QRS Wave of the Magnetocardiogram in Right Ventricular Overload: Correlation with Right Ventricular Pressure

Abstract

The magnetocardiogram (MCG) using a second derivative gradiometer specificially detects a current source close to the detector, and it should clearly detect the electromotive force of the right ventricle. Therefore, in the present study, we examined the features of the MCG of patients with right ventricular overload. Compared with normal subjects, patients with typical right ventricular overload showed an increased amplitude of the R wave in the upper portion at the anterior chest, and of the S wave in the lower portion. On the basis of mean ± 2 SD of values for normal subjects, the MCG criteria for right ventricular overload were set as follows: (1) R wave at B-2 (R(b-2)) ≥13 × 10^–8 gauss; (2) S wave at F-3 (S(F-3)) ≥3 × 10^–8 gauss; (3) right to left ratio = (R(b-2) + S(f-3))/(S(b-2) + R(f-3)) ≥1.0. In a prospective study, the MCG criteria showed significantly higher sensitivity than the ECG criteria in patients with right ventricular overload, especially in patients with a right ventricular pressure of more than 50 mm Hg. These results suggest that the MCG is useful for diagnosis of right ventricular overload.