Findings of Transesophageal Echocardiographic Images in Placing the Coronary Sinus Perfusion Catheter

In retrograde cardioplegia (RCP), some difficulty is occasionally encountered when inserting a catheter into the coronary sinus (CS). Although the usefulness of transesophageal echocardiography (TEE) for guiding the cannulation procedures has been previously reported by other authors, we have obtained additional findings by TEE monitoring of eleven patients during placement of the CS catheter. The diameter of the CS ranged from 5.5 to 10.7 mm, indicating that it was large enough for the CS catheter to be inserted and that the resistance at insertion was not due to narrow CS. The precise time for inserting the catheter, for which myocardial protection is delayed, ranged from 8 to 376 seconds, with an average of 98 seconds. Dislodgement of the catheter was found in two cases. In case of difficult cannulation, the catheter tip was found to be pushing the right atrial wall adjacent to the CS orifice or alternatively it entered the middle cardiac vein which had a common atrial orifice with the CS in this particular case. We found that the knowing the following technical problems helps appropriate monitoring: the catheter tip becomes unclear when it is not perpendicular to the ultrasonic beam, when surgeon's fingers are placed behind the heart, or when the blood is entirely exsanguinated. Finally we present the possibility of employing images of overflow out of CS during RCP infusion, detected by TEE, as an index of efficient perfusion at the interventricular septum

Photoinduced dynamics during electronic transfer from narrow to wide bandgap layers in one-dimensional heterostructured materials

Electron transfer is a fundamental energy conversion process widely present in synthetic, industrial, and natural systems. Understanding the electron transfer process is important to exploit the uniqueness of the low-dimensional van der Waals (vdW) heterostructures because interlayer electron transfer produces the function of this class of material. Here, we show the occurrence of an electron transfer process in one-dimensional layer-stacking of carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs). This observation makes use of femtosecond broadband optical spectroscopy, ultrafast time-resolved electron diffraction, and first-principles theoretical calculations. These results reveal that near-ultraviolet photoexcitation induces an electron transfer from the conduction bands of CNT to BNNT layers via electronic decay channels. This physical process subsequently generates radial phonons in the one-dimensional vdW heterostructure material. The gathered insights unveil the fundamentals physics of interfacial interactions in low dimensional vdW heterostructures and their photoinduced dynamics, pushing their limits for photoactive multifunctional applications

Endovascular stent-grafting via the aortic arch for chronic aortic dissection combined with coronary artery bypass grafting

AbstractJ Thorac Cardiovasc Surg 1999;117:825-