Optimal fluoroscopic projections for angiographic imaging of the pulmonary vein ostia: lessons learned from the intraprocedural reconstruction of the left atrium and pulmonary veins

Abstract

Electrical isolation of the pulmonary veins (PVs) is the cornerstone of the ablative treatment of atrial fibrillation. Selective angiography of the PVs in standard fluoroscopic projections is often used for intraprocedural identification of PVs and their ostia. Variable spatial orientation and significant variability of PV anatomy are important limitations of this imaging approach. Sixty patients undergoing a PV isolation procedure received intraprocedural rotational angiography and three-dimensional reconstruction of the left atrium (LA) and PVs. For each patient, 33 angiographic projections were independently evaluated [right anterior oblique (RAO) 80 degrees to left anterior oblique (LAO) 80 degrees, in steps of 5 degrees] by two physicians in order to identify the optimal projections of the PV ostia according to the following definition: Sagittal plane: (i) clear identification of both superior and inferior segments of the LA-PV junction and (ii) no overlapping between LA (and/or left atrial appendage) and PV ostium. Frontal plane: (i) clear identification of all four quadrants of the PV ostium and (ii) fluoroscopic angles at which the maximal horizontal ostial diameter is visualized. A successful reconstruction of the LA and all PVs was obtained in 58 (97%) patients. An optimal ostial projection in a sagittal plane was identified for all four PVs. The optimal ostial projection was RAO 5 degrees for the right superior PVs in 57 out of 58 patients (98%), RAO 55 degrees for the right inferior PVs in 54 out of 58 patients (93%), LAO 45 degrees for the left superior PVs in 46 out of 58 patients (80%), and LAO 60 degrees for the left inferior PVs in 48 out of 58 patients (83%). An optimal ostial projection in a frontal plane was identified only for the inferior PVs. The optimal ostial projection was LAO 40 degrees for the right inferior PVs in 55 out of 58 patients (95%) and RAO 45 degrees for the left inferior PVs in 51 out of 58 patients (88%). If selective angiography is to be used to delineate anatomy and location of the PV ostia to guide PV isolation, different fluoroscopic projections are required for different PVs. The preselected RAO and LAO projections proposed in our study result in optimal angiographic projections of all PV ostia in at least one plane in the majority of patients.