[Changes in ST segment on ECG of hypertensive patients]

To evaluate ST depression in hypertensive patients with electrocardiographic signs of left ventricular hypertrophy (LVH), correlation of ST segment changes with heart rate (HR) and blood pressure (BP) during Holter monitoring (HM) and bi-functional ECG and BP monitoring (BFM), and to compare ST depression and local left ventricular contractility during stress-echocardiography in hypertensive patients with unaffected coronary arteries according to the data of coronary angiography.

We examined 344 hypertensive patients without clinical signs of ischemic heart disease. Correlation between ST segment depression and ECG signs of LVH was evaluated in 192 patients. 180 patients underwent HM, 122--BFM and 30 hypertensive patients with normal coronary arteries according to the data of coronary angiography underwent stress-echocardiography.

According to the data of 12 lead ECG 40 cases of ST depression were found, with LVH signs in 26 (65%) of these patients. During HM in 34 of 180 patients 2 types of ST depression were found: type 1--short periods of transient ST depression without persistent ST depression was fond in 8 patients; type 2--persistent ST depression more than 1 mm during the whole time of recording--in 26 patients. In 7 of 8 cases of type 1 and in 5 of 26 cases of type 2 ST depression had rhythm-dependent character. During BFM in 9 cases ST depression during HR or BP increase was found. In 2 cases ST depression during BP increase was unrelated to HR increase which may be consequence of systolic myocardial strain syndrome. In 7 of 30 hypertensive patients with normal coronary arteries and without local myocardial contractility disturbances according to the data of stress-echocardiography positive criteria of ischemia were found.

The cause of ST segment depression in hypertensive patients more often are secondary disturbances of repolarizaion processes related with LVH development. In some cases such patients during HM show rhythm-dependent valuable ST depressions. In BFM cases of left ventricular myocardial strain syndrome are found, similar cases are also seen in stress-echocardiography. However, in some cases one fails to define the reason of ST changes even approximately. One of the factors leading to disturbances of repolarization processes in hypertensive patients may be disturbances of microcirculation at the level of prearteriols and capillaries.