Multichannel Magnetocardiography (MMCG) has been proposed to detect exercise-induced myocardial ischemia in patients (pts) with coronary artery disease (CAD). Previous studies were carried out in magnetically shielded rooms only, with the patient supine and pedaling a non-magnetic bicycle ergometer. Our study was aimed to test the feasibility of exercise-MMCG carried out, in an unshielded laboratory, with a commercial bicycle ergometer, simultaneously with 12-lead stress ECG. Method: A 36-channel DC-SQUID system (CMI), (sensitivity is 20 fT/Hz), was used to record the cardiac magnetic field component perpendicular to the anterior chest wall (Bz). 6 pts, with CAD, documented by coronary angiography, were investigated. 12-lead ECG was continuously recorded during exercise and until 10 minutes of recovery. MMCG of 90 seconds was performed before and 1, 3, 5, 7 and 9 minutes after exercise. Magnetic field gradient orientation of the integral of the second quarter of the ST interval from the J-point (ST  angle) and that of the T wave apex (T  angle) were computed according to Hänninen et al. (H) [1] and compared with an automatic ST-T score analysis (ST-ASA) provided by our system and used elsewhere for the detection of acute myocardial ischemia [2]. The same parameters were calculated in 7 normal control subjects. Results: At rest, ST  angle was: 121.4° ± 80.6° in pts and 63.8° ± 16.4° in controls (p: n.s.). Within the first 2 minutes after exercise, ST angle was: 189° ± 82.8° in pts and 67.5° ± 13.3° in controls (p: 0.002). T angle was normal in all conditions (p: n.s.). Discussion: Exercise-MMCG is feasible also in an unshielded hospital unit, using a standard ergometer during simultaneous 12-lead ECG recording. MMCG seems to provide high sensitivity to detect ventricular repolarization abnormalities due to exercise-induced ischemia, in pts with CAD.

Brisinda, D., Meloni, A. M., Nenonen, J., Fenici, R., Unshielded Stress Multichannel Magnetocardiography of Patients with Coronary Disease and Normal Subjects with standard ergometer. Comparison with ECG., <<BIOMEDIZINISCHE TECHNIK>>, 2004; (48(2)): 137-139 [http://hdl.handle.net/10807/16013]

Unshielded Stress Multichannel Magnetocardiography of Patients with Coronary Disease and Normal Subjects with standard ergometer. Comparison with ECG.

Brisinda, Donatella;Meloni, Anna Maria;Fenici, Riccardo
2004

Abstract

Multichannel Magnetocardiography (MMCG) has been proposed to detect exercise-induced myocardial ischemia in patients (pts) with coronary artery disease (CAD). Previous studies were carried out in magnetically shielded rooms only, with the patient supine and pedaling a non-magnetic bicycle ergometer. Our study was aimed to test the feasibility of exercise-MMCG carried out, in an unshielded laboratory, with a commercial bicycle ergometer, simultaneously with 12-lead stress ECG. Method: A 36-channel DC-SQUID system (CMI), (sensitivity is 20 fT/Hz), was used to record the cardiac magnetic field component perpendicular to the anterior chest wall (Bz). 6 pts, with CAD, documented by coronary angiography, were investigated. 12-lead ECG was continuously recorded during exercise and until 10 minutes of recovery. MMCG of 90 seconds was performed before and 1, 3, 5, 7 and 9 minutes after exercise. Magnetic field gradient orientation of the integral of the second quarter of the ST interval from the J-point (ST  angle) and that of the T wave apex (T  angle) were computed according to Hänninen et al. (H) [1] and compared with an automatic ST-T score analysis (ST-ASA) provided by our system and used elsewhere for the detection of acute myocardial ischemia [2]. The same parameters were calculated in 7 normal control subjects. Results: At rest, ST  angle was: 121.4° ± 80.6° in pts and 63.8° ± 16.4° in controls (p: n.s.). Within the first 2 minutes after exercise, ST angle was: 189° ± 82.8° in pts and 67.5° ± 13.3° in controls (p: 0.002). T angle was normal in all conditions (p: n.s.). Discussion: Exercise-MMCG is feasible also in an unshielded hospital unit, using a standard ergometer during simultaneous 12-lead ECG recording. MMCG seems to provide high sensitivity to detect ventricular repolarization abnormalities due to exercise-induced ischemia, in pts with CAD.
Inglese
Brisinda, D., Meloni, A. M., Nenonen, J., Fenici, R., Unshielded Stress Multichannel Magnetocardiography of Patients with Coronary Disease and Normal Subjects with standard ergometer. Comparison with ECG., <>, 2004; (48(2)): 137-139 [http://hdl.handle.net/10807/16013]
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10807/16013
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