Application of X-ray topography to USSR and Russian space materials science.

The authors' experience of the application of X-ray diffraction imaging in carrying out space technological experiments on semiconductor crystal growth for the former USSR and for Russia is reported, from the Apollo-Soyuz programme (1975) up to the present day. X-ray topography was applied to examine defects in crystals in order to obtain information on the crystallization conditions and also on their changes under the influence of factors of orbital flight in space vehicles. The data obtained have promoted a deeper understanding of the conditions and mechanisms of crystallization under both microgravity and terrestrial conditions, and have enabled the elaboration of terrestrial methods of highly perfect crystal growth. The use of X-ray topography in space materials science has enriched its methods in the field of digital image processing of growth striations and expanded its possibilities in investigating the inhomogeneity of crystals.

Exercise and heart failure.

This report will review the abnormalities of the peripheral circulation and skeletal muscle which are part of the heart failure syndrome and can limit exercise tolerance; introduce trials that have shown benefits of exercise training in a variety of heart failure patients; suggest strategies for recommending activity training in patients with heart failure. Finally, this report will identify areas where data are missing and where trials are currently being undertaken.

Risks and benefits of a multidrug approach to mild-to-moderate heart failure.

Multidrug therapy offers several advantages in the management of mild-to-moderate heart failure. Treatment with a combination of agents, such as diuretics, digoxin, angiotensin-converting enzyme inhibitors, and beta blockers, can provide relief of symptoms while also addressing specific pathophysiologic factors. By allowing therapy to be tailored to the individual, the multidrug approach can slow progression of the disease, reduce or prevent the need for hospitalization, and decrease health-care costs. Evidence of the benefit of the multidrug approach has come from numerous trials in which newer treatments for heart failure have been evaluated in the context of the background therapy considered standard at the time of the trial. Compliance may be a challenge with multidrug therapy, particularly for patients who generally feel well and do not experience symptoms that interfere with normal daily function. The clinician must ensure that patients understand the need to comply with the prescribed regimen to prevent more serious problems in the future. Multidrug therapy may also require that patients be more closely monitored so that dosages of the individual medications can be adjusted to provide maximum benefit with a minimum of side effects.

A controlled trial of cardiac rehabilitation in the home setting using electrocardiographic and voice transtelephonic monitoring.

OBJECTIVE: The goal of this study was to compare the effectiveness of home-based, transtelephonically monitored cardiac rehabilitation with standard, on-site, supervised cardiac rehabilitation. BACKGROUND: Participation in cardiac rehabilitation has been demonstrated to increase exercise capacity, decrease cardiovascular symptoms, improve psychosocial status, and decrease total and cardiovascular mortality rates in patients with coronary heart disease. Because of multiple factors, national overall participation is only at 15% of eligible patients. METHODS: Effects of a 3-month home-based, transtelephonically monitored rehabilitation program (n = 83 patients) with simultaneous voice and electrocardiographic transmission to a centrally located nurse coordinator were compared with effects of a standard on-site rehabilitation program (n = 50 patients). The study design was a multicenter, controlled trial. Primary outcome variables were peak aerobic capacity and quality of life, as measured by the Health Status Questionnaire. RESULTS: Patients in the home-based monitoring program increased peak aerobic capacity to a similar degree as patients who exercised on site (18% vs 23%). Quality of life domains of physical functioning, social functioning, physical role limitations, emotional role limitations, bodily pain, and energy/fatigue improved similarly in both groups. There were no circulatory arrests or other major exercise-related medical events in either group. A total of 3100 hours of home exercise were transtelephonically monitored. CONCLUSIONS: Patients with coronary heart disease can effectively participate in home-based, monitored cardiac rehabilitation, with exercise and quality of life improvements comparable to those demonstrated at on-site programs.

The AHF SCENE II Preceptorship Program: rationale and design of an educational program to optimize management of advanced heart failure.

Advanced heart failure requires specialized treatment to improve symptoms, increase survival, and reverse or slow disease progression. The Advanced Heart Failure Shared Clinical Experiences Network, or AHF SCENE, was founded in 1995 to provide small groups of health care professionals with better advanced heart failure management strategies by sharing clinical experiences from centers treating large numbers of patients. The original AHF SCENE program has since been modified to provide health care professionals with more information on current strategies for advanced heart failure management and to better serve the educational needs of professionals who care for these patients. AHF SCENE II promotes new methods, programs, procedures, and pharmacologic interventions and also describes strategies for tracking and improving clinical and economic outcomes in the management of advanced heart failure. AHF SCENE II supports the understanding that rapid, aggressive medical management is essential and is more effective in the context of a well designed program that spans the continuum of care. (c)2000 by CHF, Inc.

Tolerability of extended duration intravenous milrinone in patients hospitalized for advanced heart failure and the usefulness of uptitration of oral angiotensin-converting enzyme inhibitors.

Milrinone is a phosphodiesterase inhibitor that has been shown to improve hemodynamic parameters in patients with class III to IV heart failure when administered intravenously for < or =48 hours. This study examines the tolerability of long-term intravenous milrinone therapy and assesses its utility in allowing upward titration of oral vasodilator agents. A retrospective review of hospital records identified 63 patients who underwent hemodynamic monitoring and received intravenous milrinone for >24 hours in a critical care setting. Hemodynamics and medications were recorded before and after 24 hours of milrinone therapy. Additional medications, as well as any adverse events, were recorded throughout milrinone therapy. The mean dose of milrinone was 0.43 +/- 0.10 microg/kg/min, with a mean duration of 12 +/- 15 days (range 1 to 70). Therapy was continued for >48 hours in 89% of patients. After 24 hours of milrinone therapy, patients exhibited significant improvements in pulmonary artery pressures, pulmonary capillary wedge pressures, and cardiac index. When compared with baseline, significantly more patients received angiotensin-converting enzyme (ACE) inhibitors after 24 hours of milrinone and at the end of milrinone therapy (67% vs 86%, p <0.01). Likewise, significantly more patients also received oral hydralazine and/or nitrates at the end of milrinone therapy (38% vs 65%, p <0.01) when compared with baseline. The mean doses of most oral medications at the 3 time periods were similar. The ACE inhibitor dose was significantly higher at the end of milrinone therapy when compared with baseline, and hydralazine dose was significantly higher at the end of therapy when compared with 24 hours. Few adverse effects were noted, with only 10% of patients experiencing symptomatic ventricular tachycardia and 2 patients with significant hypotension requiring discontinuation of the drug. The adverse events were similar in the group of patients who received milrinone for > or =7 days compared with the entire cohort. Milrinone was well tolerated over the long term in a controlled inpatient setting, and allowed uptitration of oral vasodilator therapy.

Cytomegalovirus infection presenting as an apple-core lesion of the colon.

Cytomegalovirus infection is highly prevalent among heart transplant recipients. Symptomatic cytomegalovirus infection can occur in all parts of the gastrointestinal tract. Colonic lesions are usually manifest as hemorrhagic colitis. This is a case of cytomegalovirus colitis presenting as a colonic stricture mimicking a colonic carcinoma. The initial presentation was that of both cellular and humoral rejection with fever, abdominal pain, and microcytic anemia with heme-positive stools. An abdominal computed tomogram was pertinent for a suspicion of carcinoma in the midtransverse colon. After resolution of the rejection episode, colonoscopy was performed, the result of which was abnormal for a short, high-grade stricture in the midtransverse colon. The patient underwent a right hemicolectomy for the suspected tumor. The pathologic specimen showed cytomegalovirus inclusion bodies with acute suppurative ulceration. The early diagnosis and treatment of cytomegalovirus colitis may lead to avoidance of more serious complications such as stricture formation.

Donor-specific HLA antibodies after transplantation are associated with deterioration in cardiac function.

Although there is increasing evidence that mismatched donor HLA antigens are associated with a lowering of survival of human cardiac allografts, the effect of antibodies that bind those antigens is less clear. The existence of lymphocytotoxic antibodies prior to cardiac transplantation has been associated with a poor outcome in the majority of reports of relevant studies, as has their appearance post-transplantation. But how such antibodies, especially those with HLA specificity, cause poor outcomes has been poorly understood. The purpose of this study was to investigate the effect of anti-HLA antibodies appearing in the circulation after human orthotopic heart transplantation. Such antibodies were identified by a standard microlymphocytotoxicity technique using panels of frozen lymphocytes from normal donors who had been tissue typed. Of 74 patients transplanted over a 12-month period, 4 (5.4%) developed alloantibodies specific for mismatched donor HLA antigens. The first patient developed antibodies to HLA-A23 and B44 together with poor ventricular function and vascular rejection requiring retransplantation within 4 months. The other patients (3) developed antibodies specific for HLA-DQ antigens and experienced variable numbers of episodes of cellular rejection with no evidence of vascular rejection on endomyocardial biopsy. Two of these three patients died (8 and 11 months post-transplant) after three and six rejection episodes, respectively. The one surviving patient had seven rejection episodes and continues to have poor ventricular function 18 months post-transplant. We conclude that alloantibodies specific for mismatched donor HLA antigens may have a deleterious effect on the outcome of the human cardiac allograft and should be monitored closely post-transplant. Furthermore, such antibodies may mediate effects on the transplanted heart which are not detectable in specimens obtained by endomyocardial biopsy.

Functional and morphologic adaptation of undersized donor hearts after heart transplantation.

OBJECTIVES: This study analyzes our experience with transplantation of small donor hearts in a subgroup of moribund patients who could not be bridged to transplantation with mechanical assist devices. BACKGROUND: The major problem facing transplant programs in the United States is the lack of donor heart availability. One method of expanding the donor pool may be to liberalize the criteria for an acceptable donor heart. METHODS: We analyzed the growth and adaptation of 14 undersized and 14 conventionally sized donor hearts over a period of 10 weeks after heart transplantation. The left ventricular systolic and diastolic diameters, septal and posterior wall thicknesses, left ventricular mass calculated by the Penn convention and left ventricular ejection fraction were obtained by M-mode and two-dimensional echocardiography and documented by a single reader in blinded manner. Echocardiographic measurements were obtained before implantation and at 5 and 10 weeks after orthotopic heart transplantation. RESULTS: The mean (+/- SD) donor/recipient weight ratios were 0.53 +/- 0.06 for undersized hearts and 0.98 +/- 0.05 for normal-sized hearts. All 28 patients received similar immunosuppressive regimens, including intravenous steroids, cyclosporine and azathioprine. The length of hospital stay after transplantation did not vary significantly between the two groups. All the patients had at least one rejection episode during the 10-week study period. There was a tendency toward higher pulmonary pressures in undersized hearts, which was not statistically significant. Heart rate was significantly higher for undersized hearts, due in part to the use of theophylline or terbutaline to maintain tachycardia. There was a significant increase in left ventricular systolic and diastolic dimensions in undersized hearts compared with conventionally sized hearts. Undersized hearts increased in left ventricular mass over the 10-week period, whereas the conventionally sized donor hearts did not change between 5 and 10 weeks. CONCLUSIONS: In undersized hearts the increase in left ventricular mass and internal dimensions, with preservation of the posterior/septal wall thickness ratio, suggests that the left ventricle adapts to the larger recipient circulation early after transplantation. Despite denervation and a mismatched load, undersized transplanted hearts adapt appropriately to their new hemodynamic milieu.