Search

Background: Several allometric methods for indexing cardiac structures to body size have been proposed but the optimal way for normalization of cardiac structures is still controversial. We aimed to estimate the allometric exponents that best describe the relationships between cardiac dimensions and body size, propose normative values, and analyze how the different scaling metrics influence the prevalence of left ventricular hypertrophy (LVH) and chambers enlargement as well as predictive models for cardiovascular outcome in the community., Methods: We measured left ventricular end-diastolic dimension, end-diastolic volume, left ventricular mass, and left atrial volume in randomly recruited population cohorts (n = 1509; 52.8% women; mean age, 47.8 years)., Results: In a healthy subgroup (n = 656), the allometric exponents that described the relationships between left ventricular end-diastolic dimension and body size were 1, 0.5, and 0.33 for body height, body surface area (BSA), and estimated lean body mass, respectively. With regard to left ventricular end-diastolic volume, left ventricular mass, and left atrial volume the allometric exponents for body height were 2.9, 2.7, and 2.0, respectively; for BSA, they ranged from 1.7 to 1.8; for estimated lean body mass all exponents were around 1. These exponents were used to appropriately scale the cardiac dimensions to body size and derived sex-specific cut-off limits for different indexed cardiac dimensions. The hazard ratios of cardiovascular outcome were highest for LVH defined by left ventricular mass/height., Conclusion: Our study resulted in a proposal for thresholds for various indexed cardiac dimensions. Left ventricular mass indexed to height was sensitive in detection of LVH associated with obesity and slightly better predicted outcome.

Background: Late-systolic loading of the left ventricular (LV) is determined by arterial wave reflections and central vascular stiffening. We, therefore, investigated the relationship between various Doppler indexes reflecting LV systolic and diastolic function and arterial stiffness in the framework of a large population study of randomly recruited study participants., Methods: In 1233 study participants (51.7% women; mean age, 48 years; 41.5% hypertensive), using conventional and tissue Doppler imaging, we measured: the transmitral early (E) and late (A) diastolic velocities; tissue Doppler imaging systolic and early (e') and late diastolic mitral annular velocities; and end-systolic longitudinal and radial strain. Using applanation tonometry, we assessed central pulse pressure (cPP), augmentation pressure and carotid-femoral pulse wave velocity., Results: After full adjustment, transmitral E and A peaks increased with augmentation pressure and cPP (P less than 0.0001) and e' was positively associated with cPP (P = 0.013). The E/e' ratio increased significantly with augmentation pressure (P less than 0.0001), cPP (P less than 0.0001) and pulse wave velocity (P = 0.048). Although accounting for covariables, all arterial indexes were on average significantly higher in the diastolic dysfunction group with elevated filling pressure (n = 171) when compared to participants with normal diastolic function (n = 961; P ≤ 0.0004) or with impaired relaxation (n = 101; P ≤ 0.008). Longitudinal strain decreased independently with mean arterial pressure (P = 0.03). The correlation between radial strain and the arterial indexes shifted from positive at middle age (50-60 years) to negative at older (P less than 0.0001 for interaction)., Conclusion: Our study underscored the importance of arterial characteristics as a mediator of LV systolic and diastolic dysfunction. We demonstrated an age-dependent relationship between radial strain and indexes of arterial stiffness.

Background: Left ventricular (LV) function depends on the activity of transmembrane electrolyte transporters. Failing human myocardium has lower Na(+)/K(+) ATPase expression and higher intracellular sodium concentrations. The ATP12A gene encodes a catalytic subunit of an ATPase that can function as a Na(+)/K(+) pump. We, therefore, investigated the association between LV function and common genetic variants in ATP12A., Methods: A random sample of 1166 participants (53.7% women; mean age 49.5 years, 44.8% hypertensive) was recruited in Belgium, Poland, Italy and Russia. We measured transmitral early and late diastolic velocities (E and A) by pulsed wave Doppler, and mitral annular velocities (e' and a') by tissue Doppler. Using principal component analysis, we summarized 7 Doppler indexes - namely, E, A, e' and a' velocities, and their ratios (E/A, e'/a', and E/e') - into a single diastolic score. We genotyped 5 tag SNPs (rs963984, rs9553395, rs10507337, rs12872010, rs2071490) in ATP12A. In our analysis we focused on rs10507337 because it is located within a transcription factor binding site., Results: In the population-based analyses while adjusting for covariables and accounting for family clusters and country, rs10507337 C allele carriers had significantly higher E/A (P = 0.003), e' (P = 5.8×10(-5)), e'/a' (P = 0.003) and diastolic score (P = 0.0001) compared to TT homozygotes. Our findings were confirmed in the haplotype analysis and in the family-based analyses in 74 informative offspring., Conclusions: LV diastolic function as assessed by conventional and tissue Doppler indexes including a composite diastolic score was associated with genetic variation in ATP12A. Further experimental studies are necessary to clarify the role of ATP12A in myocardial relaxation.

Aims: Left ventricular (LV) (dys)synchrony has an important impact on LV function and structure. Our study aimed to describe the distribution and determinants of LV mechanical delay indexes in the general population and to assess an association of different Doppler indexes reflecting LV diastolic function with LV mechanical delay indexes., Methods and Results: In 200 subjects enrolled in a family-based population study (46.5% women; mean age, 57.9; 48% hypertensive), we performed echocardiography with tissue synchronization imaging (TSI) and two-dimensional speckle tracking. We measured the maximum difference in time to peak systolic velocity between any 2 of 12 LV segments (Ts-max); the standard deviation of time to peak systolic velocity of 12 segments (Ts-sd); the difference in time to peak systolic velocity and strain between septal and lateral LV walls and the strain delay index in septal and lateral walls [septal and lateral (SDI)]. In univariable and multivariable regression analyses, TSI indexes and lateral SDI independently increased with age (P ≤ 0.027) and body mass index (P ≤ 0.010). Ts-max and Ts-sd also increased with female sex (P ≤ 0.0002) and decreased with heart rate (P ≤ 0.0004). Septal SDI only increased with female sex (P < 0.0001). Among the Doppler indexes of LV diastolic function, only E/e' was significantly and positively associated with TSI indexes (P ≤ 0.037) and lateral SDI (P = 0.0026), but not with septal SDI (P = 0.69). In participants with advanced stage of LV diastolic dysfunction, TSI indexes were prolonged compare with subjects with normal LV diastolic function (P ≤ 0.002)., Conclusion: We demonstrated that in unselected subjects LV diastolic dysfunction was associated with mechanical LV dyssynchrony as assessed by echocardiography.

Background: To understand better the mechanism of left ventricular (LV) remodeling related to hypertension, it is important to evaluate LV function in relation to the changes in loading conditions. The aim of this study was to investigate changes in conventional ventricular-arterial coupling indexes, LV strain, and a new index reflecting regional myocardial work assessed noninvasively at rest and during isometric exercise in a random sample including participants with normal blood pressure and those with hypertension., Methods: A total of 148 participants (53.4% women; mean age, 52.0 years; 39.2% with hypertension) underwent simultaneous echocardiographic and arterial data acquisition at rest and during increased afterload (handgrip exercise). End-systolic pressure was determined from the carotid pulse wave. Arterial elastance (Ea) and LV elastance (Ees) were calculated as end-systolic pressure/stroke volume and end-systolic pressure/end-systolic volume. Doppler tissue imaging and two-dimensional speckle tracking were used to derive LV longitudinal strain. Regional myocardial work (ejection work density [EWD]) was the area of the pressure-strain loop during ejection., Results: At rest, with adjustments applied, Ees (3.06 vs 3.71 mm Hg/mL, P = .0003), Ea/Ees (0.54 vs 0.47, P = .002) and EWD (670 vs 802 Pa/m(2), P = .0001) differed significantly between participants with normal blood pressure and those with hypertension. During handgrip exercise, Ea and Ea/Ees significantly increased (P < .0001) in both groups. Doppler tissue imaging and two-dimensional LV strain decreased in participants with hypertension (P ≤ .008). Only in subjects with normal blood pressure EWD significantly increased (+14.7%, P = .0009)., Conclusions: Although patients with hypertension compared with those with normal blood pressure have increased LV systolic stiffness and regional myocardial work to match arterial load at rest, they might have diminished cardiac reserve to increase myocardial performance, as estimated by EWD during isometric exercise., (Copyright © 2012 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.)