Faculty Bibliography

Left atrial appendage (LAA) contrast filling defects are commonly found in patients undergoing multidetector cardiac computed tomography (CCT) before catheter ablation of atrial fibrillation. Delayed CCT allows quantification of the LAA delayed/initial attenuation ratio and improves accuracy for LAA thrombus detection, which may obviate routine transesophageal echocardiography (TEE) before ablation. CCT with contrast-enhanced scans (initial CCT) and with noncontrast-enhanced scans (delayed CCT) was performed in 176 patients. LAA was evaluated for filling defects. LAA apex, left atrial (LA) body, and ascending aorta (AA) attenuations (Hounsfield units) were measured on initial and delayed cardiac computed tomograms to calculate LAA, LA, LAA/LA, and LAA/AA attenuation ratios. LAA, initial LAA/LA, and initial LAA/AA attenuation ratios differed significantly in patients with versus without filling defects on cardiac computed tomogram, those with atrial fibrillation versus normal sinus rhythm, and those with abnormal left ventricular ejection fraction versus larger LA volumes (p <0.05). In 70 patients (40%) who underwent TEE, 13 LAA filling defects were seen on initial cardiac computed tomogram. Two defects persisted on delayed cardiac computed tomogram and thrombus was confirmed on transesophageal echocardiogram. Sensitivity, specificity, and positive and negative predictive values of initial CCT for LAA thrombi detection were 100%, 84%, 15%, and 100%, respectively. With delayed CCT these values increased to 100%. Intraobserver and interobserver reproducibilities for cardiac computed tomographic measurements were good (intraclass correlation 0.72 to 0.97, kappa coefficients 0.93 to 1.00). In conclusion, delayed CCT provided an increase in diagnostic accuracy of CCT for detection of LAA thrombus in patients with atrial fibrillation before ablation, which may decrease the need for routine TEE before the procedure.

UNLABELLED:Endovascular lead infection is an uncommon but serious problem. Transesophageal echocardiography (TEE) is a useful tool for identification of pacemaker lead vegetations. Additionally, incidental echogenic masses are occasionally identified by TEE. The prognosis and optimal treatment of either suspected lead infection or an incidental mass is poorly understood. OBJECTIVE:The purpose of this study was to examine the incidence and clinical course of pacemaker lead masses. METHODS:A total of 1,569 sequential TEE examinations performed from January 2002 to January 2005 were reviewed. Retrospective chart analysis of patients with a pacing lead-associated mass was performed to review the indication for TEE as well as clinical management. Telephone follow up was also performed. RESULTS:During 125 TEE examinations, pacemaker leads were visualized in the right-sided chambers. Fifteen studies demonstrated an echogenic mass associated with the lead. In 9 of these studies, endocarditis was suspected, and the mass was felt to be a vegetation: 6 were treated with antibiotics alone, with 1 death attributed to a complication of endocarditis (autopsy proven massive pulmonary embolus); 3 patients were treated with lead extraction, both were alive at follow up; 1 patient was lost to follow up after the TEE. Six patients (5%) were found incidentally to have a mass on the pacing lead during TEE: 3 were treated with warfarin; 2 received no specific therapy; and 1 underwent surgical debridement of the lead during valve surgery. All of the patients in this group were alive at follow up, and no significant clinical events attributable to the lead-associated mass were observed. CONCLUSIONS:TEE identified an echogenic mass on 12% of the leads imaged, with 60% having suspected endocarditis. The mortality rate of lead vegetation was 11%. An incidental mass was noted on 5% of the leads, with no significant associated morbidity or mortality observed.