Night-time blood pressure predicts left atrial enlargement
Higher values and variability of night-time blood pressure are linked with left atrial enlargement, a recent study has found.
A total of 140 patients (mean age 64±10 years; 74 percent male) were eligible for analysis, of whom 59 percent (n=82) had paroxysmal while 41 percent (n=58) had persistent atrial fibrillation (AF). Majority (74 percent) had well-controlled hypertension without the coexistence of left ventricular hypertrophy.
Multiple regression analysis adjusted for age, sex, antihypertensive medication and left ventricular mass index showed that mean night-time systolic (SBP; β, 0.32; p<0.0001) and diastolic (DBP; β, 0.35; p<0.0001) blood pressure, along with their respective variabilities (SBP: β, 0.20; p<0.01; DBP: β, 0.23; p<0.01) were significantly correlated with left atrial volume index.
These remained significant predictors of volume even after additional adjustments for the timing of antihypertensive medication, left ventricular ejection fraction, cardio-ankle vascular index and the type of atrial fibrillation.
In contrast, no such significant influence on left atrial volume was exerted by casual SBP (β, 0.14; p=0.07) and DBP (β, 0.14; p=0.07).
To test its predictive value, researchers divided the participants into four groups according to night-time blood pressure and its variability. Those with the highest night-time BP (≥120/70 mm Hg) and variability (standard deviation≥12.2/7.9 mm Hg) had significantly larger left atrial volume indices than those with lower values (46.6±13.5 vs 35.0±8.8 mL/m2; p<0.0001).
For the present study, a home monitoring device was provided for the measurement of night-time BP, which collected hourly measurements during sleep hours. Left atrial volume was assessed through transthoracic echocardiography.