[Show abstract][Hide abstract] ABSTRACT: Background
Left ventricular (LV) dyssynchrony is related to adverse outcomes in systolic heart failure, but its prognostic importance in asymptomatic population is not known. Our objective was to assess the prognostic implications of LV mechanical dyssynchrony in a large multiethnic population before the occurrence of global LV dysfunction.
Methods and Results
A total of 1392 participants in the Multi‐Ethnic Study of Atherosclerosis (MESA; mean age: 64.7 years; 46% were women) with cardiac magnetic resonance imaging at baseline were followed for a median duration of 8.3 years. Harmonic phase imaging analysis was used to derive systolic circumferential strain. Greater standard deviation of time to peak systolic strain (SD‐TPS) indicates greater dyssynchrony. With SD‐TPS as a continuous variable, Cox proportional hazards analysis was used to assess hazards ratio after adjusting for demographics, cardiovascular risk factors, LV mass‐to‐volume ratio, and ejection fraction. Using the 75th percentile of SD‐TPS as a cutoff, Kaplan–Meier analysis was performed between 2 categorical groups for each gender. Higher values of dyssynchrony in women predicted major adverse cardiovascular events, defined as myocardial infarction, heart failure, stroke, and death (hazard ratio: 1.01 per 1‐ms increment in SD‐TPS, P=0.015), hard coronary events (hazard ratio: 1.05 per 1‐ms increment in SD‐TPS, P=0.026), and cerebrovascular events (hazard ratio: 1.03 per 1‐ms increment in SD‐TPS, P=0.013). In contrast, dyssynchrony in men was not predictive of events. Kaplan–Meier analyses in women revealed increased event occurrence in the higher dyssynchrony group, but this was not the case in men.
In an asymptomatic cohort, greater LV dyssynchrony determined by cardiac magnetic resonance imaging predicts adverse cardiovascular outcome in women but not in men.
Clinical Trial Registration
URL: http://clinicaltrials.gov. Unique identifier: NCT00005487.
Journal of the American Heart Association 06/2014; 3(4). DOI:10.1161/JAHA.114.000975 · 4.31 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To investigate the relationship between baseline resting heart rate and incidence of heart failure (HF) and global and regional left ventricular (LV) dysfunction.
The association of resting heart rate to HF and LV function is not well described in an asymptomatic multi-ethnic population.
Participants in the Multi-Ethnic Study of Atherosclerosis had resting heart rate measured at inclusion. Incident HF was registered (n=176) during follow-up (median 7 years) in those who underwent cardiac MRI (n=5000). Changes in ejection fraction (ΔEF) and peak circumferential strain (Δεcc) were measured as markers of developing global and regional LV dysfunction in 1056 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.
Cox analysis demonstrated that for 1 bpm increase in resting heart rate there was a 4% greater adjusted relative risk for incident HF (Hazard Ratio: 1.04 (1.02, 1.06 (95% CI); P<0.001). Adjusted multiple regression models demonstrated that resting heart rate was positively associated with deteriorating εcc and decrease in EF, even in analyses when all coronary heart disease events were excluded from the model.
Elevated resting heart rate is associated with increased risk for incident HF in asymptomatic participants in MESA. Higher heart rate is related to development of regional and global LV dysfunction independent of subclinical atherosclerosis and coronary heart disease.
Journal of the American College of Cardiology 12/2013; 63(12). DOI:10.1016/j.jacc.2013.11.027 · 16.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this study is to determine the test-retest reliability of the measurement of regional myocardial function by cardiovascular magnetic resonance (CMR) tagging using spatial modulation of magnetization.
Twenty-five participants underwent CMR tagging twice over 12 ± 7 days. To assess the role of slice orientation on strain measurement, two healthy volunteers had a first exam, followed by image acquisition repeated with slices rotated ±15 degrees out of true short axis, followed by a second exam in the true short axis plane. To assess the role of slice location, two healthy volunteers had whole heart tagging. The harmonic phase (HARP) method was used to analyze the tagged images. Peak midwall circumferential strain (Ecc), radial strain (Err), Lambda 1, Lambda 2, and Angle α were determined in basal, mid and apical slices. LV torsion, systolic and early diastolic circumferential strain and torsion rates were also determined.
LV Ecc and torsion had excellent intra-, interobserver, and inter-study intra-class correlation coefficients (ICC range, 0.7 to 0.9). Err, Lambda 1, Lambda 2 and angle had excellent intra- and interobserver ICC than inter-study ICC. Angle had least inter-study reproducibility. Torsion rates had superior intra-, interobserver, and inter-study reproducibility to strain rates. The measurements of LV Ecc were comparable in all three slices with different short axis orientations (standard deviation of mean Ecc was 0.09, 0.18 and 0.16 at basal, mid and apical slices, respectively). The mean difference in LV Ecc between slices was more pronounced in most of the basal slices compared to the rest of the heart.
Intraobserver and interobserver reproducibility of all strain and torsion parameters was excellent. Inter-study reproducibility of CMR tagging by SPAMM varied between different parameters as described in the results above and was superior for Ecc and LV torsion. The variation in LV Ecc measurement due to altered slice orientation is negligible compared to the variation due to slice location.
This trial is registered as NCT00005487 at National Heart, Lung and Blood institute.
Journal of Cardiovascular Magnetic Resonance 05/2013; 15(1):37. DOI:10.1186/1532-429X-15-37 · 4.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Systemic inflammation has been linked to the development of heart failure in population studies including Multi-Ethnic Study of Atherosclerosis (MESA), but little evidence exists regarding potential mechanism of this relationship. In this study, we used longitudinal magnetic resonance imaging follow-up analysis to examine whether C-reactive protein (CRP) levels relate to progressive myocardial functional deterioration as a potential mechanism of incident heart failure.
Regional myocardial functional data from MESA participants who had baseline CRP measurement and also underwent tagged cardiac magnetic resonance imaging both at baseline and at 5-year follow-up were analyzed. Left ventricular midwall and midslice peak circumferential strain (Ecc), of which a more negative value denotes stronger regional myocardial function, was measured. Circumferential strain change was calculated as the difference between baseline and follow-up Ecc.
During the follow-up period, participants (n = 785) with elevated CRP experienced a decrease in strain, independent of age, gender, and ethnicity (B = 0.081, ∆Ecc change per 1 mg/L CRP change, 95% CI 0.036-0.126, P < .001, model 1) and, additionally, beyond systolic blood pressure, heart rate, diabetes, smoking status, body mass index, current medication, and glomerular filtration rate (B = 0.099, 0.052-0.145, P < .001, model 2). The relationship remained statistically significant after further adjustment for left ventricular mass, coronary calcium score, and interim clinical coronary events (B = 0.098, 0.049-0.147, P < .001, model 3).
Higher CRP levels are related to progressive myocardial functional deterioration independent of subclinical atherosclerosis and clinical coronary events in asymptomatic individuals without previous history of heart disease.
American heart journal 08/2012; 164(2):251-8. DOI:10.1016/j.ahj.2012.05.010 · 4.46 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Invasive and non-invasive tests have been used to identify the risk of ventricular tachycardia (VT) in patients with chronic Chagas' heart disease (CCHD). Cardiac magnetic resonance imaging (CMRI) using the delayed enhancement (DE) technique can be useful to select patients with global or segmentary ventricular dysfunction, with high degree of fibrosis and at higher risk for clinical VT.
To improve the identification of predictors of VT in patients with CCHD.
This study assessed 41 patients with CCHD [30 (72%) males; mean age, 55.1 ± 11.9 years]. Twenty-six patients had history of VT (VT group), and 15 had no VT (NVT group). All patients enrolled had DE and segmentary ventricular dysfunction. In each case, the following variables were determined: left ventricular volume; percentage of ventricular wall thickness impairment in each segment; and DE distribution.
No statistical difference regarding the DE volume between both groups was observed: VT group = 30.0 ± 16.2%; NVT group = 21.7 ± 15.7%; p = 0.118. The probability of VT was greater in the presence of two or more contiguous transmural fibrosis areas, and that was a predictive factor of clinical VT (RR 4.1; p = 0,04). Agreement between observers was 100% regarding that criterion (p < 0.001).
The identification of two or more segments of transmural DE by use of CMRI is associated with the occurrence of clinical VT in patients with CCHD. Thus, CMRI improved risk stratification in the population studied.