Effects of agricultural conservation practices on N loads in the Mississippi-atchafalaya river basin.

A modeling framework consisting of a farm-scale model, Agricultural Policy Environmental Extender (APEX); a watershed-scale model, Soil and Water Assessment Tool (SWAT); and databases was used in the Conservation Effects Assessment Project to quantify the environmental benefits of conservation practices on cropland. APEX is used to simulate conservation practices on cultivated cropland and Conservation Reserve Program land to assess the edge-of-field water-quality benefits. Flow and pollutant loadings from APEX are input to SWAT. SWAT simulates the remaining noncultivated land and routes flow and loads generated from noncultivated land, point sources, and cropland to the basin outlet. SWAT is used for assessing the effects of practices on local and in-stream water-quality benefits. Each river basin is calibrated and validated for streamflow and loads at multiple gauging stations. The objectives of the current study are to estimate the effects of currently existing and additional conservation practices on total N (TN) loads in the Mississippi-Atchafalaya River Basin (MARB) and draw insights on TN load reductions necessary for reducing the hypoxic zone in the Gulf of Mexico. The effects of conservation practice scenarios on local and in-stream (riverine) water quality are evaluated. Model results indicate that conservation practices currently on cropland have reduced the TN losses to local waters between 20 and 59% in the six river basins within MARB and the TN load discharged to the Gulf by 17%. Further water-quality improvement can be obtained in the MARB with additional conservation treatment.

Carotid artery examination, an important tool in patient evaluation.

Examination of the arteries is an age old medical tradition. Examination of the carotid artery is of unique importance because it is an easily accessible large artery. Through the methods of inspection, palpation, and auscultation, carotid artery examination gives clinicians important diagnostic clues about the health and disease of the patient. Inspection and palpation of the carotid give insight into left ventricular systolic function and distinguish types of valvular heart disease. Auscultation identifies patients with high-risk atherosclerosis. In most cases carotid examination is neither sensitive nor specific, but in the correct clinical context it offers important evidence leading to specific diagnoses and treatment. In this review, we discuss the examination of the carotid artery under normal conditions and describe how abnormalities in the carotid artery examination are indicators of disease.

Carotid bruits and cerebrovascular disease risk: a meta-analysis.

BACKGROUND AND PURPOSE: Current guidelines recommend against routine auscultation of carotid arteries, believing that carotid bruits are poor predictors of either underlying carotid stenosis or stroke risk in asymptomatic patients. We investigated whether the presence of a carotid bruit is associated with increased risk for transient ischemic attack, stroke, or death by stroke (stroke death). METHODS: We searched Medline (1966 to December 2009) and EMBASE (1974 to December 2009) with the terms "carotid" and "bruit." Bibliographies of all retrieved articles were also searched. Articles were included if they prospectively reported the incidence of transient ischemic attack, stroke, or stroke death in asymptomatic adults. Two authors independently reviewed and extracted data. RESULTS: We included 28 prospective cohort articles that followed a total of 17 913 patients for 67 708 patient-years. Among studies that directly compared patients with and without bruits, the rate ratio for transient ischemic attack was 4.00 (95% CI, 1.8 to 9.0, P<0.0005, n=5 studies), stroke was 2.5 (95% CI, 1.8 to 3.5, P<0.0005, n=6 studies), and stroke death was 2.7 (95% CI, 1.33 to 5.53, P=0.002, n=3 studies). Among the larger pool of studies that provided data on rates, transient ischemic attack rates were 2.6 per 100 patient-years (95% CI, 2.0 to 3.2, P<0.0005, n=24 studies) for those with bruits compared with 0.9 per 100 patient-years (95% CI, 0.2 to 1.6, P=0.02, n=5 studies) for those without carotid bruits. Stroke rates were 1.6 per 100 patient-years (95% CI, 1.3 to 1.9, P<0.0005, n=26 studies) for those with bruits compared with 1.3 per 100 patient-years (95% CI, 0.8 to 1.7, P<0.0005, n=6) without carotid bruits, and death rates were 0.32 (95% CI, 0.20 to 0.44, P<0.005, n=13 studies) for those with bruits compared with 0.35 (95% CI, 0.00 to 0.81, P=0.17, n=3 studies) for those without carotid bruits. CONCLUSIONS: The presence of a carotid bruit may increase the risk of cerebrovascular disease.

Carotid bruits as a prognostic indicator of cardiovascular death and myocardial infarction: a meta-analysis.

BACKGROUND: Although carotid bruits are deemed to be markers of generalised atherosclerosis, they are poor predictors of cerebrovascular events. We investigated whether a carotid bruit predicts myocardial infarction and cardiovascular death. METHODS: In this meta-analysis, we searched Medline (1966 to August, 2007) and Embase (1974 to August, 2007) with the terms "carotid" and "bruit". Bibliographies of all the retrieved articles were also searched. Articles were included if they reported the incidence of myocardial infarction or cardiovascular death in adults. Outcome variables were extracted in duplicate and included the rate of myocardial infarction and cardiovascular mortality. Quality of the articles was independently assessed with the Hayden rating scheme. Data were pooled with a random effects model. FINDINGS: Of the 22 articles included, 20 (91%) used prospective cohorts. Our analysis included 17,295 patients with 62 413.5 patient-years of follow-up, with a median sample size of 273 patients (range 38-4736) followed up for 4 years (2-7). The rate of myocardial infarction in patients with carotid bruits was 3.69 (95% CI 2.97-5.40) per 100 patient-years (eight studies) compared with 1.86 (0.24-3.48) per 100 patient-years in those without bruits (two studies). Yearly rates of cardiovascular death were also higher in patients with bruits (16 studies) than in those without (four studies) (2.85 [2.16-3.54] per 100 patient-years vs 1.11 [0.45-1.76] per 100 patient-years). In the four trials in which direct comparisons of patients with and without bruits were possible, the odds ratio for myocardial infarction was 2.15 (1.67-2.78) and for cardiovascular death 2.27 (1.49-3.49). INTERPRETATION: Auscultation for carotid bruits in patients at risk for heart disease could help select those who might benefit the most from an aggressive modification strategy for cardiovascular risk.

Amiodarone versus sotalol for atrial fibrillation.

BACKGROUND: The optimal pharmacologic means to restore and maintain sinus rhythm in patients with atrial fibrillation remains controversial. METHODS: In this double-blind, placebo-controlled trial, we randomly assigned 665 patients who were receiving anticoagulants and had persistent atrial fibrillation to receive amiodarone (267 patients), sotalol (261 patients), or placebo (137 patients) and monitored them for 1 to 4.5 years. The primary end point was the time to recurrence of atrial fibrillation beginning on day 28, determined by means of weekly transtelephonic monitoring. RESULTS: Spontaneous conversion occurred in 27.1 percent of the amiodarone group, 24.2 percent of the sotalol group, and 0.8 percent of the placebo group, and direct-current cardioversion failed in 27.7 percent, 26.5 percent, and 32.1 percent, respectively. The median times to a recurrence of atrial fibrillation were 487 days in the amiodarone group, 74 days in the sotalol group, and 6 days in the placebo group according to intention to treat and 809, 209, and 13 days, respectively, according to treatment received. Amiodarone was superior to sotalol (P<0.001) and to placebo (P<0.001), and sotalol was superior to placebo (P<0.001). In patients with ischemic heart disease, the median time to a recurrence of atrial fibrillation was 569 days with amiodarone therapy and 428 days with sotalol therapy (P=0.53). Restoration and maintenance of sinus rhythm significantly improved the quality of life and exercise capacity. There were no significant differences in major adverse events among the three groups. CONCLUSIONS: Amiodarone and sotalol are equally efficacious in converting atrial fibrillation to sinus rhythm. Amiodarone is superior for maintaining sinus rhythm, but both drugs have similar efficacy in patients with ischemic heart disease. Sustained sinus rhythm is associated with an improved quality of life and improved exercise performance.

Basophils in tuberculin and "Jones-Mote" delayed reactions of humans.

Jones-Mote reactions are delayed, erythematous, and mildly indurated cutaneous reactions originally described in humans sensitized by skin injection of heterologous proteins. Similar reactions in guinea pigs contain many basophils and are called cutaneous basophil hypersensitivity. In contrast, guinea pigs immunized with mycobacterial adjuvants have classical tuberculin-type delayed hypersensitivity reactions, which contain few basophils. This has led to a new classification of delayed responses, based largely on the presence or absence of basophils. We induced sensitization for Jones-Mote reactions in 20 normal humans by intradermal injections of keyhole limpet hemocyanin. Skin tests with KLH 1 wk later showed erythematous and indurated delyaed reactions in all subjects. Rebuck skin windows showed specific accumulations of basophils with a delayed time-course in 18 of 20 subjects. In 12 normals sensitized with oxazolone-keyhole limpet hemocyanin conjugates, skin reactions and in vitro lymphocyte stimulation showed carrier and not hapten specificity, suggesting that cutaneous responses were probably mediated by T cells. A comparative study of strongly positive PPD skin tests in patients with tuberculosis showed significant basophil accumulations in five of nine subjects. Thus, basophils occurred in human tuberculin and Jones-Mote reactions and were not a distinguishing feature of Jones-Mote reactions. We suggest that the occurrence of basophils at delayed reactions is under complex regulation and that basophil accumulations are an aspect of delayed hypersensitivity, rather than an indication of a distinctive and separate response.

Exercise capacity and mortality among men referred for exercise testing.

BACKGROUND: Exercise capacity is known to be an important prognostic factor in patients with cardiovascular disease, but it is uncertain whether it predicts mortality equally well among healthy persons. There is also uncertainty regarding the predictive power of exercise capacity relative to other clinical and exercise-test variables. METHODS: We studied a total of 6213 consecutive men referred for treadmill exercise testing for clinical reasons during a mean (+/-SD) of 6.2+/-3.7 years of follow-up. Subjects were classified into two groups: 3679 had an abnormal exercise-test result or a history of cardiovascular disease, or both, and 2534 had a normal exercise-test result and no history of cardiovascular disease. Overall mortality was the end point. RESULTS: There were a total of 1256 deaths during the follow-up period, resulting in an average annual mortality of 2.6 percent. Men who died were older than those who survived and had a lower maximal heart rate, lower maximal systolic and diastolic blood pressure, and lower exercise capacity. After adjustment for age, the peak exercise capacity measured in metabolic equivalents (MET) was the strongest predictor of the risk of death among both normal subjects and those with cardiovascular disease. Absolute peak exercise capacity was a stronger predictor of the risk of death than the percentage of the age-predicted value achieved, and there was no interaction between the use or nonuse of beta-blockade and the predictive power of exercise capacity. Each 1-MET increase in exercise capacity conferred a 12 percent improvement in survival. CONCLUSIONS: Exercise capacity is a more powerful predictor of mortality among men than other established risk factors for cardiovascular disease.

Exercise capacity in atrial fibrillation: a substudy of the Sotalol-Amiodarone Atrial Fibrillation Efficacy Trial (SAFE-T).

BACKGROUND: Therapy for chronic atrial fibrillation (AF) focuses on rate versus rhythm control, but little is known about the effects of common therapeutic interventions on exercise tolerance in AF. METHODS: Six hundred fifty-five patients with chronic AF underwent maximal exercise testing at baseline and 8 weeks, 6 months, and 1 year after randomization to sotalol, amiodarone, or placebo therapy and attempted direct current cardioversion. Analyses of baseline determinants of exercise capacity, predictors of change in exercise capacity at 6 months and 1 year, and the short- and long-term effects of cardioversion on exercise capacity were made. RESULTS: Age, obesity, and presence of symptoms accompanying AF were inversely associated with baseline exercise capacity, but these factors accounted for only 10% of the variance in exercise capacity. Patients most likely to benefit from cardioversion were those most limited initially, younger, not obese or hypertensive, and with an uncontrolled ventricular rate at baseline. Conversion to sinus rhythm (SR) resulted in significant reductions in resting (approximately 25 beat/min) and peak exercise (approximately 40 beat/min) heart rates at 6 months and 1 year (P < .001). Successful cardioversion improved exercise capacity by 15% at 8 weeks, and these improvements were maintained throughout the year. This improvement was observed both among those who maintained SR and those with intermittent AF. CONCLUSION: Cardioversion resulted in a sustained improvement in exercise capacity over the course of 1 year, and this improvement was similar between those in SR and those with SR and recurrent AF. Patients most likely to improve with treatment tended to be younger and nonobese and have the greatest limitations initially.

Peripheral edema due to heart disease: diagnosis and outcome.

BACKGROUND: The purpose of this study was to determine whether baseline physical examination and history are useful in identifying patients with cardiac edema as defined by echocardiography, and to compare survival for patients with cardiac and noncardiac causes of edema. HYPOTHESIS: Physical examination and history data can help to identify patients with edema who have significant cardiac disease. METHODS: We reviewed the medical records of 278 consecutive patients undergoing echocardiography for evaluation of peripheral edema. We classified cardiac edema as the presence of any of the following: left ventricular ejection fraction < 45%, systolic pulmonary artery pressure > 45 mmHg, reduced right ventricular function, enlarged right ventricle, and a dilated inferior vena cava. RESULTS: The mean age of the 243 included patients was 67 +/- 12 years and 92% were male. A cardiac cause of edema was found in 56 (23%). Independent predictors of a cardiac cause of edema included chronic obstructive pulmonary disease (COPD, odds ratio [OR] 1.74, 95% confidence interval [CI] 1.14-2.60) and crackles (OR 1.98, 95% CI 1.26-3.10). The specificity for a cardiac cause of edema was high (91% for COPD, 93% for crackles); however, the sensitivity was quite low (27% for COPD, for 24% crackles). Compared with patients without a cardiac cause of edema, those with a cardiac cause had increased mortality (25 vs. 8% at 2 years, p < 0.01), even after adjustment for other characteristics (hazard ratio 1.55, 95% CI 1.08-2.24). CONCLUSIONS: A cardiac cause of edema is difficult to predict based on history and examination and is associated with high mortality.

Effects of dietary wheat bran fiber on rectal epithelial cell proliferation in patients with resection for colorectal cancers.

A preponderance of carcinogenesis studies in rodents and epidemiologic studies in humans suggests a potential role of dietary fiber in the prevention of colorectal cancer. Recently, wheat bran fiber used as a dietary supplement has been shown to decrease the growth of rectal adenomatous polyps in patients with familial polyposis; however, few studies of high-risk human populations have been attempted to determine the effects of dietary fiber supplementation on markers of carcinogenesis in the colon or rectum. We have designed a one-arm study to evaluate the effects of dietary supplementation with wheat bran fiber [i.e., 13.5 g/day for 8 wk; after 1 mo, 2 g/day (compliance evaluation period)] on [3H]thymidine rectal mucosa cell labeling (i.e., percent of epithelial cells incorporating [3H]thymidine into DNA in intact rectal crypt cells over a 90-min exposure as well as in minced rectal biopsy tissue over a 24-hr exposure) in rectal biopsy specimens. The biopsy specimens were obtained at sigmoidoscopy in 17 compliant patients with a history of resected colon or rectal cancer. We categorized patients as having initially low or initially high [3H]thymidine-labeling indices (i.e., percent of mucosa cells that incorporate [3H]thymidine into DNA during 1.5- or 24-hour in vitro incubations) by using the median baseline labeling index as a cutoff between high and low values. On the basis of a chi-square test used to identify patients with a statistically significant (P less than .001) change, six of the eight patients who initially had high 24-hour outgrowth labeling indices showed a significant decrease in the rectal mucosa biopsy specimens obtained after treatment. An overall 22% decrease was observed in rectal mucosa cell biopsy specimens obtained at study termination (P less than .001). Of the eight patients with initially high total [3H]thymidine-labeling indices in crypt organ culture, four had a significant (P less than .001) decrease from baseline values, one had a significant increase, and three showed no change following the fiber intervention. The wheat bran fiber dietary supplement of 13.5 g/day was well tolerated by this group of older (54-70 yr) patients. Although the [3H]-thymidine labeling index data suggest that the wheat bran fiber supplement can inhibit DNA synthesis and rectal mucosa cell proliferation in high-risk patients, the results of this small pilot study should not be overinterpreted vis à vis the potential role of wheat bran fiber as a chemopreventive agent for colorectal cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

Randomized, double-blinded, placebo-controlled study of effect of wheat bran fiber and calcium on fecal bile acids in patients with resected adenomatous colon polyps.

BACKGROUND: Ongoing epidemiologic and nutritional studies suggest that colorectal carcinogenesis is consistent with complex interactions between genetic susceptibility and environmental and dietary factors. Among the dietary components found to reduce colon cancer risk are high intakes of dietary fiber and calcium. PURPOSE: We designed and conducted a randomized, double-blinded, placebo-controlled trial involving supplementation of the customary dietary intake with fiber and calcium and measurements of fecal bile acids to examine the potential mechanisms by which added dietary interventions might reduce colorectal cancer risk. METHODS: In a randomized, double-blinded, phase II study, we used a factorial design to measure the effects of dietary wheat bran fiber (2.0 or 13.5 g/day) in the form of cereal and supplemental calcium carbonate (250 or 1500 mg/day elemental calcium) taken as a tablet on fecal bile acid concentrations and excretion rates. Measurements were made at base-line randomization (i.e., after a 3-month placebo run-in period using 2.0 g wheat bran fiber plus 250 mg calcium carbonate) and after 3 and 9 months on treatment in a randomly selected 52-patient subsample of the 95 fully assessable study participants who had a history of colon adenoma resection. Concentrations of fecal bile acids, total, primary (i.e., chenodeoxycholic and cholic), and secondary (i.e., deoxycholic, lithocholic, and ursodeoxycholic), were measured in 72-hour stool samples by gas-liquid chromatography. All P values resulted from two-sided tests. RESULTS: All geometric mean fecal bile acid concentrations and excretion rates were lower at 9 months than at 0 months or 3 months on treatment in the high-dose fiber, high-dose calcium, and high-dose fiber/high-dose calcium treatment groups. The high-dose fiber effect at 9 months of supplementation was statistically significant with respect to virtually all geometric mean fecal bile acid concentrations and excretion rates. For example at 9 months versus 0 months, high-dose fiber supplementation caused a reduction in fecal concentrations of total bile acids (52% reduction; P = .001) and deoxycholic acid (48% reduction; P = .003). High-dose calcium supplementation also had a significant, but lower, effect at 9 months versus 0 months on the geometric mean total bile acid (35% reduction; P = .044) and deoxycholic fecal bile acid (36% reduction; P = .052) concentrations. CONCLUSIONS: High-dose wheat bran fiber and calcium carbonate supplements given for 9 months are associated with statistically significant reductions in both total and secondary fecal bile acid concentrations and excretion rates in patients with resected colon adenomas. This study supports the hypothesis that one of the important ways in which a high intake of wheat bran fiber and calcium may reduce the risk of colorectal neoplasia and cancer is by reduction of the concentrations of fecal bile acids. IMPLICATION: Phase III studies of these agents in the prevention of adenoma recurrence are necessary to confirm this hypothesis and have now been initiated at multiple institutions.

Absence of cardioversion-induced ventricular arrhythmias in patients with therapeutic digoxin levels.

To determine the incidence of cardioversion-induced ventricular arrhythmias in patients with therapeutic serum levels of digoxin, 19 patients (average age [+/- standard deviation] 61 +/- 12 years) undergoing elective direct current cardioversion for atrial fibrillation were studied. Only patients with therapeutic serum digoxin levels (range 0.5 to 1.9 ng/ml; mean 1.1 +/- 0.5) at the time of cardioversion were included. Patients with acute myocardial ischemia or unstable angina, serious electrolyte disturbance or those requiring class I antiarrhythmic agents for control of ventricular or supraventricular arrhythmias were excluded. Ambulatory electrocardiograms were recorded for 24 hours before and 6 hours after cardioversion. No patient developed malignant ventricular arrhythmias (ventricular triplets or tachycardia) in the immediate 3 hour period after cardioversion. Furthermore, there were no significant (p less than 0.05) differences in the frequency of ventricular premature beats or couplets before and after cardioversion. To determine whether the level of serum digoxin or the strength of the applied shock had a significant effect on the development of postcardioversion arrhythmias, the change in frequency of single premature ventricular beats after cardioversion was compared with the serum digoxin level (ng/ml) and the applied energy level (joules) by means of linear regression analysis. There was no significant (p less than 0.05) relation between these variables. These findings suggest that patients with therapeutic serum levels of digoxin may safely undergo cardioversion without the concomitant use of class I antiarrhythmic agents.

Effect of beta-adrenergic blockade on exercise performance in patients with chronic atrial fibrillation.

Beta-adrenergic blocking agents are commonly used in combination with digitalis to control excessive heart rate during exercise in patients with chronic atrial fibrillation. However, little is known about the effect of beta-adrenergic blockade on exercise capacity in these patients. Accordingly, a randomized, double-blind, cross-over placebo-controlled study was performed to assess the efficacy of celiprolol, a new cardioselective beta-blocker with partial intrinsic sympathomimetic activity, on exercise performance in nine men with chronic atrial fibrillation. All but one patient was receiving maintenance digitalis during the study. Heart rate, blood pressure and gas exchange variables were measured at rest and during treadmill exercise testing while the patients were receiving maintenance celiprolol or placebo. Significant reductions in heart rate and systolic blood pressure compared with control values were observed at submaximal exercise, at the gas exchange anaerobic threshold and at maximal exertion while the patients were taking celiprolol. However, oxygen uptake at the gas exchange anaerobic threshold during celiprolol therapy was 12.3 versus 14.0 ml oxygen/kg per min during placebo administration (a 12% difference, p less than 0.01). Similarly, oxygen uptake at maximal exertion during celiprolol therapy was 17.6 versus 21.0 ml/kg per min during placebo administration (a 16% difference, p less than 0.01). Treadmill time was also reduced during the celiprolol phase compared with placebo (11.3 versus 10.3 minutes; a 19% difference, p less than 0.01). These results indicate that in patients with atrial fibrillation the major beneficial effects of beta-adrenergic blockade--reduced submaximal and maximal exercise heart rate and blood pressure--must be weighed against the decrease in exercise capacity.

Increased exercise capacity after digoxin administration in patients with heart failure.

Failure to objectively assess the effect of digitalis on exercise capacity has resulted in controversy regarding its use in patients with chronic congestive heart failure. To clarify this situation, maximal treadmill testing with respiratory gas exchange analysis was performed on 11 patients (mean age 57 +/- 9 years) with chronic congestive heart failure with and without digoxin therapy. Ten of the 11 had a consistent third sound gallop, and the mean ejection fraction of the group was 24 +/- 10%. Rest heart rate was significantly higher (91 +/- 16 versus 102 +/- 16 beats/min; p less than 0.05) and rest systolic blood pressure was significantly reduced in the absence of digoxin (130 +/- 23 versus 121 +/- 15 mm Hg; p less than 0.05). No differences in heart rate or blood pressure were observed during exercise. Significant increases in ventilatory oxygen uptake were observed with digoxin submaximally (3.0 mph, 0% grade), at the gas exchange anaerobic threshold and at maximal exercise (mean increase of 2.6 ml/kg per min; p less than 0.02). An improvement in the estimated ratio of ventilatory dead space to tidal volume (VD/VT), an index of physiologic efficiency, occurred throughout exercise during digoxin therapy, and there was a significant negative correlation between the change in maximal oxygen uptake and change in maximal estimated VD/VT (r = -0.63; p less than 0.05). Thus, digoxin therapy is associated with a significant improvement in exercise capacity in patients with chronic heart failure, most likely due to an improved matching of ventilation to perfusion.

Maximal exercise testing and gas exchange in patients with chronic atrial fibrillation.

To evaluate the response of patients with chronic atrial fibrillation to exercise, 50 men (mean age 65 +/- 8 years) with atrial fibrillation underwent a maximal exercise test using respiratory gas exchange techniques. Patients were classified by the presence (n = 29) or absence ("lone atrial fibrillation," n = 21) of underlying heart disease. Responses were evaluated at a standard submaximal work load (3.0 mph, [4.8 km/h] 0% grade), at the gas exchange anaerobic threshold and at maximal exercise. For all 50 patients, the mean maximal oxygen uptake was 20.6 ml/kg per min, which approximates 85% of the aerobic capacity predicted for age-matched normal individuals. Patients with lone atrial fibrillation demonstrated normal exercise capacity in contrast to patients with atrial fibrillation and known heart disease (22.7 +/- 5 versus 19.1 +/- 5.0 ml/kg per min, p less than 0.05). The mean maximal heart rate (176 +/- 30 beats/min) was approximately 20 beats/min higher than that expected for age, was extremely variable and accounted for only 8% of the variance in maximal oxygen uptake. Maximal heart rate in subjects with lone atrial fibrillation was higher than that of subjects with atrial fibrillation and known heart disease (189 +/- 32 versus 166 +/- 24 beats/min, p less than 0.01). Stepwise regression analysis revealed that maximal systolic blood pressure accounted for 19% of the variance in maximal oxygen uptake (VO2 max), suggesting that systolic function is an important determinant of exercise performance in atrial fibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Smallpox vaccination and myopericarditis: a clinical review.

Smallpox is a devastating viral illness that was eradicated after an aggressive, widespread vaccination campaign. Routine U.S. childhood vaccinations ended in 1972, and routine military vaccinations ended in 1990. Recently, the threat of bioterrorist use of smallpox has revived the need for vaccination. Over 450,000 U.S. military personnel received the vaccination between December 2002 and June 2003, with rates of non-cardiac complications at or below historical levels. The rate of cardiac complications, however, has been higher than expected, with two confirmed cases and over 50 probable cases of myopericarditis after vaccination reported to the Department of Defense Smallpox Vaccination Program. The practicing physician should use the history and physical, electrocardiogram, and cardiac biomarkers in the initial evaluation of a post-vaccination patient with chest pain. Echocardiogram, cardiac catheterization, magnetic resonance imaging, nuclear imaging, and cardiac biopsy may be of use in further workup. Treatment is with non-steroidal anti-inflammatory agents, four to six weeks of limited exertion, and conventional heart failure treatment as necessary. Immune suppressant therapy with steroids may be uniquely beneficial in myopericarditis related to smallpox vaccination, compared with other types of myopericarditis. If a widespread vaccination program is undertaken in the future, many more cases of post-vaccinial myopericarditis could be seen. Practicing physicians should be aware that smallpox vaccine-associated myopericarditis is a real entity, and symptoms after vaccination should be appropriately evaluated, treated if necessary, and reported to the Vaccine Adverse Events Reporting System.

Incidence and follow-up of inflammatory cardiac complications after smallpox vaccination.

OBJECTIVES: The purpose of this study was to assess the follow-up of patients with vaccinia-associated myocarditis. BACKGROUND: With the threat of biological warfare, the U.S. Department of Defense resumed a program for widespread smallpox vaccinations on December 13, 2002. One-year afterwards, there has been a significant increase in the occurrence of myocarditis and pericarditis among those vaccinated. METHODS: Cases were identified through sentinel reporting to military headquarters, systematic surveillance, and spontaneous reports. RESULTS: A total of 540,824 military personnel were vaccinated with a New York City Board of Health strain of vaccinia from December 2002 through December 2003. Of these, 67 developed myopericarditis at 10.4 +/- 3.6 days after vaccination. The ST-segment elevation was noted in 57%, mean troponin on admission was 11.3+/- 22.7 ng/dl, and peak cardiac enzymes were noted within 8 h of presentation. On follow-up of 64 patients (96%) at a mean of 32 +/- 16 weeks, all patients had objective normalization of echocardiography, electrocardiography, laboratory testing, graded exercise testing, and functional status; 8 (13%) reported atypical, non-limiting persistent chest discomfort. CONCLUSIONS: Post-vaccinial myopericarditis should be considered in patients with chest pain within 30 days after smallpox vaccination. Normalization of echocardiography, electrocardiography, and treadmill testing is expected, and nearly all patients have resolution of chest pain on follow-up.

Comparison of clinical presentation of acute myocarditis following smallpox vaccination to acute coronary syndromes in patients <40 years of age.

Smallpox vaccine-associated myopericarditis may have a similar presentation to acute coronary syndrome (ACS). The clinical records of 78 young patients (<40 years of age) presenting with ACS (n = 16) or myocarditis after smallpox vaccination (n = 62) were reviewed. Comparisons were made among clinical presentation, cardiac enzymes, echocardiographic findings, and electrocardiographic changes. The presence of cardiac risk factors or focal wall motion abnormalities on echocardiography were associated with a diagnosis of ACS. There was a trend toward earlier elevation of troponin-I and creatine kinase in patients with myocarditis compared with ACS.

Relation of QTc duration heterogeneity to mortality following orthotopic heart transplantation.

Studies of heart failure patients have demonstrated that serial QT prolongation and abnormally prolonged QT intervals are associated with greater mortality. Serial QT interval measurements in patients who undergo orthotopic heart transplantation (OHT) may quantify the degree of myocardial repolarization heterogeneity and serve as a marker of arrhythmogenic substrate. In this study, the mean survival for those with "stable" QT(c) intervals (a change of -10 to 10 ms/year) was 124 +/- 8 months versus 63 +/- 25 months in those with annual QT(c) changes of >10 ms (p = 0.009). Ventricular repolarization heterogeneity may serve as a marker of identifying high-risk patients after OHT.