Quantitative Evaluation of a Directly Depolarized Area Induced by High-Output Pacing on the Cardiac Muscle
Autor: | Shinichi Niwano, Tohru Izumi, Yoshikazu Kitano, Shigeyoshi Maruyama, Naoto Yoshizawa, Masahiko Moriguchi, Yoshihiko Masaki |
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Rok vydání: | 2000 |
Předmět: |
Tachycardia
medicine.medical_specialty Materials science Physiology Membrane Potentials Pectinate muscles Dogs Perpendicular medicine Electrode array Animals Electrodes Myocardium Cardiac Pacing Artificial Cardiac muscle Heart Equipment Design Radius Electric Stimulation Surgery medicine.anatomical_structure Ventricle Electrode Data Display medicine.symptom Cardiology and Cardiovascular Medicine Biomedical engineering |
Zdroj: | Japanese Circulation Journal. 64:876-882 |
ISSN: | 1347-4839 0047-1828 |
DOI: | 10.1253/jcj.64.876 |
Popis: | Quantitative information is needed on the directly depolarized area (DDA) induced by high-output energy during a precise mapping procedure to detect the origin of a tachycardia. In the present study, a DDA caused by high-output energy was quantitatively evaluated in the exposed canine heart. In 8 dogs, the right atrial and ventricular surfaces were exposed through a right thoracotomy and pacing with various outputs was delivered from the epicardial surface. A comb-shaped 16 polar electrode array and/or a 224 polar mat electrode array were used for recording the epicardial electrograms. The local activation time was measured at each electrode site, and the relationship of the distance between the electrode location from the pacing site and the local activation time was plotted and fitted to a primary regression line. The intercept of the regression line on the horizontal axis was defined as the radius of the 'DDA' and this was evaluated at each pacing output. The radius of the DDA was 0.6+/-0.1 mm with a 2 V and 3.8+/-0.2 mm with a 10 V output when it was evaluated in a direction perpendicular to the fiber orientation of the pectinate muscle, 0.8+/-0.1 mm with a 2 V and 4.1+/-0.3 mm with a 10 V output in a direction parallel to the pectinate muscle fiber orientation, and 0.9+/-0.3 mm with a 2 V and 3.6+/-0.5 mm with a 10 V output in the right ventricle. The DDA extended according to the increase in stimulation outputs at all sites, and there was no significant difference in the pacing site or the direction of the stimulation propagation. The DDA caused by high-output energy is a purely physical phenomenon that depends only on stimulation output and tissue resistance. The diameter of the DDA exceeded 4 mm (ie, the size of a standard tip electrode for catheter ablation) when pacing was delivered with an output greater than 6 V. |
Databáze: | OpenAIRE |
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