The Relationship Between Circadian Blood Pressure Profile and Left Atrial Mechanics, Arterial Stiffness and Left Ventricular Performance in Hypertensive Patients

Objective: Background: The left atrium plays a crucial role in managing left ventricular filling and contractility through its functions as a reservoir, conduit, and boost pump. Consequently, the interaction between the left atrium(LA), left ventricle(LV), and the arterial system appears as a critical determinant of comprehensive cardiovascular performance. Non-dipping profile of blood pressure(BP) in 24-hr monitoring(ABPM) is associated with increased cardiovascular mortality and morbidity, including atrial fibrillation and stroke. We aimed to investigate the association between LA mechanics, LV performance, arterial stiffness and circadian rhythm of BP in essential hypertension. Design and method: Hypertensive patients without overt cardiovascular disease were recruited. In all subjects 24-hr ABPM and extended echocardiographic image acquisition protocol were performed(Vivid E95, GE). Carotid-femoral pulse wave velocity(PWV) was measured with the SphygmoCor device(Atcor Medical). All analyses, including LV global longitudinal strain(GLS) and LA reservoir strain(LAR), LA conduit strain(LACD), LA booster pump strain(LACT) were performed off-line. The related factors were evaluated by multivariate linear regression analysis to find the independent factors. Statistical analysis was conducted using SPSS statistics software Results: Study group included 219 patients(age 55.3±13.5 years, 55% females). According to BP patterns patients were divided into two groups: non-dippers(n=53), presenting with <10% reduction in both systolic and diastolic BP at nighttime, and dippers(n=166). Non-dippers were older(61.3±11.3 vs 54.2±13.7 years, p<0.01) and exhibited higher BMI(30.2±4.9 vs 28.6±4.5 kg/m2 p<0.01). There were no differences between groups in office BP(non-dippers 128.3±13.3/72.9±9.5 vs 128.1±14.6/75.8±10.8 mmHg in dippers), neither 24hr BP(124.2±13.3/73.5±9.6 vs 121.4±11.5/74.2±7.1 mmHg, respectively). After adjustments for age and BMI, in the non-dipper group higher PWV(8.3±1.2 vs 7.9±1.2, p=0.05) and LACD(-14.7±5.7 vs -17.0±6.7, p<0.001) were observed, with no-differences in LV GLS(-20.7±3.3 vs -19.8±3.9; NS). Multivariate linear regression analysis revealed that age(p<0.001), office(p<0.001) and nighttime SBP(p=0.008)(but not dipping status, p=0.50), diabetes(p=0.02) and creatinine level(p=0.02) were independently corelated with PWV. LACD was independently corelated with age(p<0.001), LV mass(p=0.04) and LV GLS(p=0.03) Conclusions: Arterial stiffness and left atrial performance are associated with circadian rhythm of BP. Nocturnal systolic BP but not dipping profile is the independent risk factor of worse arterial and left atrial performance.