Real-time three-dimensional echocardiographic determination of right ventricular outflow tract high septal pacing sites.

OBJECTIVE To investigate the feasibility of determination of right ventricular outflow tract (RVOT) high septal pacing site visualized by real-time three-dimensional echocardiography (RT3DE). METHODS The forty subjects with RVOT pacing were analysed. RT3DE determination of RVOT high septal pacing sites was compared with chest X-ray (CXR). RESULTS RVOT septal pacing sites could be obtained in all patients by RT3DE.When pacing sites were categorized as septal or non-septal, there were good agreements between echocardiography and CXR (kappa = 0.745). However, when RVOT pacing sites were categorized as high septal or non-high septal in identifying the exact anatomic location of pacing sites, there was only mild agreement between echocardiography and CXR (kappa = 0.275). Moreover, when RT3DE was used as the gold standard in identifying the exact anatomic location of RVOT, pacing at the RVOT high septal could only be achieved in 37.5% (n= 15) of patients using RT3DE, but in 65% (n= 26) using CXR, because the RVOT septal pacing lead tip found at high septal by CXR is actually found at low septal or free wall by RT3DE. CONCLUSION It is limited to accurately locate RVOT high septal pacing site only by CXR, RT3DE allows to determinate the RVOT high septal pacing sites helpfully.