Left anterior oblique projection

Fluoroscopic radiation exposure is another potential source of morbidity, particularly for complex or lengthy procedures. Peak skin doses of radiation during AF ablation procedures have been measured in the range of 0.5 to 2.0 Gy, (with average values of 1.0 and 1.5 Gy in the right and left anterior oblique projections) (177). At these dose levels, the estimated lifetime risk of excess fatal malignancies is estimated in the range 0.1% (177,178). 

Fig 9 3 Left anterior oblique projection showing posterolateral branch of the coronary sinus vein right anterior oblique projection demonstrates stenosis at the entry left ventricular lead [Pg.141]

Use of the left anterior oblique projection is extremely important in defining the tributaries of the coronary sinus (Fig. 4.76). In the frontal and right anterior oblique projections, tributaries of the coronary sinus appear to run perpendicular to the coronary sinus obliquely from a superior to an inferior direction (Fig. 4.77). The branches appear to be parallel, and differentiation of anteroseptal, lateral, and posterolateral branches is almost impossible. For simplicity and for the purpose of this discussion, branches or tributaries of the coronary sinus are described from their ostia in the coronary sinus. In the LAO projection, the great cardiac vein or anterior cardiac vein comes off of the coronary sinus superiorly into the right. It then turns acutely, descending inferiorly... 

The 40° left anterior oblique projection is used to differentiate right ventricular outflow tract, septal, and free wall positions (Fig. 4.102). 

Fig 9 4 Left a and right (b)anterior oblique projections showing stenosis of the posterolateral branch of the coronary sinus vein... 

Fig. 4. 96 Right anterior oblique (RAO) (panel A) and left anterior oblique (LAO) (panel B) sections of the male heart obtained from the EPFL s visible human surface server, EPFL 1998. Panel A shows the inferior caval vein (ICV), the inferior isthmus (CTI), the supraventricular crest (SVC), the aorta (Ao), and right ventricular outflow tract (RVOT). The white dot signals the site corresponding to the membranous septum or the maximal His-Bundle potential is usually recorded. In the LAO projection, the right atrial appendage (RAA) and the right and left atria at the level of the atrial ventricular junction s are depicted. The white dot also signals the area were the his bundle is recorded. The left atrial appendage (LAA) is superior, (from Farre J, Anderson RH, Cabrera JA, et al Fluorscopic cardiac anatomy for catheter ablation of tachycardia. PACE 25 88, 2002)...

---