Strain rate evaluation of phasic atrial function in hypertension

Suzanne Eshoo ^1*, Anita C Boyd ², David L Ross ¹, Thomas H Marwick ³ and Liza Thomas ⁴

¹ University of Sydney, Westmead Hospital, Australia
² Westmead Hospital, Australia
³ University of Queensland, Princess Alexandra Hospital, Brisbane, Australia
⁴ University of NSW, Liverpool Hospital, Australia

^* To whom correspondence should be addressed. E-mail: suz2153{at}yahoo.com.au.

Accepted 16 December 2008

Abstract

Objectives: The objective of this study is to examine the feasibility of using strain (SI) and strain rate (SR) to evaluate phasic atrial function in patients with mild HT.

Background: Strain and strain rate measure regional myocardial deformation and may be a novel technique to assess phasic atrial function.

Design: The study population consisted of 54 patients with mild essential HT (29 females) and 80 age-matched normal controls (47 females). Standard two-dimensional and Doppler echocardiography was performed as well as Doppler tissue imaging. The following left atrial (LA) volumes were measured: 1) maximal LA volume or Vol_max, 2) minimal LA volume or Volmin and 3) just prior to the ‘p’ wave on ECG (Vol_p). Phasic LA volumes were also calculated. Systolic (S-Sr), early diastolic (E-Sr), late diastolic (A-Sr) strain rate and SI were measured.

Results: Despite no differences in indexed maximal LA volume with only mild increases in LV mass in the HT cohort compared to normals (86 ± 18 g/m2 vs. 67 ± 14 g/m2; p = 0.001), E-Sr was significantly lower in the HT cohort. There was a corresponding reduction in indexed conduit volume in the HT cohort vs. normals (10.5 ± 7.5 mL/m2 vs. 13.8 ± 6.1 mL/m2; p = 0.006). Global E-Sr showed modest negative correlations with LA Vol_max and LAEF. No significant difference was present in S-Sr, A-Sr or global atrial strain between the normal and HT cohorts.

Conclusion: We have demonstrated that mild HT results in a reduction in LA conduit volume although maximal LA volume is unchanged. This is reflected by a reduction in E-Sr with preserved S-Sr and A-Sr.