Xm. Mueller et al., ACUTE EFFECTS OF TRANSMYOCARDIAL LASER REVASCULARIZATION ON LEFT-VENTRICULAR FUNCTION - AN HEMODYNAMIC AND ECHOCARDIOGRAPHIC STUDY, The thoracic and cardiovascular surgeon, 46(3), 1998, pp. 126-129
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.