C. Opasich

Peak Exercise Oxygen Consumption in Chronic Heart Failure: Toward Efficient Use in the Individual Patient

OBJECTIVESnThis study sought to 1) assess the short-, medium-and long-term prognostic power of peak oxygen consumption (VO2) in patients with heart failure; 2) verify the consistency of a nonmeasurable anaerobic threshold (AT) as a criterion of nonapplicability of peak VO2; 3) develop simple rules for the efficient use of peak VO2 in individualized prognostic stratification and clinical decision making.nnnBACKGROUNDnPeak VO2, when AT is identified, is among the indicators for heart transplant eligibility. However, in clinical practice the application of defined peak VO2 cutoff values to all patients could be inappropriate and misleading.nnnMETHODSnSix hundred fifty-three patients consecutively considered for eligibility for heart transplantation were followed up. Outcomes (cardiac death and urgent transplantation) were determined when all survivors had a minimum of 6 months of follow-up.nnnRESULTSnContraindication to the exercise test identified very high risk patients. The relatively small sample of women did not allow inferences to be drawn. In men, peak VO2 stratified into three levels (< or = 10, 10 to 18 and >18 ml/kg per min) identified groups at high, medium and low risk, respectively. The prognostic power of peak VO2 < or = 10 ml/kg per min was maintained even when the AT was not detected. In patients in New York Heart Association functional class III or IV, peak VO2 did not have prognostic power. In patients in functional class I or II, peak VO2 stratification was prognostically valuable, but less so at 6 than at 12 or 24 months. Age did not influence peak VO2 prognostic stratification.nnnCONCLUSIONSnA contraindication to exercise testing should be considered a priority for listing patients for heart transplantation. Only in less symptomatic male patients does a peak VO2 < or = 10 ml/kg per min identify short-, medium- and long-term high risk groups. A peak VO2 >18 ml/kg per min implies good prognosis with medical therapy.

Concomitant factors of decompensation in chronic heart failure.

The concomitant factors implicated in 328 nonfatal decompensations of 304 patients with congestive heart failure were: arrhythmias in 24%, infections in 23%, poor compliance in 15%, angina in 14%, iatrogenic factors in 10%, and other causes in 5% of cases. New York Heart Association class and right atrial pressure significantly related to the occurrence of decompensation. Poor compliance and angina were unpredictable, infection was related to pulmonary wedge pressure, iatrogenic factors were predicted by the more advanced functional classes, whereas arrhythmias were more frequent in patients with renal failure.

Reproducibility of the six-minute walking test in patients with chronic congestive heart failure: Practical implications

This study assesses the reproducibility of the 6-minute walking test in patients with chronic heart failure using 2 different measurement protocols. Practical suggestions for the clinical setting are given.

Reproducibility of the six-minute walking test in chronic heart failure patients.

The six-minute walking test (WT) is used in trials and clinical practice as an easy tool to evaluate the functional capacity of chronic heart failure (CHF) patients. As WT measurements are highly variable both between and within individuals, this study aims at assessing the contribution of the different sources of variation and estimating the reproducibility of the test. A statistical model describing WT measurements as a function of fixed and random effects is proposed and its parameters estimated. We considered 202 stable CHF patients who performed two baseline WTs separated by a 30 minute rest; 49 of them repeated the two tests 3 months later (follow-up control). They had no changes in therapy or major clinical events. Another 31 subjects performed two baseline tests separated by 24 hours. Collected data were analysed using a mixed model methodology. There was no significant difference between measurements taken 30 minutes and 24 hours apart (p = 0.99). A trend effect of 17 (1.4) m (mean (SE)) was consistently found between duplicate tests (p < 0.001). REML estimates of variance components were: 5189 (674) for subject differences in the error-free value; 1280 (304) for subject differences in spontaneous clinical evolution between baseline and follow-up control, and 266 (23) for the within-subject error. Hence, the standard error of measurement was 16.3 m, namely 4 per cent of the average WT performance (403 m) in this sample. The intraclass correlation coefficient was 0.96. We conclude that WT measurements are characterized by good intrasubject reproducibility and excellent reliability. When follow-up studies > or = 3 months are performed, unpredictable changes in individual walking performance due to spontaneous clinical evolution are to be expected. Their clinical significance, however, is not known.

Exercise Testing after Nontransmural Myocardial Infarction

In order to ascertain the prognostic value of exercise testing in patients suffering nontransmural myocardial infarction, 74 patients performed a bicycle-ergometric test 4 weeks after the onset of the

Intravenous inotropic agents in the intensive therapy unit: do they really make a difference?

Part of the management of refractory heart failure is treatment aimed at preventing organ damage due to inadequate oxygen delivery, improving hemodynamics, and maximizing cardiac output while maintaining only mildly elevated ventricular filling pressures The aim of this paper is to review the most updated indications on intravenous inotropic agents, and to compare their cardiac and peripheral effects. Finally, clinical implications of their use (alone or in combination) are reviewed.

Short-term reproducibility of ergometric parameters in functional stress test after recent myocardial infarction

In order to assess the short-term reproducibility of the most important ergometric parameters, 108 males (mean age 50.3 +/- 7.8 years) underwent a functional stress test (FST) on average 35 days after myocardial infarction. The exercise test was repeated 3 days later in the same conditions. Patients were fasting and in pharmacological washout. The following parameters were analyzed: total work performed (TWP), VO2, heart rate (HR), systolic blood pressure (SBP), arrhythmias and S-T segment depression and elevation. TWP and VO2 values did not show any significant difference during the two tests under the various workloads. HR and SBP responses proved to be well reproducible in patients with HR and SBP not exceeding the mean values obtained from 222 normal subjects who underwent the same exercise test by more than +/- 1 SD; reproducibility was significantly lower in the other patients, particularly in patients with HR and SBP exceeding normal values by more than +/- 1 SD. Therefore, in this case, further FST are necessary to obtain more reliable parameters to decide on individual pharmacological and exercise prescriptions. Arrhythmias were reproducible up to 67% (p less than 0.01) regardless of Lowns class and the presence of S-T segment depression or elevation. S-T segment depression or elevation was reproducible up to 100%.

Beurteilung von Gallopamil (D 600) bei Patienten mit chronisch stabiler Angina pectoris —, Ergebnisse einer plazebokontrollierten Einfachblindstudie

Die antianginosen Effekte von Kalziumantagonisten beruhen auf verschiedenen Wirkmechanismen, die entweder in einer Verringerung des myokardialen Sauerstoffverbrauchs und/ oder einer Verbesserung der Sauerstoffzufuhr zum Myokard bestehen, je nach Affinitat fur spezifische Wirkorte und Unterschieden in der Pathogenese der Myokardischamie.

Beta blockade therapy in chronic heart failure: diastolic function and mitral regurgitation improvement by carvedilol

BACKGROUNDnIn patients with chronic heart failure, the use of carvedilol therapy induces clinical and hemodynamic improvement. However, although the benefits of this beta-blocker have been established in patients with chronic heart failure, the mechanisms underlying them and the changes in left ventricular systolic function, diastolic function, and mitral regurgitation during long-term therapy remain unclear.nnnOBJECTIVEnTo identify the clinical and functional effects of carvedilol, focusing on diastolic function and mitral regurgitation variations.nnnMETHODSnForty-five consecutive patients with chronic heart failure (ejection fraction 24% +/- 7%), 17 with dilated ischemic and 28 with nonischemic cardiomyopathy, were treated with carvedilol (mean dose 44 +/- 30 mg) and matched for clinical (New York Heart Association functional class and heart failure duration) and hemodynamic (cardiac index and pulmonary wedge pressure) characteristics to a control group. Clinical and echocardiographic variables were measured in the 2 groups at baseline and after 6 months and the results compared.nnnRESULTSnAfter 6 months of treatment with carvedilol, left ventricular ejection fraction had increased from 24% +/- 7% to 29% +/- 9% (P <.0001); this change was caused by a reduction in end-systolic volume index (106 +/- 41 vs 93 +/- 37 mL/m(2); P <. 0001). Deceleration time of early diastolic filling increased (134 +/- 74 vs 196 +/- 63 ms; P <.0001). Seventeen of the 27 patients with demonstrated improvement of left ventricular diastolic filling moved from having a restrictive filling pattern to having a normal or pseudonormal left ventricular filling pattern. In the control group, no significant changes in deceleration time of early diastolic filling were found (139 +/- 74 vs 132 +/- 45 ms; P = not significant). The effective regurgitant orifice area decreased significantly in the carvedilol group but not in the control group. These changes were associated with a significant reduction of the mitral regurgitant stroke volume in the carvedilol group (50 +/- 25 vs 16 +/- 13 mL; P <.0001) but not in the control group (57 +/- 29 vs 47 +/- 24 mL; P = not significant). These changes of mitral regurgitation were closely associated with significant improvement of forward aortic stroke volume (r = -.57, P <.0001). These findings were not observed in patients in the control group.nnnCONCLUSIONSnThe results of this study show that long-term carvedilol therapy in patients with chronic heart failure was able to prevent or partially reverse progressive left ventricular dilatation. The effects on left ventricular remodeling were associated with a concomitant recovery of diastolic reserve and a decrease of mitral regurgitation, which have been demonstrated to be powerful prognostic predictors in such patients. Overall these findings provide important insights into the pathophysiologic mechanisms by which carvedilol improves the clinical course of patients with chronic heart failure.

Assessment of gallopamil (D 600) in patients with chronic stable angina pectoris Results of a placebo-controlled single-blind study

The anti-anginal effects of calcium antagonists are due to a reduction of myocardial oxygen uptake and/or an improvement of oxygen supply to the myocardium, depending on the affinity of the drug to specific sites of action and differences in the pathogenesis of the myocardial ischaemia.