Recognition of fibrotic infarct density by the pattern of local systolic-diastolic myocardial electrical impedance

Gerard Amorós-Figueras, Esther Jorge, Tomás García-Sánchez, Ramón Bragós, Javier Rosell-Ferrer, Juan Cinca

Research output: Contribution to journalArticleResearchpeer-review

3 Citations (Scopus)

Abstract

© 2016 Amorós-Figueras, Jorge, García-Sánchez, Bragós, Rosell-Ferrer and Cinca. 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.
Original languageEnglish
Article number389
JournalFrontiers in Physiology
Volume7
Issue numberAUG
DOIs
Publication statusPublished - 31 Aug 2016

Keywords

  • Healed myocardial infarction
  • Hemodynamics
  • Myocardial electrical impedance
  • Novel bioimpedance device
  • Swine

Fingerprint Dive into the research topics of 'Recognition of fibrotic infarct density by the pattern of local systolic-diastolic myocardial electrical impedance'. Together they form a unique fingerprint.

Cite this