Abstract 2999: Left Ventricular Mass Predicts Greater Dyssynchrony and Delayed Contraction among Asymptomatic Individuals: The Multi-Ethnic Study of Atherosclerosis.
Background: Left ventricular hypertrophy is associated with a higher prevalence of CHF. Myocardial dyssynchrony contributes to LV dysfunction and CHF. Yet, the relationship between dyssynchrony and LV mass has not been investigated among asymptomatic individuals. Our aim was to determine the relationship between LV mass and myocardial dyssynchrony in the general population as a potential contributor to CHF.
Methods: Regional LV function was measured by tagged MRI in 1,100 asymptomatic participants of the Multi-Ethnic Study of Atherosclerosis with no history of cardiovascular disease (age: 45– 84 years old). Timing of peak systolic strain and strain rate was determined in four regions (septum, anterior, lateral and inferior wall) in three short axis slices. Dyssynchrony was determined as standard deviation (SD) of time to peak strain and strain rate in 12 LV wall segments. The association between LV mass and dyssynchrony was determined after adjustment for age, gender, ethnicity, BMI and risk factors including hypertension, diabetes, smoking and hypercholesterolemia and treatment for hypertension.
Results: (Table⇓) Higher LV mass was associated with greater extent of dyssynchrony expressed as SD of time to peak strain rate (after multivariate adjustment, RC=0.08 msec/gr. LV mass, 95% CI= 0.035 to 0.13, p< 0.001).Increased LV mass was also related to longer time to peak systolic strain averaged across all 12 LV wall segments (RC after multivariate adjustment was 0.33 msec/gr, 95% CI= 0.22– 0.44, p< 0.001), and time to peak strain rate was directly related to LV mass (R.C= 0.20 msec/g, p< 0.001). There was no significant relationship between LV mass and SD of time to peak systolic strain.
Conclusion: Higher LV mass is related to delayed myocardial contraction and greater extent of dyssynchrony even among asymptomatic individuals. LV mass related contractile dyssynchrony may be an important contributor to the higher prevalence of CHF in individuals with LV hypertrophy.