Introduction: Left atrial strain is an emerging concept to measure LA hemodynamics which also correlates indirectly with LVEDP. It has been well studied in atrial fibrillation and HFrEF. Its use in HFpEF is still being evaluated.
Hypothesis: To study the relationship between LA strain and other parameters like e/e’ - the ratio of early mitral inflow velocity to mitral annular early diastolic velocity, left atrial volume index(LAVI), age and global longitudinal strain, thereby assessing if LA strain could be a viable tool in evaluating diastolic dysfunction.
Methods: A comprehensive search was done across all relevant databases for studies that assessed LA strain in HFpEF. We identified 16 pertinent studies. We evaluated the patient demographics as well as the customary measurements of LV diastolic dysfunction. Multivariate meta-regression was then employed to detect those parameters that were likely to influence LA strain.
Results: Using echocardiographic parameters for diastolic dysfunction, patients were divided into symptomatic & asymptomatic groups. Of particular interest was the relationship between LA strain and e/e’. While a univariate statistically significant inverse linear correlation was noted, age seemed to be a confounder. After controlling for age, this relationship was no longer evident. Interestingly, studies involving younger patients had an inverse correlation between the two, whereas those involving elderly patients had a direct correlation. LA strain was also found to be negatively correlated with LAVI and age.
Conclusion: LA strain by speckle tracking echocardiography is a promising tool for assessment of LA and LV function. Given certain limitations in measurement of e/e’ (atrial fibrillation, dilated LV, poor CI and CRT), LA strain which is easier to perform and a more accurate measure of LA function could be useful. Interestingly, the utility of this measurement seems to be determined by age which should be addressed in future studies.