Echocardiography overestimates left ventricular mass in hemodialysis patients relative to magnetic resonance imaging

Echocardiography overestimates left ventricular mass in hemodialysis patients relative to magnetic resonance imaging.

BACKGROUND

Left ventricular hypertrophy (LVH) is a common finding and a strong adverse prognostic factor in patients with chronic renal failure. An accurate method of measuring left ventricular mass (LV mass) is therefore a prerequisite in the management of these patients. Recent evidence has suggested that echocardiography overestimates LV mass in patients with essential hypertension, and this error increases with increasing LV mass.

METHODS

We studied 35 patients on maintenance hemodialysis within 24 hours of their last dialysis. LV mass was measured by both echocardiography and magnetic resonance imaging (MRI) performed less than three hours apart. Clinic and ambulatory blood pressure (ABPM), resting echocardiogram, and blood sampling were performed at the same visit.

RESULTS

Thirty-two patients had results from both methods. Clinic blood pressure, ABPM, and QT dispersion all correlated with LV mass, with a stronger correlation observed for MRI values. Intraobserver and interobserver variability were significantly greater for echocardiography (although similar to other published data). Comparing the two methods, the difference in LV mass values (echo minus magnetic resonance) increased in a linear fashion with an increasing mean mass and chamber diameter.

CONCLUSIONS

Echocardiography significantly overestimates LV mass relative to MRI in the presence of LVH and dilation. This overestimation is the result of assumptions made in the calculation of mass from echocardiography M-mode images, which are invalid when LV geometry is abnormal. This error is therefore amplified in dialysis patients, the majority of whom have LVH and in whom intravascular volume is constantly changing.

Echocardiography overestimates left ventricular mass in hemodialysis patients relative to magnetic resonance imaging

Echocardiography overestimates left ventricular mass in hemodialysis patients relative to magnetic resonance imaging.

BACKGROUND

Left ventricular hypertrophy (LVH) is a common finding and a strong adverse prognostic factor in patients with chronic renal failure. An accurate method of measuring left ventricular mass (LV mass) is therefore a prerequisite in the management of these patients. Recent evidence has suggested that echocardiography overestimates LV mass in patients with essential hypertension, and this error increases with increasing LV mass.

METHODS

We studied 35 patients on maintenance hemodialysis within 24 hours of their last dialysis. LV mass was measured by both echocardiography and magnetic resonance imaging (MRI) performed less than three hours apart. Clinic and ambulatory blood pressure (ABPM), resting echocardiogram, and blood sampling were performed at the same visit.

RESULTS

Thirty-two patients had results from both methods. Clinic blood pressure, ABPM, and QT dispersion all correlated with LV mass, with a stronger correlation observed for MRI values. Intraobserver and interobserver variability were significantly greater for echocardiography (although similar to other published data). Comparing the two methods, the difference in LV mass values (echo minus magnetic resonance) increased in a linear fashion with an increasing mean mass and chamber diameter.

CONCLUSIONS

Echocardiography significantly overestimates LV mass relative to MRI in the presence of LVH and dilation. This overestimation is the result of assumptions made in the calculation of mass from echocardiography M-mode images, which are invalid when LV geometry is abnormal. This error is therefore amplified in dialysis patients, the majority of whom have LVH and in whom intravascular volume is constantly changing.

Autoimmune hemolytic anemia in patients with SCID after T cell-depleted BM and PBSC transplantation

We report a high incidence (19.5%) of autoimmune hemolytic anemia (AIHA) in 41 patients with SCID who underwent a T cell-depleted haploidentical transplant. Other than infections, AIHA was the most common post-transplant complication in this patient cohort. Clinical characteristics and treatment of eight patients who developed AIHA at a median of 8 months after the first T cell-depleted transplant are presented. All patients had warm-reacting autoantibodies, and two of eight had concurrent cold and warm autoantibodies. Clinical course was most severe in two patients who had cold and warm autoantibodies. Five patients received specific therapy for AIHA. Successful taper off immunosuppressive therapy for AIHA coincided with T cell reconstitution. Delayed reconstitution of T cell immunity, due to T cell depletion, immunosuppressive conditioning and CsA, as well as paucity of regulatory T cells, are the likely explanations for the occurrence of AIHA in our patient cohort. Screening of the population at risk may prevent morbidity and mortality from AIHA.

Respiratory response during arm elevation in isolated diaphragm weakness

Upper extremity exercise is associated with a significant metabolic and ventilatory cost that is particularly evident in patients with severe chronic airflow obstruction. In these patients abnormal ventilatory muscle recruitment has been hypothesized to relate to impaired diaphragm function resulting from hyperinflation. Similar data have never been reported in patients with isolated diaphragm weakness but without airflow obstruction or hyperinflation, a group that would ideally define the role of diaphragm function during arm elevation (AE). We prospectively studied 15 patients with isolated diaphragm weakness of varying severity (Pdi(sniff), 31.74 +/- 3.75 cm H(2)O) as contrasted with eight normal subjects (Pdi(sniff), 111. 77 +/- 13.35 cm H(2)O) of similar age. Patients with diaphragm weakness demonstrated significant lung volume restriction with normal DL(CO)/VA. There was no difference in resting oxygen consumption (V O(2)), carbon dioxide production (V CO(2)), minute ventilation (V E), and tidal volume (VT) between the two groups; however, a borderline difference in resting breathing frequency (f(b)) (p = 0.056) was evident. Both groups demonstrated a rise in V O(2), V CO(2), and V E during 2 min of AE anteriorly. Normal subjects demonstrated a statistically significant rise in VT but a statistically insignificant rise in f(b) during AE. In contrast, patients with diaphragm weakness demonstrated a statistically significant rise in f(b) during AE but a statistically insignificant rise in VT. In patients the observed rise in VT directly correlated with baseline Pdi(sniff) (r = 0.59, p = 0.02) and Pdi(max) (r = 0.81, p = 0.002). Both groups demonstrated a rise in Pdi during AE. The rise in Pdi during AE directly correlated to Pdi(sniff) in the patients (r = 0.69, p = 0.004). Observed end-expiratory Ppl rose during arm elevation in both the patient group and in the normal control group, but no evidence of a differential response to AE was found. In those patients with greater diaphragm weakness (Pdi(sniff) < 30 cm H(2)O), abnormal respiratory muscle function (lesser rise in Pdi) and a lesser increase in VT during AE were more evident. These data highlight the importance of diaphragm function in determining the metabolic and respiratory muscle response to arm elevation.

Mutually exclusive expression of human red and green visual pigment-reporter transgenes occurs at high frequency in murine cone photoreceptors

This study examines the mechanism of mutually exclusive expression of the human X-linked red and green visual pigment genes in their respective cone photoreceptors by asking whether this expression pattern can be produced in a mammal that normally carries only a single X-linked visual pigment gene. To address this question, we generated transgenic mice that carry a single copy of a minimal human X chromosome visual pigment gene array in which the red and green pigment gene transcription units were replaced, respectively, by alkaline phosphatase and beta-galactosidase reporters. As determined by histochemical staining, the reporters are expressed exclusively in cone photoreceptor cells. In 20 transgenic mice carrying any one of three independent transgene insertion events, an average of 63% of expressing cones have alkaline phosphatase activity, 10% have beta-galactosidase activity, and 27% have activity for both reporters. Thus, mutually exclusive expression of red and green pigment transgenes can be achieved in a large fraction of cones in a dichromat mammal, suggesting a facile evolutionary path for the development of trichromacy after visual pigment gene duplication. These observations are consistent with a model of visual pigment expression in which stochastic pairing occurs between a locus control region and either the red or the green pigment gene promotor.

Interferon-gamma stimulates human Clara cell secretory protein production by human airway epithelial cells

Clara cell secretory protein (CCSP) is an inhibitor of secretory phospholipase A2. It is produced by airway epithelial cells and is present in airway secretions. Because interferon (IFN)-gamma can induce gene expression in airway epithelial cells and may modulate the inflammatory response in the airway, it was of interest to study the effect of this cytokine on epithelial cell CCSP mRNA expression and CCSP protein synthesis. A human bronchial epithelial cell line (BEAS-2B) was used for this study. CCSP mRNA was detected by ribonuclease protection assay. IFN-gamma was found to increase CCSP mRNA expression in a time- and dose-dependent manner. The CCSP mRNA level increased after IFN-gamma (300 U/ml) treatment for 8-36 h, with the peak increase at 18 h. Immunobloting of CCSP protein also demonstrated that IFN-gamma induced the synthesis and secretion of CCSP protein in a time-dependent manner. Nuclear run-on, CCSP reporter gene activity assay, and CCSP mRNA half-life assay demonstrated that IFN-gamma-induced increases in CCSP gene expression were mediated, at least in part, at the posttranscriptional level. The present study demonstrates that IFN-gamma can induce increases in steady-state mRNA levels and protein synthesis of human CCSP protein in airway epithelial cells and may modulate airway inflammatory responses in this manner.

Antisense inhibition of 85-kDa cPLA2 blocks arachidonic acid release from airway epithelial cells

Inflammatory cytokines play a critical role in the initiation and perpetuation of inflammation. Several cytokines are known to increase the production of arachidonic acid (AA) metabolites, which may mediate cytokine-induced acute and chronic inflammation. Although cytokines upregulate phospholipase A2 (PLA2) in several target cells, the contribution of individual PLA2 to cytokine-induced AA release and eicosanoid production remains unclear because of the existence of various forms of cellular PLA2. To examine the role of 85-kDa cytosolic PLA2 (cPLA2) in cytokine-induced AA release, a system was developed to inhibit the expression of cPLA2 in a human bronchial epithelial cell line (BEAS-2B cells) by antisense RNA. Cells stably expressing antisense cPLA2 exhibited decreased cPLA2 protein levels as well as decreased cPLA2 activity assayed in vitro. The effects of cytokines interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 alpha (IL-1 alpha) on the release of prelabeled [3H]AA were then tested in cells stably transfected with vector alone as well as cells transfected with cPLA2 antisense plasmid. IFN-gamma (300 U/ml), TNF-alpha (20 ng/ml), and IL-1 alpha (20 ng/ml) all induced a significantly increased release of prelabeled [3H]AA after 15 min to 2 h of treatment in control cells, and their effects were significantly reduced in cells transfected with cPLA2 antisense vector. These results demonstrate a critical role of cPLA2 in inflammatory cytokine-induced AA metabolism.

Gender, gender role, and drawing skill

Separate bodies of research suggest that performance in spatial reasoning covaries with gender and with gender role. Typically studies employ a spatial task whose variance is then used to account for differences in scores between gender groups or variance in a measure of gender role. A methodological issue in such research is that the tasks used to represent spatial reasoning may be differentially available or differentially appealing as a function of gender. Also, authors tend to analyze data in terms of either gender or gender role but rarely both. A collection of personality assessments administered to 204 college students each contained a completed Minnesota Multiphasic Personality Inventory (MMPI-2) and a drawing of a human figure. Within MMPI-2 are three measures of gender role. Drawing talent is unquestionably spatial and has the advantage of being equally available and encouraged among the two genders. Male gender predicted drawing skill. Within both genders, self-perceived masculinity in gender role also predicted higher scores on the drawing skill. Outcomes are seen as compatible with Geschwind and Galaburda's 1987 formulation regarding the behavioral manifestations of fetal androgenization.

Radiofrequency catheter ablation of multiple morphologies of ventricular tachycardia by targeting a single region of the left ventricle

INTRODUCTION

As treatment options for ventricular tachycardia (VT) continue to evolve, the use of radiofrequency catheter ablation is rapidly expanding. However, in the presence of multiple morphologies of VT, achieving successful results may seem less likely. We report two patients with multiple morphologies of VT who underwent successful radiofrequency ablation by application of radiofrequency energy to a single region in the left ventricle.

METHODS AND RESULTS

Two patients, each without any apparent cardiac dysfunction and a history of documented VT, were referred to our institution for further management. They underwent an electrophysiologic study and were found to have easily inducible VT, of three morphologies in one patient and two in the other. Using a transaortic approach, left ventricular mapping was performed for detecting a site with presystolic potentials, earliest ventricular activation, or both. Application of radiofrequency energy to a single area in the left ventricle resulted in the elimination of all previously inducible VT in each patient.

CONCLUSION

VTs with distinctly different morphologies can occur in patients with no detectable structural heart disease. These VT circuits may share a common pathway and, therefore, may readily be amenable to therapy with radiofrequency catheter ablation.

Clinical nursing management of sickle cell disease and trait during pregnancy

Sickle cell-related hemoglobinopathies present challenges for clinical management during pregnancy, labor, delivery, and the postpartum course because perinatal morbidity remains a significant practice concern. Nursing strategies that strive for synthesis of knowledge pertaining to pathophysiology, genetic counseling, life events that have affected the patient's health history, treatment modalities, and psychosocial needs may improve obstetric and neonatal outcomes. Clinical management strategies for the prenatal, intrapartum, and postpartum courses are provided. Nursing intervention strategies such as follow-up teaching, involvement of the partner and support network in aspects of care, and patient advocates, in conjunction with independent nursing practice activities involving emotional support and measures to alleviate symptoms associated with disease manifestations, are cornerstones in the contribution of nursing to the multidisciplinary care of the pregnant woman with sickle cell disease and trait.

Diagnosing and managing unstable angina. Agency for Health Care Policy and Research

This Quick Reference Guide for Clinicians contains recommendations on the care of patients with unstable angina based on a combination of evidence obtained through extensive literature reviews and consensus among members of an expert panel. Principal conclusions include the following. (1) Many patients suspected of having unstable angina can be discharged home after adequate initial evaluation. (2) Further outpatient evaluation may be scheduled for up to 72 hours after initial presentation for patients with clinical symptoms of unstable angina judged at initial evaluation to be at low risk for complications. (3) Patients with acute ischemic heart disease judged to be at intermediate or high risk of complications should be hospitalized for careful monitoring of their clinical course. (4) Intravenous thrombolytic therapy should not be administered to patients without evidence of ST segment elevation and acute myocardial infarction. (5) Assessment of prognosis by noninvasive testing often aids selection of appropriate therapy. (6) Coronary angiography is appropriate for patients judged to be at high risk for cardiac complications or death based on their clinical course or results of noninvasive testing. (7) Coronary artery bypass surgery should be recommended for almost all patients with left main disease and many patients with three-vessel disease, especially those with left ventricular dysfunction. (8) The discharge care plan should include continued monitoring of symptoms; appropriate drug therapy, including aspirin; risk-factor modification; and counseling.

Aminosulfonic acid buffer preserves myocardium during prolonged ischemia

Prevention of myocardial acidosis during global ischemia in operative cardiopreservation was explored in two series of dogs where acid-base control was the only variable. A specifically designed aminosulfonic acid buffer composition, 3:1 molar equivalents NaMOPS to HEPES, 0.2 mol/L, was compared with NaHCO3 (pH 8). Dissolved in standard cardioplegic solution it was given every 30 minutes by coronary infusion at 20 degrees C during 3 hours of global ischemia. Glass electrode intramyocardial pH, adenosine triphosphate (ATP) level, left ventricular contractility (Dp/Dt) and compliance (-Dp/Dt), and other cardiovascular parameters were measured frequently throughout ischemia and for 75 minutes thereafter. In the buffer group (n = 6) myocardial pH remained above entry levels throughout the study period, adenosine triphosphate level remained normal during ischemia, and Dp/Dt and -Dp/Dt at 75 minutes of reperfusion were above entry levels. In the NaHCO3 group (n = 6) pH declined and remained depressed throughout ischemia, adenosine triphosphate level fell steadily and significantly throughout the experiment, and Dp/Dt and -Dp/Dt never regained entry levels. The difference in each parameter between the two groups was statistically significant (p < 0.05). We conclude that control of myocardial acid-base equilibrium alone during global ischemia will preserve myocardial function and minimize reperfusion injury.

Nycthemeral profile of nonspectral heart rate variability measures in women and men. Description of a normal sample and two sudden cardiac arrest subsamples

Heart rate variability (HRV), a noninvasive systemic index of the central autonomic nervous system, demonstrates considerable within-subject variability, including a strong systematic 24-hour nycthemeral (or less precisely, circadian) component. Recent interest in the timing of sudden cardiac arrest (SCA), especially the pronounced morning rise in sudden deaths, has motivated research into coincident dynamic phenomena in HRV indices of central autonomic nervous system activity. In this study, statistical (nonspectral) HRV measures (SD and %RR50) were summarized for consecutive 15-minute blocks from 24-hour Holter electrocardiogram tapes. Six subgroups were scrutinized: women and men respectively in three clinical strata (normal subjects [n = 85 women and 40 men], SCA with no current or prior myocardial infarction [MI] [n = 9 women and 31 men], SCA with old MI [n = 7 women and 48 men]). Significant nycthemeral effects were observable for all HRV measures in five of the six groups, with a dramatic fall in HRV during the hours of the morning with the highest phenomenologic incidence of SCA. Both strata of SCA subjects had much lower HRV than the normal subjects. This effect was strongest during the night-time hours, particularly for a purported index of vagal tone (%RR50). For reasons that are not known, the nine female SCA survivors who had no current or previous MI presented very distinct 24-hour patterns for the HRV measures studied. Twenty-four-hour profiles of short-term statistical HRV provide a rich field for the observation of within-subject adaptations of the central autonomic nervous system inputs to the heart in both normal and clinical subgroups.

Measurement of recovery from myocardial infarction using heart rate variability and psychological outcomes

This pilot study was designed to describe heart rate variability (HRV), anxiety, anger, denial, and depression during the first 4 days and 6 months after acute myocardial infarction (AMI). The sample was composed of 21 post-AMI males aged 40 to 83. State anxiety was elevated early. At 6 months it had significantly decreased. The nonpower measure of HRV, the Kleiger global standard deviation, was decreased to a mean score of 86 (SD = 29) msec during AMI and was 117 (SD = 30) msec at 6 months. Although there were no significant correlations between HRV, psychological response, age, and education, there were moderate correlations between HRV and state anger (r = .33), denial (r = .35), and education (r = .45). HRV, as measured by the power spectral density function of an autoregressive model, demonstrated an increased peak across the band of frequency associated with the high-frequency components of the parasympathetic system and a decreased peak across the band associated with the low-frequency components of the sympathetic system at 6 months as compared to the AMI period.

Wegener's granulomatosis. Typical symptoms in an atypical patient

Wegener's granulomatosis classically involves the respiratory tract and kidneys, and the disorder may be confused with any of a number of diseases having similar symptoms. Although most common in middle-aged whites, Wegener's granulomatosis may occur in atypical patients, as in the case described here. Accurate diagnosis depends on lung biopsy, and prompt treatment prevents permanent damage and significant sequelae.

Microgranulomatous aspergillosis after shoveling wood chips: report of a fatal outcome in a patient with chronic granulomatous disease

Chronic granulomatous disease is characterized by recurrent infections that result from an inability of phagocytes to kill organisms effectively. We describe a patient with this disease who developed aspergillus pneumonia after shoveling moldy cedar wood chips. Despite aggressive therapy, the patient's condition deteriorated and he died. At autopsy, the lungs revealed diffuse granulomas, all of the same age, with aspergillus organisms confined to the granulomas. We propose the term "microgranulomatous aspergillosis" for this response, which does not conform to the commonly described aspergillus syndromes. We conclude that susceptible immunosuppressed patients should be advised to avoid occupational situations where high spore concentrations are generated.

Case studies of the ischemic foot and management with bypass surgery

Four case studies are presented to demonstrate the interdisciplinary approach used in management of the ischemic foot. In each case, bypass surgery was used to increase vascularity to the affected limb. This surgical aggressive approach, medical management combined with local wound care, provided a satisfying clinical outcome.

Inhibition of rate of tumour growth in rodent species by inoculation of herpesviruses and encephalomyocarditis virus

Inoculation of herpesviruses and encephalomyocarditis virus into subcutaneous tumours in hamsters and mice reduced the rate of tumour growth compared to untreated tumours or secondary tumours which had arisen following surgical excision of the primary tumour; in addition, survival times were increased in animals whose tumours were inoculated with virus. It is suggested that the role of virus in the modification of tumour growth merits further exploration.