Fabien Squara1, Etienne Fourrier2, Yann Diascorn3, Alexandre Poulard2, Didier Scarlatti2, Sok-Sithikun Bun2, Pamela Moceri2, Emile Ferrari2. 1. Cardiology Department, Pasteur University Hospital, 30 avenue de la Voie Romaine, CS 51069, 06001, Nice CEDEX 1, France. fabiensquara@gmail.com. 2. Cardiology Department, Pasteur University Hospital, 30 avenue de la Voie Romaine, CS 51069, 06001, Nice CEDEX 1, France. 3. Radiology Department, Pasteur University Hospital, Nice, France.
Abstract
BACKGROUND: The fluoroscopic individualized LAO (i-LAO) projection has demonstrated high accuracy for identifying right ventricular (RV) lead positioning, likely by approximating a view along the septal or RV long axes. However, RV and septal anatomical axes have not been studied, and their relation with i-LAO is unknown. We sought to determine RV, septal, and left ventricular (LV) long-axis orientations by CT scan and to compare them to the i-LAO angle, to confirm the anatomical relevance of i-LAO. METHODS: We prospectively included patients (pts) for whom i-LAO angle was determined during pacemaker or defibrillator implant. Then, RV, septal, and LV long-axis orientations were determined by CT scan by a physician blinded to i-LAO data. The horizontal components of the cardiac axes were compared with those of the i-LAO angle. RESULTS: We included 26 pts. Median values were 57.5° for i-LAO angle (range 47.5-70), 64.5° for RV axis (range 48-90), 51.5° for septal axis (range 39-74), and 37° for LV axis (range 25-67). i-LAO angle best correlated with septal axis (r = 0.91 and ρc = 0.71). Up to an angle of 70° (maximal measurable i-LAO value; 23/26 pts), the i-LAO angle was comprised between the septal and the RV axes (21/23 pts, 91.3%), or within 2° of this interval (2/23 pts, 8.7%). CONCLUSIONS: RV and septal anatomical axes present major interindividual variations, prompting the use of individualized fluoroscopy criteria for lead implantation. i-LAO angle demonstrated to be almost constantly between the septal and RV long axes, thus confirming its anatomical relevance for RV lead implantation.
BACKGROUND: The fluoroscopic individualized LAO (i-LAO) projection has demonstrated high accuracy for identifying right ventricular (RV) lead positioning, likely by approximating a view along the septal or RV long axes. However, RV and septal anatomical axes have not been studied, and their relation with i-LAO is unknown. We sought to determine RV, septal, and left ventricular (LV) long-axis orientations by CT scan and to compare them to the i-LAO angle, to confirm the anatomical relevance of i-LAO. METHODS: We prospectively included patients (pts) for whom i-LAO angle was determined during pacemaker or defibrillator implant. Then, RV, septal, and LV long-axis orientations were determined by CT scan by a physician blinded to i-LAO data. The horizontal components of the cardiac axes were compared with those of the i-LAO angle. RESULTS: We included 26 pts. Median values were 57.5° for i-LAO angle (range 47.5-70), 64.5° for RV axis (range 48-90), 51.5° for septal axis (range 39-74), and 37° for LV axis (range 25-67). i-LAO angle best correlated with septal axis (r = 0.91 and ρc = 0.71). Up to an angle of 70° (maximal measurable i-LAO value; 23/26 pts), the i-LAO angle was comprised between the septal and the RV axes (21/23 pts, 91.3%), or within 2° of this interval (2/23 pts, 8.7%). CONCLUSIONS: RV and septal anatomical axes present major interindividual variations, prompting the use of individualized fluoroscopy criteria for lead implantation. i-LAO angle demonstrated to be almost constantly between the septal and RV long axes, thus confirming its anatomical relevance for RV lead implantation.