We sought to investigate (1) left atrial (LA) and right atrial (RA) phasic function and mechanics; (2) heart rate variability (HRV); and (3) their relationship in untreated hypertensive patients. This cross-sectional study involved 73 untreated hypertensive patients and 51 subjects without cardiovascular risk factors with similar gender and age. All the subjects underwent a 24-hour Holter monitoring and comprehensive two- and three-dimensional echocardiography examination. LA and RA reservoir and conduit function, estimated by total and passive atrial emptying fractions and systolic and early diastolic strain rates, were reduced in the hypertensive patients. On the other hand, LA and RA booster function, assessed by active atrial emptying fraction and late diastolic strain rate, was increased in this group. All time and frequency domain heart-rate variability parameters were reduced in the hypertensive subjects. In the whole study population, parameters of cardiac sympathovagal balance (standard deviation of all normal RR intervals, root mean square of the difference between the coupling intervals of adjacent R-R intervals, 24-hour low-frequency domain [0.04-0.15 Hz], 24-hour high-frequency domain [0.15-0.40 Hz], and 24-hour total power [0.01-0.40 Hz]) correlated with LA and RA volume indexes, biatrial booster function assessed by active emptying fraction, biatrial longitudinal function evaluated by longitudinal strain; and biatrial expansion index. LA and RA phasic function and mechanics are significantly impaired in the untreated hypertensive patients. Heart-rate variability parameters are also deteriorated in the hypertensive population. Biatrial function and mechanics correlated with cardiac autonomic nervous system indexes in the whole study population.
Keywords: Arterial hypertension; heart rate variability; left atrium; mechanics; phasic function; right atrium.