Morphologic study of the ascending aorta and aortic arch in hypoplastic left hearts: Surgical implications

ObjectivesThe ascending aorta and aortic arch in patients with hypoplasia of the left heart are hypoplastic as a result of diminished blood flow. In this study, the presence and degree of obstruction owing to areas of narrowing or infolding within the diminutive aorta are quantified, and their surgical significance is discussed.MethodsNinety-six specimens with hypoplasia of the left heart were studied and measurements were taken at specified sites to evaluate areas of narrowing. Quantitative assessments of infoldings and their contribution to obstruction of flow are made.ResultsNarrowing of the distal ascending aorta was found in 60 (62.5%) specimens, with a decrease in circumference of the distal ascending aorta (0.72 ± 1.06 mm) present when compared with its midpoint (P < .05). Tissue infolding at the orifice of the brachiocephalic artery and its junction with the distal ascending aorta was observed in 56 (58.3%) hearts, with major infolding in 29 (30.2%) and minor infolding in 27 (28.5%). Tissue infolding at this site correlated with a smaller ascending aorta (P < .001) but not with narrowing in the distal ascending aorta (P = .53). Ductal coarctations were detected in 77 (81.1%) specimens. Their presence correlated with a smaller diameter of the ascending aorta (P < .05), and their severity correlated with the presence of aortic and mitral valvular atresia (P < .05).ConclusionsImportant areas of obstruction in the ascending aorta in patients with hypoplasia of the left heart were found, and their pathogenesis is discussed. The findings highlight the importance of incorporating the ascending aorta into the aortic reconstruction at the time of initial palliation for patients with hypoplasia of the left heart

The echo-transponder electrode catheter: A new method for mapping the left ventricle

AbstractThe ability to locate catheter position in the left ventricle with respect to endocardial landmarks might enhance the accuracy of ventricular tachycardia mapping. An echotransponder system (Telectronics, Inc.) was compared with biplane fluoroscopy for left ventricular endocardial mapping. A 6F electrode catheter was modified with the addition of a piezoelectric crystal 5 mm from the tip. This crystal was connected to a transponder that received and transmitted ultrasound, resulting in a discrete artifact on the two-dimensional echocardiographic image corresponding to the position of the catheter tip.Catheters were introduced percutaneously into the left ventricle of nine anesthetized dogs. Two-dimensional echotransponder and biplane fluoroscopic images were recorded on videotape with the catheter at multiple endocardial sites. Catheter location was marked by delivering radiofrequency current to the distal electrode, creating a small endocardial lesion. Catheter location by echo-transponder and by fluoroscopy were compared with lesion location without knowledge of other data. Location by echo-transponder was 8.7 ± 5.1 mm from the center of the radiofrequency lesion versus 14 + 7.8 mm by fluoroscopy (n = 15, p = 0.023). Echo-transponder localization is more precise than is biplane fluoroscopy and may enhance the accuracy of left ventricular eledrophysiologic mapping