Abstract

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

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

Patients and methods: 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.

Results: 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/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 compared with normal subjects (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 LA ejection fraction. No significant difference was present in S-Sr, A-Sr or global atrial strain between the normal and HT cohorts.

Conclusion: 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.