Study on the vectorcardiogram in hypertensive patients

Abstract

Hypertension is noted for its very slow but long clinical course. It is important to predict the case prior to the development of organic changes in the cardiovascular system. The prognosis of hypertension is considered poor when the case is complicated with cardiac disturbances. It is well known that hypertension frequently causes left ventricular hypertrophy as a result of hemodynamic overloading. Many reports have been made on the electrocardiographic findings in left ventricular hypertrophy in hypertensives. However, it is one of the most difficult diagnostic procedures to predict left ventricular hypertrophy on the basis of electrocardiogram. It seems that many criteria proposed for left ventricular hypertrophy so far reported have failed to reach any agreement. The present study was made on possible relationship between vectorcardiographic findings and severity in hypertensives. Material and Method One-hundred and thirty-six cases with essential hypertension were studied. Forty cases without cardiovascular disorders were studied a controls. The subjects studied were divided into 4 groups, from I to IV, according to their severity. The chest was X rayed; the conventional twelve lead electrocardiogram and the vectorcardiogram on Frank's system were recorded at the same time. On the vectorcardiogram, the pattern of QRS loop in horizontal plane, direction and magnitude of maximal QRS vector and maximal T vector, leftward, rightward, anterior, posterior, superior and inferior diameter of QRS loop, width / length ratio of T loop, QRS-T angle and magnitude of maximal T vector/magnitude of maximal QRS vector ratio, etc. were discussed in reference to the grade of severity of hypertension. Result Regarding the pattern of QRS loop in horizontal plane and the grade of severity, Normal type was more frequently found in mild cases (Grade I), than other groups (Grade II to IV), and Left ventricular Hypertrophic type was frequently found in more advanced cases (Grade III to IV). There was no Normal type in severe and progressive cases (Grade III and IV). The magnitude of maximal QRS vector both in frontal and horizontal planes was correlated with the grade of severity and was greater in severe cases.