ACUTE EFFECTS OF TRANSMYOCARDIAL LASER REVASCULARIZATION ON LEFT-VENTRICULAR FUNCTION - AN HEMODYNAMIC AND ECHOCARDIOGRAPHIC STUDY

While the lesions produced by transmyocardial laser revascularisation (TMLR) induce scar formation, it is important to determine whether thi s procedure can be deleterious for the left-ventricular function, whic h is already impaired by the underlying ischaemic process in some pati ents. Ten channels were drilled in the left lateral wall of the hearts of ten pigs (mean weight, 61 +/- 8.2 kg) with a Holmium:YAC laser. Ha emodynamic measurements and echocardiographic assessment of left-ventr icular function were performed before the TMLR procedure, 5 and 30 min after, and lastly after 5 min of pacing at a rate increased by 30 % o f the baseline value. Echocardiographic assessment was in the short ax is at the level of the laser channels, and included left-ventricular e jection fraction and segmental wall motility of the lasered area (scal e 0-3: 0 = normal 1 = hypokinesia, 2 = akinesia, 3 = dyskinesia). Valu es at 5 and 30 min were compared with baseline values; the difference was considered significant if p < 0.05. Haemodynamical values were sta ble throughout all the procedures. The ejection fraction showed a slig ht but significant decrease 5 min after the creation of the channels ( 60.4 +/- 6.8 % vs 54 +/- 7.6%, p = 0.02) and recovered at 30 min. The segmental motility score of the involved areas increased to 1 after 5 min in five animals, and came back to 0 at 30 min except in one animal . Even with pacing no segmental dysfunction occurred. The reversibilit y of the segmental hypokinesia induced by TMLR, as well as the absence of pace-induced dysfunction 30 min after the procedure strongly sugge st the inocuity of TM LR in this experimental set-up.