ELECTROCARDIOGRAPHIC SIGNS OF ATRIAL OVERLOAD IN HYPERTENSIVE PATIENTS - INDEXES OF ABNORMALITY OF ATRIAL MORPHOLOGY OR FUNCTION

Left atrial electrocardiographic (ECG) abnormalities have been reported as common findings in hypertension; however, their relationships with atrial anatomy are still uncertain. In addition, in arterial hypertension several studies demonstrated an abnormal left ventricular filling. The aim of this study was to investigate the relationships of the ECG signs of left atrial abnormality to atrial anatomy and left ventricular filling as evaluated by pulsed-wave (PW) Doppler in a group of patients with uncomplicated essential hypertension. To this end, 53 untreated essential hypertensive patients (age 44 +/- 8 years; blood pressure 160.5 +/- 21.5/104.7 +/- 13.5 mm Hg) underwent a complete 12-lead ECG and a PW Doppler study of the transmitral flow velocities. The ECG criteria of left atrial abnormality were: P wave wider than 0.12 (or 0.10) second or higher than 0.25 mV in lead II; P wave/PR segment ratio (Macruz index) greater than 1.6 in lead II; and P wave terminal forces in lead V1 equal to or more negative than 0.04. Echocardiographic measurements were made according to American Society of Echocardiography (ASE) convention. Doppler parameters of left ventricular filling were measured as E and A peak velocity, A/E ratio, and the ratio between the velocity-time integral under the E peak and that of the whole diastolic flow, which represents the rapid filling fraction (RFF). At least one ECG sign of atrial abnormality was present in 34 patients (64%); the Macruz index gave the most common ECG index of atrial abnormality (31 patients). The group of patients with a Macruz index greater than 1.6 had a significantly greater relative contribution to left ventricular filling, thicker left ventricular walls, a faster heart rate but no different atrial dimensions (p from < 0.05 to < 0.001). In a subgroup matched for R-R interval, significant differences between patients with normal and abnormal Macruz index were still observed for interventricular septum thickness and A peak. Echocardiographic left atrial (LA) dimension did not show any significant correlation with the ECG parameters of LA involvement. On the contrary, significant correlations were observed between several ECG indexes of atrial abnormality and A, A/E, RFF, and heart rate. In conclusion, our results suggest that, at least in hypertensive patients, the ECG signs of LA abnormality are more related to increased atrial work, possibly secondary to an impaired ventricular filling, rather than to LA enlargement.