Swings between rotation and accretion power in a binary millisecond pulsar.

It is thought that neutron stars in low-mass binary systems can accrete matter and angular momentum from the companion star and be spun-up to millisecond rotational periods. During the accretion stage, the system is called a low-mass X-ray binary, and bright X-ray emission is observed. When the rate of mass transfer decreases in the later evolutionary stages, these binaries host a radio millisecond pulsar whose emission is powered by the neutron star's rotating magnetic field. This evolutionary model is supported by the detection of millisecond X-ray pulsations from several accreting neutron stars and also by the evidence for a past accretion disc in a rotation-powered millisecond pulsar. It has been proposed that a rotation-powered pulsar may temporarily switch on during periods of low mass inflow in some such systems. Only indirect evidence for this transition has hitherto been observed. Here we report observations of accretion-powered, millisecond X-ray pulsations from a neutron star previously seen as a rotation-powered radio pulsar. Within a few days after a month-long X-ray outburst, radio pulses were again detected. This not only shows the evolutionary link between accretion and rotation-powered millisecond pulsars, but also that some systems can swing between the two states on very short timescales.

Quality of care and hospital readmission in congestive heart failure: an explicit review process.

BACKGROUND: The effect of hospital quality of care on hospital readmission for patients with congestive heart failure (CHF) has not been widely studied. METHODS AND RESULTS: We examined the effects of clinical factors, hospital quality of care, and cardiologist involvement on 3-month readmission rates in patients with CHF by using a 125-item explicit review instrument comprising 3 major domains: admission work-up, evaluation and treatment, and readiness for discharge. During the 3 months after discharge, 59 (30%) of 205 patients were readmitted for CHF. The average evaluation and treatment score was lower for readmitted patients (63% v 58%; P = .04). The specific quality criteria differing between patients readmitted or not readmitted included the performance of any diagnostic evaluation, performance of echocardiography in patients with unknown ejection fraction or suspected valvular disease, and therapy with an angiotensin-converting enzyme inhibitor on discharge. Patients with

Electronic home monitoring of congestive heart failure patients: design and feasibility.

The efficacy of electronic monitoring in the home care of heart failure (HF) patients has not been widely reported. We developed a Vital Sign System (VSS) monitoring device capable of measuring the weight, blood pressure, and heart rate of congestive heart failure (CHF) patients in the home and transmitting these measurements via modem to a World Wide Web server. In this study of 22 CHF patients, we tested the reliability of the VSS electronic measurements compared to manual measurements taken by visiting home care nurses and ease of use of the VSS units as rated by both patients and home care nurses. The correlation of electronic to manual measurements was high (weight r=0.99; systolic blood pressure [SBP] r=0.84; diastolic blood pressure [DBP] r=0.54; heart rate [HR] r=0.88). The mean difference between electronic and manual measurements was within an acceptable range for clinical surveillance and care of CHF patients (weight 1.6 lbs; SBP 8.8 mm Hg; DBP 9.2 mm Hg; HR 0.7 bpm) The devices were rated favorably by both nurses and patients. The VSS monitoring device is a reliable, feasible, and favorably rated technology for home surveillance of CHF patients. (c)1999 by CHF, Inc.

Usefulness of echocardiographic determined tricuspid regurgitation in predicting event-free survival in severe heart failure secondary to idiopathic-dilated cardiomyopathy or to ischemic cardiomyopathy.

Two-dimensional and color Doppler echocardiograms obtained in 117 patients during cardiac transplantation evaluation were reviewed. Right ventricular hypokinesia and dilation were more prevalent in patients with tricuspid regurgitation. In multivariate event-free survival analysis of 61 patients with complete clinical, echocardiographic, and cardiopulmonary exercise data, the absence of tricuspid regurgitation and New York Heart Association class were the only independent predictors of survival.

A new casemix adjustment index for hospital mortality among patients with congestive heart failure.

OBJECTIVES: Comparative analysis of hospital outcomes requires reliable adjustment for casemix. Although congestive heart failure is one of the most common indications for hospitalization, congestive heart failure casemix adjustment has not been widely studied. The purposes of this study were (1) to describe and validate a new congestive heart failure-specific casemix adjustment index to predict in-hospital mortality and (2) to compare its performance to the Charlson comorbidity index. METHODS: Data from all 4,608 admissions to the Massachusetts General Hospital from January 1990 to July 1996 with a principal ICD-9-CM discharge diagnosis of congestive heart failure were evaluated. Massachusetts General Hospital patients were randomly divided in a derivation and a validation set. By logistic regression, odds ratios for in-hospital death were computed and weights were assigned to construct a new predictive index in the derivation set. The performance of the index was tested in an internal Massachusetts General Hospital validation set and in a non-Massachusetts General Hospital external validation set incorporating data from all 1995 New York state hospital discharges with a primary discharge diagnosis of congestive heart failure. RESULTS: Overall in-hospital mortality was 6.4%. Based on the new index, patients were assigned to six categories with incrementally increasing hospital mortality rates ranging from 0.5% to 31%. By logistic regression, "c" statistics of the congestive heart failure-specific index (0.83 and 0.78, derivation and validation set) were significantly superior to the Charlson index (0.66). Similar incrementally increasing hospital mortality rates were observed in the New York database with the congestive heart failure-specific index ("c" statistics 0.75). CONCLUSION: In an administrative database, this congestive heart failure-specific index may be a more adequate casemix adjustment tool to predict hospital mortality in patients hospitalized for congestive heart failure.

Inhaled nitric oxide improves exercise capacity in patients with severe heart failure and right ventricular dysfunction.

Fourteen cardiac transplant candidates were studied with cardiopulmonary exercise testing at baseline and while breathing nitric oxide (40 ppm). Oxygen consumption at the anaerobic threshold was improved by breathing nitric oxide in patients with pulmonary hypertension and in patients with an elevated left ventricular end-diastolic volume index.

Left ventricular end-diastolic volume index, age, and maximum heart rate at peak exercise predict survival in patients referred for heart transplantation.

BACKGROUND: This study sought to define clinical predictors of survival in patients under consideration for heart transplantation and demonstrate possible improvements in the prediction of outcome when considering the identified predictors in addition to peak oxygen consumption. Peak oxygen consumption is currently the most important criterion for determining the timing and appropriateness of heart transplantation in ambulatory patients. METHODS: To identify other possible predictors of survival in patients with heart failure, we reviewed clinical, exercise, and radionuclide ventriculographic data on 112 patients referred for heart transplantation evaluation. Predictors of 1-year (n = 86) and overall (n = 112) survival to the combined end point of freedom from death or pretransplantation admission for inotropic or mechanical support were identified in multivariate analysis. RESULTS: The mean age was 51+/-9 years, and the mean duration of follow-up was 408+/-366 days. The mean left ventricular ejection fraction was 0.22+/-0.07, and the mean peak oxygen consumption was 12.3+/-3.7 ml/min/kg. Age (odds ratio 1.087, 95% confidence interval [CI] 1.021 to 1.157), percentage of the maximum predicted heart rate at peak exercise (odds ratio 0.958, 95% CI 0.924 to 0.992), and left ventricular end-diastolic volume index (odds ratio 1.019, 95% CI 1.006 to 1.033) were independent predictors of the 1-year combined end point. CONCLUSION: Age, heart rate at peak exercise, and left ventricular end-diastolic volume index are independent predictors of prognosis in patients with advanced heart failure and may provide additional prognostic information for the risk-stratification of potential heart transplant recipients.

Sex and left ventricular volume predict survival in heart transplant candidates with peak oxygen uptake between ten and fourteen milliliters per kilogram per minute.

BACKGROUND: The purpose of this study was to identify predictors of survival in patients referred for heart transplantation evaluation who had a peak oxygen uptake of 10 to 14 ml/kg/min measured during initial cardiopulmonary exercise testing. METHODS: Seventy-two patients were identified retrospectively from a database of 304 patients who underwent heart transplantation evaluations at our center from 1985 to 1995. All 72 patients underwent right-sided heart catheterization and first-pass right and left ventricular radionuclide ventriculography during cardiopulmonary exercise testing. RESULTS: There were 14 women and 58 men in the study (mean age 52 +/- 9 years, 80% male, 79% New York Heart Association class III/IV, left ventricular ejection fraction of 0.24 +/- 0.9, and left ventricular end-diastolic volume index of 144 +/- 59 ml). During a mean follow-up of 19 +/- 23 months, two women and 32 men (47%) reached the combined end point of death (n = 20) or pretransplantation admission for inotropic or mechanical support (n = 14). For the entire cohort, analysis of clinical, ventriculographic, and exercise parameters identified female sex, younger age, and age/ sex-adjusted peak oxygen uptake as independent predictors of survival. In men only, age, left ventricular end-diastolic volume index, and age/sex adjusted peak oxygen uptake were independent predictors of survival. CONCLUSIONS: Among patients referred for heart transplantation evaluation with a peak oxygen uptake between 10 to 14 ml/kg/min, younger age, female sex, and higher age/ sex-adjusted peak oxygen uptake predict longer survival to the combined end point of death or pretransplantation admission for inotropic or mechanical support. These measures may be useful in additional risk stratification of such patients.

Left ventricular dysfunction after heart transplantation: incidence and role of enhanced immunosuppression.

BACKGROUND: The purpose of this study was to examine the incidence, natural history, and outcome of left ventricular dysfunction in 102 consecutive heart transplant recipients. Left ventricular dysfunction (defined as a decline in the echocardiographic ejection fraction to < 0.45) occurred in 16 of 102 transplant recipients (16%) at a mean of 9.7 +/- 8.6 (standard deviation) months after transplantation. METHODS: Diagnostic evaluation included right heart catheterization and endomyocardial biopsy in all patients and coronary angiography in 13 patients. RESULTS: Four patients were found to have moderate cellular rejection (International Society for Heart and Lung Transplantation grade 2 or higher) and were treated with enhanced immunosuppression. Two patients had angiographically apparent coronary allograft vasculopathy; both died of electromechanical dissociation within 4 months. The remaining ten patients had no or mild cellular rejection (International Society for Heart and Lung Transplantation grade 0 or 1). Therapy in these ten patients included corticosteroids (n = 8). OKT3 (n = 5), and plasmapheresis (n = 2). Three patients died within 2 months of diagnosis, two from undetected severe coronary allograft vasculopathy and one from unrecognized constrictive pericarditis. The echocardiographic ejection fraction improved in the surviving patients after enhanced immunosuppressive therapy (0.33 to 0.53, p < 0.005). With the benefit of long-term clinical follow-up and autopsy data, the origins of left ventricular dysfunction in the 16 patients included moderate cellular rejection (n = 4), vascular rejection (n = 1), coronary allograft vasculopathy (n = 3), intercurrent cytomegalovirus infection (n = 1), constrictive pericarditis (n = 1), and either mild or no evident rejection (n = 6). Survival of the 16 patients with left ventricular dysfunction was similar to that of the 86 patients without left ventricular dysfunction. CONCLUSIONS: The cause of left ventricular dysfunction after heart transplantation includes cellular rejection, vascular rejection, coronary allograft vasculopathy, cytomegalovirus infection, constrictive pericarditis, and unexplained mechanisms. Given the improvement in left ventricular function observed after empiric therapy with enhanced immunosuppression in patients with left ventricular dysfunction, immune-mediated phenomena may play an important pathogenic role.

Care of acute myocardial infarction by noninvasive and invasive cardiologists: procedure use, cost and outcome.

OBJECTIVES: This study sought to determine how noninvasive and invasive cardiologists may differ in the hospital care of patients with acute myocardial infarction. BACKGROUND: Scant information exists regarding the effect of noninvasive and invasive cardiology subspecialization on invasive cardiac procedural use, cost and outcome in the care of patients with acute myocardial infarction. METHODS: This study analyzed a prospective cohort of 292 patients admitted to an urban tertiary care hospital from the emergency room under the care of noninvasive or invasive cardiologists. Clinical characteristics; hospital course, including management, utilization of diagnostic coronary angiography and percutaneous transluminal coronary angioplasty; direct hospital costs; length of hospital stay; and post-hospital discharge follow-up data were collected by a prospective data base instrument. RESULTS: Despite similar clinical characteristics, extent and severity of coronary artery disease and utilization of diagnostic coronary angiography in the two groups of patients, those under the care of an invasive cardiologist were significantly more likely to undergo coronary angioplasty than those under the care of a noninvasive cardiologist. The direct hospital costs and length of stay of the noninvasive and invasive group patients who underwent coronary angioplasty were similar, although overall the direct hospital costs and length of stay were higher for the invasive than for the noninvasive group patients. CONCLUSIONS: Noninvasive and invasive cardiologists differ in their rate of utilization of coronary angioplasty in similar patients with acute myocardial infarction.

Torsade de pointes caused by high-dose intravenous haloperidol in cardiac patients.

Intravenous haloperidol is the agent of choice for controlling severe agitated delirium in seriously ill cardiac patients in many institutions. Prior reports have proposed that high-dose intravenous haloperidol may be without untoward effects in these patients. Recently, however, a few reports of significant QTc prolongation and torsade de pointes as complications of high-dose intravenous haloperidol therapy have appeared. The present report describes three patients with definite haloperidol-induced QTc prolongation and torsade. In each case, QTc prolongation preceded the arrhythmia and disappeared following the discontinuation of haloperidol. Neither electrolyte imbalance, therapy with other cardiac drugs, bradycardia, ischemia, left ventricular dysfunction, nor other known cause of torsade was present in these patients. It is hypothesized that QTc prolongation and torsade likely are idiosyncratic, unpredictable reactions to high-dose haloperidol in select patients. Careful serial electrocardiographic monitoring and prompt discontinuation of the drug should suffice to prevent this relatively uncommon, life-threatening complication of high-dose intravenous haloperidol.

Preserved right ventricular ejection fraction predicts exercise capacity and survival in advanced heart failure.

OBJECTIVES: This study was undertaken to determine which exercise and radionuclide ventriculographic variables predict prognosis in advanced heart failure. BACKGROUND: Although cardiopulmonary exercise testing is frequently used to predict prognosis in patients with advanced heart failure, little is known about the prognostic significance of ventriculographic variables. METHODS: The results of maximal symptom-limited cardiopulmonary exercise testing and first-pass radionuclide ventriculography in patients with advanced heart failure referred for evaluation for cardiac transplantation were analyzed. RESULTS: Sixty-seven patients with advanced heart failure (mean [+/- SD]; age 51 +/- 10 years, New York Heart Association functional classes III (58%) and IV (18%); mean left ventricular ejection fraction 0.22 +/- 0.07) underwent simultaneous upright bicycle ergometric cardiopulmonary exercise testing and first-pass rest/exercise radionuclide ventriculography. Mean peak oxygen consumption (VO2) was 11.8 +/- 4.2 ml/kg per min, and mean peak age- and gender-adjusted percent predicted oxygen consumption (%VO2) was 38 +/- 11.9%. Univariate predictors of overall survival included right ventricular ejection fraction > or = 0.35 at rest and > or = 0.35 at exercise and %VO2 > or = 45% (all p < 0.05). In a multivariate proportional hazards survival model, right ventricular ejection fraction > or = 0.35 at exercise (p < 0.01) and %VO2 > or = 45% (p = 0.01) were selected as independent predictors of overall survival. Univariate predictors of event-free survival included right ventricular ejection fraction > or = 0.35 at rest (p = 0.01) and > or = 0.35 at exercise (p < 0.01), functional class II (p < 0.05) and %VO2 > or = 45% (p = 0.05). Right ventricular ejection fraction > or = 0.35 at exercise (p = 0.01) was the only independent predictor of event-free survival in a multivariate proportional hazards model. Cardiac index at rest, VO2, left ventricular ejection fraction at rest, and exercise-related increase or decrease > 0.05 in left or right ventricular ejection fraction were not predictive of overall or event-free survival in any univariate or multivariate analysis. CONCLUSIONS: 1) Right ventricular ejection fraction > or = 0.35 at rest and exercise is a more potent predictor of survival in advanced heart failure than VO2 or %VO2; 2) %VO2 rather than VO2 predicts survival in advanced heart failure; 3) neither %VO2 nor VO2 predicts survival to the combined end point of death or admission for inotropic or mechanical support in patients with advanced heart failure.

Antithrombotic therapy in coronary artery disease.

Antithrombotic therapy has assumed a central role in the therapy of the acute coronary syndromes and chronic coronary artery disease. The theoretical rationale for antithrombotic therapy, and the established and evolving roles of antiplatelet agents and anticoagulants in coronary disease are reviewed. Emphasis is focused on new antithrombotic agents and novel combinations of existing agents.

Fatal intracerebral hemorrhage following thrombolytic therapy of embolic myocardial infarction in unsuspected infective endocarditis.

Cerebral hemorrhage occurs in 0.2% of patients under the age of 60 years treated with thrombolytic therapy for acute myocardial infarction. A case of fatal cerebral hemorrhage following TPA therapy for myocardial infarction due to probable coronary artery embolism during unsuspected native valve infective endocarditis is reported.