Magnetocardiography detected multiple dipoles more frequently than isopotential mapping (15 vs. 5; P<0.01), suggesting it is helpful for diagnosing ischaemia undetected by standard electrocardiogram.
Case-Control (n=73)
Does magnetocardiogram (MCG) improve the detection of ventricular repolarization abnormalities compared to standard electrocardiogram in patients with old inferior myocardial infarction?
Magnetocardiography may be helpful in diagnosing myocardial ischaemia by detecting localized T vector abnormalities when standard electrocardiograms appear normal.
p-value: p=<0.01
Isomagnetic maps of 50 normal subjects (control group) and 23 patients with old inferior myocardial infarction (IMI group) were recorded in order to analyse T wave abnormalities in inferior myocardial infarction. The T wave of the magnetocardiogram (MCG) in the control group showed negative deflections in the left upper portion and positive deflections in the right lower portion, thus resulting in a T vector directed leftward and inferiorly. The T wave of the IMI group was flat or positive in the left upper portion and flat or negative in the right lower portion, suggesting a T vector directed superiorly. In addition, opposing dipoles were observed in 36.4% of the IMI group; i.e. one directed superiorly, presumably due to inferior myocardial ischaemia, and the other directed inferiorly due to normal repolarization. Localized T vector abnormalities could be detected by the MCG in some cases, in which coronary T waves of the standard electrocardiogram had returned to normal. Furthermore, multiple dipoles were more frequently observed in the isomagnetic map than in the isopotential map (5 vs. 15; P less than 0.01). These results suggest that the MCG is helpful in diagnosing myocardial ischaemia when this is not detectable on the electrocardiogram.
Nomura et al. (Sun,) conducted a case-control in Old inferior myocardial infarction (n=73). Magnetocardiogram (isomagnetic map) vs. Isopotential map / standard electrocardiogram was evaluated on Detection of multiple dipoles (p=<0.01). Magnetocardiography detected multiple dipoles more frequently than isopotential mapping (15 vs. 5; P<0.01), suggesting it is helpful for diagnosing ischaemia undetected by standard electrocardiogram.