Detection of atrial electrical and mechanical dysfunction in non-dipper pre-hypertensive subjects.

Introduction: A relationship between atrial conduction time and hypertension was shown in previous studies. Increased atrial electromechanical intervals used to predict atrial fibrillation by measured tissue Doppler imaging (TDI). So we aimed to search if there was any association between the non-dipping status and atrial electromechanical intervals in pre-hypertensive patients.

Methods: Forty-one non-dipper and 33 dipper pre-hypertensive subjects enrolled in the study. Systolic and diastolic blood pressures were measured with a mercury sphygmomanometer. Twenty-four hours blood pressure was measured with cuff-oscillometric method. All patients were evaluated by transthoracic echocardiography. Using tissue Doppler imaging (TDI), atrial electromechanical coupling (PA) was measured from the lateral mitral annulus (PA lateral), septal mitral annulus (PA septum) and right ventricular tricuspid annulus (PA tricuspid).

Results: Systolic and diastolic blood pressures were significantly higher in subjects with non-dipper phenomenon than dipper ones at night. Twenty-four hours average systolic and diastolic blood pressures were higher in non-dipper pre-hypertensive subjects, but this elevation was not significant. Left and right intraatrial (PA lateral-PA septum and PA septum-PA tricuspid) and interatrial (PA lateral-PA tricuspid) electromechanical coupling intervals were measured significantly higher in non-dipper pre-hypertensive patients (31.3 ± 3.9 versus 24.1 ± 2.3, p = 0.001; 19.5 ± 4.3 versus 13.8 ± 2.1, p = 0.001; and 11.4 ± 2.8 versus 8.8 ± 1.5, p = 0.001). Also, interatrial electromechanical delay was negatively correlated with dipping levels.

Conclusion: This study showed that prolonged atrial electromechanical intervals were related non-dipper pattern in pre-hypertensive patients. Prolonged electromechanical intervals may be an early sign of subclinical atrial dysfunction and arrhythmias' in non-dipper pre-hypertensive patients.