relaxation time was, however, positively related to diastolic blood pressure, a measure of load, in normal controls (r=0.44) and obese without IR (r=0.62) but not in insulin resistant subjects (r=0.14). CONCLUSION: IR does not independently influence myocardial relaxation in uncomplicated obesity, but modulates the effect of load on active diastole.

Interaction between body size and cardiac workload: influence on left ventricular mass during body growth and adulthood.

The development of the left ventricle parallels body growth. During infancy, the relation between body size and left ventricular (LV) mass is very close. With advancing age, variability of LV mass in relation to body size markedly increases. To test the hypothesis that the age-related increase in variability of LV mass is due to the progressive impact of hemodynamic stimuli on LV growth, quantitative M-mode echocardiograms were obtained in 766 normal-weight, normotensive individuals over a range of ages from 1 day to 85 years (330 female subjects, 373 subjects younger than 18 years). LV mass was linearly related to height2.7 (r2=.69). Prediction of values of LV mass by body size was more accurate at birth and progressively less precise with increasing age. Stroke work (stroke volume times systolic pressure) was closely related to LV mass (r2=.74). The explained variance of LV mass increased from 69% in the univariate regression with height2.7 to 82% in a multivariate model including height2.7, stroke work, and gender. In children and adolescents (younger than 18 years), height2.7 was the main determinant of LV mass, whereas during adulthood stroke work and gender were more important predictors of LV mass than height2.7. Thus (1) the influence of body growth on development of LV mass decreases after early infancy because of both the variability of hemodynamic load and the increasing effect of gender; (2) after adolescence, during adulthood, in normotensive, normal-weight individuals, the impact of hemodynamic load and male gender on LV mass is greater than the one of body size; and (3) an appreciable proportion of variability of LV mass remains unexplained with the studied models. This might be due to genotypic variations and/or measurement error.

Relations of left ventricular geometry and function to body composition in children with high casual blood pressure.

To determine whether abnormal casual blood pressure (BP) is associated with left ventricular (LV) abnormalities in children, 190 6- to 11-year-old children (77 girls, 113 boys) were studied at a school site in Naples, Italy, by limited echocardiography and bioelectric impedance to calculate fat-free body mass (FFM). Single-visit BP measurements (defined as casual BP) were high (based on the Italian tables of BP) in 34 children (18%; 9 girls, 25 boys; 133+/-8/81+/-10 mm Hg) and obesity was present in 44 (23%; 15 girls, 29 boys). Sex- and age-independent risk of high casual BP value was 2.9-fold (odds ratio) greater in obese than in normal-weight children (95% confidence interval, 1.3 to 6.5; P<.01). LV mass (as both absolute value and normalized for height or FFM) was higher and relative wall thickness increased in children with high casual BP (all P<.01). Prevalence of LV hypertrophy was 21% among children with high casual BP (P<.004 versus 4.3% in normal group). Risk of LV hypertrophy was 5.5-fold higher in the presence of high casual BP (P<.004), whereas obesity, age, and sex did not have independent effects. Endocardial shortening was slightly higher in children with high casual BP (36.8+/-8.2%) than in children with normal BP (34.3+/-4.8%, P<.02), whereas midwall shortening was identical in the two groups (20%). Both endocardial shortening and midwall shortening were negatively related to end-systolic stress (r=-.62, SEE=3.8% and r=-.32, SEE=2.4% in normal children). Shortening as a percentage of predicted from wall stress was increased in children with high casual BP at the endocardial level (P<.001), whereas it was normal at the midwall. Therefore, (1) casual detection of high BP in school children is associated with LV geometric abnormalities similar to those found in adults with sustained hypertension (LV hypertrophy, concentric pattern); (2) similar to in adult hypertension, endocardial chamber function in children is supranormal; and (3) in contrast to findings in adults, midwall shortening is normal in children with high casual BP.

Age-related changes in total arterial capacitance from birth to maturity in a normotensive population.

We evaluated the effect of body growth and aging on the ratio of echocardiographic (Teichholz) stroke volume to pulse pressure (SV/PP ratio) in 373 normal-weight, normotensive children to adolescents (1 day to 17 years old; 166 girls, 87 nonwhite) and 393 normal adults (17 to 85 years old; 164 women, 112 nonwhite). Stroke volume increased with age in children (r = .64, P < .0001) and was stable in adults; pulse pressure decreased slightly with age in children (r = -.10, P = .06) and increased in adults (r = .29, P < .0001). As a consequence, SV/PP ratio increased with age in children (r = .51, P < .0001) and decreased in adults (r = -.18, P = .0004). To control for changes in body size that influence the size of the arterial tree, we used ANCOVA to adjust SV/PP for body size. Body size-adjusted SV/PP ratio was no longer related to age in children, whereas the negative relation with aging in adults remained statistically significant (r = -.19, P < .0002). Heart rate was negatively related to SV/PP ratio in both children and adolescents and adults, but this relation did not influence the relation with age. In multivariate analysis, high SV/PP ratio was predicted by greater height (P < .002) and weight (P < .04) and nonwhite race (P < .001) in children and adolescents and by younger age (P < .0001), greater weight (P < .0001), and low heart rate (P < .001) in adults. Sex did not enter the regression models. Thus, (1) SV/PP ratio is a measure of increasing capacity of the arterial tree during growth, whereas it depends on arterial compliance during adulthood through old age; (2) arterial compliance decreases progressively with aging; (3) the apparent difference between males and females might be due to their different body sizes.

Stroke volume and cardiac output in normotensive children and adults. Assessment of relations with body size and impact of overweight.

BACKGROUND: Relations between organs and body size are not linear but rather follow allometric (growth) relations characterized by their powers (exponents). METHODS AND RESULTS: Stroke volume (SV) by M-mode echocardiography was related to height, weight, body surface area (BSA), and ideal BSA (derived from ideal body weight for given height) in 970 normotensive individuals (1 day to 85 years old; 426 < 18 years old; 204 overweight to obese; 426 female). In normal-weight children, adults, and the entire population, SV was related by allometric relations to BSA (power = 0.82 to 1.19), body weight (power = 0.57 to 0.71), and height (power = 1.45 to 2.04) (all P < .0001). Relations of cardiac output to measures of body size had lower allometric powers than those for SV in the entire population (0.41 for body weight, 0.62 for BSA, and 1.16 for height). In overweight adults, observed SVs were 17% greater than predicted for ideal BSA, a difference that was approximated by normalization of SV for height to age-specific allometric powers. Similarly, observed cardiac output was 19% greater than predicted for ideal BSA, a difference that was accurately detected by use of cardiac output/height to age-specific allometric powers but not of BSA to the first power. CONCLUSIONS: Indices of SV and cardiac output for BSA are pertinent when the effect of obesity needs to be removed, because these indices obscure the impact of obesity. To detect the effect of obesity on LV pump function, normalization of SV and cardiac output for ideal BSA or for height to its age-specific allometric power should be practiced.