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Identification of R-peak in the ECG leads to maintain «transmyocardial laser revascularization» operations

Keywords:

A.G. Arakcheev, Y.K. Danileyko, V.V. Osiko, A.B. Egorov, L.G. Shilin


Ischemic heart disease (IHD) is currently treated either pharmacologically or surgically. Surgical approach implies revascularization operations on myocardium (a surgical procedure for the restoration of blood supply to tissues). Myocardial revascularization can be either direct or indirect. The most common method of indirect myocardial revascularization is transmyocardial revascularization (TMR), when small channels in the myocardial muscle wall are made with following creation of vessels. Various surgical methods can be used to create such channels, including transmyocardial laser revascularization (TMLR). During this operation channels opening into the cardiac cavity are created by laser in the left ventricle of the heart. Usually TMLR surgery includes creation of dozens of channels in the myocardium with the diameter range 0.3 to 1.5 mm. The apparatus is synchronized with the heart beat through a synchronizer unit. A special unit (device) for R-peak of ECG channel identifier-detector was developed to maintain this working cycle. Based on the developed R-peak detection algorithm, sync pulse generation mode is implemented to control working cycle activation of the apparatus for TMLR. Transmyocardial channels are created as a result of 15 to 40 laser “shots”. Laser impulse, perforator and injector working cycles are synchronized with R-peak of a patient’s ECG. At this time the left ventricle of the heart is filled with blood absorbing a part of radiation coming through the channel that protects the inner structures of the heart from destroy. The risk of triggered arrhythmia incidence due to acoustooptical effect of the laser impulse is therefore minimized. This corresponds to the necessity of laser influence on the heart during so called absolute refractory period. R-peak is characterized by very high front increase and decline and relatively short duration. The norm is no more than 100 ms. R-peak is always positive with the amplitude range of 0.5 mV to 5 mV. In one of the end leads the amplitude of R-peak will reach its possible maximal values. The peak amplitude depends greatly on position of the electrical axis of heart (EAH). ECG amplitude peaks of a particular patient depend on conductivity. The results of detector’s operation were tested as per the methods of ECG channels testing and were approved as complying with the product’s technical assignment. The most important result of the presented work is creation of functioning hard-and-software complex with possible upgrade and enhancement. The developed equipment enables to reduce myocardial traumatism during TMLR operations due to considerably less values of output laser emission required and allows for application of a vast range of additional terminal devices (applicators) for combined effects of laser emission and drug injections into the TMLR zone. The work is carried out with the support of the Ministry of Education and Science of the RF under the State Contract No. 16.522.12.2007 of July 06, 2011.
References:
June 24, 2020
May 29, 2020

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