Age, increased left ventricular mass, and lower regional myocardial perfusion are related to greater extent of myocardial dyssynchrony in asymptomatic individuals: the multi-ethnic study of atherosclerosis

Abstract

Background: Age and left ventricular (LV) hypertrophy are risk factors for the development of LV dysfunction and congestive heart failure. Our goal was to study the relationships of LV mass and age with myocardial dyssynchrony among asymptomatic participants of the Multi-Ethnic Study of Atherosclerosis.

Methods and results: A total of 1100 individuals underwent tagged magnetic resonance imaging. Regional LV function was analyzed with the use of harmonic phase imaging. Time to peak systolic circumferential strain and strain rate were measured in 12 segments, and myocardial dyssynchrony was expressed as the SD of time to peak strain and strain rate. Relationships of age, LV mass, and myocardial perfusion with timing of strain, strain rate, and dyssynchrony were studied. There was a positive relationship between age and time to peak strain before (regression coefficient=0.37 ms/year of age; 95% confidence interval, 0.05 to 0.70; P=0.025) and after adjustment for demographic characteristics and risk factors (P=0.007). Positive associations between age and SD of time to peak strain (regression coefficient=0.33 ms/year of age; P=0.002) and SD of time to peak systolic strain rate were documented (P=0.045). Importantly, we found that LV mass index is directly related to time to peak strain (P<0.001), time to peak strain rate, and the SD of time to strain rate (P=0.001 for all). Finally, decreased myocardial perfusion at rest was associated with delayed contraction and increased extent of dyssynchrony.

Conclusions: In asymptomatic individuals, age, increased LV mass, and decreased myocardial perfusion are related to delayed myocardial contraction and greater extent of dyssynchrony. Increased dyssynchrony may mediate the association of myocardial dysfunction with age and LV hypertrophy.

Trial registration: ClinicalTrials.gov NCT00005487.

Conflict of interest statement

Disclosures

There are no conflicts of interest or disclosures.

Figures

Figure 1. Strain and strain rate curves

Circumferential strain (upper curve) and strain rate plots (lower curve). X axis indicates time from end-diastole (ms). Peak systolic circumferential strain and strain rates are shown. Ecc- circumferential strain, SRs- peak systolic strain rate, SRE – peak early diastolic relaxation rate. (E wave). SRA– peak late diastolic relaxation rate. (A wave).

Figure 2. Relation between age and time to peak systolic strain, strain rate and their standard errors (trend tested by ANOVA, p- significance value)

Relation between increasing age and time (ms) to peak systolic strain (a), strain rate (b) and SD of strain (c) and strain rate (d). X axis shows age groups (45–54, 55–64, 65–74, and 75–85 years). Y axis indicates time to peak systolic strain (a), strain rate (b), SD of time to peak systolic strain (c) and SD of time to peak systolic strain rate (d). Standard error (SE) bars are depicted.

Figure 2. Relation between age and time to peak systolic strain, strain rate and their standard errors (trend tested by ANOVA, p- significance value)

Relation between increasing age and time (ms) to peak systolic strain (a), strain rate (b) and SD of strain (c) and strain rate (d). X axis shows age groups (45–54, 55–64, 65–74, and 75–85 years). Y axis indicates time to peak systolic strain (a), strain rate (b), SD of time to peak systolic strain (c) and SD of time to peak systolic strain rate (d). Standard error (SE) bars are depicted.

Figure 3. Relation between LV mass index (LV mass/height2.7) and time to peak systolic strain, strain rate and their standard errors (trend was tested by ANOVA, p- significance value)

Relation between quartiles of increasing LV mass index (LV mass/height2.7) and time (ms) to peak systolic strain (a), strain rate (b) and SD of strain (c) and strain rate (d). X axis shows quartiles of LV mass index, Y axis indicates time to peak systolic strain (a), strain rate (b), SD of time to peak systolic strain (c) and SD of time to peak systolic strain rate (d). S.E bars are shown.

Figure 3. Relation between LV mass index (LV mass/height2.7) and time to peak systolic strain, strain rate and their standard errors (trend was tested by ANOVA, p- significance value)

Relation between quartiles of increasing LV mass index (LV mass/height2.7) and time (ms) to peak systolic strain (a), strain rate (b) and SD of strain (c) and strain rate (d). X axis shows quartiles of LV mass index, Y axis indicates time to peak systolic strain (a), strain rate (b), SD of time to peak systolic strain (c) and SD of time to peak systolic strain rate (d). S.E bars are shown.

Figure 3. Relation between LV mass index (LV mass/height2.7) and time to peak systolic strain, strain rate and their standard errors (trend was tested by ANOVA, p- significance value)

Relation between quartiles of increasing LV mass index (LV mass/height2.7) and time (ms) to peak systolic strain (a), strain rate (b) and SD of strain (c) and strain rate (d). X axis shows quartiles of LV mass index, Y axis indicates time to peak systolic strain (a), strain rate (b), SD of time to peak systolic strain (c) and SD of time to peak systolic strain rate (d). S.E bars are shown.

Figure 3. Relation between LV mass index (LV mass/height2.7) and time to peak systolic strain, strain rate and their standard errors (trend was tested by ANOVA, p- significance value)

Relation between quartiles of increasing LV mass index (LV mass/height2.7) and time (ms) to peak systolic strain (a), strain rate (b) and SD of strain (c) and strain rate (d). X axis shows quartiles of LV mass index, Y axis indicates time to peak systolic strain (a), strain rate (b), SD of time to peak systolic strain (c) and SD of time to peak systolic strain rate (d). S.E bars are shown.