Magnetocardiographic and Electrocardiographic Exercise Mapping in Healthy Subjects

Takala, Panu; Hänninen, Helena; Montonen, Juha; Mäkijärvi, Markku; Nenonen, Jukka; Oikarinen, Lasse; Simelius, Kim; Toivonen, Lauri; Katila, T.

doi:10.1114/1.1376388

Cited by 32 publications

(23 citation statements)

References 19 publications

(17 reference statements)

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“…24 The magnetic field peak gradient orientation parameter introduced produces results resembling results in evaluation of the magnetic field orientation as the visual inspection of the field polarity. Therefore, magnetocardiographic evaluation of myocardial ischemia cannot be based solely on ST-segment amplitude changes similar to those used in the standard 12lead ECG.…”

Section: Discussionmentioning

confidence: 95%

Detection of Exercise‐Induced Myocardial Ischemia by Multichannel Magnetocardiography in Single Vessel Coronary Artery Disease

Hänninen

Takala

Mäkijärvi

et al. 2000

Noninvasive Electrocardiol

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Background: Detection of myocardial ischemia was studied with multichannel exercise magnetocardiography (MCG). A surface gradient method was applied to analyze cardiac magnetic fields.Methods: We studied 27 patients with single vessel coronary artery disease (CAD) and 17 healthy volunteers. The MCG was recorded over anterior chest during supine bicycle ergometry. The two-dimensional direction of the maximum spatial magnetic field gradient was determined during the ST segment and at the T-wave apex at different phases of stress test.Results: The CAD patient group was separated from controls by the orientation of the magnetic field gradient during the ST segment at cessation of exercise (CAD 167 ? 68" vs controls 106 ? 49"; P < 0.005) and at 4 minutes postexercise, but not at rest. The CAD patient group was separated from controls also by the orientation of the magnetic field gradient at the T-wave apex at 4 minutes postexercise (CAD 87 ? 60" vs controls 58 +-18"; P < 0.05), but not at rest. The change in the orientation of the field gradient at the T-wave apex 4 minutes postexercise, compared to baseline, was greater in CAD patients (31 +-43") than in controls (9 ? 8"; P < 0.05). This change was larger in the patient group with stenosis in the right than in the left coronary artery (P < 0.05).Conclusions: Transient acute myocardial ischemia causes well-recognizable changes in the magnetocardiogram at the ST segment and the T wave. The orientation of the maximum spatial gradient of the magnetic field can be used as a parameter to determine these changes.

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Section: Discussionmentioning

confidence: 95%

Detection of Exercise‐Induced Myocardial Ischemia by Multichannel Magnetocardiography in Single Vessel Coronary Artery Disease

Hänninen

Takala

Mäkijärvi

et al. 2000

Noninvasive Electrocardiol

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“…[20][21][22] In brief, the BSPM device records unipolar potentials with 120 electrodes placed on the subject's thorax (Figure 1), and three standard limb potentials. The recorded signals were digitized with a sampling frequency of 1 kHz, and selectively averaged off-line.…”

Section: Bspmmentioning

confidence: 99%

Electrocardiographic assessment of left ventricular hypertrophy with time–voltage QRS and QRST-wave areas

et al. 2003

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The sum of time-voltage QRS areas in the 12-lead electrocardiogram (ECG) has outperformed other 12-lead ECG indices for detection of left ventricular hypertrophy (LVH). We assessed indices of time-voltage QRS and T-wave (QRST) areas from body surface potential mapping (BSPM) for detection of and quantitation of the degree of LVH. We studied 42 patients with echocardiographic LVH (LVH group) and 11 healthy controls (controls). QRST area sums were calculated from 123-lead BSPM and from the 12-lead ECG for comparison. Leadwise discriminant indices and correlation coefficients were used to identify optimal recording locations for QRST area-based LVH assessment. BSPM QRS area sum was greater in the LVH group than in controls (3752 7 1259 vs 2278 7 627 lV s, respectively; Po0.001) and at 91% specificity showed 74% sensitivity for LVH detection. The 12-lead QRS area sum performed similarly. Taking T-wave areas into account did not improve the results. QRS area sum from two most informative leads (located in the upper and lower right precordium) also separated the LVH group from controls (61.1 7 23.5 vs 27.8 7 6.5 lV s, respectively; Po0.00001). This 2-lead QRS area sum showed 90% sensitivity with 100% specificity for LVH detection and maintained high correlation to indexed left ventricular mass (r ¼ 0.732; Po0.001). In conclusion, the BSPM QRS area sum compared to 12-lead QRS area sum does not substantially improve LVH assessment. The 2-lead QRS area sum may improve ECG QRS area-based LVH assessment.

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“…This method, recently evaluated in a preliminary clinical study, provided 75% sensitivity, 85% specificity, 83% positive predictive value, 78% negative predictive value and 80% predictive accuracy for automatic MCG detection of IHD [84]. Although the results are encouraging, additional work is warranted to define the normality range of MCG ventricular repolarization (VR) parameters, taking into account age-and gender-related variability [78,85] and beat-to-beat variability [50]. Furthermore, definite criteria to differentiate MCG abnormalities due to IHD, from similar ones observed in patients with dilated cardiomyopathy [86,87], myocarditis [88] or mitral valve prolapse [89], and to diagnose myocardial ischemia in the presence of bundle branch block [90], are still lacking.…”

Section: Studies On Myocardial Ischemiamentioning

confidence: 90%

Clinical application of magnetocardiography

Fenici¹,

Brisinda²,

Meloni³

2005

Expert Review of Molecular Diagnostics

132

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Magnetocardiography is a noninvasive contactless method to measure the magnetic field generated by the same ionic currents that create the electrocardiogram. The time course of magnetocardiographic and electrocardiographic signals are similar. However, compared with surface potential recordings, multichannel magnetocardiographic mapping (MMCG) is a faster and contactless method for 3D imaging and localization of cardiac electrophysiologic phenomena with higher spatial and temporal resolution. For more than a decade, MMCG has been mostly confined to magnetically shielded rooms and considered to be at most an interesting matter for research activity. Nevertheless, an increasing number of papers have documented that magnetocardiography can also be useful to improve diagnostic accuracy. Most recently, the development of standardized instrumentations for unshielded MMCG, and its ease of use and reliability even in emergency rooms has triggered a new interest from clinicians for magnetocardiography, leading to several new installations of unshielded systems worldwide. In this review, clinical applications of magnetocardiography are summarized, focusing on major milestones, recent results of multicenter clinical trials and indicators of future developments.

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Magnetocardiographic and Electrocardiographic Exercise Mapping in Healthy Subjects

Cited by 32 publications

References 19 publications

Detection of Exercise‐Induced Myocardial Ischemia by Multichannel Magnetocardiography in Single Vessel Coronary Artery Disease

Detection of Exercise‐Induced Myocardial Ischemia by Multichannel Magnetocardiography in Single Vessel Coronary Artery Disease

Electrocardiographic assessment of left ventricular hypertrophy with time–voltage QRS and QRST-wave areas

Clinical application of magnetocardiography

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