[Constellations of findings and derived treatment interventions in telemedical monitoring of patients with heart failure, cardiac arrhythmia or increased risk for sudden cardiac death : Recommendations of the working group 33 telemonitoring of the German Cardiac Society]

The specification of standard operating procedures (SOPs) is a basic requirement for a successful implementation of telemonitoring with implanted cardiac devices and with external measuring devices in patients with heart failure, cardiac arrhytmia or increased risk of sudden cardiac death. The following article summarizes the possibilities of telemonitoring from a technical and organizational point of view and descibes basic requirements on SOPs. these basic requirements should be further specified and anchored in the organizational structure of the individual telemonitoring concept. Moreover, they should de understood as a basic guideline fpr the actions of telemonitoring center (TMC) employees.

[Is heart rate adequately controlled in chronic systolic heart failure patients in Germany? results from a nationwide survey (INDICATE)]

BACKGROUND

Elevated resting heart rate is associated with increased morbidity and mortality in patients with chronic systolic heart failure (CHF). Lowering of heart rate improves cardiovascular outcome in these patients. Therefore, heart rate reduction is an important element of therapeutic management and consistently reflected in current European guidelines for heart failure. Methods: The INDICATE study was initiated as a multicenter nationwide cross-sectional survey aiming to analyze the current quality of care in outpatients with CHF (documented left ventricular systolic dysfunction) in Germany. 20 consecutive patients were to be included in the survey from February until June 2012 by 793 cardiologic private practices. Detailed documentation of each patient was performed using a standardized questionnaire.

RESULTS

CHF was known for more than 6 months in 88 % of the 15 148 included patients. Mean heart rate in the study population was 73 ± 13 min⁻¹. In 42 % of patients the heart rate was ≥ 75 min⁻¹. 86 % were treated with betablockers. However, higher doses of betablockers were not associated with lower resting heart rate. 27 % of patients remained on heart rates ≥ 75 min⁻¹ although receiving at least 50 % of betablocker target dose.

CONCLUSION

INDICATE reveals a considerable proportion of outpatients with CHF showing an elevated heart rate despite beta blockade - irrespective of applied dose. These results emphasize the importance of optimizing the pharmacological management of resting heart rate according to guidelines in these patients.

[Differentiated antiplatelet therapy for acute coronary syndromes]

Dual antiplatelet therapy is the cornerstone of maintenance medication following invasive treatment of patients with acute coronary syndromes (ST elevation myocardial infarction, non-ST elevation myocardial infarction, unstable angina). Over the last decade, P2Y12 inhibition in addition to low-dose acetylsalicylic acid has been intensively debated. The debate was enriched by the results of the large phase III clinical trials for prasugrel (TRITON) and ticagrelor (PLATO) compared to clopidogrel in patients with acute coronary syndromes. This article summarizes the critical details und subanalyses of both study programmes and highlights on clinical decision making when using the three P2Y12 blockers in acute coronary syndromes. A special focus is on higher risk patients such as those with ST elevation myocardial infarction and those with coexisting diabetes, but also on minimizing relevant bleedings, which are common during more intense platelet inhibition.

Increased adherence after switch from twice daily calcineurin inhibitor based treatment to once daily modified released tacrolimus in heart transplantation: a pre-experimental study

BACKGROUND

Modified release tacrolimus (TAC) is a new, once-daily oral formulation of the established immunosuppressive agent TAC. Simplification of regimen has been associated with better adherence. This study evaluated patient adherence, as well as safety and efficacy among chronic stable heart transplantation (HT) patients switched from a conventional twice daily calcineurin inhibitor-based regimen (TAC or cyclosporine A [CsA]) to (once daily) modified release TAC.

METHODS

We switched 54 chronic stable patients (41 males and 13 females) from twice daily dosing with conventional TAC or CsA to once daily dosing with modified release TAC. Self-reported adherence was assessed at baseline and at 4 months after the switch using the Basel Assessment of Adherence with Immunosuppressive Medication Scale [BAASIS]), a 4-item validated questionnaire including also a Visual Analogue Scale (VAS). Nonadherence was defined as any self-reported nonadherence on any item.

RESULTS

Modified release TAC was discontinued in 4 patients because of diarrhea (n = 1) or gastrointestinal discomfort (n = 3) leaving 50 evaluable patients. Overall nonadherence at baseline for any of the 4 items was 74% versus 38% after 4 months (P = .0001). Thereafter, adherence improved in 28 patients (56.0%), was unchanged in 18 (36.0%), and decreased in 4 subjects (8.0%). The VAS score improved from 82.3% ± 2.6% to 97.5% ± 4.8% (P < .0001). No significant changes were observed after 4 months regarding hematologic, renal, or liver function parameters (all P = NS).

CONCLUSIONS

Therapeutic regimens for transplant recipients are often complex, contributing to a high incidence of medication nonadherence. This study in chronic, stable, heart transplantation patients demonstrated a significant improvement in patient adherence after a switch to modified release TAC, which was generally well tolerated.

Exercise reduces airway sodium ion reabsorption in cystic fibrosis but not in exercise asthma

When ventilating large volumes of air during exercise, airway fluid secretion is essential for airway function. Since these are impaired in cystic fibrosis and exercise-induced asthma, it was the aim of this study to determine how exercise affects airway Na(+) and Cl(-) transport and whether changes depend on exercise intensity. Nasal potential was measured in Ringer's solution, with amiloride to block Na(+) transport, and in low chloride-containing isoproterenol to assess Cl(-) channels. Nasal potential was measured at rest and during submaximal and maximal bicycle ergometer exercise in individuals with cystic fibrosis, exercise-induced asthma and controls. At rest, nasal potential was significantly higher in cystic fibroses than in the others. Maximal exercise decreased nasal potentials in cystic fibrosis and controls but not in exercise asthma. Submaximal exercise decreased nasal potentials only in cystic fibrosis. Cl(-) transport was not affected. Our results indicate that nasal potentials and Na(+) transport were decreased by maximal exercise in healthy and cystic fibrosis, whereas submaximal exercise decreased potentials in cystic fibrosis only. Exercise did not affect nasal potentials in asthmatics. Decreased reabsorption during exercise might favour airway fluid secretion during hyperpnoea. This protective effect appears blunted in patients with exercise-induced asthma.

[Telemedicine--ready for use in the cardiological field?]

The changes in the demographic structure, the increasing multi-morbidity in connection with a rise in the number of chronic illnesses and the absence of an effective coordination of the different levels of health care services with its discontinuous processes and redundancies will increase the economic burdens in the health care system. The latest developments and appropriate logistic premises nowadays offer a realistic basis for implementing telemonitoring as a central service and information tool as well as an instrument controlling the information- and data-flow between patient, hospital and medical practitioner.

Gender and age related predictive value of walk test in heart failure: Do anthropometrics matter in clinical practice?

BACKGROUND

The six-minute walk test (6 WT) is a valid and reliable predictor of morbidity and mortality in chronic heart failure (CHF) patients, frequently used as an endpoint or target in clinical trials. As opposed to spiroergometry, improvement of its prognostic accuracy by correction for height, weight, age and gender has not yet been attempted comprehensively despite known influences of these parameters.

METHODS

We recorded the 6 WT of 1035 CHF patients, attending clinic from 1995 to 2005. The 1-year prognostic value of 6 WT was calculated, alone and after correction for height, weight, BMI and/or age. Analysis was performed on the entire cohort, on males and females separately and stratified according to BMI (<25, 25-30 and >30 kg/m(2)).

RESULTS

6 WT weakly correlated with age (r=-0.32; p<0.0001), height (r=0.2; p<0.0001), weight (r=0.11; p<0.001), not with BMI (r=0.01; p=ns). The 6 WT was a strong predictor of 1-year mortality in both genders, both as a single and age corrected parameter. Parameters derived from correction of 6 WT for height, weight or BMI did not improve the prognostic value in univariate analysis for either gender. Comparison of the receiver operated characteristics showed no significant gain in prognostic accuracy from any derived variable, either for males or females.

CONCLUSION

The six-minute walk test is a valid tool for risk prediction in both male and female CHF patients. In both genders, correcting 6 WT distance for height, weight or BMI alone, or adjusting for age, does not increase the prognostic power of this tool.

Prognostic impact of peakVO2-changes in stable CHF on chronic beta-blocker treatment

BACKGROUND

Peak oxygen uptake (pVO2) is used for risk stratification in chronic heart failure (CHF), but little is known about the prognostic impact of pVO2-changes in patients on chronic beta-blocker (BBL) therapy. We therefore prospectively evaluated individual pVO2-changes at a 6-month interval in patients all receiving BBL.

METHODS

194 patients with stable CHF on stable medication were included (V1) and underwent clinical evaluation and exercise testing. Testing was repeated (V2) at 5.7+/-1.5 months after V1 and patients were followed >12 months after V2. Death or hospitalisation due to cardiac reasons was the predefined EP (EPP, end-point positive; n=62; EPN, end-point negative; n=113).

RESULTS

Initial characteristics did not differ between EPP and EPN. Multivariate cox regression analysis revealed that change of pVO2 (EPP: -0.6+/-2.6 ml/kg min; EPN: +2.5+/-3.3 ml/kg min; p<0.001) was independent to pVO2, LVEF, NTproBNP and NYHA at V2 for prediction of the combined end-point during follow-up. An increase of pVO2 by 10% was identified as an adequate cut-off value for risk stratification and ROC-analysis showed the significant incremental prognostic value of the determination of pVO2 changes in combination with pVO2.

CONCLUSIONS

Serial measurements of pVO2 yield additional information for risk stratification in clinically homogenous CHF patients receiving BBL. This is the first study demonstrating this fact within a narrow predefined interval with all patients on BBL.

[Telemonitoring in chronic heart failure patients. Which diagnostic finding prevents hospital readmission?]

Heart failure exhibits a significant clinical and health economic problem. The implementation of new therapeutic strategies favorably affecting the course of disease is still insufficient in day-to-day practice. Thus, the usage of telemedicine offers a central instrument for service and information, so that an optimized therapy can be achieved by consequent surveillance of the patient with chronic heart disease. Predefined vital parameters are automatically transmitted to the telemedicine center; if individually predefined limits are exceeded, therapeutic means are immediately initiated. For the patient, the center is attainable 24 h throughout the year in case he experiences cardio-pulmonary symptoms. This patient-oriented usage of technology should not replace the physician-patient relationship, but improves and supports the participation and self-management of patients. Furthermore, the results show that this technology can significantly reduce the amount of emergency physician services, hospital admissions and primary care physician visits, and displays for health economics purposes a clearly more cost-effective treatment strategy, while allowing for additional costs inherent to the system. The usage of telemonitoring in chronic heart failure patients may be a trendsetting form of care, which can be used to drastically optimize the information and data flow between patient, hospital and primary care physician individually and at any time.

Heart rate variability enhances the prognostic value of established parameters in patients with congestive heart failure

This prospective study evaluated whether heart rate variability (HRV) assessed from Holter ECG has prognostic value in addition to established parameters in patients with congestive heart failure (CHF). The study included 222 patients with CHF due to dilated or ischemic cardiomyopathy (left ventricular ejection fraction LVEF 21+/-1%; mean+/-SEM). During a mean follow-up of 15+/-1 months, 38 (17%) patients died and 45 (20%) were hospitalized due to worsening of CHF. The HRV parameter SDNN (standard deviation of all intervals between normal beats) was significantly lower in non-surviving or hospitalized than in event-free patients (118+/-6 vs 142+/-5 ms), as were LVEF (18+/-1 vs 23+/-1%), and peak oxygen uptake during exercise (peak VO(2)) (12.8+/-0.5 vs 15.6+/-0.5 ml/min/kg). While each of these parameters was a risk predictor in univariate analysis, multivariate analysis revealed that HRV provides both independent and additional prognostic information with respect to the risk 'cardiac mortality or deterioration of CHF'. It is concluded that the determination of HRV enhances the prognostic power given by the most widely used parameters LVEF and peak VO(2) in the prediction of mortality or deterioration of CHF and thus enables to improve risk stratification.

Health related quality of life in patients with congestive heart failure: comparison with other chronic diseases and relation to functional variables

OBJECTIVE

To assess health related quality of life of patients with congestive heart failure; to compare their quality of life with the previously characterised general population and in those with other chronic diseases; and to correlate the different aspects of quality of life with relevant somatic variables.

SETTING

University hospital.

PATIENTS AND DESIGN

A German version of the generic quality of life measure (SF-36) containing eight dimensions was administered to 205 patients with congestive heart failure and systolic dysfunction. Cardiopulmonary evaluation included assessment of New York Heart Association (NYHA) functional class, left ventricular ejection fraction, peak oxygen uptake, and the distance covered during a standardised six minute walk test.

RESULTS

Quality of life significantly decreased with NYHA functional class (linear trend: p < 0.0001). In NYHA class III, the scores of five of the eight quality of life domains were reduced to around one third of those in the general population. The pattern of reduction was different in patients with chronic hepatitis C and major depression, and similar in patients on chronic haemodialysis. Multiple regression analysis showed that only the NYHA functional class was consistently and closely associated with all quality of life scales. The six minute walk test and peak oxygen uptake added to the explanation of the variance in only one of the eight quality of life domains (physical functioning). Left ventricular ejection fraction, duration of disease, and age showed no clear association with quality of life.

CONCLUSIONS

In congestive heart failure, quality of life decreases as NYHA functional class worsens. Though NYHA functional class was the most dominant predictor among the somatic variables studied, the major determinants of reduced quality of life remain unknown.

Do cytokines enable risk stratification to be improved in NYHA functional class III patients? Comparison with other potential predictors of prognosis

AIMS

Elevated plasma levels of proinflammatory cytokines have been reported in patients with congestive heart failure. The purpose of this study was to assess whether cytokines improve risk stratification in a homogeneous group of NYHA class III patients with a left ventricular ejection fraction <40%.

METHODS AND RESULTS

Plasma concentrations of big endothelin, tumour necrosis factor alpha, interleukins -1, -6, -10 and -12, sCD14 and GM-CSF were measured by ELISA in 91 NYHA III patients [mean (SD) age: 55 (10) years, 69% male, 34% coronary artery disease, 66% dilated cardiomyopathy] with a left ventricular ejection fraction and a peak oxygen uptake (peak VO2) of 19 (9)% and 12.1 (3.6) ml x min(-1) x kg(-1), respectively. During follow-up [22 (13) months], 31 patients (34%) died due to cardiovascular causes. In non-survivors, interleukin-6 was twice as high as in survivors [12.8 (16.9) pg x ml(-1)vs 5.6(5.3) pg x ml(-1), P<0.003], whereas plasma concentrations of the other cytokines showed no significant differences. Concerning long-term survival (> or =1 year), multivariate Cox regression analysis revealed an independent prognostic power for interleukin-6, which was further improved by combining with left ventricular ejection fraction and peak VO2, while for short-term survival (up to 6 months) interleukin-6 did not allow risk stratification.

CONCLUSION

In NYHA class III patients, plasma concentrations of interleukin-6 are predictive of long-term survival. However, its value may be limited for clinical decision-making for cardiac transplantation (short-term survival).

Risk stratification in middle-aged patients with congestive heart failure: prospective comparison of the Heart Failure Survival Score (HFSS) and a simplified two-variable model

AIMS

The performance of a US-American scoring system (Heart Failure Survival Score, HFSS) was prospectively evaluated in a sample of ambulatory patients with congestive heart failure (CHF). Additionally, it was investigated whether the HFSS might be simplified by assessment of the distance ambulated during a 6-min walk test (6'WT) instead of determination of peak oxygen uptake (peak VO(2)).

METHODS AND RESULTS

In 208 middle-aged CHF patients (age 54+/-10 years, 82% male, NYHA class 2.3+/-0.7; follow-up 28+/-14 months) the seven variables of the HFSS: CHF aetiology; heart rate; mean arterial pressure; serum sodium concentration; intraventricular conduction time; left ventricular ejection fraction (LVEF); and peak VO(2), were determined. Additionally, a 6'WT was performed. The HFSS allowed discrimination between patients at low, medium and high risk, with mortality rates of 16, 39 and 50%, respectively. However, the prognostic power of the HFSS was not superior to a two-variable model consisting only of LVEF and peak VO(2). The areas under the receiver operating curves (AUC) for prediction of 1-year survival were even higher for the two-variable model (0.84 vs. 0.74, P<0.05). Replacing peak VO(2) with 6'WT resulted in a similar AUC (0.83).

CONCLUSION

The HFSS continued to predict survival when applied to this patient sample. However, the HFSS was inferior to a two-variable model containing only LVEF and either peak VO(2) or 6'WT. As the 6'WT requires no sophisticated equipment, a simplified two-variable model containing only LVEF and 6'WT may be more widely applicable, and is therefore recommended.

d,l-sotalol enhances baroreflex sensitivity in conscious rats surviving acute myocardial infarction

The aim of the present study was to characterize the influence of D,L-sotalol on arterial baroreflex sensitivity (BRS) which is generally considered as an estimate of vagal activity and has prognostic value in patients after myocardial infarction (MI). Conscious rats were studied 3 days after left anterior descending coronary artery ligation (n= 5) or sham-operation (SH, n= 6). BRS was determined by linear regression analysis of the RR-interval (interval between heart beats) and mean arterial pressure changes evoked by i.v. bolus injections of methoxamine (inducing reflex bradycardia, RB) and nitroprusside (inducing reflex tachycardia, RT). In MI-rats heart rate and mean arterial pressure were not significantly different from values in SH-rats, left ventricular end-diastolic pressure was increased and contractility was depressed. The BRS (RB: MI: 0.48 +/- 0.04(*), SH: 0.79 +/- 0.08; RT: MI: 0.41 +/- 0.05(*), SH: 0.86 +/- 0.08 ms mmHg(-1)) ((*)P< 0.05 vs SH) was markedly reduced. d, l -Sotalol (1.5 mg kg(-1)i.v.) reduced heart rate (MI: -11 +/- 3 %(*), SH: -11 +/- 3 %(*)) and mean arterial pressure only moderately [MI: -6 +/- 4 %(n.s.), SH: -7 +/- 2 %(*)], while BRS depression in MI-rats was completely neutralized [RB: MI: 1.08 +/- 0.14(*), SH: 1.19 +/- 0.11(*); RT: MI: 0.84 +/- 0.08(*), SH: 0.88 +/- 0.12 (n.s.) ms mmHg(-1)] ((*)P< 0.05 vs pretreatment). The BRS is reduced in rats early after MI, indicating a depressed reflex vagal activity. Treatment with D,L-sotalol at a dose with little effect on heart rate and mean arterial pressure markedly enhances and, thus, restores BRS in MI-rats. These data suggest that D,L-sotalol has both peripheral and central effects leading to an increase of reflex vagal control of heart rate in rats.

Respiratory muscle dysfunction in congestive heart failure: clinical correlation and prognostic significance

BACKGROUND

In congestive heart failure (CHF), the prognostic significance of impaired respiratory muscle strength has not been established.

METHODS AND RESULTS

Maximal inspiratory pressure (Pi(max)) was prospectively determined in 244 consecutive patients (207 men) with CHF (ischemic, n=75; idiopathic dilated cardiomyopathy, n=169; age, 54+/-11 years; left ventricular ejection fraction [LVEF], 22+/-10%). Pi(max) was lower in the 244 patients with CHF than in 25 control subjects (7.6+/-3.3 versus 10.5+/-3.7 kPa; P=0.001). The 57 patients (23%) who died during follow-up (23+/-16 months; range, 1 to 48 months) had an even more reduced Pi(max) (6.3+/-3.2 versus 8.1+/-3.2 kPa in survivors; P=0.001). Kaplan-Meier survival curves differentiated between patients subdivided according to quartiles for Pi(max) (P=0.014). Pi(max) was a strong risk predictor in both univariate (P=0.001) and multivariate Cox proportional hazard analyses (P=0.03); multivariate analyses also included NYHA functional class, LVEF, peak oxygen consumption (peak VO(2)), and norepinephrine plasma concentration. The areas under the receiver-operating characteristic curves for prediction of 1-year survival were comparable for Pi(max) and peak VO(2) (area under the curve [AUC], 0.68 versus 0.73; P=0.28), and they improved with the triple combination of Pi(max), peak VO(2), and LVEF (AUC, 0.82; P=0.004 compared with AUC of Pi(max)).

CONCLUSIONS

In patients with CHF, inspiratory muscle strength is reduced and emerges as a novel, independent predictor of prognosis. Because testing for Pi(max) is simple in clinical practice, it might serve as an additional factor to improve risk stratification and patient selection for cardiac transplantation.

Prognostic value of Doppler echocardiographic mitral inflow patterns: implications for risk stratification in patients with chronic congestive heart failure

OBJECTIVES

This prospective study tested whether transmitral flow patterns add incremental value to peak oxygen consumption (VO2) in determining the prognosis of patients with chronic congestive heart failure (CHF) and systolic dysfunction.

BACKGROUND

Peak VO2 is an objective marker of functional capacity and is routinely used as a criterion to identify heart transplant candidates. Diastolic dysfunction limits functional capacity, but its prognostic importance relative to that of peak VO2 is unknown.

METHODS

Peak VO2 and mitral inflow velocities were prospectively measured in 311 consecutive patients (mean age 54 years, 84% male) with impaired left ventricular function (ejection fraction <40%; 88 patients with ischemic and 223 with dilated cardiomyopathy) who were evaluated for heart transplant candidacy.

RESULTS

During a mean follow-up period of 512 +/- 314 days, 65 patients died and 43 patients underwent heart transplantation. Diastolic filling patterns, peak VO2 and left ventricular end-diastolic diameters were independent predictors of cardiac mortality. In patients with peak VO2 < or = 14 ml/min per kg body weight, the outcome was markedly poorer in the presence of restrictive filling patterns as compared with their absence (two-year survival rate 52% vs. 80%). Similarly, despite peak VO2 levels >14 ml/min per kg, the outcome was less favorable in the presence of restrictive filling patterns (two-year survival rate 80% vs. 94%). A risk-stratification model based on the identified independent noninvasive predictors separated groups into those with high (93%), intermediate (65%) and low (39%) two-year survival rates.

CONCLUSIONS

Transmitral flow patterns add incremental value to peak VO2 in determining the prognosis of patients with CHF and impaired systolic function.

Inefficient ventilation and reduced respiratory muscle capacity in congestive heart failure

The extent and time-course of changes in lung volumes, ventilatory efficiency at rest and during exercise, and respiratory muscle function and their influence on exercise limitation in congestive heart failure (CHF) are unclear. It is unknown whether respiratory muscle function may predict changes in exercise limitation or may be impaired in patients with poor outcome. 145 male patients (54 +/- 1 years) suffering from CHF (NYHA class I-III, mean 2.3 +/- 0.1), with a LVEF of 23 +/- 1%, and a mean peak O2 uptake (VO2peak) 15.0 +/- 0.5 mL X min(-1) X kg(-1), were studied. They were grouped in Weber functional classes A to D according to their VO2peak. Significant increases in ventilatory equivalents for O2 and CO2 (VE/VCO2peak) and in dead space ventilation at rest and during exercise were found with increasing exercise limitation. Moreover, there was a correlation of static and dynamic lung volumes (inspiratory vital capacity, IVC, r = 0.43, P < 0.01), as well as of maximal inspiratory pressure (MIP; r = 0.46, P < 0.01) with VO2peak. Patients who died (n = 26) or were heart transplanted (n = 20) during a follow-up (mean 800 +/- 10 days) had a reduced MIP (6.4 +/- 0.4 kPa) as compared with survivors (n = 82; 9.3 +/- 0.7 kPa, P < 0.01). In a subgroup of 33 patients re-evaluated after six months, individual changes in IVC and VE/CO2peak, but not in MIP, correlated to changes in VO2peak (r = 0.69 and r = 0.72 respectively; P < 0.01). In CHF, exercise limitation is associated with reversible lung restriction and inefficient ventilation at rest and during exercise. Patients with severe CHF have a significant reduction in MIP, a finding that is associated with poor outcome.

Is the 6-minute walk test a reliable substitute for peak oxygen uptake in patients with dilated cardiomyopathy?

AIMS

The 6-min walk test may serve as a more simple clinical tool to assess functional capacity in congestive heart failure than determination of peak oxygen uptake by cardiopulmonary exercise testing. The purpose of the study was to prospectively examine whether the distance ambulated during a 6-min walk test (i) correlates with peak oxygen uptake, (ii) allows peak oxygen uptake to be predicted, and (iii) provides prognostic information similar to peak oxygen uptake in patients with dilated cardiomyopathy and left ventricular ejection fraction < or = 35%.

METHODS AND RESULTS

In 113 patients (age: 54+/-12 years, NYHA: 2.2+/-0.8) with dilated cardiomyopathy (left ventricular ejection fraction 19+/-7%) a 6-min walk test and cardiopulmonary exercise testing were performed. The 6-min walk test and peak oxygen uptake were closely correlated at the initial visit (r=0.68, n=113), as well as after 263+/-114 (r=0.71, n=28) and 381+/-170 days (r=0.74, n=14). During serial exercise testing the 6-min walk test allowed peak oxygen uptake to be reliably predicted (r=0.76 between calculated and real peak oxygen uptake). After 528+/-234 days, 42 patients were hospitalized due to worsening heart failure and/or died from cardiovascular causes. Compared to clinically stable patients, these 42 patients walked a shorter distance (423+/-104 vs 501+/-95 m, P<0.001) and had a lower peak oxygen uptake (12.7+/-4.0 vs 17.4 + 5.6 ml x min(-1) x kg(-1), P<0.001). By univariate analysis the 6-min walk test outperformed other prognostic parameters such as left ventricular ejection fraction, cardiac index and plasma norepinephrine concentration and conferred a prognostic power similar to peak oxygen uptake. This predictive value could be further improved in a multivariate model, by combining the 6-min walk test with independent variables, such as left ventricular ejection fraction or cardiac index.

CONCLUSION

The 6-min walk test correlated with peak oxygen uptake when tested serially over the course of the disease. Although both tests define two distinct domains of functional capacity, the 6-min walk test provides prognostic information very similar to peak oxygen uptake in congestive heart failure patients with dilated cardiomyopathy.

The bradycardic agent zatebradine enhances baroreflex sensitivity and heart rate variability in rats early after myocardial infarction

OBJECTIVE

The bradycardic agent zatebradine (UL-FS 49) reduces heart rate without negative inotropic or proarrhythmic effects. The aim was to experimentally characterize the influence of zatebradine on arterial baroreflex sensitivity (BRS) and heart rate variability (HRV) which are generally considered as estimates of vagal activity and have prognostic value in patients after myocardial infarction (MI).

METHODS

Conscious rats were studied 3 days after left coronary artery ligation or sham-operation (SH). BRS was determined by linear regression analysis of RR-interval and mean arterial pressure changes evoked by intravenous (i.v.) injections of methoxamine and nitroprusside. HRV at rest was calculated from high-resolution electrocardiogram-recordings.

RESULTS

In MI-rats heart rate was similar to SH-rats, mean arterial pressure was lower and both BRS and HRV were markedly reduced. Zatebradine (0.5 mg/kg i.v.) reduced heart rate in MI-rats from 400 +/- 15 to 350 +/- 19 and in SH-rats from 390 +/- 19 to 324 +/- 6 beats/min without changing mean arterial pressure. Both BRS and HRV were restored in MI- and further increased in SH-rats by the drug. Effects of 0.05, 0.5 and 5 mg/kg zatebradine revealed a dose-dependency of heart rate reduction. The lowest dose enhanced reflex bradycardia despite little effect on heart rate and lack of effect on both reflex tachycardia and HRV.

CONCLUSIONS

Both BRS and HRV are reduced in rats early after MI, indicating a depressed reflex and tonic vagal activity. Treatment with zatebradine enhances both BRS and HRV. These data suggest that the drug has both peripheral and central effects, leading to an increase of vagal control of heart rate.

[The 6 minute walking test: a cost-effective alternative to spiro-ergometry in patients with chronic heart failure?]

In contrast to the often debated NYHA classification, the determination of peak oxygen uptake (peak VO2) by cardiopulmonary exercise testing allows an objective assessment of the exercise capacity of patients with congestive heart failure (CHF). However, cardiopulmonary exercise testing is a time consuming and costly diagnostic tool, which requires sophisticated equipment and specially trained personel. Exercise capacity can also be determined by the 6 minute walk test. This test simply measures the distance covered by strong walking on a hallway level within 6 minutes. The 6 minute walk test is a submaximal exercise test, which is associated with much smaller increments in heart rate, blood pressure and plasma catecholamines than cardiopulmonary exercise testing. It is characterized by a very small intraindividual variance. Furthermore, it can be easily performed and, due to low logistic and personal requirements, it is very cost effective. The results of the 6 minute walk test--as well as of cardiopulmonary exercise testing--are influenced by extracardial exercise-limiting disorders, such as pulmonary diseases. Independent from the etiology of CHF, the results of the 6 minute walk test are closely related to peak VO2. In serial exercise testing the distance covered within 6 minutes allow to predict the individual peak VO2. Like peak VO2 the 6 minute walk test has been shown to be a predictor of morbidity and mortality in CHF, with its predictive value being independent from left ventricular ejection fraction and other potential prognostic parameters. In CHF patients a walking distance < 300 m is associated with a one-year-mortality of up to 50%, whereas the one-year-mortality in patients reaching a walking distance > 450 m amounts to only a few percent. In addition, the hospitalization rate of patients reaching a walking distance of < 300 m is several fold higher than in those with a walking distance > or = 450 m. Like cardiopulmonary exercise testing, the 6 minute walk test allows to control the efficiency of specific treatments and to monitor the natural course of the disease. The 6 minute walk test is, thus, a cost effective alternative to cardiopulmonary exercise testing in CHF patients. However, neither the 6 minute walk test alone nor the results of cardiopulmonary exercise testing alone are sufficient for selecting patients, e.g., for cardiac transplantation, as each individual case requires a synopsis of all relevant facts and parameters.

Characterization of a novel Hodgkin cell line, HD-MyZ, with myelomonocytic features mimicking Hodgkin's disease in severe combined immunodeficient mice

A novel Hodgkin cell line, designated HD-MyZ, was established from the pleural effusion of a 29-yr-old patient with Hodgkin's disease (HD) of nodular sclerosing type. The majority of cells grow adherently and display typical morphological characteristics of Reed-Sternberg (RS) and Hodgkin (H) cells, i.e., large multi- and mononucleated cells with prominent nucleoli. Immunofluorescence analysis revealed a myelomonocytoid immunophenotype (expression of CD13 and CD68, and lack of lymphoid markers). HD-MyZ cells strongly expressed restin, a recently described intermediate filament-associated protein, the expression of which is restricted to H cells, RS cells, and in vitro cultivated peripheral blood monocytes. In addition mRNA expression of c-fms (colony-stimulating factor 1 receptor) could be induced in HD-MyZ cells by phorbol myristate acetate (PMA) stimulation. Southern blot analysis did not detect rearrangement of T cell receptor beta and immunoglobulin H loci, thus demonstrating the lack of lymphoid commitment. HD-MyZ cells were also devoid of Epstein-Barr virus genomes. HD-MyZ cells constitutively express mRNAs for interleukin 1 alpha (IL-1 alpha), IL-1 beta, IL-5, IL-6, IL-7, IL-8, IL-10, IL-1 receptor (type I), and IL-6 receptor. Stimulation of cells with PMA increased mRNA expression as well as the secretion of IL-1 beta, IL-6, and IL-8, and induced the de novo expression of IL-8 receptors. Xenotransplantation into severe combined immunodeficient (SCID) mice by intravenous or subcutaneous inoculation led to development of disseminated tumors with infiltrative and destructive growth. In addition lymphadenopathy, pleural effusion, and infiltration of spleen were observed. Morphological and immunological analysis of tumor cells revealed the same features as HD-MyZ cells. This cell line might be an important tool for understanding the pathogenesis and biology of HD. In addition the SCID mice model might prove helpful in developing new therapeutic strategies.

APO-1 mediated apoptosis or proliferation in human chronic B lymphocytic leukemia: correlation with bcl-2 oncogene expression

We studied induction of apoptosis in several human malignant B cells from chronic lymphocytic leukemias (BCLL) by triggering the APO-1 antigen. The APO-1 antigen was found to be expressed on the surface of malignant B cells. In BCLL cells from most patients, APO-1 antigen expression increased following in vitro activation by Staphylococcus aureus Cowan I (SAC) or interleukin-2 (IL-2). In certain cases of BCLL co-stimulation with SAC plus IL-2 resulted in a synergistic up-regulation of the APO-1 antigen on the cell surface and prepared BCLL cells for monoclonal antibody anti-APO-1 mediated apoptosis. Interestingly, bcl-2 mRNA expression decreased upon stimulation with SAC plus IL-2, whereas SAC or IL-2 alone did not affect the level of bcl-2 expression. Thus, in these BCLL cells induction of anti-APO-1-mediated apoptosis appeared to be correlated with bcl-2 mRNA down-regulation. One informative BCLL, however, with a similar pattern of APO-1-antigen expression, did not show SAC plus IL-2-dependent bcl-2 down-regulation. Surprisingly, these cells proliferated in response to anti-APO-1 only when cells were co-stimulated with SAC plus IL-2. Our data suggest that down-regulation of bcl-2 prepares BCLL cells for induction of APO-1-mediated apoptosis. In addition they demonstrate that triggering of the APO-1 antigen may also lead to the induction of proliferation in special cases of BCLL.