Left atrial mechanical function in patients with essential hypertension

Objective - This study was carried out to assess the left atrial (LA) mechanical function in patients with essential hypertension with two-dimensional echocardiography by means of left atrial volume measurements. Methods - LA volumes were measured echocardiographically in 36 untreated hypertensive patients and 20 age-sex-matched healthy controls according to biplane area-length method. LA volume measurements were done at the time of mitral valve opening (V-max), at the onset of atrial systole (p wave at the electrocardiography = V-p) and at closure (V-min). All volumes were indexed for body surface area, and the following left atrial emptying functions were calculated: LA passive emptying volume = V-max - V-p, LA passive emptying fraction = LA passive emptying volume / V-max, conduit volume = left ventricular stroke volume-(V-max - Vmin), LA active emptying volume = V-p - V-min, LA active emptying fraction = LA active emptying volume / V-p, LA total emptying volume = (V-max - V-min), LA total emptying fraction = LA total emptying volume / V-max. Results - V-max (p < 0.01), V-min (P < 0.005) and V-p (p < 0.001) were significantly greater in hypertensives than in controls. Although LA passive emptying volume (p < 0.001), LA, passive emptying fraction (p < 0.001), conduit volume (p < 0.005) and LA total emptying fraction (p < 0.05) were found to be significantly lower in hypertensives than in controls, LA active emptying volume (p < 0.001) and LA active emptying fraction (p < 0.01) were found to be significantly greater in hypertensives than in controls. LA total emptying volume (p > 0.05) was similar in both groups. Conclusion - The results of the present study indicate that chronic hypertension is associated with an increased in left atrial volumes, a decrease in left atrial passive emptying function, and an increase systolic pump function. Increased left atrial pump function represents a compensatory mechanism in hypertensive patients with left ventricular hypertrophy.