Recognition of Fibrotic Infarct Density by the Pattern of Local Systolic-Diastolic Myocardial Electrical Impedance
Por:
Amoros-Figueras, G, Jorge, E, Garcia-Sanchez, T, Bragos, R, Rosell-Ferrer, J, Cinca, J
Publicada:
31 ago 2016
Resumen:
Myocardial electrical impedance is a biophysical property of the heart that is influenced by the intrinsic structural characteristics of the tissue. Therefore, the structural derangements elicited in a chronic myocardial infarction should cause specific changes in the local systolic-diastolic myocardial impedance, but this is not known. This study aimed to characterize the local changes of systolic-diastolic myocardial impedance in a healed myocardial infarction model. Six pigs were successfully submitted to 150 min of left anterior descending (LAD) coronary artery occlusion followed by reperfusion. 4 weeks later, myocardial impedance spectroscopy (1-1000 kHz) was measured at different infarction sites. The electrocardiogram, left ventricular (LV) pressure, LV dP/dt, and aortic blood flow (ABF) were also recorded. A total of 59 LV tissue samples were obtained and histopathological studies were performed to quantify the percentage of fibrosis. Samples were categorized as normal myocardium (<10% fibrosis), heterogeneous scar (10-50%) and dense scar (>50%). Resistivity of normal myocardium depicted phasic changes during the cardiac cycle and its amplitude markedly decreased in dense scar (18 +/- Omega-cm vs. 10 +/- 1 Omega-cm, at 41 kHz; P < 0.001, respectively). The mean phasic resistivity decreased progressively from normal to heterogeneous and dense scar regions (285 +/- 10 Omega-cm, 225 +/- 25 Omega-cm, and 162 +/- 6 Omega-cm, at 41 kHz; P < 0.001 respectively). Moreover, myocardial resistivity and phase angle correlated significantly with the degree of local fibrosis (resistivity: r = 0.86 at 1 kHz, P 0.001; phase angle: r = 0.84 at 41 kHz, P < 0.001). Myocardial infarcted regions with greater fibrotic content show lower mean impedance values and more depressed systolic-diastolic dynamic impedance changes. In conclusion, this study reveals that differences in the degree of myocardial fibrosis can be detected in vivo by local measurement of phasic systolic-diastolic bioimpedance spectrum. Once this new bioimpedance method could be used via a catheter-based device, it would be of potential clinical applicability for the recognition of fibrotic tissue to guide the ablation of atrial or ventricular arrhythmias.
Filiaciones:
Amoros-Figueras, G:
Univ Autonoma Barcelona, Dept Cardiol, Hosp Santa Creu & St Pau, Inst Invest Biomed St Pau, Barcelona, Spain
Jorge, E:
Univ Autonoma Barcelona, Dept Cardiol, Hosp Santa Creu & St Pau, Inst Invest Biomed St Pau, Barcelona, Spain
Garcia-Sanchez, T:
Univ Politecn Cataluna, Elect & Biomed Instrumentat Grp, Dept Elect Engn, Barcelona, Spain
Bragos, R:
Univ Politecn Cataluna, Elect & Biomed Instrumentat Grp, Dept Elect Engn, Barcelona, Spain
Rosell-Ferrer, J:
Univ Politecn Cataluna, Elect & Biomed Instrumentat Grp, Dept Elect Engn, Barcelona, Spain
Cinca, J:
Univ Autonoma Barcelona, Dept Cardiol, Hosp Santa Creu & St Pau, Inst Invest Biomed St Pau, Barcelona, Spain
Gold, Green Published
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