Evaluation of heart size measurements

Autor: Harry E. Ungerleider, Richard S. Gubner
Rok vydání: 1942
Předmět:
Zdroj: American Heart Journal. 24:494-510
ISSN: 0002-8703
DOI: 10.1016/s0002-8703(42)90966-9
Popis: Accurate estimation of the size of the heart is important. So far as possible, an attempt should be made to define enlargement in terms of the individual chambers, for characteristic changes occur in various types of heart disease. Enlargement of the cardiac chambers other than the left ventricle cannot be detected on physical examination except in advanced stages. Fluoroscopic or roentgenographic examination in frontal and oblique positions is of greater advantage in evaluating enlargement because the contours of the separate chambers may be visualized. If proper account is taken of the physiologic variables which influence the size of the heart, mensuration is of value in ascertaining whether the heart is enlarged. Measurements are of greater value as an index of generalized enlargement of the heart than in ascertaining the size of the individual chambers. There is a definite field of usefulness for measurement standards in evaluating the size of the heart as a whole, for frequently enlargement does not involve individual chambers distinctly, and one can state only that the heart is enlarged. Mensuration is unnecessary when gross enlargement exists, but lesser degrees of enlargement often escape detection on inspection. Conversely, an apparently large cardiac shadow may assume less significance when it is considered in relation to body build. The most practicable measurements are the transverse diameter and the area of the frontal heart silhouette. Planimetric measurement of the cardiac area is difficult and inaccurate in the teleroentgenogram, but the area may be calculated with considerable accuracy from the product of the long and broad diameters. A nomogram which enables one to calculate the frontal area from the long and broad diameters is presented. Predicted values for the frontal area from weight and height are shown on the same nomogram, and, in addition, the predicted transverse diameter of the heart and of the frontal aortic arch silhouette are included. These measurements, i.e., the frontal area, the transverse diameter of the heart, and the transverse diameter of frontal aortic arch silhouette suffice for evaluating the size of the heart. Employment of the nomograms permits the convenient application of these more valuable cardiac measurements. Measurements are not to be regarded as final, but should be employed to complement careful study of the individual cardiac chambers by fluoroscopic examination; and the diagnostic significance of cardiac enlargement should always be considered in relation to the associated clinical observations. Characteristic electrocardiographic patterns are observed when there is enlargement of the various chambers, and it is emphasized that the electrocardiogram provides the most sensitive method for detecting hypertrophy of the left ventricle. Roentgenologic methods are superior in revealing auricular and right ventricular enlargement, or when generalized enlargement exists. The electrocardiographic changes are the result of hypertrophy, rather than enlargement as such. The electrocardiogram may be relatively normal when enlargement is the result of dilatation without associated hypertrophy.
Databáze: OpenAIRE
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