Left ventricular mass and systolic dysfunction in essential hypertension

Relationship between overweight and obesity and cardiac dimensions and function in a paediatric population

Obesity in adults is associated with left ventricular hypertrophy, dilatation, and myocardial fibrosis, as well as heart failure and coronary heart disease. These associations have been studied to a lesser extent in the paediatric population. This study aims to investigate the relationship between obesity and cardiac structure and function in the paediatric population. In a southern Spanish village, we selected all inhabitants aged 6-17 years stratifying by age, gender, and educational centres. We performed a complete transthoracic echocardiogram evaluating all the cardiac morphological and functional parameters commonly measured in an echocardiographic study. There were 212 children and adolescents included. Of them, 48.1% were males. The mean age was 10.9 ± 3.0 years. A total of 106 (50%) were normal weight, 57 (26.9%) overweight, and 49 (23.1%) obese. Sex and age were similar in all three groups. Overweight and obesity were associated with larger left ventricular end-diastolic and end-systolic volumes (p < 0.0005), greater left ventricular mass (p < 0.0005), and smaller ejection fraction (p < 0.0005). They were also associated with larger atrial, aortic, and right ventricular size. Lateral and mean E/e' ratios were higher (p = 0.007 and p = 0.01 respectively). Body mass index was independently associated with all cavity size variables as well as left ventricular ejection fraction.

CONCLUSION

Childhood obesity is independently associated with larger heart chambers, greater left ventricle mass, and smaller left ventricle ejection fraction.

WHAT IS KNOWN

• Childhood obesity is related to the development of cardiovascular risk factors and is considered an epidemic of the twenty-first century; its prevalence is rising.

WHAT IS NEW

• Childhood overweight and obesity lead to changes in cardiac structure and function which, although not considered clinically pathological, are significant and a result of obesity, and which behave as unfavourable incipient alterations at an early age.

Unattended compared to traditional blood pressure measurement in patients with rheumatoid arthritis: a randomised cross-over study

BACKGROUND

Hypertension is characterised by a high prevalence, low awareness and poor control among rheumatoid arthritis (RA) patients. Correct blood pressure (BP) measurement is highly important in these subjects. The "unattended" BP measurement aims to reduce the "white-coat effect," a phenomenon associated with cardiovascular risk. Data on "unattended" BP measurement in RA and its impact on hypertensive organ damage are very limited.

METHODS

BP was measured in the same patient both traditionally ("attended" BP) and by the "unattended" protocol (3 automated office BP measurements, at 1-min intervals, after 5 min of rest, with patient left alone) by a randomised cross-over design. Patients underwent clinical examination, 12-lead electrocardiography and trans-thoracic echocardiography to evaluate cardiac damage.

RESULTS

Sixty-two RA patients (mean age 67 ± 9 years, 87% women) were enrolled. Hypertension was diagnosed in 79% and 66% of patients according to ACC/AHA and ESC/ESH criteria, respectively. Concordance correlation coefficients between the two techniques were 0.55 (95%, CI 0.38-0.68) for systolic BP and 0.73 (95%, CI 0.60-0.82) for diastolic BP. "Unattended" (121.7/68.6 mmHg) was lower than "attended" BP (130.5/72.8 mmHg) for systolic and diastolic BP (both p < .0001). Among the two techniques, only "unattended" systolic BP showed a significant association with left ventricular mass (r = 0.11; p = .40 for "attended" BP; r = 0.27; p = .036 for unattended BP; difference between slopes: z = 3.92; p = .0001).

CONCLUSIONS

In RA patients, "unattended" BP is lower than traditional ("attended") BP and more closely associated with LV mass. In these patients, the "unattended" automated BP measurement is a promising tool which requires further evaluation.KEY MESSAGES"Unattended" automated blood pressure registration, aimed to reduce the "white-coat effect" is lower than "attended" value in rheumatoid arthritis patients."Unattended" blood pressure is more closely associated with left ventricular mass than "attende" registration.

Cardiac adaptation to hypertension in adult female Dahl salt-sensitive rats is dependent on ovarian function, but loss of ovarian function does not predict early maladaptation

Aim of study was to examine experimentally the adult female hypertensive heart in order to determine the role of ovary function in the response of the heart to salt-dependent hypertension. Dahl salt-sensitive rats, age 12 weeks, with/without ovariectomy were fed a standard (0.3% NaCl) or high-salt diet (8%) for 16 weeks. Mean arterial blood pressure monitored noninvasively in conscious state increased significantly by high salt. Echocardiography was performed at baseline and endpoint. Heart function and molecular changes were evaluated at endpoint by left ventricle catheterization, by sirius red staining for collagen and by gene expression using quantitative RT-PCR for selected genes. At endpoint, significant concentric hypertrophy was present with high salt. Increase in relative wall thickening with high salt compared to normal diet was more pronounced with intact ovaries (0.33 ± 0.02 and 0.57 ± 0.04 vs. 0.29 ± 0.00 and 0.46 ± 0.03) as was the reduction in midwall fractional shortening (20 ± 0.6 and 14 ± 2 vs. 19 ± 0.9 and 18 ± 1). Ovariectomy increased stroke volume and decreased the ratio of mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (E') (E/E' ratio) when compared to hearts from intact rats. High salt increased expression of collagen I and III genes and perivascular collagen in the heart slightly, but % interstitial collagen by sirius red staining remained unchanged in intact rats and decreased significantly by ovariectomy. Added volume load but not deterioration of function or structure characterized the nonfailing hypertensive heart of salt-sensitive females ovariectomized at mature age when compared to corresponding intact females.

Left Ventricular Hypertrophy Phenotype in Childhood-Onset Essential Hypertension

The aim of this study was to determine the risk factors associated with left ventricular (LV) hypertrophy (LVH) among 89 untreated children with primary hypertension. Clinic hypertension was confirmed by 24-hour ambulatory blood pressure (BP) monitoring. LV mass (LVM) index was calculated as LVM (g)/height (m)(2.7) and LVH was defined as LVM index >95th percentile. Children with (n=32) and without (n=57) LVH were compared. Both obesity and systolic BP were independently associated with LVH, with a higher contribution by body mass index. Obesity contributed significantly, with a nearly nine-fold increased risk of LVH. There was evidence of effect modification by the presence or absence of obesity on the relationship between systolic BP and LVH, whereby the relationship existed mainly in nonobese rather than obese children. Hence, to achieve reversal of LVH, clinicians should take into account both BP control and weight management.

Left ventricular ejection fraction is determined by both global myocardial strain and wall thickness

Objectives

The purpose of this study was to determine the mathematical relationship between left ventricular ejection fraction and global myocardial strain. A reduction in myocardial strain would be expected to cause a fall in ejection fraction. However, there is abundant evidence that abnormalities of myocardial strain can occur with a normal ejection fraction. Explanations such as a compensatory increase in radial or circumferential strain are not supported by clinical studies. We set out to determine the biomechanical relationship between ejection fraction, wall thickness and global myocardial strain.

Methods

The study used an established abstract model of left ventricular contraction to examine the effect of global myocardial strain and wall thickness on ejection fraction. Equations for the relationship between ejection fraction, wall thickness and myocardial strain were obtained using curve fitting methods.

Results

The mathematical relationship between ejection fraction, ventricular wall thickness and myocardial strain was derived as follows: φ = e^{(0.14Ln(ε) + 0.06)ω + (0.9Ln(ε) + 1.2)}, where φ is ejection fraction (%), ω is wall thickness (cm) and ε is myocardial strain (−%).

Conclusion

The findings of this study explain the coexistence of reduced global myocardial strain and normal ejection fraction seen in clinical observational studies. Our understanding of the pathophysiological processes in heart failure and associated conditions is substantially enhanced. These results provide a much better insight into the biophysical inter-relationship between myocardial strain and ejection fraction. This improved understanding provides an essential foundation for the design and interpretation of future clinical mechanistic and prognostic studies.

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Ejection fraction has a limited value in predicting mortality and functional capacity.

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Myocardial mechanics including the relationship between myocardial strain and ejection fraction are currently poorly understood.

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We showed that there is biophysical relationship between end-diastolic wall thickness, myocardial strain and ejection fraction.

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Such a relationship explains the poor correlation of ejection fraction with prognosis and functional capacity.

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The study provides the foundation for determining the relationship between ventricular hypertrophy, ejection fraction and prognosis.

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Cardio-ankle vascular index and subclinical heart disease

The relationship between arterial stiffness, measured as pulse wave velocity (PWV), and the left ventricle is confounded by the effects of blood pressure. We evaluated the relationship between carotid-femoral PWV and cardio-ankle vascular index (CAVI), a less pressure-dependent measurement of the stiffness constant (β) of the aorta and the iliac, femoral and tibial arteries, and obtained prognostically relevant measurements of left ventricular structure and systolic function. CAVI, carotid-femoral PWV and echocardiographic left ventricular mass and systolic function were determined in 133 subjects with either hypertension or high-normal blood pressure (33% treated; 56 ± 16 years, blood pressure 145/89 ± 21/12 mm Hg). Carotid-femoral PWV exhibited a direct relationship with systolic and diastolic blood pressure (r = 0.33/0.26, P < 0.001/0.014), whereas CAVI demonstrated no such relationship (r = 0.12/-0.05, both P > 0.1). Both CAVI and PWV correlated significantly with left ventricular mass index (r = 0.31, P<0.001; r = 0.21, P = 0.014). Subjects with inappropriately high left ventricular masses for a given cardiac workload (n = 44) had higher CAVI values (9.1 ± 2.0 vs. 7.9 ± 1.6, P < 0.001), but not higher PWV values (8.5 ± 2.5 vs. 8.7 ± 2.4, P>0.1). In a multivariate regression model, CAVI was independently associated with inappropriate left ventricular mass (β = 0.40, P < 0.001), along with body mass index. CAVI also demonstrated a negative relationship with left ventricular midwall fractional shortening (r = -0.41, P = 0.001) that was independent of age, sex, blood pressure and left ventricular mass in a multivariate analysis. In conclusion, a high CAVI is associated with inappropriately high left ventricular mass and low midwall systolic function. As a marker of arterial diastolic-to-systolic stiffening, CAVI may have a relationship with left ventricular structure and function that is independent of blood pressure levels.

Increased short-term blood pressure variability is associated with early left ventricular systolic dysfunction in newly diagnosed untreated hypertensive patients

BACKGROUND AND AIM

Twenty-four-hour blood pressure (BP) variability, by ambulatory BP monitoring (ABPM), has been related to left ventricular hypertrophy, independent of mean BP values. We tested the hypothesis that short-term BP variability (BPV) is also related to subclinical left ventricular systolic dysfunction.

METHODS

We assessed 24-h SBP and DBP variabilities, quantified as standard deviation (SD) of daytime (awake) BP values and as weighted SD of 24-h BP (24-h-weighted BPV), in 309 recently (<6 months) diagnosed, prospectively recruited, and untreated hypertensive patients. Patients were included only if with normal (≥55%) left ventricular ejection fraction (LVEF). Left ventricular systolic function was assessed by echocardiography measuring midwall fractional shortening (MFS), circumferential end-systolic stress (cESS), MFS/cESS, peak systolic wall stress, left ventricular fractional shortening (LVFS), and LVEF.

RESULTS

At multivariate analysis, awake and 24-h-weighted SBP variabilities (directly, P = 0.038 and P = 0.002, respectively) as well as relative wall thickness (RWT) (inversely, P = 0.001) were significantly related to cESS. Awake and 24-h SBP average values (inversely, P = 0.011 and P = 0.002, respectively), awake and 24-h-weighted SBP variabilities (inversely, P = 0.017 and P = 0.024, respectively), and RWT (directly, P = 0.001) were all significantly related to MFS/cESS. Finally, awake and 24-h average SBP (directly, P = 0.01 for both), awake and 24-h-weighted SBP variability (directly, P = 0.001 and P = 0.032, respectively), and RWT (inversely, P = 0.001) were all significantly and independently related to peak systolic wall stress.

CONCLUSION

In newly diagnosed never-treated hypertensive patients, in the absence of LVEF changes and independent of left ventricular mass index, higher awake, or 24-h-weighted short-term SBP variabilities are associated with early depressed left ventricular systolic function.

Global left ventricular performance in non-diabetic non-hypertensive metabolic syndrome adults

AIM

To evaluate the left ventricular structure and function in isolated metabolic syndrome.

METHODS

One hundred and fifty six consecutive adults with metabolic syndrome were enrolled in the study. Fifty nine had isolated metabolic syndrome (group A) and 97 had metabolic syndrome with hypertension and/or diabetes (group B). There was a control group of 34 healthy adults. In addition to classic echocardiographic assessment of myocardial structural and functional changes, the Tei index was used to evaluate global left ventricular performance.

RESULTS

There were no statistically significant differences between group A and controls in all parameters of left ventricular structural, systolic, and diastolic function except global myocardial performance (Tei index). On the other hand, significant differences were observed between group B and the control group in most of the parameters of left ventricular structural and global performance.

CONCLUSION

The early identification of isolated metabolic syndrome in non-diabetic, non-hypertensive adults may be an indication that aggressive preventive measures should not be postponed until overt obesity, hypertension or diabetes mellitus has developed.

Melatonin ameliorates calcium homeostasis in myocardial and ischemia-reperfusion injury in chronically hypoxic rats

Chronic hypoxia (CH) leads to the deterioration of myocardial functions with impaired calcium handling in the sarcoplasmic reticulum (SR), which may be mediated by oxidative stress. We hypothesized that administration of antioxidant melatonin would protect against cardiac and ischemia-reperfusion (I/R) injury by ameliorating SR calcium handling. Adult Sprague-Dawley rats that had received a daily injection of melatonin or vehicle were exposed to 10% oxygen for 4 wk. The heart of each rat was then dissected and perfused using a Langendorff apparatus. The ratio of heart-to-body weight, ventricular hypertrophy and hematocrit were increased in the hypoxic rats compared with the normoxic controls. Malondialdehyde levels were also increased in the heart of hypoxic rats and were lowered by the treatment of melatonin. The hearts were subjected to left coronary artery ischemia (30 min) followed by 120-min reperfusion. Lactate dehydrogenase leakage before ischemia, during I/R and infarct size of the isolated perfused hearts were significantly elevated in the vehicle-treated hypoxic rats but not in the melatonin-treated rats. Spectroflurometric studies showed that resting calcium levels and I/R-induced calcium overload in the cardiomyocytes were more significantly altered in the hypoxic rats than the normoxic controls. Also, the hypoxic group had decreased levels of the SR calcium content and reduced amplitude and decay time of electrically induced calcium transients, indicating impaired contractility and SR calcium re-uptake. Moreover, there were reductions in protein expression of calcium handling proteins, markedly shown at the level of SR-Ca(2+) ATPase (SERCA) in the heart of hypoxic rats. Melatonin treatment significantly mitigated the calcium handling in the hypoxic rats by preserving SERCA expression. The results suggest that melatonin is cardioprotective against CH-induced myocardial injury by improving calcium handling in the SR of cardiomyocytes via an antioxidant mechanism.

Is echo-determined left ventricular geometry associated with ventricular filling and midwall shortening in hypertensive ventricular hypertrophy?

BACKGROUND

The correlation between left ventricular (LV) geometry, mass, diastolic function, and midwall fractional shortening (MFS) in hypertensive patients with left ventricular hypertrophy (LVH) is not well established owing to limited diffusion of MFS evaluation. The aim of the study was to evaluate this correlation in 1887 consecutive hypertensive patients, all affected by LVH (mean age 66 years, 924 males), with LV ejection fraction (LVEF) >45% for early detection of ventricular dysfunction rather than LVEF and diastolic function impairment.

METHODS AND RESULTS

All patients underwent M-B mode echocardiography and PW-Doppler evaluation. LV geometry and mass were compared with Doppler-determined mitral flow and tissue velocities. LV geometry was eccentric (E) for 1018 subjects (53.9%) and concentric (C) for 869 (46.1%). There was no difference concerning LV diastolic dysfunction (P: n.s.) between 576 (30.6%) of the ELVH and 368 (19.4%) of the CLVH patients. The following parameters showed significant statistical differences: LV MFS impairment (P < 0.01) between 86 (4.6%) of the ELVH and 177 (9.4%) of the CLVH patients. LV MFS impairment rate was higher in 171 patients without LV diastolic dysfunction (9.1%), than in 92 patients affected (4.9%, P < 0.02). In CLVH patients, a higher prevalence of LV MFS impairment was observed in 143 without LV diastolic dysfunction (7.6%), than in 34 patients affected (1.8%, P < 0.01). In ELVH patients, a lower prevalence of LV MFS impairment was observed in 28 without diastolic dysfunction (1.5%), than in 58 patients affected (3.1%, P < 0,03).

CONCLUSION

Midwall LV impairment, an independent predictor of cardiac death and morbidity in hypertensive patients, can allow early identification of patients with LV dysfunction even when LVEF or assessment of diastolic function are normal. LV MFS impairment rate is higher in CLVH patients, and even higher when considering only those CLVH patients with no diastolic dysfunction. These results suggest that the ventricular dysfunction with normal LVEF is not always due to diastolic dysfunction, but often to systolic dysfunction as assessed by MFS impairment, an important early sign of ventricular dysfunction in hypertensive patients, even when diastolic function is normal.

Different impact of the metabolic syndrome on left ventricular structure and function in hypertensive men and women

Metabolic syndrome (MS) is increasingly recognized as an important cardiovascular risk factor in hypertension, but its influence on left ventricular (LV) mass and function in the 2 genders has not been specifically addressed. Among 618 nondiabetic, untreated hypertensive subjects, echocardiographically detected LV mass was significantly greater in subjects with MS. A significant interaction was observed between sex and the MS (P<0.003 for the multiplicative interaction term). Compared with women without the MS, those with the syndrome had a 24% greater LV mass (49.5+/-12 versus 40.0+/-10 g x m(-2.7); P<0.001), whereas the difference was only 9% in men (50.3+/-12 versus 46.1+/-10 g x m(-2.7); P=0.003). A greater prevalence of LV hypertrophy was found in women (37% versus 14%; P<0.001) but not in men (39% versus 29%; P=0.09) with the MS. After adjustment for the effect of age, body mass index, 24-hour systolic blood pressure, and several confounders, the MS was independently associated with a greater LV mass index in women (regression coefficient, 4.80; P<0.001) but not in men. Women with the MS also had a greater LV relative wall thickness (0.42+/-0.07 versus 0.39+/-0.07; P=0.004) and a depressed afterload-corrected midwall fractional shortening (94.0+/-12% versus 101.0+/-13%; P<0.001) than women without the syndrome, whereas no differences emerged in men. We conclude that, in untreated hypertension, MS has a different impact on LV hypertrophy and function in men and women. The effect of MS is more pronounced in women and is partly independent from the effect of several hemodynamic and nonhemodynamic determinants of LV mass.

Midwall mechanics in physiologic and hypertensive concentric hypertrophy

OBJECTIVE

We sought to analyze and compare midwall fractional shortening (mFS), and its relations with circumferential end-systolic stress (cESS) and relative wall thickness (RWT), among subjects with physiologic concentric left ventricular (LV) hypertrophy, patients with hypertension and concentric LV hypertrophy, and control subjects.

METHODS

A total of 51 normotensive athletes and 56 young patients with hypertension and echocardiographic evidence of concentric LV hypertrophy were enrolled. In addition, 49 age- and sex-matched control subjects were recruited. LV cavity size and wall thicknesses, LV mass, RWT, cESS, and mFS were determined by echocardiography.

RESULTS

The 3 groups were similar in age, sex, height, weight, body surface area, LV diameters, and conventional indices of systolic function. LV thicknesses, RWT, LV mass, and LV mass index were similarly increased in the athletes and in the hypertensive group when compared with the control subjects. A similar depression in mFS was observed in both the athletes (22.4 +/- 2.6%) and hypertensive group (22.5 +/- 3.6%) in comparison with the control group (24.5 +/- 2.5%, P =.0003). The depression in mFS was still significant after taking into account the effect of cESS, but was no more evident after indexation of mFS by RWT or LV mass. At regression analysis, the relation between mFS and cESS showed a steeper negative slope in the patients with hypertension than in the other 2 groups.

CONCLUSIONS

MFS is similarly depressed in physiologic and hypertensive concentric LV hypertrophy. The depression is abolished by adjustment for RWT or LV mass, suggesting that geometric factors are the major determinants of midwall performance in both types of concentric LV hypertrophy. However, an impaired response to different values of cESS seems to exist only in hypertensive concentric LV hypertrophy, because increasing levels of cESS may be associated with more evident mFS depression in patients with hypertension than in the athletes and control subjects.

Blood pressure independent association of microalbuminuria and left ventricular hypertrophy in hypertensive men

BACKGROUND

Rather unique amongst the prognostic predictors, microalbuminuria (MA, albuminuria: 15-200 microg min-1) is associated with several cardiovascular risk factors including left ventricular hypertrophy (LVH). The relationship, usually assumed to reflect an increased blood pressure (BP) load on the heart and the kidney, may, however, represent more than a haemodynamic correlate.

METHODS

To evaluate this possibility, we related MA to left ventricular mass index (LVMI) and other functional and structural echocardiographic parameters, office and 24-h BP, weight, lipids and smoking status in 330 never treated nondiabetic hypertensive men.

RESULTS

The risk of MA increased linearly by ascending quartiles of LVMI and was 2.3-fold higher in the presence of LVH after adjustment for age, left atrial size, mean fractional shortening. Systolic BP, either office or 24 h, and smoking status were the only additional independent predictors in multivariate logistic regression models. The BP-adjusted risk of MA was about twofold higher in patients with LVH, either concentric or eccentric, and neutral in those with concentric remodelling compared with normal geometry.

CONCLUSIONS

The association between elevated LVMI and MA independent of several other potential confounders, systolic BP in particular, is consistent with the existence of cardiac albuminuric factors, possibly of hormonal nature, which are to be identified more precisely. The extent to which LVH explains the predictive power of MA for morbid events independent of the BP load remains unknown.

Influence of hypertension on cardiac contractile response of human erythrocyte-derived depressing factor in ventricular myocytes

BACKGROUND

Erythrocyte-derived depressing factor (EDDF), a novel hypotensive factor purified from human erythrocytes, elicits endothelium-dependent vasorelaxation by reducing intracellular Ca2+ in vascular smooth muscle cells. However, its cardiac response is unknown.

OBJECTIVE

This study was designed to examine the cardiac contractile response of EDDF under both normotensive and hypertensive conditions.

METHODS

Ventricular myocytes were isolated from adult male spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto (WKY) normotensive rats. Mechanical properties were evaluated using an IonOptix MyoCam system and intracellular Ca2+ was measured with fura-2 fluorescence. Myocytes were electrically stimulated to contract at 0.5 Hz. The contractile properties analyzed included peak shortening (PS), time-to-PS (TPS), time-to-90% re-lengthening (TR(90)), maximal velocity of shortening/re-lengthening (+/- dl/dt), fura-fluorescence intensity change (DeltaFFI), and fura-fluorescence decay rate (tau).

RESULTS

SHR rats displayed significantly elevated blood pressure. EDDF (10-9-10-4 g/ml) did not affect PS, TPS, TR(90), DeltaFFI and tau but depressed +/- dl/dt at higher doses in WKY myocytes. However, EDDF depressed PS, +/- dl/dt and DeltaFFI, shortened TPS without affecting TR(90) and tau in SHR myocytes. Pretreatment of the myocytes with the nitric oxide synthase inhibitor Nvarpi-nitro-l-arginine methyl ester (l-NAME) did not affect the EDDF-induced inhibition of PS and +/- dl/dt in SHR myocytes but unmasked an EDDF-induced negative response in WKY myocytes.

CONCLUSIONS

These data indicate that EDDF may participate in the modulation of cardiac contractile function under hypertensive, but not normotensive, conditions. The cardiac depressive effect of EDDF is unlikely due to release of nitric oxide, as suggested in vascular smooth muscles.