Assessing heart disease using a novel magnetocardiography device

Abstract

The aim of this paper is to present the use of a portable, unshielded magnetocardiograph (MCG) and identify key characteristics of MCG scans that could be used in future studies to identify parameters that are sensitive to cardiac pathology. We recruited 50 patients with confirmed myocardial infarction (MI) within the past 12 weeks and 46 volunteers with no history of cardiac disease. A set of 38 parameters were extracted from MCG features including both signals from the sensor array and from magnetic images obtained from the device and principal component analysis was used to concentrate the information contained in these parameters into uncorrelated predictors. Linear fits of these parameters were then used to examine the ability of MCG to distinguish between sub-groups of patients. In the first instance, the primary aim of this study was to ensure that MCG has a basic ability to separate a highly polarised patient group (young controls from post infarction patients) and to identify parameters that could be used in future studies to build a formal diagnostic tool kit. Parameters that parameterised left ventricular ejection fraction (LVEF) were identified and an example is presented to show differential low and high ejection fractions.

Magnetocardiograph as a noninvasive and radiation-free diagnostic device for myocardial infarction: a systematic review and meta-analysis

“…(D) Outlier detection. ①, Ono et al [16] ; ②, Lim et al [17] ; ③, Goernig et al [18] ; ④, Lim et al [19] ; ⑤, Zhao et al [20] ; ⑥, Beadle et al [21]…”

“…AUC, the area under the curve; SENS, sensitivity; SPEC, specificity; SROC, the summary receiver operator characteristic. ①, Ono et al [16] ; ②, Lim et al [17] ; ③, Goernig et al [18] ; ④, Lim et al [19] ; ⑤, Zhao et al [20] ; ⑥, Beadle et al [21] provides high sensitivity (91%) with a good −LR (0.1). To our knowledge, this is the first systematic review and meta-analysis assessing the diagnostic accuracy of MCG for MI.…”

“…With regard to the risk of bias in flow and timing, 2 studies were rated at high risk because 5 eligible patients dropped out in 1 study, [21] and patients with unstable angina pectoris were excluded from the evaluation of diagnostic power in the other study. [19] With regard to the applicability concerns in index test, 2 studies [18,21] were rated as high risk because their testing environments were in nonshielded rooms. Weak changes in the environment may undermine the robustness of the measurements.…”

“…Regarding the risk of bias in patient selection, we conservatively classified as "unclear" what was not recounted in detail in the included studies. With regard to the risk of bias in flow and timing, 2 studies were rated at high risk because 5 eligible patients dropped out in 1 study, [21] and patients with unstable angina pectoris were excluded from the evaluation of diagnostic power in the other study. [19] With regard to the applicability concerns in index test, 2 studies [18,21] were rated as high risk because their testing environments were in nonshielded rooms.…”

“…For the purpose of this analysis, we performed primary data synthesis. The pooled sensitivity was 0.91 (95% CI: 0.81-0.96; I 2 = 88.54); specificity was Ono et al [16] Goernig et al [18] Beadle et al [21] 0.83 (95% CI: 0.75-0.89; I 2 = 83); positive likelihood ratio was 5.3 (95% CI: 3.5-8.2); negative likelihood ratio (−LR) was 0.1 (95% CI: 0.04-0.24); and diagnostic odds ratio was 51 (95% CI: 16-161). The summary receiver operator characteristic curve is shown in Fig.…”