Impact of abnormal circadian blood pressure profile on left atrial function assessed by 2D speckle tracking echocardiography and its effect on the functional capacity of hypertensive patients

Background
The left atrial (LA) function has an important role in hypertension as it is strongly predictive of adverse cardiac events and death, assessment of the circadian blood pressure (BP) profile is more predictive than assessment of the office BP reading in estimating the cardiovascular risk. The 2D speckle tracking echocardiography (2D-STE) provides more insight into early hypertension-induced LA dysfunction.
Aim
The aim of this work is to assess the impact of abnormal circadian BP profile on LA function using 2D-STE and its effect on functional capacity in hypertensive patient with preserved ejection fraction assessed by conventional echocardiography.
Patients and methods
This work included 60 consecutive hypertensive patients with preserved ejection fraction by conventional echocardiography [mean age 48±5 years and body surface area (BSA) 1.9±1.1] they were classified into two groups according to the data derived from 24 h ambulatory BP, group 1: dipper group that included 28 patients (mean age 48±8 years and BSA 1.9±0.1) and group 2: nondipper group that included 32 patients (mean age 50±6 years and BSA 1.9±0.09). All patients were evaluated by comprehensive 2D and Doppler echocardiographic techniques, TDI and 2D-STE, ambulatory BP, and stress. Myocardial perfusion imaging using treadmill exercise test was done to exclude coronary artery disease (CAD) and to assess the functional capacity.
Results
The results showed a statistically high significant decrease in the average peak left atrial global longitudinal strain in group 2 (the nondipper group) (group 1=26±4 vs. 20.4±3.5 in group 2, <0.00), and a statistically significant decrease in the functional capacity parameter using treadmill metabolic equivalents (METs) in group 2 (group 1=7.3±1.4 vs. 6.2±0.8 in group 2, <0.01) in comparison with group 1. Also we found a significant positive correlation between the average peak atrial longitudinal strain and the functional capacity assessed by treadmill stress test (=0.424, =0.05). There were no other significant differences between the two groups with respect to other LA parameters by conventional echo Doppler, TDI, and 2D-STE.
Conclusion
Abnormal circadian BP profile add more deleterious effect on LA function in hypertensive patients as detected by 2D-STE that denotes more decrease in functional capacity and worse cardiac events.