ISSN:
1540-8159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Healed myocardial infarction has been recognized by its particular tissue electrical impedance spectrum measured with intramural needle electrodes in animal models. The aim of this study was to develop a percutaneous approach for in vivo recognition of areas of healed myocardial infarction by measuring myocardial electrical impedance with an intracavitary contact electrocatheter. Electrical impedance (resistance and phase angle) of normal myocardium and of a 2-month-oid anterior transmural infarction were measured in nine chloralose anesthetized pigs by applying alternating currents from 1 kHz to 1 MHZ between a bipolar intracavitary catheter and a reference electrode placed on the epicardium (group I, n = 4) or on the precordium (group II, n = 5). Resistance of the infarcted myocardium was lower than that of healthy tissue at all current frequencies (ANOVA, P 〈 0.001) (i.e., at 1 kHz: 15 ± 4 Ω vs 50 ± 19 Ω in group I, and 64+ 13 Ω vs 76 ± 13 Ω in group II). Phase angle at 316 kHz best differentiated transmural infarction from normal tissue (group I: -2.5 ± 1.9 degrees vs -14.8 ± 4.6 degrees, P 〈 0.001; group II: +0.7 ±1.0 degrees vs -2.7 ± 1.4 degrees, P 〈 0.001). This study shows that analysis of myocardial impedance spectrum using a percutaneous intracavitary contact catheter approach permits on-line recognition of areas of healed transmural myocardial infarction. This technique may be useful to optimize clinical application of energy sources (i.e., radiofrequency ablation, laser myocardial revascularization).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1540-8159.2000.tb00945.x
Permalink
