Repolarization Heterogeneity of Magnetocardiography Predicts Long-Term Prognosis in Patients with Acute Myocardial Infarction

Abstract

PurposeMagnetocardiography (MCG) has been proposed as a noninvasive, diagnostic tool for risk-stratifying patients with acute myocardial infarction (AMI). This study evaluated whether MCG predicts long-term prognosis in AMI.Materials and MethodsIn 124 AMI patients (95 males, mean age 60±11 years), including 39 with ST-elevation myocardial infarction, a 64-channel MCG was performed within 2 days after AMI. During a mean follow-up period of 6.1 years, major adverse cardiac events (MACE) were evaluated.ResultsMACE occurred in 31 (25%) patients, including 20 revascularizations, 8 deaths, and 3 re-infarctions. Non-dipole patterns were observed at the end of the T wave in every patients. However, they were observed at T-peak in 77% (24/31) and 54% (50/93) of patients with and without MACE, respectively (p=0.03). Maximum current, field map angles, and distance dynamics were not different between groups. In the multivariate analysis, patients with non-dipole patterns at T-peak had increased age- and gender-adjusted hazard ratios for MACE (hazard ratio 2.89, 95% confidence interval 1.20–6.97, p=0.02) and lower cumulative MACE-free survival than those with dipole patterns (p=0.02).ConclusionNon-dipole patterns at T-peak were more frequently observed in patients with MACE and were related to poor long-term prognosis. Thus, repolarization heterogeneity measured by MCG may be a useful predictor for AMI prognosis.

Effectiveness of magnetocardiography to identify patients in need of coronary artery revascularization: a cross-sectional study

“…Although there is no clear standardization for MCG to diagnose CAD. Several MCG parameters calculated along the ST interval and T-wave were typically abnormal at rest in patients with CAD, and appear to be sensitive diagnostic parameters (3,5,6,11,(15)(16)(17).…”

“…Therefore, artefacts from unreliable and/or fluctuating electrode-skin contacts, such as in practical ECG, cannot occur (1). Recently, it has been reported that MCG has shown high performance in diagnosing coronary artery disease (CAD) (3)(4)(5)(6). Typical parameters useful for CAD diagnosis were current angle, field map angle, pole distance, QTc dispersion and non-dipolar phenomenon in the magnetic field maps (MFMs) (5)(6)(7).…”

“…Recently, it has been reported that MCG has shown high performance in diagnosing coronary artery disease (CAD) (3)(4)(5)(6). Typical parameters useful for CAD diagnosis were current angle, field map angle, pole distance, QTc dispersion and non-dipolar phenomenon in the magnetic field maps (MFMs) (5)(6)(7). Although MCG could record spatial and temporal magnetic field signals during repolarization period at the same time, those parameters above couldn't reflect the spatial and temporal information together.…”

Unshielded magnetocardiography: Repeatability and reproducibility of automatically estimated ventricular repolarization parameters in 204 healthy subjects

“…VR analysis is considered one of the most useful applications of MCG, mainly to recognize ischemic, inflammatory, or degenerative abnormalities (Tavarozzi, Comani, Del Gratta, Di Luzio et al., ). However, although some attempts to assess the reproducibility and comparability of MCG parameters gathered with different instrumentations have been reported (Burghoff, Nenonen, Trahms, & Katila, ; Nalbach et al., ; Pesola et al., ; Smith et al., ; Takala et al., ), a standardization adequate for clinical application is still missing, especially taking into account the potential source of error due to different S/Nr and/or sequential data acquisition (Bang et al., ; Hänninen et al., ; Kawakami et al., ; Mäkijärvi et al., ; Shin et al., ) as occurs with most instrumentations for unshielded MCG (Fenici, Brisinda, & Meloni, ; Leder et al., ) due to their limited number of sensors.…”

Repolarization Heterogeneity of Magnetocardiography Predicts Long-Term Prognosis in Patients with Acute Myocardial Infarction

“…The authors report on the association of non-dipole patterns at T-peak in resting magnetocardiography (MCG) and major adverse cardiac event (MACE), including composite of death from any cause, reinfarction, and percutaneous coronary intervention, during the follow-up period (mean 6.1 years) in 124 patients with acute coronary syndromes (ACS) 1. In multivariate analysis, patients with non-dipole patterns at T-peak showed increased hazard ratios for MACE ( p =0.02) and lower cumulative MACE-free survival than those with dipole patterns ( p =0.02).…”