Faculty Bibliography

In an 80-year-old patient with syncope, a markedly tortuous descending thoracic aorta produced images on transesophageal echocardiography which were suggestive of an intimal flap caused by dissection. A magnetic resonance aortogram clearly showed that the trans-esophageal echocardiogram was a false positive. In addition, multiplanar reconstructed images of the magnetic resonance aortogram through the tortuous descending thoracic aorta could reproduce images similar to that seen by transesophageal echocardiography. Because transesophageal echocardiography has become a popular imaging modality for the detection of aortic dissection, it is essential for echocardiographers to be aware of possible pitfalls which may create false positive findings

High density lipoprotein has been shown to have a strong negative correlation with the presence of coronary artery atherosclerosis, whereas total cholesterol and low density lipoprotein are positively correlated and the role of triglycerides is complex. The purpose of this study was to determine whether levels of these lipids also correlate with large vessel atherosclerotic plaque burden (ATH) as seen in the thoracic aorta on transesophageal echocardiography. Maximal plaque area in the aortic arch and the proximal and distal descending thoracic aorta was measured by planimetry in 100 pts (mean age 68.5±1.4; 51% males). Maximal plaque areas were added to yield an estimate of total plaque burden. Both plaque burden and lipid measurements were performed in a double-blind manner. Results: There was a significant negative correlation of high density lipoprotein with ATH (R = -0.26, p = 0.009). However, neither total cholesterol (R = 0.08, p = 0.4), low density lipoprotein (R = 0.11, p = 0.28, nor triglycerides (R = 0.06, p = 0.54) were significantly correlated with ATH. Conclusion: Serum high density lipoprotein levels are significantly negatively correlated with thoracic aortic atherosclerotic plaque burden as imaged by transesophageal echocardiography

Surgical treatment of left ventricular aneurysms have recently focused on maintaining normal left ventricular geometry by using a circular patch repair to exclude the aneurysmal cavity (endoaneurysmorrhaphy). We describe two patients who underwent this procedure and were subsequently found by echocardiography and angiography to have a residual communication between the left ventricular cavity and the aneurysm which contained thrombus. This finding may have implications regarding the optimal hemodynamic result of the surgery and the risk of thromboembolism

1. The effects of the calcium channel blockers, funnel-web spider toxin (FTX), omega-agatoxin IVA (omega-Aga IVA) and omega-conotoxin GVIA (omega-CgTX), were tested on transmitter release and presynaptic currents in frog motor nerve endings. 2. Evoked transmitter release was blocked by FTX (IC50 = 0.02 microliter ml-1) and omega-CgTX (1 microM) but was not affected by omega-Aga IVA (0.5 microM). When FTX (0.1 microliter ml-1) was assayed on spontaneous release either in normal Ringer solution or in low Ca(2+)-high Mg2+ solution, it was found not to affect miniature endplate potential (MEPP) amplitude but to increase MEPP frequency by approximately 2-fold in both conditions. 3. Presynaptic calcium currents (ICa), measured by the perineurial technique in the presence of 10 mM tetraethylammonium chloride (TEA) and 200 microM BaCl2 to block K+ currents, were blocked by omega-CgTX (5 microM), partially blocked by FTX (1 microliter ml-1) and not affected by omega-Aga IVA (0.5 microM). 4. The presynaptic calcium-activated potassium current (IK(Ca)) measured by the perineurial technique in the presence of 0.5 microM 3,4-aminopyridine (DAP) to block voltage-dependent K+ currents, was strongly affected by charybdotoxin (ChTX) (300 nM) and completely abolished by BaCl2 (200 microM). This current was also blocked by omega-CgTX (5 microM) and by CdCl2 (200 microM) but was not affected by FTX (1 microliter ml-1). The blockade by omega-CgTX could not be reversed by elevating [Ca]o to 10 mM. 5. The results suggest that in frog synaptic terminals two omega-CgTX-sensitive populations might coexist. The transmitter release process seems to be mediated by calcium influx through a omega-CgTX- and FTX-sensitive population

The purpose of this study was to compare transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) in the evaluation of the coronary sinus and its blood flow. Forty patients were studied by TTE and TEE. The distal coronary sinus and its right atrial communication could be identified in 21 of 40 by TTE, and in all patients by TEE. Coronary sinus diameter measurement at the right atrial communication was possible by TTE in 16 of 40, and in all patients by TEE (maximal diameter 6 to 14 mm, mean 9 +/- 2). Flow velocity measurement by pulsed Doppler was possible in 25 of 40 patients (63%) by TEE, and in none by TTE. The flow velocity pattern was similar to central vein flow velocity, with systolic and diastolic antegrade waves, and a small retrograde end diastolic wave. The coronary sinus cross-sectional area was measured in 5 patients by intravascular ultrasound. It varied in size and shape during the cardiac cycle, reaching a maximum (0.3 to 1.5 cm2) at end diastole, and decreasing by 40% to 70% at end systole. TEE is superior to TTE in the evaluation of the coronary sinus and its blood flow velocity. However, because of the variability in cross-sectional area size and shape, measurement of coronary sinus blood flow may be inaccurate