Relation between projection positions and X-ray radiation doses during placement of the coronary sinus mapping electrode.

PURPOSE: To reduce X-ray radiation injury, we investigated the relation between projection positions and X-ray radiation doses when a coronary sinus mapping electrode was placed.
METHODS: There were 400 patients in whom a coronary sinus mapping electrode was placed for intracardiac electrophysiologic examination or radio-frequency catheter ablation in our hospital between 1 June 2008 and 31 May 2011. The doctors who placed the coronary sinus mapping electrode and the projection positions including posteroanterior, left anterior oblique 45°, and right anterior oblique 30° projection positions were randomly selected. X-ray doses were recorded when the coronary sinus mapping electrode was placed, and then, these were compared between the three projection positions.
RESULTS: The X-ray dose was significantly lower in the right anterior oblique 30° projection position (50.01 ± 11.38 mGy) than in the posteroanterior projection position (68.05 ± 18.85 mGy, q = 12.924, p = 0.000) and the left anterior oblique 45° projection position (71.66 ± 16.95 mGy, q = 15.214, p = 0.000). There were no statistical significances in X-ray doses between the posteroanterior and the left anterior oblique 45° projection positions (p = 0.066) and different operators (p = 0.985).
CONCLUSION: Based on the results of this study, we suggest that in placing the coronary sinus mapping electrode, the right anterior oblique 30° projection position should be first adopted because it can allow the electrode to be easily placed and reduce the X-ray radiation dose as much as possible.