PowerPoint-Prsentation

Experimental Study of the Magnetohydrodynamic (MHD) Effect with respect to Intracardiac ECG SignalsW. B. Buchenberg1, G. Hoppe1, R. Lorenz1, W. Mader2, P. Laudy3, C. Bienek4 and B. Jung1

1Dept. of Radiology, Medical Physics, University Medical Center, Freiburg, Germany,2Freiburg Center for Data Analysis and Modeling, Albert-Ludwigs-University, Freiburg, Germany, 3CardioTek B.V., Maastricht-Airport, Netherlands, 4R&D, Schwarzer GmbH, Heilbronn, Germany20.09.2013

ELECTROPHYSIOLOGIC (EP) STUDIES assess cardiac electrical systemdiagnosis and therapy of EP disorderscatheter guidance:X-ray fluoroscopic imaging disadvantages: x-ray exposure (staff + patient)poor tissue contrastalternative imaging modalities: Magnetic Resonance Imaging (MRI) 1 SERVIER Medical Art

catheters1

MAGNETOHYDRODYNAMIC (MHD) EFFECT

1 Tenforde et al. Bioelectromagnetics 1983;4:1-9 2 Tenforde Biophysics & Molecular Biology 2005;151:521-23 3 Gupta et al. IEEE 2008; 55(7):1890-96 4 Tse et al. ISMRM2012 talk #206distortion of surface ECGs1,2,3 and intracardiac ECGs (iEGMs)4

B = 0 TB 1.5 Ts u r f a c e E C G sMAGNETOHYDRODYNAMIC (MHD) EFFECT1 Gupta et al. IEEE 2008; 55(7):1890-96 2 Kolin A. Review of Scientific Instruments 1945;16(6): 109-116 3 SERVIER Medical Art

30establish experimental setup for simulating MHD signal with common clinical EP-devicescharacterization of measured MHD-signal Umeas (bipolar): magnetic field strength electrode distance filter settings of recording modalitycomparison of Umeas with UMRI,calc from MR flow measurements implementation of methods to remove MHD signals from intracardiac ECG signal (iEGMs)

OBJECTIVESBy using this knowledge, methods for separating the MHD signal from intracardiac electrogams can be implemented5EXPERIMENTAL SETUP

simulate electrical conductivity of blood: dist. H2O + NaCl1.5 Tesla50 bpmEXPERIMENTAL SETUP

simulate electrical conductivity of blood: dist. H2O + NaClVAD (Ventricular Assist Device):1.5 Tesla50 bpm

EXPERIMENTAL SETUPsimulate electrical conductivity of blood: dist. H2O + NaClcatheter positioning:(1)

1.5 Tesla50 bpmUMHDEXPERIMENTAL SETUPsimulate electrical conductivity of blood: dist. H2O + NaCl(1)

1.5 Tesla50 bpmEXPERIMENTAL SETUPsimulate electrical conductivity of blood: dist. H2O + NaCl(1)

1.5 Tesla50 bpm

MRI FLOW MEASUREMENTS

2D slice

imaging parametersTE / TR [ ms ]4.9 / 7.2temp. res. [ ms ]7.2voxel size [ mm ]0.9 x 0.9 x 6.0VENC IN / THROUGH-PLANE [ m/s ]0.15 / 0.55RESULTS MHD SIGNAL vs. TIME

UMHD,PP

RESULTS MHD SIGNAL vs. TIME

UMHD,PP

RESULTS MHD VOLTAGE vs. DISTANCE

RESULTS MHD VOLTAGE vs. MAGNETIC FIELD

RESULTS MHD VOLTAGES

(2/9)RESULTS MHD VOLTAGES

high pass filtered (fcut off = 0.05 Hz)(2/9)RESULTS HIGH PASS FILTERSUMHD,PP (fcut off : 0.2 Hz) UMHD,PP (fcut off : 0.05 Hz) (within 4%)UMHD,PP (fcut off : 40 Hz) remaining UMHD,PP 3% UMHD,PP (fcut off : 80 Hz)remaining UMHD,PP 2% DISCUSSION & OUTLOOKexperimental setup established successfullyMHD potential (bipolar measured) was characterized: shows linear dependency on B0, dfollows characteristics of velocity patternsame order of magnitude as intracardiac signals1MR flow data - post processing: MHD signal reconstructed using MR velocity data measured and calculated MHD signal agree very well OutlookiEGM data correction based on MR flow measurements 1 Cassidy et al. Circulation 1984;70(1):37-42.

THANK YOU FOR YOUR ATTENTION!

ACKNOWLEDGEMENTS:

Christoph BenkMr. Knieriem, St. Jude MedicalMr. Simon, Mr. Baecke, seleon gmbh

Grant support byEUROSTARS Program Grant #01QE1004D