Abstract 729: Assessment of Interatrial Conduction Time by Means of Echo-Tissue Doppler in Patients With Hypertension
Objectives: Prolongation of interatrial conduction time (IACT) as an index of atrial electrical dysfunction is considered an important factor in the pathophysiology of atrial fibrillation. The purpose of this study was to assess atrial electrical function by tissue Doppler imaging (TDI) and to determine related structural and hemodynamic alterations of the heart by conventional echocardiography in hypertensive patients.
Methods: The study included 70 hypertensive patients and 33 control subjects who underwent echocardiographic studies. We measured the interval of time from initiation of the P wave on the electrocardiogram (ECG) until the beginning of the late diastolic TDI signal at the left atrial wall (P-LA′) and the right atrial wall (P-RA′) for the assessment of IACT which was defined as the difference between the P-LA′ and P-RA′ intervals (LA′ - RA′). The other echocardiographic measurements to determine the structral and hemodynamic changes in the heart in consequence of hypertension were the following: left atrial volume index (LAVI), left ventricular mass index (LVMI), ejection fraction (EF), E/e′ and myocardial performance index (MPI).
Results: (see Table⇓). LAVI, LVMI, E/e’ and MPI were significantly higher in patients with hypertension compared with controls. IACT was longer in hypertensive patients (27.71±13.01 vs 20.30±10.02 msec, respectively; P=0,005). A positive correlation was found between IACT and LV mass index (P=0,006). There was no significant correlation between the IACT and other echocardiographic parameters.
Conclusions: The TDI-derived IACT can be prolonged in hypertensive patients. This electrical alteration in the atrium is associated with increased left ventricular mass index. A potential mechanism explaining this observation may be that the left atrial remodeling parallels the devolopment of changes in left ventricular mass is accompanied by changes in atrial synchronization.