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ObjectivesThe aim of the present study was to characterize the contraction pattern of the systemic right ventricle (RV).BackgroundReduced longitudinal function of the systemic RV compared with the normal RV has been interpreted as ventricular dysfunction. However, longitudinal shortening represents only one aspect of myocardial deformation, and changes in contraction in other dimensions have not previously been described.MethodsFourteen Senning-operated patients age 18.4 ± 0.9 years (mean ± SD) with transposition of the great arteries were studied. We compared the contraction pattern of the systemic RV with findings in the RV and left ventricle (LV) of normal subjects (n = 14) using tissue Doppler imaging and magnetic resonance imaging.ResultsIn the systemic RV free wall, circumferential strain exceeded longitudinal strain (−23.3 ± 3.4% vs. −15.0 ± 3.0%, p < 0.001) as was also the case in the normal LV (−25.7 ± 3.1% vs. −16.5 ± 1.7%, p < 0.001), opposite from the findings in the normal RV (−15.8 ± 1.3% vs. −30.7 ± 3.3%, p < 0.001). Strain in the interventricular septum did not differ from normal. Ventricular torsion was essentially absent in the systemic RV (0.3 ± 1.8°), in contrast to a torsion of 16.7 ± 4.8° in the normal LV (p < 0.001).ConclusionsIn the systemic RV as in the normal LV, there was predominant circumferential over longitudinal free wall shortening, opposite from findings in the normal RV. This may represent an adaptive response to the systemic load. Noticeably, however, the systemic RV did not display torsion as found in the normal LV.

ObjectivesThe aim of this study was to validate speckle tracking echocardiography (STE) as a method for angle-independent measurement of regional myocardial strain, using sonomicrometry and magnetic resonance imaging (MRI) tagging as reference methods.BackgroundTissue Doppler imaging allows non-invasive measurement of myocardial strain in the left ventricle (LV), but is limited by angle dependency.MethodsStrain measurements with STE were obtained by a custom-made program that allowed tracking of two-dimensional motion of speckle patterns in a B-mode image. In anesthetized dogs, we compared LV long- and short-axis measurements by STE to sonomicrometry during preload changes and regional myocardial ischemia. Measurements in the two orthogonal axes were obtained simultaneously in a single imaging plane. In human subjects, long-axis strain by STE and MRI tagging were compared in multiple segments of the LV.ResultsIn the experimental study there was good correlation and agreement between STE and sonomicrometry for systolic strain in the long axis (r = 0.90, p < 0.001; 95% limits of agreement −4.4% to 5.0%) and systolic shortening in the short axis (r = 0.79, p < 0.001; −5.6% to 5.1%). In the clinical study, 80% of the segments could be analyzed, and correlation and agreement between STE and MRI tagging were good (r = 0.87, p < 0.001; −9.1% to 8.0%).ConclusionsSpeckle tracking echocardiography provides accurate and angle-independent measurements of LV dimensions and strains and has potential to become a clinical bedside tool for quantifying myocardial strain.

ObjectivesThe objective of this study was to investigate the relationship between baseline resting heart rate and incidence of heart failure (HF) and global and regional left ventricular (LV) dysfunction.BackgroundThe association of resting heart rate to HF and LV function has not been well described in an asymptomatic multi-ethnic population.MethodsResting heart rate was measured in participants in the MESA (Multi-Ethnic Study of Atherosclerosis) trial at inclusion. Incident HF was registered (n = 176) during follow-up (median 7 years) in those who underwent cardiac magnetic resonance imaging (n = 5,000). Changes in ejection fraction (ΔEF) and peak circumferential strain (Δεcc) were measured as markers of developing global and regional LV dysfunction in 1,056 participants imaged at baseline and 5 years later. Time to HF (Cox model) and Δεcc and ΔEF (multiple linear regression models) were adjusted for demographics, traditional cardiovascular risk factors, calcium score, LV end-diastolic volume, and mass in addition to resting heart rate.ResultsCox analysis demonstrated that for 1 beat/min increase in resting heart rate, there was a 4% greater adjusted relative risk for incident HF (hazard ratio: 1.04; 95% CI: 1.02 to 1.06; p < 0.001). Adjusted multiple regression models demonstrated that resting heart rate was positively associated with deteriorating εcc and decrease in EF, even when all coronary heart disease events were excluded from the model.ConclusionsElevated resting heart rate was associated with increased risk for incident HF in asymptomatic participants in the MESA trial. Higher heart rate was related to development of regional and global LV dysfunction independent of subclinical atherosclerosis and coronary heart disease. (Multi-Ethnic Study of Atherosclerosis [MESA]; NCT00005487)

ObjectivesThis study sought to determine whether increased carotid intima-media thickness (IMT) is related to reduced regional myocardial function in participants of the Multi-Ethnic Study of Atherosclerosis (MESA).BackgroundCarotid artery IMT is an established index of subclinical atherosclerosis, and tagged magnetic resonance imaging (MRI) can detect incipient alterations of segmental function that precede overt myocardial failure.MethodsThe MESA study is a prospective observational study including four ethnic groups free from clinical cardiovascular disease. Peak midwall systolic circumferential strain (ECC) and regional strain rates were calculated by harmonic phase from tagged MRI data of 500 participants. Systolic ECC and diastolic strain rate were regressed on IMT of the common carotid artery defined by ultrasound, with adjustments for body mass index, blood pressure, cholesterol, diabetes, smoking, left ventricular hypertrophy, C-reactive protein, age, and gender.ResultsThe mean participant age was 66 ± 10 years (mean ± SD). Among the 58 participants, 4% were male and the interquartile (25th to 75th percentile) range for IMT was 0.25 mm. Multiple linear regression analyses showed that increased IMT was related to reduced systolic regional function (less shortening ECC) in all myocardial regions (p < 0.05), except in the inferior wall. The analyses also showed that greater IMT was associated with a lower diastolic strain rate (diastolic reduced function) in all regions (p < 0.01), except in the anterior wall.ConclusionsGreater carotid IMT is associated with alterations of myocardial strain parameters reflecting reduced systolic and diastolic myocardial function. These observations indicate a relationship between subclinical atherosclerosis and incipient myocardial dysfunction in a population free of clinical heart disease.

ObjectivesThis study sought to investigate the relationship between C-reactive protein (CRP) and regional left ventricular (LV) function in asymptomatic individuals without a history of cardiovascular disease.BackgroundC-reactive protein is associated with an increased risk for developing cardiovascular disease. However, the relationship between CRP and subclinical LV dysfunction has not been evaluated in asymptomatic individuals.MethodsRegional myocardial function was analyzed as peak systolic circumferential shortening strain (Ecc) using the harmonic-phase method by tagged magnetic resonance imaging in 1,164 individuals without symptomatic cardiovascular disease from the MESA (Multi-Ethnic Study of Atherosclerosis) trial (age 66.4 ± 9.6 years old). Regions were defined by coronary territories: left anterior descending artery (LAD), left circumflex artery (LCX), and right coronary artery (RCA). The relationship between log-CRP concentration and Ecc was studied by multivariable linear regression after adjustment for demographic characteristics, risk factors, and therapy (including hormone replacement therapy).ResultsFor each region, associations differed by gender with no association of CRP and regional LV function among women. In men, after adjustment, higher log-CRP was significantly associated with lower (absolute) Ecc in the LAD and RCA regions (regression coefficient 0.37 per unit higher log-CRP [95% confidence interval [CI] 0.08 to 0.65] and 0.31 [95% CI 0.02 to 0.59], respectively) and peak systolic Ecc overall (regression coefficient 0.32 [95% CI 0.05 to 0.58]). In the LCX region, the association was weaker (p = 0.06).ConclusionsAmong individuals without evident heart failure or other cardiovascular disorders, higher CRP was associated with lower systolic myocardial function in all regions in men but not in women. These findings support the role of inflammation and atherosclerosis in incipient myocardial dysfunction. (Multi-Ethnic Study of Atherosclerosis; http://clinicaltrials.gov/ct/show/NCT00005487).