A Clinical Application of the “Brody Effect”
Journal Title: Heart Research – Open Journal - Year 2015, Vol 2, Issue 3
Abstract
Brody described the importance of differences in resistivity between blood in the left ventricular lumen and the myocardium, and the distance between the primary dipole in the myocardium and the image dipole in the lumen. The image dipole existing in the ventricular lumen influences the ECG voltages recorded from leads either radial or tangential to the left ventricular mass. The intensity of the image dipole and the magnitude of the effect on the body surface ECG are proportional to the differences in resistivity and the distance between primary and image dipoles. Tacrolimus, a commonly-used immunosuppressant, decreases left ventricular lumen and thickens the left ventricular free-wall tremendously; thus, although left ventricular myocardial mass does not change, ECG voltages in leads facing the left ventricular free-wall should decrease monumentally. The hypothesis of this study is that ECG voltages in lead aVF facing the left ventricular free-wall and oriented radially from its mass would decrease proportional with the decrease in luminal radius and thickening of the free-wall. ECG’s and 2D-directed M-mode ECHO’s of the left ventricle were recorded from dogs before and after receiving tacrolimus and developing drastic reductions in left ventricular luminal volumes. R waves in lead aVF determined by the radial spread of depolarization from subendocardium to subepicardium of the left ventricular free-wall decreased precipitously as the ratio of luminal radius to wall thickness decreased. The hypothesis that ECG voltages would decrease as luminal volume decreases and the wall thickens was accepted. This study demonstrates that factors other than wall mass must be considered in electrocardiology
Authors and Affiliations
Yunusemre Ozkanlar
Keywords
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- EP ID EP556862
- DOI 10.17140/HROJ-2-116
- Views 154
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