Direct intramuscular injection of plasmid DNA encoding angiopoietin-1 but not angiopoietin-2 augments revascularization in the rabbit ischemic hindlimb

BACKGROUND

Angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2) have recently been identified as ligands for the endothelial cell-specific Tie2 receptor. Little is known regarding the impact of these Tie2 ligands on postnatal neovascularization. Accordingly, we tested the hypothesis that gene transfer of plasmid DNA encoding Ang1 and Ang2 could modulate collateral vessel development in a rabbit model of hindlimb ischemia.

METHODS AND RESULTS

pAng1* (n=15), pJFE control (no Ang1* insert) (n=9), pAng2 (n=9), pcDNA3 control (no Ang2 insert) (n=10), or saline (n=5) was injected intramuscularly into the rabbit ischemic hindlimb. Collateral vessel development and limb perfusion were assessed before and 30 days after treatment. Calf blood pressure ratio (ischemic to normal hindlimb) was increased 30 days after Ang1* gene transfer versus controls (Ang1*, 0.90+/-0.02; pJFE, 0.76+/-0.05; saline, 0.77+/-0. 03; P<0.05). Angiographic score was higher (P<0.05) in the pAng1* group (0.63+/-0.02) than in the pJFE (0.51+/-0.03) or saline (0. 52+/-0.02) group. Maximal (postpapaverine) blood flow in the ischemic limb was higher (P<0.05) after pAng1* (67.8+/-4.9 mL/min) than pJFE (51.2+/-4.4 mL/min) or saline (52.9+/-4.9 mL/min). Capillary density and capillary/muscle fiber ratio (242+/-12/mm2 and 0.89+/-0.06, respectively) were higher (P<0.01) with pAng1* than pJFE (172+/-11/mm2 and 0.64+/-0.05) or saline (166+/-10/mm2 and 0. 67+/-0.05). Neovascularization was not enhanced with pAng2.

CONCLUSIONS

Ang1 but not Ang2 gene transfer produces anatomic and physiological evidence of enhanced collateral vessel formation. Ang1 may modulate neovascularization in adult animals and thus represents a feasible therapeutic strategy for patients with tissue ischemia. The role of Ang2 in postnatal neovascularization remains to be clarified.

A method to reduce response times in prehospital care: the motorcycle experience

This study compared the response times of a motorcycle and a standard ambulance in a congested urban emergency medical services (EMS) setting. The study was performed in Taipei, Taiwan, a densely populated urban area. A basic life support (BLS) motorcycle (without defibrillation capability) and an advanced life support (ALS) ambulance were based at three study hospitals and simultaneously dispatched when there was a perceived need for ALS ambulance transport. Over a 3-month period, prehospital personnel evaluated 307 medical and trauma emergencies. Time data were insufficient for analysis in 33 cases, leaving a study population of 274. Response times of the motorcycle and the ambulance were prospectively assessed and compared. During rush hours, the response times of the motorcycle and ambulance were 4.9+/-3.0 minutes and 6.3+/-3.4 minutes (P < .05), respectively, and in non-rush hours, 4.2+/-2.1 minutes and 5.1+/-2.5 minutes (P < .05), respectively. Using motorcycles to transport EMTs to the emergency scene significantly reduced response time compared with a standard ambulance in a congested urban setting. Large prospective studies are required to determine the impact on patient outcome of shorter EMS response times using motorcycles. EMS motorcycles appear feasible and deserve consideration to help expedite prehospital care in other systems in densely populated cities.

Cardiac troponin T, creatine kinase, and its isoform release after successful percutaneous transluminal coronary angioplasty with or without stenting

BACKGROUND

Cardiac troponin T is a sensitive and specific marker for the detection of minor myocardial injury. However, it has been rarely used to monitor myocardial injury after coronary stenting. The purpose of the study was to measure troponin T after apparently successful percutaneous transluminal coronary angioplasty (PTCA) with or without coronary stenting and to compare its result with serum creatine kinase and its isoform, CKMB.

METHODS

The incidence of cardiac troponin T elevation was compared with that of creatine kinase or CKMB in 120 consecutive patients with symptomatic ischemia undergoing visually successful PTCA with (n = 59) or without stenting (n = 61). Troponin T, creatine kinase, and CKMB were measured before, immediately after, and 18 to 24 hours after the procedures were performed.

RESULTS

No patient had abnormal troponin T, creatine kinase, or CKMB levels before and immediately after the procedures. Moreover, no patient showed electrocardiographic evidence of myocardial infarction. Troponin T was elevated in 17 patients at 18 to 24 hours after coronary stenting and in eight patients after PTCA. Both creatine kinase and CKMB were elevated in five patients after coronary stenting and in three patients after PTCA. The frequency of abnormal troponin T levels was significantly higher than that of creatine kinase or CKMB after coronary interventions (21% vs 6.7%; p < 0.01), and it was significantly higher after stenting when compared with angioplasty alone (29% vs 13%; p < 0.05). Patients with abnormal troponin T levels were more likely to undergo repeat revascularization than those without (24% vs 6%; p < 0.01).

CONCLUSION

Cardiac troponin T is more sensitive than creatine kinase and CKMB in detecting minor myocardial injury after coronary interventions. The incidence of troponin T release is higher in the patients undergoing stent implantation than in patients treated with angioplasty alone.

Concentrations of serum interleukin-8 after successful cardiopulmonary resuscitation in patients with cardiopulmonary arrest

To assess differences in serum interleukin-8 concentrations in resuscitated and nonresuscitated patients after cardiopulmonary resuscitation (CPR), and to compare changes of interleukin-8 levels with hemodynamic variables after restoration of spontaneous circulation, 39 patients with out-of-hospital cardiopulmonary arrest who had undergone CPR were studied. Venous blood samples were taken after CPR and 1 and 2 hours after restoration of spontaneous circulation to measure serum interleukin-8 levels by the enzyme-linked immunosorbent assay method. The median serum interleukin-8 levels after CPR were significantly higher in resuscitated than in nonresuscitated patients (64.9 pg/ml; range 30.2 to 1497 vs 0 pg/ml; range 0 to 31.6 pg/ml; p < 0.001). One and 2 hours after restoration of spontaneous circulation, the median serum interleukin-8 levels were 96.2 pg/ml and 155.4 pg/ml, respectively. Mean values of systolic blood pressure immediately after and 1 and 2 hours after restoration of spontaneous circulation were 117 +/- 9 mm Hg, 130 +/- 11 mm Hg, and 136 +/- 13 mm Hg, respectively. No significant correlations were found between hemodynamic values and serum interleukin-8 levels. In conclusion, successful initial resuscitation was associated with increased serum interleukin-8 concentrations. The interleukin-8 levels remained at high values 2 hours after restoration of spontaneous circulation.

Influence of additional partition on the recovery of atrial function after atrial compartment operation for atrial fibrillation

Chronic atrial fibrillation can be eliminated by an atrial compartment operation, but additional partition on the right atrium impairs the recovery of right atrial mechanical function. Thus, it is important to appropriately divide the atria for both maintaining sinus rhythm and maximizing atrial mechanical function.

Serum levels of intercellular adhesion molecule-1 and E-selectin in patients with acute ischaemic stroke

To investigate the role of circulating intercellular adhesion molecule-1 (ICAM-1) and E-selectin in ischaemic stroke, serum levels of ICAM-1 and E-selectin were measured by ELISA in 51 patients with acute ischaemic stroke within 24 h, and in 25 age-matched healthy controls and 10 young healthy volunteers. Carotid Doppler ultrasonography showed a significant stenosis (> 50%) of the carotid or vertebrobasilar artery in 11 of 51 stroke patients. Serum levels of ICAM-1 [mean (SE)] were higher (P < 0.01) in patients with ischaemic stroke [381 (30) ng/ ml] than in age-matched controls [271 (27) ng/ml] and young controls [246 (6) ng/ml]. There was no significant difference in serum E-selectin levels [mean (SE)] among stroke patients, age-matched and young controls [47 (6), 39 (3), and 41 (3) ng/ ml, respectively; P = NS]. The leucocyte count [mean (SD)] was higher (P < 0.01) in patients with ischaemic stroke [8310 (2800)] than in age-matched controls [6040 (930)]. Serum levels of ICAM-1 and E-selectin did not significantly differ between patients with or without abnormal carotid or vertebrobasilar artery disease. In conclusion, serum ICAM-1 level and leucocyte count were elevated in acute ischaemic stroke within 24 h, while the E-selectin level did not change significantly. This finding suggests that adhesion molecules may play an important role in the post-rolling process of leucocyte-endothelial cell interaction in acute ischaemic stroke.

Use of cardiac troponin T, creatine kinase and its isoform to monitor myocardial injury during radiofrequency ablation for supraventricular tachycardia

To determine whether radiofrequency ablation for supraventricular tachycardia causes significant minor myocardial injury, 16 patients with supraventricular tachycardia undergoing radiofrequency ablation were studied. Cardiac troponin T, creatine kinase and its MB form (CKMB) were measured before, immediately after ablation and every 6 h thereafter for 24 h to detect myocardial injury. Elevation of creatine kinase, CKMB and cardiac troponin T was observed in 6, 4 and 5 patients, respectively. The peak mean creatine kinase concentration was 167 +/- 152 IU/l and that of CKMB was 9 +/- 6 IU/l. The peak mean cardiac troponin T level was 0.44 +/- 0.47 ng/ml. The frequency of elevated measurements was not statistically different among creatine kinase CKMB and cardiac troponin T. The mean pulse numbers of ablation, mean duration of ablation, radiofrequency current and mean total energy did not differ statistically between those with or without elevated cardiac troponin T. It was concluded that radiofrequency ablation for supraventricular tachycardia indeed caused some minor myocardial injury and the frequency of elevated cardiac troponin T was comparable to that of CKMB.

Circulating intercellular adhesion molecule-1 and E-selectin in patients with acute coronary syndrome

To characterize the role of circulating intercellular adhesion molecules (ICAM-1) and E-selectin in patients with acute coronary syndrome, serum levels of ICAM-1 and E-selectin were measured by enzyme-linked immunosorbent assay (ELISA). Group 1 comprised 17 patients with acute myocardial infarction; group 2 included 17 patients with unstable angina; and group 3 included 19 control subjects. These 53 patients all had prolonged chest pain within 24 h and all underwent coronary angiography. Group 1 and 2 patients had significant coronary artery disease, while group 3 had normal coronary arteries. Blood samples were collected at the emergency department before antiplatelet agents were given. Serum levels of 1CAM-1 were higher in group 1 and 2 (383 +/- 27 and 337 +/- 11 ng/mL, respectively) as compared with group 3 (282 +/- 18 ng/mL) (group 1 vs 3, p<0.01; group 2 vs 3, p<0.05). The serum levels of ICAM-1 were not significantly different between group 1 and 2. Serum levels of E-selectin in group 1, 2, and 3 were 58 +/- 8, 51 +/- 4, and 58 +/- 5 ng/mL, respectively. The serum levels of E-selectin showed no significant difference among the three groups. In conclusion, serum levels of ICAM-1 were elevated in patients with acute coronary syndrome within 24 h, while the E-selectin levels did not change significantly. This finding suggests that adhesion molecule may play an important role in the postrolling process of leukocyte-endothelial cell interaction in acute coronary syndrome.

Low-serum, high-density lipoprotein cholesterol concentration is an important coronary risk factor in Chinese patients with low serum levels of total cholesterol and triglyceride

The significance of low-serum high-density lipoprotein concentrations (<35 mg/dl) with respect to coronary atherogenesis in Chinese patients with low levels of total serum cholesterol (<200 mg/dl) and triglycerides (<250 mg/dl) was assessed. Persons with such a lipid profile pattern were still at high risk, and high-density lipoprotein. like smoking, appeared to be the most predictive independent coronary risk factor.

Diagnostic accuracy of transesophageal echocardiography for detecting patent ductus arteriosus in adolescents and adults

To compare the accuracy of transesophageal echocardiography (TEE) with that of transthoracic echocardiography (TTE) in the detection of patent ductus arteriosus (PDA) in the adolescent and the adult, 40 patients with PDA and 50 patients with other congenital heart diseases were studied. All echocardiograms were recorded before cardiac catheterization and surgery. The echocardiographic diagnosis of PDA was made by direct visualization of a shunt flow in the duct. A mosaic flow in the pulmonary artery without direct visualization of the duct was considered possible but not definitely diagnostic of PDA. TEE showed greater sensitivity and negative predictive value than TTE (97% vs 42%, and 98% vs 68%, respectively; p < 0.001) in confirming the diagnosis of PDA. The specificity and positive predictive value in establishing the diagnosis of PDA were the same for both techniques. In the subgroup of patients with Eisenmenger's syndrome, the sensitivity of TEE and TTE in confirming diagnosis of PDA was 100% and 12% (p < 0.01), respectively. The sensitivity of monoplane and biplane TEE in the diagnosis of PDA was comparable (95% and 100%, respectively; p = NS). In conclusion, TEE was highly sensitive and specific in detecting PDA in adolescents and adults. It was also highly valuable for detecting the cause of pulmonary hypertension in patients with Eisenmenger's syndrome.

Transesophageal echocardiographic assessment of mitral valve position and pulmonary venous flow during cardiopulmonary resuscitation in humans

BACKGROUND

The mechanisms of blood flow during closed-chest cardiopulmonary resuscitation (CPR) in humans have been debated since the technique was first described in 1960. Two competing models, the cardiac pump theory and the thoracic pump theory, have been proposed, and some investigators have used mitral valve position during the downstroke of chest compression to distinguish between them. Previous studies using either transthoracic or transesophageal echocardiography have yielded conflicting results, and there have been few, if any, hemodynamic or echocardiographic studies on pulmonary venous flow (PVF) during CPR.

METHODS AND RESULTS

In this study, transesophageal two-dimensional and pulsed Doppler echocardiography were used to study mitral valve position and flow, together with PVF, in 20 adult patients undergoing manual CPR. In the 17 patients who could be analyzed, the mitral valve closed in 5 patients (group 1) during chest compression but stayed open or opened further in the remaining 12 patients (group 2). Peak forward mitral flow occurred during the release phase in group 1 but during the compression phase in group 2. During chest compression, PVF occurred in the forward direction (from the pulmonary vein to the left atrium) in 8 of the group 2 patients (group 2a) and in the backward direction (from the left atrium to the pulmonary vein) in all group 1 patients and the remaining 4 patients in group 2 (group 2b). The downtime (time from collapse to CPR) was significantly shorter (P < .05) for those in group 1 (7.0 +/- 4.4 minutes) than in groups 2a (19.8 +/- 7.7 minutes) and 2b (17.8 +/- 6.8 minutes).

CONCLUSIONS

Transesophageal echocardiography performed during manual CPR in humans disclosed three different patterns of mitral valve position and PVF during chest compression. The presence of an opened mitral valve with forward mitral flow and backward pulmonary venous flow during chest compression in a small number of subjects underscores this heterogeneity in blood flow and suggests the possible existence of a "left atrium pump" in addition to the currently known "left ventricle pump" and "chest pump" mechanisms.

Angiotensinogen gene expression is induced by cyclical mechanical stretch in cultured rat cardiomyocytes

The effect of cyclical mechanical stretch on angiotensinogen gene expression was examined using a neonatal rat cardiocyte culture system. Cultured cardiocytes grown on a flexible membrane base were stretched by vacuum to 20% of maximum elongation, at 60 cycles/min. The angiotensinogen gene was activated 2 to 5 fold after stretch for 3 to 24 hr, as shown by quantitative reverse transcription polymerase chain reaction. The 5'-flanking region of the angiotensinogen promoter was activated after stretch for 24 hr. This gene expression could be completely suppressed by losartan, a specific antagonist of angiotensin II receptor. These results indicate that (1) cyclical mechanical stretching of cardiocytes is a good model for the study of cardiac hypertrophy-related gene expression; (2) cyclical stretch up-regulates expression of the angiotensinogen gene and (3) the increase in promoter activity may contribute to the induction of angiotensinogen mRNA by cyclical stretch.

Regulation of human cardiac myosin heavy chain genes by cyclical mechanical stretch in cultured cardiocytes

We examined the effect of cyclical mechanical stretch on the regulation of cardiac myosin heavy chain genes using an isolated neonatal rat cardiocyte culture system. Cultured cardiocytes grown on a flexible membrane were deformed by vacuum to 20% of maximum elongation, at 60 cycles/min in a serum-free medium. Cyclical stretch did not cause myocyte damage as assessed by supernatant LDH measurement and trypan blue exclusion test. The levels of myosin heavy chain (MyHC) mRNA increased as early as 1 h after stretch, reaching 12-fold over the control in 24 h, as shown by Northern blot analysis. However, the proximal 5'-flanking regions of the alpha- and beta-MyHC gene which were linked to chloramphenicol acetyltransferase (CAT) reporter gene did not exhibit enhanced CAT activity following cyclical stretch. Deletion of the chimeric constructs to shorten the 5'-flanking regions of the MyHC genes generated by polymerase chain reaction amplification did not enhance the CAT activity under cyclical stretch. This finding suggests that the stretch-response element of the alpha- and beta-MyHC gene promoter is probably not present in the proximal region of either the alpha- or beta-MyHC genes.

Regression of left ventricular mass after mitral valve repair of pure mitral regurgitation

To evaluate the effect of mitral valve repair on the regression of left ventricular mass, we studied 50 consecutive patients with severe, pure mitral regurgitation undergoing mitral valve repair. Two-dimensional echocardiograms were recorded a mean 2.5 +/- 2.0 weeks before and 6.5 +/- 2.5 months after valve operation. Postoperative significant mitral regurgitation was present in 3 patients. After mitral valve repair there were significant decreases in left ventricular end-diastolic volume index (133 +/- 39 mL/m2 to 79 +/- 35 mL/m2; p < 0.001), end-systolic volume index (44 +/- 26 mL/m2 to 30 +/- 26 mL/m2; p < 0.001), stroke volume index (89 +/- 29 mL/m2 to 49 +/- 19 mL/m2; p < 0.001), and mass index (211 +/- 82 g/m2 to 134 +/- 52 g/m2; p < 0.001). There also were significant decreases in left atrial dimension (47 +/- 9 mm to 38 +/- 9 mm; p < 0.001), left ventricular end-diastolic dimension (61 +/- 8 mm to 48 +/- 7 mm; p < 0.001), and end-systolic dimension (39 +/- 8 mm to 32 +/- 7 mm; p < 0.001). Left ventricular ejection fraction decreased slightly from 0.69 +/- 0.12 to 0.64 +/- 0.12; p < 0.01) after repair. Thus, correction of pure mitral regurgitation leads to reduction of the cardiac chamber size and left ventricular volumes as well as regression of the left ventricular mass.

Recovery of atrial function after atrial compartment operation for chronic atrial fibrillation in mitral valve disease

OBJECTIVES

We prospectively studied the recovery of atrial function after atrial compartment operation and mitral valve surgery in patients with chronic atrial fibrillation caused by mitral valve disease.

BACKGROUND

Chronic atrial fibrillation is the most common arrhythmia in mitral valve disease. This arrhythmia is associated with excessive morbidity and mortality. Mitral valve surgery alone rarely eliminates it.

METHODS

Twenty-two patients underwent mitral valve surgery and a new surgical method, atrial compartment operation. Doppler echocardiography was performed in all patients before operation and at 1 week and 2 and 6 months after operation in the successful cardioversion group. Peak early diastolic (E) and atrial (A) filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves were measured.

RESULTS

Sinus rhythm was restored immediately after operation in 91% of patients and was maintained for > 1 week in 15 (68%) of 22 patients and > 6 months in 14 (64%) of 22. Eleven of 15 patients had left atrial paralysis (A/E integral ratio 0) at 1 week and 6 of 14 patients at 2 months. Nine of 15 patients had right atrial paralysis (A/E integral ratio 0) at 1 week and 1 of 14 patients at 2 months. Both left and right atrial contractile function (presence of an A wave on Doppler findings) was detected at 6 months in 14 patients. Mean (+/- SD) peak atrial filling velocity of the mitral valve was 15 +/- 26 cm/s at 1 week, 38 +/- 39 cm/s at 2 months and 93 +/- 32 cm/s at 6 months (p < 0.001). Mean peak atrial filling velocity of the tricuspid valve was 14 +/- 19 cm/s at 1 week, 33 +/- 19 cm/s at 2 months and 50 +/- 19 cm/s at 6 months (p < 0.001). Peak early diastolic and atrial filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves increased significantly from 1 week to 6 months.

CONCLUSIONS

Chronic atrial fibrillation in mitral valve disease can often be eliminated by atrial compartment operation. No surgical mortality or significant complications were encountered. Both left and right atrial function, as manifested by Doppler findings, recover after compartment operation and improve over time. The mechanical function of the right atrium recovers earlier than that of the left.

Significant mitral regurgitation is protective against left atrial spontaneous echo contrast formation, but not against systemic embolism

The prevalence of left atrial spontaneous echo contrast (SEC) and the occurrence of systemic embolism were prospectively studied in 176 consecutive patients. All had significant mitral regurgitation (MR) and underwent transesophageal echocardiographic (TEE) studies. Left ventriculography was performed in all patients to document the severity of MR. The underlying causes of MR included rheumatic heart disease in 84 patients, ruptured chordae tendineae in 37, mitral valve prolapse in 18, infective endocarditis in 20, coronary artery disease in 8, congenital heart disease in 5, and dilated cardiomyopathy in 4. No patient was found to have left atrial thrombus. Left atrial SEC was observed in three patients (1.7 percent), all of whom had atrial fibrillation, concomitant mitral stenosis, and huge left atria. Color flow mapping revealed that left atrial SEC was prominent in regions where the turbulent flow of MR was not present. Systemic embolism occurred in ten patients (5.7 percent). The underlying disease was infective endocarditis, rheumatic heart disease, and dilated cardiomyopathy in 6, 3, and 1 patient, respectively. The sites of embolization involved the central nervous system in eight patients and the spleen in the remaining two. Three patients with rheumatic heart disease and the one with dilated cardiomyopathy were in atrial fibrillation and had dilated left atria (diameter > 45 mm) when systemic embolism occurred. Only one patient with rheumatic heart disease was found to have left atrial SEC. The remaining six, with infective endocarditis, all had sinus rhythm. In conclusion, left atrial SEC or thrombus detected by TEE is uncommon in patients with significant MR. Clinical conditions may be of help to identify the subsets of patients at higher risk for systemic embolism.

Comparison of transthoracic and transesophageal echocardiography in the diagnosis of intracardiac tumors in adults

To compare transthoracic and transesophageal echocardiography in the diagnosis of intracardiac tumors, 17 patients (8 men and 9 women, aged 19 years to 67 years) whose intracardiac tumors were detected by echocardiography were studied in a 4-year period. Of these, 14 patients underwent cardiac surgery and 13 were proved to have tumors. There were 4 false-positive and 2 false-negative diagnoses by transthoracic echocardiography, but only one false-positive and no false-negative diagnosis by transesophageal echocardiography. The stalk of a myxoma was detected clearly in 5 of 11 patients by transthoracic echocardiography, whereas in 10 of 11 it was detected by transesophageal echocardiography. The detailed morphologic characteristics of the tumor, such as contour of the tumor, and the presence of cysts and calcification in the tumor, were seen more clearly with transesophageal echocardiography than with transthoracic echocardiography.

Clinical implications of left atrial appendage flow patterns in nonrheumatic atrial fibrillation

Left atrial appendage (LAA) function and flow patterns in 29 patients with chronic nonrheumatic atrial fibrillation were studied by transesophageal echocardiography. These 29 patients (16 men and 13 women; mean age, 63.8 years; range, 38 to 77 years) were classified into two groups according to different LAA flow patterns. Seventeen patients (group 1) had well-defined LAA emptying and filling Doppler flow signals, and the other 12 patients (group 2) had very low LAA flow signals. No significant differences were found in age, sex, mean duration of atrial fibrillation, left ventricular end diastolic dimension, and left ventricular ejection fraction between the two groups. However, group 2 patients had larger left atrial diameter (42.8 +/- 4.2 mm vs 36.6 +/- 8.8 mm; p < 0.05), lower LAA ejection fraction (26.4 +/- 15.2 percent vs 42.6 +/- 14.1 percent; p < 0.05), and lower LAA peak emptying velocity (0.13 +/- 0.03 m/s vs 0.36 +/- 0.16 m/s; p < 0.001). Higher incidence of LAA spontaneous echocardiographic contrast formation in group 2 patients (8/12 vs 1/17; p < 0.001) was noted. In conclusion, a subset of patients with nonrheumatic atrial fibrillation were found to have lower LAA blood flow and poorer LAA function. These patients had higher incidence of left atrial or LAA spontaneous echo contrast formation which had been proved previously to be a marker for future systemic thromboembolism.

Salmonella prosthetic valve endocarditis. A case report

A patient with Björk-Shiley mechanical mitral valve was noted to have Salmonella prosthetic valve endocarditis, which was confirmed by positive blood cultures and vegetation found by transesophageal echocardiography. Up to now, only 5 cases of Salmonella prosthetic valve endocarditis have been reported in the literature. Because of the malignant course of this rare infection, the authors suggest that early surgical intervention should be considered in Salmonella prosthetic valve endocarditis, especially when the patients have recurrent fever during medical treatment.

Left atrial appendage function determined by transesophageal echocardiography in patients with rheumatic mitral valve disease

Left atrial thrombi have been considered to be the major source of systemic arterial embolization in patients with rheumatic mitral valve disease. Almost half of the left atrial thrombi are found in the left atrial appendage (LAA). To investigate LAA size and LAA contractile function in patients with rheumatic mitral valve disease, transesophageal echocardiographic and Doppler studies were performed in 61 patients. Among them, 46 patients were in atrial fibrillation (group 1), while the other 15 were in sinus rhythm (group 2). Thirty-six patients with nonrheumatic atrial fibrillation were chosen as control to group 1. Another 22 patients with various cardiovascular diseases and sinus rhythm served as control to group 2. When compared to the patients with nonrheumatic atrial fibrillation (control group), group 1 patients tended to have a larger LAA maximal area (9.7 +/- 5.2 vs. 5.9 +/- 2.8 cm2; p < 0.001). LAA ejection fraction and LAA peak emptying velocity were also lower. A significantly higher incidence of LAA spontaneous echo contrast (SEC) and thrombus formation was also found in these patients. Group 2 patients were also found to have a larger LAA maximal area when compared to the control group (8.8 +/- 3.7 vs. 5.2 +/- 3.0 cm2; p < 0.001). LAA ejection fraction and LAA peak emptying velocity were lower in this group, too. A higher incidence of LAA SEC formation was found in these patients with rheumatic mitral valve disease (4/15 vs. 0/22; p = 0.021). There was no significant difference, however, in LAA thrombus formation between group 2 and its control group (1/15 vs. 1/22; p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Change in left ventricular diastolic filling patterns in patients with supraventricular tachycardia treated by radiofrequency ablation: a Doppler echocardiographic study

To evaluate changes in left ventricular diastolic filling patterns resulting from radiofrequency ablation for supraventricular tachycardia (SVT), 44 patients with SVT undergoing radiofrequency ablation (study group), and 16 patients with SVT undergoing electrophysiologic study without ablation (control group) were studied by pulsed Doppler echocardiography. Peak early diastolic filling velocity (E), peak atrial filling velocity (A), and an E/A ratio were obtained from the transmitral flow velocity pattern before and 24-48 h after ablation or electrophysiologic study. In the study group, E and E/A ratio decreased from 67 +/- 16 and 1.26 +/- 0.42 to 61 +/- 16 cm/s and 1.09 +/- 0.39 (p < 0.001), respectively. In the control group, only E/A ratio decreased from 1.40 +/- 0.47 to 1.26 +/- 0.44 (p < 0.001). Heart rate increased from 71 +/- 10 to 80 +/- 10 beats/min (p < 0.001) in the study group and from 67 +/- 8 to 72 +/- 10 beats/min (p < 0.05) in the control group. E and E/A ratio decreased significantly from 73 +/- 17 and 1.35 +/- 0.49 to 60 +/- 18 cm/s and 0.96 +/- 0.40 (p < 0.001) in patients with heart rate change of > 20% after ablation. E, A, and E/A ratio did not change significantly in patients with heart rate change of < 10% and of between 10 and 20% after ablation. Blood pressure and left ventricular ejection fraction did not change in either the study or control groups. It was concluded that left ventricular ejection fraction and Doppler diastolic filling patterns are unaffected by radiofrequency ablation.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of transesophageal echocardiography in the diagnostic assessment of cardiac sources of embolism in patients with acute ischemic stroke

To evaluate the role of transesophageal echocardiography (TEE) in the diagnostic assessment of cardiac sources of embolism in acute ischemic stroke, 94 consecutive patients (44 men and 50 women, aged 22-82 years) with acute ischemic stroke were prospectively studied. Of these, 34 patients had clinical evidence of heart disease. Both transthoracic and transesophageal echocardiograms were recorded on the same day for each patient. Transthoracic echocardiography (TTE) identified a possible cardiac source of embolism in 2 patients (6%) with and in 3 (5%) without clinical heart disease. TEE identified a possible cardiac source of embolism in 21 patients (62%) with and in 18 (30%) without clinical heart disease. TEE was superior to TTE for the detection of a cardiac source of embolism in patients with acute ischemic stroke (41 vs. 5%, p < 0.001). Factors significantly associated with a greater likelihood of such cardiac sources of embolism included left atrial enlargement, atrial fibrillation and a younger age. The yield of TEE in identifying a possible cardiac source of embolism was higher in patients with clinical evidence of heart disease than in those without.

Clinical implications of left atrial appendage function: its influence on thrombus formation

This study evaluated the relation between left atrial appendage (LAA) function and LAA spontaneous echo contrast (SEC) or thrombus formation. Seventy-five patients (45 men and 30 women, aged 14-79 years) referred for transesophageal echocardiography (TEE) were examined for LAA area (maximal and minimal), LAA ejection fraction ([LAA maximal area--LAA minimal area]/LAA maximal area), LAA peak emptying velocity, and these patients were classified into three groups by different LAA blood flow patterns: Group 1--25 patients with well-defined biphasic configuration of LAA flow; Group 2--28 patients with multiphasic configuration of LAA flow; Group 3--22 patients with very low LAA blood flow and, sometimes, barely detected Doppler signal. All the 25 patients in Group 1 had a sinus rhythm during TEE study, while the other 50 patients in Groups 2 and 3 were in atrial fibrillation. The patients in Group 3 had the lowest LAA ejection fraction and the lowest peak emptying velocity of these three groups. LAA SEC was present in five of 28 patients in Group 2 and 14 of 22 patients in Group 3, but in none of 25 patients in Group 1 (P < 0.001). LAA thrombus was present in one of 25 patients in Group 1, two of 28 patients in Group 2, and seven of 22 patients in Group 3 (P < 0.05). In conclusion, this study found that patients with poor LAA function, which was represented by lower LAA ejection fraction and lower peak emptying velocity, had higher incidence of LAA SEC or thrombus formation.

Usefulness of pulmonary venous flow pattern and maximal mosaic jet area detected by transesophageal echocardiography in assessing the severity of mitral regurgitation

Pulmonary venous flow pattern detected by transesophageal echocardiography (TEE) has been reported to be a good marker of mitral regurgitation (MR) severity. In 89 patients with MR detected by TEE, both pulmonary venous flow pattern and maximal mosaic jet area were recorded for evaluating the severity of MR. Cardiac catheterization was performed in all patients for grading the severity of MR. Systolic reversed flow in pulmonary veins was a good marker for angiographic grade 3 or 4 MR with a sensitivity of 97% (33 of 34) and specificity of 95% (52 of 55). Maximal mosaic jet area had a good correlation with the grading of MR (r = 0.79). When a maximal mosaic jet area of > 6 cm2 was used to detect grade 3 or 4 MR, the sensitivity and specificity were lower than those of the systolic reversed flow (sensitivity 82 vs 97%, p = 0.073; specificity 80 vs 95%, p = 0.013). The accuracy of systolic reversed flow was not influenced by the cardiac rhythm or jet eccentricity. However, the sensitivity of maximal mosaic jet area was lower in patients with an eccentric jet than in patients with a central jet (67 vs 95%, p = 0.046). In conclusion, systolic reversed flow in pulmonary veins detected by TEE is better than the maximal mosaic jet area in detecting grade 3 or 4 MR, especially in patients with eccentric jet.

Infundibular pulmonic stenosis with intact ventricular septum: a report of 15 surgically corrected patients

Infundibular pulmonic stenosis with intact ventricular septum of primary origin is an uncommon condition. We report 15 such patients (nine males and six females, aged 7-36 years) who had undergone surgical correction for the anomaly during the period between 1975 and 1992. The occurrence of this clinical setting represents 0.19% (15/7826) of all cardiac operations and 0.46% (15/3222) of congenital heart diseases undergoing surgical correction during that period of time. The lesion was of discrete fibromuscular hypertrophy of the infundibulum in all 15 patients. The presenting symptoms of most patients were exertional dyspnea and syncope; however, five patients with severe obstruction were asymptomatic. The peak systolic pressure gradient across the infundibulum ranged from 71 to 230 mmHg. There was only one operative death; the remainder had remained well following the surgery over a mean follow-up period of 35 months. Surgical correction for infundibular pulmonic stenosis is rewarding in the absence of heart failure.

Usefulness of transesophageal echocardiography in the treatment of critically ill patients

To evaluate the usefulness of transesophageal echocardiography (TEE) in the treatment of critically ill patients, 80 patients (51 male and 29 female; mean age, 53 years) undergoing both transthoracic echocardiography (TTE) and TEE were studied in a 2-year period. Of these, 48 patients were studied in the ICU, while the other 32 patients were directly referred from the emergency departments. Indications for the study included suspected aortic dissection (34 patients), hemodynamic instability (22 patients), suspected cardiac source of embolism (11 patients), evaluation of the severity of mitral regurgitation (7 patients), and suspected infective endocarditis (6 patients). The probe was passed successfully in 78 of 80 attempts (98 percent). No significant complications were recorded during the transesophageal echocardiographic study. Transesophageal echocardiography provided critical information that was not obtained by TTE in 39 of 78 studies (50 percent, p < 0.005). Cardiac surgery was prompted by TEE findings in 14 patients (18 percent) and these findings were all confirmed at operation. Transesophageal echocardiography was a safe, well-tolerated, and valuable diagnostic approach for the rapid detection of specific cardiac abnormalities in patients with critical illness; TEE should be considered in the treatment of critically ill patients especially when TTE provided inadequate information.

Spontaneous echo contrast in massive pericardial effusion with tamponade

Spontaneous echo contrast is uncommon in pericardial effusion. We report the case of a patient with massive malignant pericardial effusion causing cardiac tamponade in which the intense spontaneous echo contrast was found in the effusion by echocardiography. It was suggested that both the heavy blood content and a large amount of pericardial effusion were needed to create the phenomenon of spontaneous echo contrast in the pericardial cavity.

Expanded indication: diagnosis of pulmonary embolism by transesophageal echocardiography

Transesophageal echocardiography is a useful diagnostic tool not only in examination of the heart, but also in examination of the great arteries. Its role in the diagnosis of aortic aneurysm and dissection has been well-established. The pulmonary artery, especially the right pulmonary artery, also can be visualized clearly by this technique. In this report, we described a patient with massive pulmonary embolism which was diagnosed by transesophageal echocardiography, and was confirmed by pulmonary angiography.

Pericardial color Doppler flow in postpericardiotomy effusive constrictive pericarditis

A laminar color Doppler flow was discovered in the pericardial space in a 35-year-old man with postpericardiotomy effusive constrictive pericarditis. The flow was detected by transesophageal color Doppler echocardiography. A further pulsed Doppler study revealed a to-and-fro flow, which was synchronized with the cardiac rhythm. We hypothesized that this flow was generated by the rhythmic cardiac contraction. It was then augmented by hard fibrous pericardium and became detectable by color Doppler echocardiography. Pericardial effusion is a frequent echocardiographic finding but little attention has been paid to the flow in it. The laminar flow in the pericardial space in our patient is related to his hard pericardium and can aid in making the diagnosis of effusive constrictive pericarditis. We suggest that flow in the pericardial space deserves more attention and may provide valuable diagnostic aid.

Bidirectional shunt through a residual atrial septal defect after percutaneous transvenous mitral commissurotomy

A residual atrial septal defect with bidirectional shunt was detected by transesophageal echocardiography in a 28-year-old man 3 years after percutaneous transluminal mitral commissurotomy (PTMC) with the antegrade transseptal technique. He had had severe mitral stenosis, pulmonary hypertension, and tricuspid regurgitation before the procedure. The result of PTMC was suboptimal, the pulmonary hypertension regressed only partially, and the tricuspid regurgitation remained severe. These factors contributed to the bidirectional shunt. A bidirectional shunt is known to be associated with systemic desaturation and a higher risk of paradoxical embolization and brain abscess. When PTMC is considered in patients with pulmonary hypertension and tricuspid regurgitation, a retrograde left ventricular approach with or without transseptal puncture can avoid the atrial septotomy, decrease the incidence of significant shunt, and should be a rational alternative.

Infective endocarditis in the transesophageal echocardiographic era

During a 45-month period, 50 consecutive patients with infective endocarditis were evaluated at the National Taiwan University Hospital with emphasis on the role of transesophageal echocardiography (TEE) in the management of these patients. Among them, rheumatic heart disease was still the most common underlying cardiac disorder (10/50, 20%), while mitral valve prolapse (8/50, 16%) and congenital heart disease (8/50, 16%) were also frequently encountered. More than one third (19/50, 38%) had no underlying heart disease. Four intravenous drug abusers, quite rare previously in Taiwan, were found during the study period. Native valves involved were mostly mitral valve (n = 18), aortic valve (n = 15), and both mitral and aortic valves (n = 3). Tricuspid valve and pulmonic valve were involved in 3 and 2 patients, respectively. Streptococcus viridans was the leading microorganism isolated (21/50, 42%). Staphylococci and enterococci were found in 9 (18%) and 5 (10%) patients, respectively. Twelve patients (24%) were culture-negative in this series. Embolic complications occurred in 13 patients (26%), with a total of 17 episodes. No significant correlation was found between the occurrence of embolization and the vegetation size or the location of the vegetation, if patients with right-sided valvular vegetation and no identifiable vegetation were excluded. Surgery was needed by 25 patients (50%), and mortality occurred in 6 (12%). TEE was superior to transthoracic echocardiography in the detection of vegetations at the mitral or prosthetic valves. Concerning the associated complications with infective endocarditis, TEE was also superior in estimating the severity of mitral regurgitation, recognizing ruptured chordae tendineae and detecting subaortic complications such as valve ring abscess and mitral valve perforation.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective study of blood culture during transesophageal echocardiography

To ascertain the incidence and significance of bacteremia associated with transesophageal echocardiography (TEE), 132 consecutive patients (aged 17 to 73 years) free of apparent infection who were undergoing 135 transesophageal echocardiographic procedures from October 1990 to August 1991, were prospectively studied. For each procedure, two sets of blood cultures were obtained for culture 30 to 60 minutes before TEE, immediately after, and 180 to 240 minutes after the procedure. For each blood culture, 10 ml of venous blood was evenly inoculated into aerobic and anaerobic culture bottles and inoculated for 7 days using a radiometric system. A throat swab was obtained immediately before each procedure. Three of 270 preprocedure blood cultures were positive for Bacillus cereus, Staphylococcus simulans, and Peptostreptococcus species, respectively. No blood culture was positive in the immediate postprocedure period. Two of 270 late blood samples grew Staphylococcus epidermidis in the same patient. Nevertheless, the microorganisms isolated from blood cultures were different from those isolated from the throat swab. No patients had fever or evidence of infective endocarditis after TEE during the follow-up period. It is concluded that the incidence of TEE-related bacteremia is extremely low, and a general recommendation for antibiotic prophylaxis during TEE is not warranted.

Morphologic characterization and quantitative assessment of mitral regurgitation with ruptured chordae tendineae by transesophageal echocardiography

To compare the accuracy of transesophageal echocardiography (TEE) with that of transthoracic echocardiography (TTE) in the detection of morphologic characteristics and in the quantitative assessment of the severity of mitral regurgitation with ruptured chordae tendineae, 40 patients with ruptured chordae tendineae (group 1) and 20 patients with moderate or severe mitral regurgitation due to other causes (group 2) were studied. All echocardiograms were recorded before cardiac surgery. Cardiac catheterization was performed in 55 patients (92%). TEE showed greater sensitivity and negative predictive value than TTE (100 vs 65%, and 100 vs 56%, respectively; p < 0.005) in the diagnosis of ruptured chordae tendineae. Visualization of the ruptured chordae (termed snake-tongue sign) was highly sensitive and specific (93 and 95%, respectively) for establishing the diagnosis of ruptured chordae tendineae. The severity of mitral regurgitation in group 1 patients evaluated by TTE color flow mapping was underestimated by 2 grades in 1 patient and by 1 grade in 6 patients, and overestimated by 1 grade in 1 patient, compared with left ventriculography. In contrast, by TEE color flow mapping it was underestimated by 1 grade in 1 and overestimated by 1 grade in 1 patient. TEE color flow mapping showed better correlation with angiography than did TTE color flow mapping (r = 0.82 vs r = 0.49).

Streptococcus bovis endocarditis associated with colonic adenocarcinoma: report of a case

Streptococcus bovis (S. bovis) endocarditis has been increasing over recent decades, especially among the senile population. A 74-year-old man presented with intermittent fever for two months. He had a past history of aortic dissection and underwent a Bentall operation one year before admission. A Janeway lesion was noted on his right hand and six blood cultures grew S. bovis. He was treated with penicillin-G, 3 microU intravenously, every six hours, and became afebrile three days later. A colonofiberoscopy was carried out despite the absence of any gastrointestinal symptoms, and a 2 x 2 cm mass was found at the cecum, with pathologic proof of adenocarcinoma. The patient died from a massive intracranial hemorrhage on the 23rd hospital day. Review of the literature revealed an intimate association between S. bovis bacteremia (or endocarditis) and underlying colonic neoplasia. Failure to be aware of the possible consequences of this combination may lead to detrimental patient prognosis. We strongly advise that every patient presenting with bacteremia or endocarditis due to this organism, even if they are free from gastrointestinal symptoms, should undergo a thorough lower gastrointestinal investigation to rule out colonic neoplasia.

Cardiac metastasis of hepatocellular carcinoma mimicking pericardial effusion on radionuclide angiocardiography

A 51-year-old man presented with exertional dyspnea for two months. He had a history of hepatocellular carcinoma that was totally resected three years earlier. Radionuclide angiocardiography disclosed a large photopenic area separating the heart from the liver, and lung blood pools mimicking a large pericardial effusion. Echocardiography and magnetic resonance imaging of the heart, however, showed extensive tumor infiltration of the myocardium of both ventricles. Endomyocardial biopsy confirmed the diagnosis of metastatic hepatocellular carcinoma. There was no evidence of recurrent hepatoma in the liver.