[Significance of isotopes in the study of pre-excitation and ventricular tachycardia].
In normal patients, Mac Carthy has demonstrated that there was a very close correlation between the ventricular contractile activity, evaluated by Fourier's isotopic phase analysis, and electrical depolarization, evaluated by endocardial mapping. It has therefore been possible to study asynchronisms or asymmetries of the ventricular contraction-depolarization and particularly the syndromes of ventricular pre-excitation and ventricular tachycardias. In Wolff-Parkinson-White syndromes (WPW), the mapping obtained by heart cavity tomography in addition to dual-plane gamma-angiography, provides most useful informations, due to additional section planes permitting tridimensional location of the earliest site of ventricular activation. It is quite useful to locate the bundle of Kent always difficult on surface electrocardiogram, or when the endocardial exploration does not permit to precisely locate the site of the excentric atrial activation in case of multiple bundles of Kent or without retrograde conduction. When the left bundle of Kent is barely identified, the isotopic image may be improved by oesophageal stimulation. Additional parameters (use of several harmonics, factorial analysis) will permit to improve the localization of accessory pathways, to be destroyed by fulguration or surgery. In case of ventricular tachycardias with limited functional tolerance, only gamma-angiography, lasting only 3 to 5 minutes, may be used. Combined with endocardial tomography or even gamma-angiography performed in sinus rhythm, not only the site of origin of the ventricular ectopy may be localized, but it also can be correlated with ventricular kinetics abnormalities and the cardiopathy in question may be identified. Most authors consider that there is a close relationship between isotopic site, electrocardiographic appearance and the site found by endocardial mapping or "pace-mapping". In patients with ventricular tachycardias of different morphologies, isotopic mapping permits to differentiate those originating from a same lesion (which may be treated by surgery of fulguration) from those originating in remote areas. Therefore, this technique is a non aggressive and rapid method providing accurate informations on severe rhythm disorders currently treated by eradication of their anatomical substratum.
Casset-Senon
D
D
Service de Médecine nucléaire et Ultrasons, CHU Trousseau, Tours.
Cosnay
P
P
Philippe
L
L
Fauchier
J P
JP
Babuty
D
D
Pottier
J M
JM
Itti
R
R
D004562:Electrocardiography; D006352:Heart Ventricles; D006801:Humans; D011226:Pre-Excitation Syndromes / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011877:Radionuclide Imaging; D013610:Tachycardia / Q000000981:diagnostic imaging* / Q000503:physiopathology; D014927:Wolff-Parkinson-White Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology
Intérêt des isotopes dans l'étude des préexcitations et des tachycardies ventriculaires.