Chest radiography is a poor predictor of left ventricular lead position in patients undergoing cardiac resynchronization therapy: comparison with multidetector computed tomography

Optimal left ventricular (LV) lead position is thought to be a major predictor of response in patients undergoing cardiac resynchronization therapy (CRT). While the post-implant posterior-anterior (PA) and lateral chest X-ray (CXR) is commonly used to determine the position of the LV lead, the accuracy to which the CXR can correctly localize the LV lead is unknown. We collected data on 47 consecutive patients (mean age 64 years, 60% men and LV ejection fraction 23%, 49% ischemic cardiomyopathy) that underwent CRT between 2004 and 2007, who had both a post-implant CXR as well as a contrast-enhanced multi-detector computed tomography (MDCT) of the chest for any reason. The positions of the LV lead on CXR and MDCT were interpreted in a blinded fashion, independent of each other. The accuracy of the CXR in localizing various LV lead positions, with MDCT as the gold standard, was recorded. On CXR, the LV lead tip position was as follows: basal (4%), mid-ventricular (66%), and apical (30%) and anterior (2%), lateral (34%), and posterior (64%). On MDCT, the LV tip position was: basal (28%), mid-ventricular (60%), and apical (13%) and anterior (13%), lateral (19%), and posterior (68%). Compared to the MDCT gold standard, the percentage of LV lead positions the CXR correctly classified correctly were: 100% basal, 39% mid-ventricular, and 29% apical and 0% anterior, 12% lateral, and 77% posterior. Taking both PA and lateral views into consideration, the LV lead position was misclassified by CXR in 62% cases. Using MDCT as a gold standard, the routine post-implant CXR performs very modestly in terms of accurate LV lead positioning.