Co-seeded Er3+:Yb3+ single frequency fiber amplifier with 60 W output power and over 90% TEM(00) content

We report on the design and fabrication of an Er(3+):Yb(3+) triple clad fiber and on the power scaling of a single frequency fiber amplifier at 1.5 μm based on that fiber. In addition, we report on mode content measurements in order to reveal the overlap of the amplifier output with the TEM(00) mode. The triple clad design was used to enable high output power levels, a good slope efficiency and an excellent beam quality. A maximum single frequency output power of 61 W at 1.5 μm could be achieved with the aid of the co-seeding method, which was used to suppress parasitic processes at 1.0 μm. With a scanning ring cavity the mode content of the amplifier output was analyzed with respect to the TEM modes. For all output power levels the TEM(00) content was above 90%.

Clinical implications of late mitral valve regurgitation appearance in the follow-up of heart transplantation

BACKGROUND

Tricuspid regurgitation is frequently observed after orthotopic heart transplantation (OHT), in association with severe pulmonary hypertension. However, the incidence of left-sided valvular disease has not been addressed.

AIM

We analyzed the incidence and prognostic implications of left-sided valve disease in 141 patients after OHT.

METHODS

Echocardiography was performed with every endomyocardial biopsy during the first year after OHT and every 6 months thereafter. Mitral regurgitation (MR) grade II or III was considered significant. Graft vasculopathy was assessed using coronary angiography.

RESULTS

Eight patients (6%) developed significant left-sided valvular disease, namely, MR in 6 (4%) and aortic regurgitation (AR) in 2 (1.4%). The 2 cases with AR were diagnosed the first week after OHT, whereas significant MR was diagnosed at mean follow- up of 34 +/- 6 months. Mean regurgitant orifice and volume were 34 +/- 14 mm2 and 41 +/- 15 mL/beat, respectively. Patients with significant MR had experienced a greater number of acute rejection episodes >or=3A, (1.8 +/- 1.7 vs 0.8 +/- 1.05; P = .02) and were associated with allograft vasculopathy in 83% vs 6% among unaffected patients (P = .0001). Four of 6 patients with significant MR died during follow-up (67%) and 1 of the living patients underwent reparative mitral valve surgery. The probability of survival using Kaplan-Meier curves was significantly lower when patients developed late significant MR (54% vs 76%; P = .0001).

CONCLUSIONS

The incidence of significant left-sided valvular disease after OHT was low. MR was associated with a higher degree of previous acute rejection, of graft vasculopathy, and mortality. The presence of moderate or severe MR of late appearance identified a group of OHT patients with poor outcomes.

Transoesophageal echocardiography accurately detects cardiac output variation: a prospective comparison with thermodilution in cardiac surgery

BACKGROUND AND OBJECTIVE

Intraoperative Doppler ultrasound can be used to measure cardiac output by transoesophageal echocardiography. Recently, its reliability, when compared to the thermodilution technique, has been questioned. The purpose of this study was to compare intraoperative changes in cardiac output measured by echo-Doppler and by thermodilution in cardiac surgery. We also assessed the agreement between the techniques.

METHODS

Fifty cardiac surgical patients (38 male, 12 female, mean age of 63.4 +/- 14.3 yr) were prospectively included after approval by the Ethics Committee of the Institution. Cardiac output was assessed by thermodilution, with 10 mL saline at 12 degrees C, and simultaneously and blindly by echo-Doppler in deep transgastric view with pulsed wave Doppler at the level of the left ventricular outflow tract. Matched thermodilution cardiac output and echo-Doppler cardiac output measurements were taken three times at the end of expiration, both pre- and post-cardiopulmonary bypass.

RESULTS

Echo-Doppler measurements were obtained in 44 patients (88%). In three patients, Doppler recordings could not be obtained adequately, and three developed left ventricular outflow tract obstruction after bypass. Bland-Altman analysis revealed a bias of 0.015 L min(-1), with narrow limits of agreement (-1.21 to 1.22 L min(-1)) and 29.1% error. Echo-Doppler was accurate (92% sensitivity and 71% specificity, P = 0.008 by receiver operating characteristic curves) for detecting more than 10% of change in thermodilution cardiac output. There were no complications related to the study.

CONCLUSIONS

The agreement between cardiac output by echo-Doppler and by thermodilution is clinically acceptable and transoesophageal echocardiography is a reliable tool to assess significant cardiac output changes in a population of selected patients.

Long-lasting sport practice and lone atrial fibrillation

AIMS

To analyse whether the proportion of patients with lone atrial fibrillation engaged in chronic sport practice was higher than that observed in the general population.

METHODS AND RESULTS

The records of 1160 patients, seen at the arrhythmia outpatient clinic, were reviewed. A total of 70 patients (6%) suffered lone atrial fibrillation and were younger than 65 years. Thirty two of them had been engaged in long-term sport practice. All patients in the sport group were men as compared to only 50% in the sedentary group (P<0 x 0001). To avoid the confounding effect of sex distribution, women were excluded. Sportsmen started their episodes of atrial fibrillation at a younger age, they had a lower incidence of mild hypertension and their episodes of atrial fibrillation were predominantly vagal in contrast to the sedentary patients. The echocardiographic parameters were similar to those observed in the sedentary patients, but when compared with 20 healthy controls, they showed greater atrial and ventricular dimensions and a higher ventricular mass. The proportion of sportsmen among patients with lone atrial fibrillation is much higher than that reported in the general population of Catalonia: 63% vs 15% (P<0 x 05).

CONCLUSION

Long-term vigorous exercise may predispose to atrial fibrillation.

Sudden death in Staphylococcus aureus-associated infective endocarditis due to perforation of a free-wall myocardial abscess

Free-wall myocardial abscess perforation with hemopericardium and sudden death is an extremely infrequent complication of infective endocarditis (IE). We describe a case of Staphylococcus aureus-associated native aortic and tricuspid valve endocarditis complicated by a septic myocardial infarction and abscess formation of embolic origin, with fatal rupture into the pericardium. To our knowledge, only 2 cases of myocardial abscess rupture have previously been reported in relation to IE.

[Intracardial thrombosis and primary antiphospholipid syndrome. A familial case report]

The main clinical manifestation of antiphospholipid syndrome is repeated thrombotic events in young patients without cardiovascular risk factors. There are several clinical features but the most frequent ones are repeated fetal losses and acute cerebral ischemic events. Cardiac involvement is less frequent. We present a family case with intracardiac thrombosis and secondary cerebral embolism.

Genomic scan for genes affecting body composition before and after training in Caucasians from HERITAGE

An autosomal genomewide search for genes related to body composition and its changes after a 20-wk endurance-exercise training program has been completed in the HERITAGE Family Study. Phenotypes included body mass index (BMI), sum of eight skinfold thicknesses, fat mass (FM), fat-free mass, percent body fat (%Fat), and plasma leptin levels. A maximum of 364 sib-pairs from 99 Caucasian families was studied with the use of 344 markers with single-point and multipoint linkage analyses. Evidence of significant linkage was observed for changes in fat-free mass with the S100A and the insulin-like growth factor I genes (P = 0.0001). Suggestive evidence (2.0 < or = Lod < 3.0; 0.0001 < P < or = 0.001) was also observed for the changes in FM and %Fat at 1q31 and 18q21-q23, in %Fat with the uncoupling protein 2 and 3 genes, and in BMI at 5q14-q21. At baseline, suggestive evidence was observed for BMI at 8q23-q24, 10p15, and 14q11; for FM at 14q11; and for plasma leptin levels with the low-density lipoprotein receptor gene. This is the first genomic scan on genes involved in exercise-training-induced changes in body composition that could provide information on the determinants of weight loss.

Differential scanning calorimetry and (2)H nuclear magnetic resonance and Fourier transform infrared spectroscopy studies of the effects of transmembrane alpha-helical peptides on the organization of phosphatidylcholine bilayers

We have studied the effects of the incorporation of the alpha-helical transmembrane peptides Ac-K(2)-L(24)-K(2)-amide (L(24)) and Ac-K(2)-(L-A)(12)-K(2)-amide ((LA)(12)) on the thermotropic phase behavior of 1,2-dipalmitoyl-d(62)-sn-glycero-3-phosphocholine (DPPC-d(62)) and 1-palmitoyl-d(31)-2-oleoyl-sn-glycero-3-phosphocholine (POPC-d(31)) lipid bilayer model membranes by differential scanning calorimetry (DSC) and the conformational and orientational order of the phospholipid chains by Fourier transform infrared (FTIR) spectroscopy and (2)H nuclear magnetic resonance ((2)H-NMR) spectroscopy, respectively. Our DSC and FTIR spectroscopic studies indicate that the peptides L(24) and (LA)(12) both decrease the temperature and enthalpy of the gel/liquid-crystalline phase transition of DPPC-d(62) bilayers, with (LA)(12) having the greater effect in this regard. An examination of the frequencies of the CH(2) and CD(2) symmetric stretching bands of the infrared spectra of liquid-crystalline states of the peptide-free and peptide-containing DPPC-d(62) and POPC-d(31) samples, and a comparison with the orientational order as measured by (2)H-NMR spectroscopy as well as with the chain order as measured by electron spin resonance spectroscopy, lead us to conclude that the CH(2) (or CD(2)) stretching frequencies of lipid hydrocarbon chains are not a reliable measure of chain conformational order in lipid bilayers containing significant amounts of peptides or other lipophilic inclusions. In contrast, the results of our (2)H-NMR spectroscopic studies present a consistent picture in which both L(24) and (LA)(12) increased in a similar way the time-averaged orientational order of the lipid chains of their liquid-crystalline lipid bilayer hosts. The comparison of the effects L(24) and (LA)(12) on phosphatidylcholine bilayers indicates that the gel-to-liquid-crystalline phase transition appears to be more sensitive to small changes in transmembrane peptide surface topology than hydrocarbon carbon chain orientational order in the liquid-crystalline state.

Aortocardiac fistulas complicating infective endocarditis

This study sought to determine the clinical and echocardiographic features, surgical approach, and outcome of patients with infective endocarditis complicated with aortocardiac fistulas among a series of 346 consecutive cases between 1988 and 1998. Nine patients (2%) were found to have aortocardiac fistulas complicating infective endocarditis caused by highly pyogenic pathogens (4 patients had ruptured abscesses of the right sinus of Valsalva, 3 had fistulous communications from the left coronary sinus, and 1 had a fistulized abscess in the noncoronary sinus). Mortality in these patients was very high (55%), even when surgery was attempted early in the course of the disease and reconstructive procedures were implemented.

Dobutamine stress echocardiography and exercise electrocardiography for risk stratification in medically treated unstable angina

Previous reports have demonstrated the superiority of exercise echocardiography over exercise electro-cardiography (ex-ECG) for risk stratification in patients with medically stabilized unstable angina (UA). We sought to analyze the prognostic value of dobutamine stress echocardiography (DSE) compared with ex-ECG for risk stratification in patients with UA.

METHODS

Ninety-two patients with medically treated UA were studied (mean age 65 +/- 11 years, 24 women, 42% of patients had electrocardiographic abnormalities on admission). Dobutamine stress echocardiography and treadmill ex-ECG were performed on the third day after hospital admission. End points were recurrent UA, myocardial infarction (MI), or cardiac death.

RESULTS

Mean follow-up was 24 +/- 7 months. During follow-up, 22 patients had cardiac events (18 recurrent UA, 2 MI, 2 cardiac deaths). The event-free survival rate was 80% for patients with negative DSE results for ischemia and 52% for those with positive DSE results (log rank 9.57; P =.002), compared with an event-free survival rate of 79% for patients with negative ex-ECG results and 66% for those with positive ex-ECG results (log rank 2.06; P = not significant). Left ventricular dysfunction (P =.01) and a positive dobutamine stress echocardiogram (P =.03), but not a positive exercise electrocardiogram, were independent predictors of cardiac events during follow-up.

CONCLUSIONS

Dobutamine stress echocardiography performed early in medically treated patients with UA predicts cardiac events during follow-up more accurately and with more specificity than ex-ECG does in this population.

[Guidelines of the Spanish Society of Cardiology on valve heart disease]

Valvular heart diseases, which continue to be a major cause of morbidity and mortality world wide, have undergone radical changes since the first valve prostheses were implanted 40 years ago. These changes have been the result of both scientific progress and improved standard of living in developed countries. The availability of penicillin to treat streptococcal pharyngitis and less crowded living conditions have now made rheumatic fever uncommon in these countries. However, other forms of valve impairment have appeared over the past several years. The etiology of some of these valvular diseases remains obscure (e. g. myxomatous mitral valve); others, such as the senile type of calcific aortic valve stenosis, seem to be the price to be paid for the extension of life expectancy. With regard to diagnosis, echocardiography has constituted a formidable tool for visualizing anatomic valve changes, interpreting complex hemodynamic derangements, and evaluating repercussion on the left ventricle. In addition, the iteration of this non-invasive examination has allowed a much better understanding of the natural history of non-severe valvular disease and therefore of the precise timing for surgical intervention, without awaiting, in most cases, the appearance of advanced symptomatology. This has also been possible because of the great advances in cardiac surgery which can be summarised as: a) the improvement in extracorporeal circulation and myocardial preservation techniques; b) the greatly improved biologic and mechanic valve substitutes; c) the introduction of imaginative mitral valve repair procedures, and d) the use of intraoperative transesophageal echocardiography to assess the adequacy of valve repair. At the same time, percutaneous catheter balloon valvuloplasty has emerged as a valid alternative to mitral surgical commissurotomy for mitral stenosis. All these changes, and many more that can not be described in this brief summary, make a review of the management of patients with valve heart disease appropriate.

Feasibility and prognostic value of dobutamine-atropine stress echocardiography early in unstable angina

BACKGROUND AND AIM

Because unstable angina has always been considered a contraindication for dobutamine-atropine stress echocardiography (DSE), the role of dobutamine-atropine stress echocardiography in unstable angina is unknown. Our aim was to assess the safety and prognostic value of dobutamine-atropine stress echocardiography in unstable angina.

METHODS

One hundred and thirty-two patients were studied (mean age 64+/-12 years, 29 women). Dobutamine-atropine stress echocardiography was performed on the third day after hospital admission. End-points were unstable angina, myocardial infarction or cardiac death at 1 year follow-up.

RESULTS

No major complications occurred during dobutamine-atropine stress echocardiography. Ninety-six (78%) patients were on beta-blocker therapy during the test; mean maximum heart rate achieved was 106+/-23 beats x min(-1). Nine of the 21 patients (43%) with a positive dobutamine-atropine stress echocardiography presented cardiac events during follow-up: two patients died, one had a myocardial infarction and six had recurrent class III-IV angina. Among 80 patients with negative dobutamine-atropine stress echocardiography, one (1%) had myocardial infarction and six patients (7.5%) had recurrent angina. Event-free survival after 1 year for patients with a negative dobutamine-atropine stress echocardiography for ischaemia was 91% compared to 57% for those with a positive dobutamine-atropine stress echocardiography (P<0. 0001). Left ventricular dysfunction (P=0.01), prior myocardial infarction (P=0.03) and a positive dobutamine-atropine stress echocardiography (P=0.004) were independent predictors of cardiac events during follow-up.

CONCLUSIONS

Dobutamine-atropine stress echocardiography is safe in unstable angina if it is performed when patients remain asymptomatic for at least 48 h. A negative dobutamine-atropine stress echocardiogram for ischaemia predicts a good prognosis in medically treated patients with unstable angina and may allow their early discharge from hospital. Good prognostic information was obtained despite the use of beta-blockers and low heart rates during dobutamine-atropine stress echocardiography.

Spectral domain analysis of dispersion management without averaging

It is shown how a straightforward regular perturbative analysis can be used to derive an integral equation for the spectral shape of a dispersion-managed soliton that takes fiber loss and amplification into account without resorting to averaging. Using functional analysis, one can then find an accurate approximate Gaussian solution that should prove useful for the design of a dispersion-managed transmission link.

Subcellular localization of Bic-D::GFP is linked to an asymmetric oocyte nucleus

Bicaudal-D (Bic-D) is essential for the establishment of oocyte fate and subsequently for polarity formation within the developing Drosophila oocyte. To find out where in the germ cells Bic-D performs its various functions we made transgenic flies expressing a chimeric Bic-D::GFP fusion protein. Once Bic-D::GFP preferentially accumulates in the oocyte, it shows an initial anterior localization in germarial region 2. In the subsequent egg chamber stages 1–6 Bic-D::GFP preferentially accumulates between the oocyte nucleus and the posterior cortex in a focus that is consistently aligned with a crater-like indentation in the oocyte nucleus. After stage 6 Bic-D::GFP fluorescent signal is predominantly found between the oocyte nucleus and the dorso-anterior cortex. During the different phases several genes have been found to be required for the establishment of the new Bic-D::GFP distribution patterns. Dynein heavy chain (Dhc), spindle (spn) genes and maelstrom (mael) are required for the re-localization of the Bic-D::GFP focus from its anterior to its posterior oocyte position. Genes predicted to encode proteins that interact with RNA (egalitarian and orb) are required for the normal subcellular distribution of Bic-D::GFP in the germarium, and another potential RNA binding protein, spn-E, is required for proper transport of Bic-D::GFP from the nurse cells to the oocyte in later oogenesis stages. The results indicate that Bic-D requires the activity of mRNA binding proteins and a negative-end directed microtubule motor to localize to the appropriate cellular domains. Asymmetric subcellular accumulation of Bic-D and the polarization of the oocyte nucleus may reflect the function of this localization machinery in vectorial mRNA localization and in tethering of the oocyte nucleus. The subcellular polarity defined by the Bic-D focus and the nuclear polarity marks some of the first steps in antero-posterior and subsequently in dorso-ventral polarity formation.

Prognostic value of serum cytokines in patients with congestive heart failure

BACKGROUND

Increased levels of circulating cytokines have been previously reported in patients with congestive heart failure; however, whether they have prognostic implications is still unknown. The aim of this study was to assess the prognostic implications of elevated serum cytokines in patients with heart failure and to identify the predictors of cytokine activation.

METHODS AND RESULTS

We assessed neurohormonal determinations, circulating cytokines, ejection fraction (EF) and end-diastolic and end-systolic left ventricular lengths in 87 patients (aged 57 +/- 9 years) with left ventricular dysfunction (EF 24% +/- 6%). In 48 patients, we also assessed cytokine receptors. During follow-up (mean, 14 +/- 9 months), 8 patients died and 12 had new heart failure episodes that required hospital admission, 5 of whom underwent heart transplantation. The univariate predictors of these events were serum interleukin-6 (IL-6) (p = 0.00001), New York Heart Association (NYHA) functional class (p = 0.0004), tumor necrosis factor-soluble receptor I (p = 0. 001), atrial natriuretic peptide (p = 0.002), tumor necrosis factor-soluble receptor II (p = 0.004), angiotensin II (p = 0.006), serum interleukin-1 beta (p = 0.01), and plasma renin activity (p = 0.02). Increased serum interleukin-6 (>10 pg/ml) was a significant predictor of death or new heart failure episodes according to the Kaplan-Meier survival method by log-rank test (p = 0.004). By Cox regression analysis, serum IL-6 (p = 0.0005) and the NYHA functional class (p = 0.005) were identified as independent predictors of prognosis.

CONCLUSIONS

In patients with congestive heart failure, increased serum IL-6 was identified as a powerful independent predictor of the combined end point: death, new heart failure episodes, and need for heart transplantation.

Coupled-field description of zero-average dispersion management

Using a coupled-field formalism and a standard perturbation analysis, we analyze a dispersion-managed system under zero-average dispersion conditions. A nonlinear integral equation in the spectral domain allows the determination of the critical strength parameter of a two-step dispersion map. Higher-order correction terms confirm the difference observed in the pulse shapes in each fiber and comparisons with fully numerical results reveal a good agreement. The existence of an antisymmetric dispersion-managed soliton is also confirmed.

Assessment of Cmv1 candidates by genetic mapping and in vivo antibody depletion of NK cell subsets

The mouse chromosome 6 locus Cmv1 controls resistance to infection with murine cytomegalovirus (MCMV). We have previously shown that Cmv1 is tightly linked to members of the NK gene complex (NKC) including the Ly49 gene family. To assess the candidacy of individual NKC members for the resistance locus, first we followed the co-segregation of Cd94, Nkg2d, and the well-characterized Ly49a, Ly49c and Ly49g genes with respect to Cmv1 in pre-existing panels of intraspecific backcross mice. Gene order and intergene distances (in cM) were: centromere-Cd94/Nkg2d-(0.05)-Ly49a/Ly49c/Ly49 g/Cmv1-(0. 3)-Prp/Kap/D6Mit13/111/219. This result excludes Cd94 and Nkg2d as candidates whereas it localizes the Ly49 genes within the minimal genetic interval for Cmv1. Second, we monitored the cell surface expression of individual Ly49 receptors in MCMV-infected mice over 2 weeks. The proportion of Ly49C(+) and Ly49C/I(+) cells decreased, the proportion of Ly49A(+) and Ly49G2(+) remained constant, and the cell surface density of Ly49G2 increased during infection, suggesting that NK cell subsets might have different roles in the regulation of MCMV infection. Third, we performed in vivo antibody depletion of specific NK cell subsets. Depletion with single antibodies did not affect the resistant phenotype suggesting that Ly49A(+), Ly49C(+), Ly49G2(+) and Ly49C/I(+) populations are not substantial players in MCMV resistance, and arguing for exclusion of the respective genes as candidates for Cmv1. In contrast, mice depleted with combined antibodies showed an intermediate phenotype. Whether residual NK cells, post-depletion, belong to a particular subset expressing another Ly49 receptor, or a molecule encoded by a yet to be identified gene of the NKC, is discussed.

Left internal mammary artery to innominate vein fistula complicating pacemaker insertion. Treatment with endovascular transarterial coil embolization

Arteriovenous fistula (AVF) is rarely encountered as a complication of pacemaker insertion. Percutaneous angiographic therapy of such iatrogenic fistulas can be both safe and effective, leading to important reductions in costs. A 60-year-old woman was admitted to the hospital four weeks after left subclavian pacemaker insertion complaining of signs of congestive heart failure. A loud continuous machinery bruit was heard over the left upper chest. An arteriogram revealed a false aneurysm from the LIMA, 6 mm in-diameter, with formation of an AVF between the LIMA and the left innominate vein. Embolization of the LIMA was carried out using seven Platinum coils at the level of the AVF and the false aneurysm was embolized with 3 controlled-release IDC coils. The complete occlusion of the fistula was achieved and the distal LIMA persisted patent due to the opening of collateral vessels from the intercostal arteries. AVF between the subclavian artery or its branches and the subclavian or innominate veins have been reported to be congenital, traumatic and iatrogenic (associated to central venous access to hemodynamic monitoring, dialysis, and very infrequently to pacemaker insertion) but the internal mammary arteries are only rarely involved. The course of AVF is undefined, but generally, surgical or percutaneous embolization is warranted because of the potential appearance of a great number of complications. Surgical repair is associated with significant morbidity and mortality. Whenever possible, percutaneous nonsurgical occlusion of the AVF with coil embolization is the procedure of choice, because of its high success rate and low morbidity.

Predictive value of 99Tcm-sestamibi gated SPET for long-term myocardial perfusion and functional recovery after an acute myocardial infarction

We assessed the predictive value of 99Tcm-sestamibi gated single photon emission tomography (SPET) for changes in perfusion and functional outcome after an acute myocardial infarction and compared the findings on functional recovery with echocardiography using low-dose dobutamine. Gated 99Tcm-sestamibi SPET and radionuclide angiocardiography were performed in 17 patients 4-10 days after an acute myocardial infarction. Six months later, both isotopic studies and rest-dobutamine echocardiography were performed to assess outcome. Perfusion improved in six of seven severely hypoperfused segments (positive predictive value = 85.7%) that showed wall thickening but not in any of 28 segments (negative predictive value = 100%) without wall thickening. The mean ejection fraction improved from 47.7 to 52.3% (P = 0.018). Furthermore, there was a greater improvement in ejection fraction in the group of patients in whom wall thickening predicted a recovery in perfusion (9.0 vs 3.7%, P = 0.01). A comparison of the assessment of functional recovery between gated SPET and dobutamine echocardiography showed good agreement (81.4%). We conclude that the presence of wall thickening in severely hypoperfused segments on 99Tcm-sestamibi gated SPET is predictive of changes in perfusion and functional recovery after acute myocardial infarction, thus identifying the presence of viable myocardium. In contrast, segments showing hypoperfusion and dysfunction after an acute myocardial infarction probably contain scar tissue only.

Serum interleukin-6 in congestive heart failure secondary to idiopathic dilated cardiomyopathy

Increased serum interleukin-6 (IL-6) was associated with a higher incidence of New York Heart Association functional classes III to IV and worse left ventricular function during follow-up. Patients with elevated serum IL-6 had poor prognosis. These results reinforce the concept that increased serum IL-6 may also play an important role in disease progression.

[Evaluation of left ventricular contraction using heart tomography with technetium 99m tetrofosmin in synchrony with ECG. Correlation with bidimensional echocardiography]

BACKGROUND

Echocardiography is a standard method of evaluating segmental and global left ventricular function in clinical practice. The aim of this study was to determine if segmental and global ventricular function determined from Gated SPECT myocardial imaging adequately coincides with echocardiographic data.

PATIENTS AND METHODS

We studied 23 patients with ischemic heart disease referred for clinical 99mTc tetrofosmin Gated SPECT imaging. The results were compared with those obtained using a standard rest echocardiographic assessment. Both studies were performed within a 24-48 hour period. Segmental results in both studies were analyzed by semiquantitative visual scoring using a two or three-point grading system and a summed score was obtained to determine global left ventricular function.

RESULTS

There was a good segmental score agreement between both techniques for wall motion (77.5%; kappa = 0.49) and less for wall thickening (85%; kappa = 0.36). There were non significant statistical differences in the global left ventricular function with both techniques by wall motion (echocardiography 15.3 +/- 5.4 vs tetrofosmin 14.9 +/- 4.4; p = NS) and wall thickening (echocardiography 12.7 +/- 2.3 vs tetrofosmin 12.4 +/- 1.8; p = NS) scores. Correlation for global wall motion (r = 0.81; p < 0.0001) and wall thickening (r = 0.72; p = 0.0001) scores between the two modalities was good.

CONCLUSIONS

Gated SPECT 99mTc tetrofosmin myocardial imaging is a valid method to assess segmental and global left ventricular function and agrees well with echocardiography.

Polymorphism of POPE/cholesterol system: a 2H nuclear magnetic resonance and infrared spectroscopic investigation

It is well established that cholesterol induces the formation of a liquid-ordered phase in phosphatidylcholine (PC) bilayers. The goal of this work is to examine the influence of cholesterol on phosphatidylethanolamine polymorphism. The behavior of 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE)/cholesterol mixtures was characterized using infrared and 2H nuclear magnetic resonance (NMR) spectroscopy (using POPE bearing a perdeuterated palmitoyl chain in the latter case). Our results reveal that cholesterol induces the formation of a liquid-ordered phase in POPE membranes, similar to those observed for various PC/cholesterol systems. However, the coexistence region of the gel and the liquid-ordered phases is different from that proposed for PC/cholesterol systems. The results indicate a progressive broadening of the gel-to-fluid phase transition, suggesting the absence of an eutectic. In addition, there is a progressive downshift of the end of the transition for cholesterol content higher than 10 mol %. Cholesterol has an ordering effect on the acyl chains of POPE, but it is less pronounced than for the PC equivalent. This study also shows that the cholesterol effect on the lamellar-to-hexagonal (L(alpha)-H(II)) phase transition is not monotonous. It shifts the transition toward the low temperatures between 0 and 30 mol % cholesterol but shifts it toward the high temperatures when cholesterol content is higher than 30 mol %. The change in conformational order of the lipid acyl chains, as probed by the shift of the symmetric methylene C-H stretching, shows concerted variations. Finally, we show that cholesterol maintains its chain ordering effect in the hexagonal phase.

[Anatomopathological bases of latent ventricular dysfunction in insulin-dependent diabetics]

INTRODUCTION AND OBJECTIVES

The natural history of diabetic cardiomyopathy remains unclear, mainly due to concurrent coronary disease or hypertension. Since the presence of confounding factors is less likely in youngsters, they constitute a suitable study model to analyze early stages of diabetic cardiomyopathy.

PATIENTS AND METHODS

We screened 33 young normotensive asymptomatic patients with type I diabetes mellitus. Mean age was 28 +/- 8 y (range 18 to 46 y) and there were 14 men.

RESULTS

2-D Echo showed normal left ventricular size and wall motion in all patients but one. Radionuclide basal ejection fraction was 56.5 +/- 6.6% and increased to 63 +/- 7.4% (p < 0.02) on exercise. According to Rozansky criteria, 16 patients had an abnormal response. Abnormal stress sestamibi was detected in 18 patients and only 3 had reversible defects. Coronary angiography was performed in 11 patients with at least one abnormal non-invasive study response. Coronary angiography revealed normal vessels in all patients and left anterior descending blood flow velocity (Doppler) increased 4 fold after papaverine infusion. Left ventricular biopsies showed hypertrophy (either nuclear or cellular) in 11, myocytolysis in 6, interstitial fibrosis in 9 and lipid deposits in 4. Morphometric analysis of cardiac samples comparing the diabetic group and a control group showed that the volume fraction of fibrosis (0.19 +/- 0.06 vs 0.10 +/- 0.06; p < 0.01), fiber area -mu2- (1,062 +/- 547 vs 600 +/- 167; p < 0.02) and fiber diameter -mu- (24.2 +/- 3.3 vs 15.1 +/- 3.4; p < 0.001) were higher in the former; and volume fraction of the myocytes was higher in the latter (0.71 +/- 0.006 vs 0.89 +/- 0.07; p < 0.001).

CONCLUSIONS

Left ventricular dysfunction, not related to coronary atherosclerosis or small vessel disease, is frequent in asymptomatic young diabetic patients. Abnormal pathologic findings are common in the type of cell hypertrophy, interstitial fibrosis, myocytolysis and lipid deposits.

Attitude and enduring involvement of older adults in structured programs of physical activity

The purpose of this paper is to measure the influence of the affective attitudinal domain upon the intentions of a group of older adults participating in structured programs of physical activity offered in a community recreation setting. The subjects were 118 seniors participating in either a fitness, aqua-fitness, or golf program in metropolitan Ottawa. The group comprised of 65 women and 53 men were, in the most part, between 55 and 70 years of age. A questionnaire measuring attitude towards physical activity was developed. A stepwise regression analysis of intention to participate on attitudes showed that most of the variance in intention (69.0%) was explained by the variable "good/beneficial," i.e., seniors perceived the programs as being good and beneficial to them. It is recommended that further investigation of affective factors related to attitude be carried out to develop strategies to maintain seniors involvement in physical activity programs.

Severe right ventricular dysfunction following pericardiocentesis for cardiac tamponade

The accumulation of fluid in the pericardium in an amount sufficient to cause severe obstruction to blood inflow to the ventricles results in cardiac tamponade. In this condition, relief of intrapericardial pressure by pericardiocentesis usually dramatically improves cardiac output, and can be lifesaving. We report a case of a patient with malignant cardiac tamponade in which cardiogenic shock developed after pericardiocentesis due to severe right ventricular dysfunction.

Compensating for dispersion and the nonlinear Kerr effect without phase conjugation

We propose the use of a dispersive medium with a negative nonlinear refractive-index coefficient as a way to compensate for the dispersion and the nonlinear effects resulting from pulse propagation in an optical fiber. The undoing of pulse interaction might allow for increased bit rates.

Relationship between cardiomyopathy and liver disease in chronic alcoholism

Based on anecdotal impressions, there is a common clinical perception that alcoholics with liver disease do not develop cardiomyopathy and that those with alcohol-induced cardiac disease are spared cirrhosis. To determine the relationship between alcoholic cardiomyopathy and cirrhosis, we carried out a prospective cross-sectional study that included: (1) 30 alcoholic men with cardiomyopathy; (2) 30 alcoholic men without cardiomyopathy (left ventricular ejection fraction > 55%); (3) 20 actively drinking alcoholics with cirrhosis; (4) 15 abstaining alcoholics with cirrhosis; and (5) 15 nonalcoholics with cirrhosis of other etiologies. Cirrhosis was observed in 13 of 30 patients with alcoholic cardiomyopathy (43%), compared with 2 of 30 alcoholics without cardiomyopathy (6%) (P < .001). Ten of the 20 active alcoholics with cirrhosis (50%) showed evidence of dilated cardiomyopathy. Actively drinking alcoholics with cirrhosis had a significantly lower mean ejection fraction and shortening fraction, as well as a greater mean end-diastolic diameter and left ventricular mass than abstaining alcoholics with cirrhosis. Cardiac studies of patients with nonalcoholic cirrhosis were normal. We conclude that a positive correlation exists between alcoholic cardiomyopathy and cirrhosis. Alcoholics admitted solely for cardiomyopathy have a higher prevalence of cirrhosis than unselected alcoholics without heart disease. Actively drinking alcoholics admitted only for cirrhosis show impaired cardiac performance, whereas abstaining alcoholics with liver disease tend to manifest normal cardiac function.

Method for direct measurement of the variance of laser beams

A method permitting direct measurement of the spatial variance along a given transverse direction of any laser beam is described. The procedure relies on the use of a transmission filter whose local transmissivity varies spatially as an inverted parabola. The variance and the first moment of a transverse beam intensity distribution are readily obtained simply by measurement of the maximum power transmitted through the filter as this filter is moved across the beam's section.

Feasibility of early discharge after acute Q wave myocardial infarction in patients not receiving thrombolytic treatment

OBJECTIVES

The purpose of this study was to analyze the feasibility of early discharge (4 days) after acute myocardial infarction in patients not receiving thrombolytic therapy by first identifying predictors of short-term prognosis and then testing the derived risk profile in an independent cohort of patients.

BACKGROUND

Previous studies have shown that early discharge after acute myocardial infarction is possible. However, physicians are reluctant to shorten the standard 7- to 10-day hospital stay, presumably because of difficulty in selecting low risk patients.

METHODS

From January 1985 to November 1986, 358 patients with acute myocardial infarction who did not receive thrombolytic therapy were screened. Those with a Q-wave infarction showing no complications on day 4 were considered candidates for early discharge and were transferred to the ward for a mean of 12 days. During this period, we looked for any event (cardiac or noncardiac) that would have prompted readmission if the patient had been previously discharged. Univariate and multiple regression analysis were performed to identify predictors of these events among 25 baseline variables. The derived risk profile was tested in an independent validation cohort.

RESULTS

One hundred five (29.3%) of the 358 patients were free of symptoms on day 4, and 29 (27.6%) had at least one cardiac event, including four deaths and one reinfarction. Multivariate analysis selected diabetes, ejection fraction < 40% and age as independent predictors of events. Using the risk profile, 18 (13.2%) of the 136 validation cohort patients were categorized as low risk, and only 1 of them had a major event (progressive angina). Sensitivity for the risk profile was high (91%), but specificity was low (34%).

CONCLUSIONS

The use of simple clinical variables may allow the safe reduction of hospital stay after infarction in selected patients. However because the proportion of candidates for early discharge is small (12.6%), it seems unlikely that the current policies on length of hospital stay will change in the near future.

Super-Gaussian output from a CO(2) laser by using a graded-phase mirror resonator

Two super-Gaussian output resonators of orders 4 and 6 have been designed by using the inverse-propagation method for the calculation of the graded-phase feedback mirrors. The graded-phase mirrors were made by using the diamond cutting technique on a copper substrate. An increase of 40% and 50% of monomode energy extraction has been measured compared with that of a semiconfocal resonator of the same dimension in a TEA CO(2) laser.

Cardiac disease in systemic lupus erythematosus: prospective study of 70 patients

A prospective two dimensional and Doppler echocardiographic study of 70 consecutive patients with systemic lupus erythematosus (SLE) and 40 controls was carried out. Forty patients (57%) were found to have echocardiographic disturbance. Valvular abnormalities were detected in 31 patients (44%) and in only two controls (5%). Mitral valve abnormalities were the most common findings (23/70 (33%)) with mild or moderate regurgitation the most frequent lesion (16% and 9% respectively). Three patients (4%) had a morphological echocardiographic pattern suggestive of non-infective verrucous vegetations affecting the mitral valve. No patient had haemodynamically significant clinical valve disease. Pericardial effusion was identified in 19 patients (27%), of whom 14 had mild and clinically silent disease. Myocardial abnormalities were found in 14 patients (20%), but clinical features of myocardial dysfunction were present in only one. Patients with antiphospholipid antibodies were found to have an increased prevalence of endocardial lesions, mainly valvular regurgitation. It is concluded that the inclusion of echocardiography in a study protocol of patients with SLE can identify an important subset of patients with cardiac abnormalities, many of which are clinically silent. In addition, the association of antiphospholipid antibodies with endocardial lesions suggests that these antibodies may have a prominent role in the pathogenetic mechanisms of heart valve disease in SLE.

High prevalence of significant heart valve lesions in patients with the 'primary' antiphospholipid syndrome

A prospective echocardiographic study was carried out on 55 patients with the recently described 'primary' antiphospholipid syndrome derived from three university medical centres. The prevalence of valvular lesions in patients with this syndrome was 38% compared with 4% in a control group of 55 healthy volunteers (P < 0.001). Mean age of patients with valve abnormalities was 42 +/- 12 years and of those without, 30 +/- 10 years (P < 0.05). One patient had a morphologic echocardiographic pattern suggestive of non-infective verrucous mitral endocarditis. Twenty patients had a two-dimensional or Doppler echocardiographic pattern of significant valvular dysfunction--either regurgitation or stenosis--without evidence of vegetations. Mitral and aortic regurgitation were the most common lesions in these patients. During follow-up of patients with valvular disease, haemodynamically significant clinical valve disease developed in four and surgery was required in one. Eleven patients had cerebrovascular occlusions. Thus, valvular heart disease, particularly affecting the mitral and aortic valves, is common in patients with the 'primary' antiphospholipid syndrome, especially in those over 40 years old.

Impaired response of atrial natriuretic factor to blood volume expansion in acute right ventricular infarction

To assess the role of atrial natriuretic factor (ANF) in right ventricular (RV) infarction, 30 patients with inferior wall acute myocardial infarction (15 with RV involvement) and normal left heart filling pressures were studied 39 +/- 12 hours after the onset of symptoms. Serial measurements of cardiac output, right atrial, pulmonary artery and pulmonary wedge pressures, as well as plasma ANF, plasma renin activity, plasma aldosterone and vasopressin were obtained before and 30 minutes after acute volume expansion to raise wedge pressure greater than or equal to 20 mm Hg. Baseline mean right atrial pressure and plasma ANF levels were greater in patients with than without RV infarction (8 +/- 3 vs 5 +/- 2 mm Hg; p less than 0.0001, and 4.6 +/- 2.9 vs 2.7 +/- 1.5 fmol/ml; p less than 0.05, respectively). There were no differences in other baseline hemodynamic or humoral parameters between both groups. After volume expansion, pulmonary wedge pressure was similar in both groups, but right atrial pressure increased to higher levels in patients with RV infarction (19 +/- 2 vs 14 +/- 2 mm Hg; p less than 0.0001). Despite this greater stimulus for ANF secretion, the increase in plasma ANF was less pronounced in patients with RV infarction (63 +/- 81 vs 455 +/- 417%; p less than 0.002), especially among those with paroxysmal supraventricular tachyarrhythmias. Thus, despite higher baseline plasma levels of ANF, response to volume loading is markedly attenuated in patients with RV infarction complicating an inferior wall acute myocardial infarction.

Non-infective verrucous endocarditis in a patient with 'primary' antiphospholipid syndrome

A 27-year-old women with 'primary' antiphospholipid syndrome, who developed a haemodynamically significant non-infective verrucous endocarditis is reported. Her mother suffered from antiphospholipid syndrome associated with systemic lupus erythematosus. A pathogenetic role of antiphospholipid antibodies in heart valve lesions is suggested.

Optical resonators using graded-phase mirrors

Optical resonators using graded-phase mirrors are analyzed with the help of the generalized ABCD propagation law for a real optical beam. This analysis gives the second-order moment gross characteristics of the eigenmode and indicates a design procedure. An example of a super-Gaussian output beam shows that this type of optical resonator might have large transverse-mode discrimination that could provide operation in a large fundamental-mode beamwidth.

[Aortic valve replacement by a pulmonary homograft]

Minor experience still exists in our country with regard to the use of valve homografts in cardiac surgery. Only a few implantations have been performed in cases of right ventricular outflow tract reconstruction in addition to our own experience in cases of infective endocarditis of the aortic valve. We present a case of aortic valve replacement by using an antibiotic-sterilized fresh pulmonary valve autograft. The case is described and the possible advantages of the use of pulmonary allografts in the aortic position are discussed.

[Insulin-dependent diabetes and periodontal disease in young patients]

Periodontal disease is one of the well-documented complications of diabetes mellitus in adulthood. The effects of diabetes mellitus on periodontal tissues in children and teenagers have been studied only in more recent years. Although clinical studies have demonstrated a few cases of severe periodontal disease in patients with "historical" diabetes mellitus, in the overwhelming majority of cases periodontal lesions seem comparable in young subjects with and without diabetes mellitus. However, reports on this topic published both in France and in the United States fail to give a clear picture of the existence, prevalence and severity of peridontal disease in youngsters with diabetes mellitus. Consequently, an epidemiologic study was undertaken at the Herold Hospital (Paris) and at the Association of Young Diabetics. Eighty-five young patients with diabetes mellitus and 38 controls were included. The purpose of the study was to determine whether periodontal disease is only a former or still a current complication of diabetes mellitus.

Association of antibodies against phospholipids with heart valve disease in systemic lupus erythematosus

A prospective echocardiographic study was carried out on 132 consecutive patients with systemic lupus erythematosus (SLE) derived from three European university medical centres. The prevalence of valvular lesions in patients with SLE was 22.7% compared with 2.9% in a control group of 68 healthy volunteers. 50 SLE patients had antibodies against phospholipids. The prevalence of valve vegetations (8/50 [16%]) and of mitral regurgitation (19/50 [38%]) was significantly higher among the SLE patients with antiphospholipids than among those without (1 and 10/82 [1.2% and 12%], respectively). During follow-up of the patients with valvular lesions, haemodynamically significant clinical valve disease developed in 6 but surgery was required in only 1; 9 had cerebrovascular occlusions; and 7 died, although no death was due directly to the cardiac involvement. Thus, valvular heart disease, particularly affecting the mitral valve, is common in patients with SLE, and the presence of antibodies against phospholipids is associated with a higher prevalence of valvular abnormalities in these patients.

Solitary pulses in an amplified nonlinear dispersive medium

An analytical solution is obtained for solitary pulse propagation in an amplified nonlinear dispersive system. For a homogeneously broadened gain medium, this solitary pulse has a hyperbolic secant amplitude and a hyperbolic tangent instantaneous frequency variation. The pulse is a gain-guided pulse in either the positive or the negative dispersion regime as well as in the self-focusing or self-defocusing regime. A dark solitary pulse that has a hyperbolic tangent amplitude and a similar instantaneous frequency variation is also obtained.

[Reversibility of alcoholic myocardiopathy with abstinence: presentation of 2 cases]

The sustained alcohol intake results in the development of a dilated cardiomyopathy; its pathogenesis and prognostic and evolutive factors have not yet been completely defined. It is classically considered that alcoholic cardiomyopathy has a poor prognosis, as two thirds of patients die within three years. However, in recent years some isolated cases of clinical reversibility after short abstinence periods have been reported without identification of the involved factors. Two chronic alcoholic patients are reported with congestive heart failure at admission; a diagnosis of alcoholic cardiomyopathy was made after cardiac catheterization and endomyocardial biopsy. The morphometric study of endomyocardial biopsy showed a preservation of the myofibrillary fraction with mild fibrosis. The clinical outcome was favorable: after three months of alcoholic abstinence, a complete clinical recovery with definite improvement of echocardiographic parameters and left ventricular ejection fraction in the radionuclide ventriculography were observed. Finally, the factors that appear to be involved in the presence or absence of reversibility of this type of cardiomyopathy are discussed.

Transverse modulational instabilities for counterpropagating beams in Kerr media

Continuous-wave and oscillatory transverse instabilities are predicted for counterpropagating waves in Kerr media for both focusing and defocusing nonlinearities. Neither a cavity nor a finite response time is required. Computed Gaussian-beam results agree well with analytic plane-wave calculations that straddle Raman-Nath and Bragg regimes.