About 50 Arterial Hypertension patients with developed Heart Failure were examined: left atrium ECG and Echocardiogram changes were estimated comparatively in dynamics. It is well known, that in patients with Arterial Hypertension developed changes of the Left Ventricle End-Diastolic pressure manifest not only in the Left Ventricle but in Left Atrium also. So that diastolic dysfunction and systolic dysfunction both increase the loading of the Left Atrium. By the cause of the Left Atrium muscle weakness comparatively with Left Ventricle muscle, it manifests firstly by functional and structure disturbances of the Left Atrium. We investigated these disturbances in patients with Arterial Hypertension by evaluation of their Electrocardiogram and Echocardiogram indices in dynamics. Ongoing research comparing ECG and Echocardiogram changes gave us the opportunity to reveal Left Atrium ECG disturbances relatively earlier than Echocardiogram structural changes. Many times when we revealed ECG signs of Left Atrium enlargement and loading, we did not observe any changes of the Echocardiogram indices at the early period. Performed investigations in Arterial Hypertension patients with Heart Failure give the possibility to observe appropriate ECG changes firstly. These changes may be the early predictor of the possible developing Heart Failure in such patients, moreover it makes possible an optimal Arterial Hypertension management retarding and delaying the origin of the Heart Failure.