Abstract 18029: Left Ventricular Systolic Strain in Older Subjects with No Known Cardiac Disease
Introduction: It is known that with increasing age impaired myocardial relaxation increases, while systolic function is preserved. We hypothesize that there is, in fact, subclinical left ventricular (LV) systolic dysfunction in older subjects. We test this hypothesis by assessing LV systolic strain using velocity vector imaging in older subjects with no known cardiac disease.
Methods: One-hundred and ninety consecutive subjects with no known cardiac disease had their echocardiograms analyzed by VVI after excluding patients with a left ventricular ejection fraction(LVEF) <55%, grade 2 and above diastolic dysfunction and QRS duration > 120ms. Subjects were divided into 2 groups based on age; older (> 60 years) and younger (< 60 years). Demographic, clinical and echocardiographic data were collected. Time to peak longitudinal and circumferential strain were calculated from apical 4-chamber, 2-chamber and short axis views. The above collected data were compared between groups.
Results: The final cohort consisted of 136 subjects (46 were older). Mean age was 55 + 16 years, 32% were female and mean LVEF was 60 + 8%. The older group had a higher LVEF (63 + 9% vs. 59 + 6%; p=0.03), smaller LV diastolic dimension (4.4 + 0.5cm vs. 4.7 + 0.5cm; p<0.01) and higher occurrences of diastolic dysfunction (84% vs. 59%; p<0.01) and hypertension (85% vs. 63%; p=0.02), when compared to the younger group. There were no significant differences in the longitudinal and circumferential strain (even with cut-off ages of 50 or 75 years).
Conclusions: Contrary to our hypothesis, older subjects with no known cardiac disease had a better LVEF than their younger counterparts. There were no significant differences in the longitudinal and circumferential myocardial strain between the older and younger groups. Therefore, impaired myocardial relaxation does not appear to have a direct influence on the myocardial contractility or systolic function in older subjects.
- © 2011 by American Heart Association, Inc.