Relation of the Distance-Corrected Electrocardio-graphic and Vectorcardiographic Voltage with the Echocardiographically Determined Left Ventricular Muscle Volume -The Shimane Heart Study

The left ventricular muscle volume (LVMV) and the distance from the surface of the anterior chest wall to the middle of the left ventricle (D) were determined echocardiographically in 476 children as a part of the Shimane Heart Study. Correlation of the summed ECG precordial voltage (SV_1+RV_5) and the summed VCG voltage (RX+SZ) with LVMV was poor (on ECG voltage r=0.377 in males and -0.095 in females ; on VCG voltage r=0.316 in males and -0.069 in females). The ECG and VCG voltages, therefore, were corrected by the square of D to compensate for the diminution of electric potential by distance. Correlation of the corrected ECG voltage D^2(SV_1+RV_5) and the corrected VCG voltage D^2(RX+SZ) with LVMV were good in males (r=0.712 and 0.709, respectively) and relatively good in females (r=0.467 and 0.478, respectively). Moreover, the values of the corrected voltages were significantly different between both sexes at the age of 12-16 years (P＜0.002).
The thickness of subcutaneous fat may be one of the most important factors for the difference in the values of the corrected voltages and correlation coefficients.