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Pàgina inicial > Articles > Articles publicats > Recognition of Fibrotic Infarct Density by the Pattern of Local Systolic-Diastolic Myocardial Electrical Impedance |
Data: | 2016 |
Resum: | 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 ± 2 Ω·cm vs. 10 ± 1 Ω·cm, at 41 kHz; P < 0. 001, respectively). The mean phasic resistivity decreased progressively from normal to heterogeneous and dense scar regions (285 ± 10 Ω·cm, 225 ± 25 Ω·cm, and 162 ± 6 Ω·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. |
Ajuts: | Instituto de Salud Carlos III FIS-PI13-00765 Instituto de Salud Carlos III DTS-15-00099 Instituto de Salud Carlos III RIC-RD12-0042-0002] |
Nota: | Altres ajuts: Fundació "La Marató" de TV3 [20150830] |
Drets: | Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original. |
Llengua: | Anglès |
Document: | Article ; recerca ; Versió publicada |
Matèria: | Healed myocardial infarction ; Myocardial electrical impedance ; Hemodynamics ; Novel bioimpedance device ; Swine |
Publicat a: | Frontiers in physiology, Vol. 7 (august 2016) , ISSN 1664-042X |
10 p, 2.2 MB |