Strain rate evaluation of phasic atrial function in hypertension

Strain (SI) and strain rate (SR) measure regional myocardial deformation and may be a new technique to assess phasic atrial function.

To examine the feasibility of using SI and SR to evaluate phasic atrial function in patients with mild hypertension (HT).

The study group comprised 54 patients with mild essential HT (29 women) and 80 age-matched normal controls (47 women). Standard two-dimensional and Doppler echocardiography was performed as well as Doppler tissue imaging. The following left atrial (LA) volumes were measured: (a) maximal LA volume or Vol(max); (b) minimal LA volume or Vol(min); (c) just before 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.

Despite no differences in indexed maximal LA volume with only mild increases in left ventricular mass in the HT cohort compared with normal subjects (mean (SD) 86 (18) g/m(2) vs 67 (14) g/m(2); 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 compared with normal subjects (10.5 (7.5) ml/m(2) vs 13.8 (6.1) ml/m(2); p = 0.006). Global E-Sr showed modest negative correlations with LA Vol(max) and LA ejection fraction. No significant difference was present in S-Sr, A-Sr or global atrial strain between the normal and HT cohorts.

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.