Reference Values for Peak Exercise Cardiac Output in Healthy Individuals

BACKGROUND: Cardiac output (Q\u2d9) is a key parameter in the assessment of cardiac function, its measurement being crucial for the diagnosis, treatment, and prognostic evaluation of all heart diseases. Until recently, Q\u2d9 determination at peak exercise has been possible through invasive methods, so that normal values were obtained in studies based on small populations. METHODS: Nowadays, peak Q\u2d9 can be measured noninvasively by means of the inert gas rebreathing (IGR) technique. The present study was undertaken to provide reference values for peak Q\u2d9 in the normal general population and to obtain a formula able to estimate peak exercise Q\u2d9 from measured peak oxygen uptake (V\u2d9o2). RESULTS: We studied 500 normal subjects (age, 44.9 \ub1 1.5 years; range, 18-77 years; 260 men, 240 women) who underwent a maximal cardiopulmonary exercise test with peak Q\u2d9 measurement by IGR. In the overall study sample, peak Q\u2d9 was 13.2 \ub1 3.5 L/min (men, 15.3 \ub1 3.3 L/min; women, 11.0 \ub1 2.0 L/min; P < .001) and peak V\u2d9o2 was 95% \ub1 18% of the maximum predicted value (men, 95% \ub1 19%; women, 95% \ub1 18%). Peak V\u2d9o2 and peak Q\u2d9 progressively decreased with age (R2, 0.082; P < .001; and R2, 0.144; P < .001, respectively). The V\u2d9o2-derived formula to measure Q\u2d9 at peak exercise was (4.4 7 peak V\u2d9o2) + 4.3 in the overall study cohort, (4.3 7 peak V\u2d9o2) + 4.5 in men, and (4.9 7 peak V\u2d9o2) + 3.6 in women. CONCLUSIONS: The simultaneous measurement of Q\u2d9 and V\u2d9o2 at peak exercise in a large sample of healthy subjects provided an equation to predict peak Q\u2d9 from peak V\u2d9o2 values

Exercise performance, haemodynamics, and respiratory pattern do not identify heart failure patients who end exercise with dyspnoea from those with fatigue

AIMS: The two main symptoms referred by chronic heart failure (HF) patients as the causes of exercise termination during maximal cardiopulmonary exercise testing (CPET) are muscular fatigue and dyspnoea. So far, a physiological explanation why some HF patients end exercise because of dyspnoea and others because of fatigue is not available. We assessed whether patients referring dyspnoea or muscular fatigue may be distinguished by different ventilator or haemodynamic behaviours during exercise. METHODS AND RESULTS: We analysed exercise data of 170 consecutive HF patients with reduced left ventricular ejection fraction in stable clinical condition. All patients underwent maximal CPET and a second maximal CPET with measurement of cardiac output by inert gas rebreathing at peak exercise. Thirty-eight (age 65.0 \ub1 11.1 years) and 132 (65.1 \ub1 11.4 years) patients terminated CPET because of dyspnoea and fatigue, respectively. Haemodynamic and cardiorespiratory parameters were the same in fatigue and dyspnoea patients. VO2 was 10.4 \ub1 3.2 and 10.5 \ub1 3.3 mL/min/kg at the anaerobic threshold and 15.5 \ub1 4.8 and 15.4 \ub1 4.3 at peak, in fatigue and dyspnoea patients, respectively. In fatigue and dyspnoea patients, peak heart rate was 110 \ub1 22 and 114 \ub1 22 beats/min, and VE/VCO2 and VO2 /work relationship slopes were 31.2 \ub1 6.8 and 30.6 \ub1 8.2 and 10.6 \ub1 4.2 and 11.4 \ub1 5.5 L/min/W, respectively. Peak cardiac output was 6.68 \ub1 2.51 and 6.21 \ub1 2.55 L/min (P = NS for all). CONCLUSIONS: In chronic HF patients in stable clinical condition, fatigue and dyspnoea as reasons of exercise termination do not highlight different ventilatory or haemodynamic patterns during effort

Chronotropic Incompentence and Functional Capacity in CHF

SUMMARY Aim: To assess the effect of chronotropic incompetence on functional capacity in chronic heart failure (CHF) patients, as evaluated as NYHA and peak oxygen consumption (pVO2), focusing on the presence and dose of β-blocker treatment. Methods: Nine hundred and sixty-seven consecutive CHF patients were evaluated, 328 of whom were discarded because they failed to meet the study criteria. Of the 639 analyzed, 90 were not treated with β-blockers whereas the other 549 were. The latter were further subdivided in high (n = 184) and low (n = 365) β-blockers daily dose group in accordance with an arbitrary cut-off of 25 mg for carvedilol and of 5 mg for bisoprolol. Failure to achieve 80% of the percentage of maximum age predicted peak heart rate (%Max PHR) or of HR reserve (%HRR) constituted chronotropic incompetence. Results: No differences were found in NYHA or pVO2 between patients with and without β-blockers and, similarly, between high and low β-blocker dose groups. Twenty and sixty-nine percent of not β-blocked patients showed chronotropic incompetence according to %Max PHR and %HRR, respectively, whereas this prevalence rose to 61% and 84% in those on β-blocker therapy. Patients taking β-blockers without chronotropic incompetence, as inferable from both %Max PHR and %HRR, showed higher NYHA and pVO2 regardless of drug dose, whereas, in not β-blocked patients, only %HRR revealed a difference in functional capacity. At multivariable analysis, HR increase during exercise (ΔHR) was the variable most strongly associated to pVO2 (β: 0.572; SE: 0.008; P < 0.0001) and NYHA class (β: −0.499; SE: 0.001; P < 0.0001). Conclusions: ΔHR is a powerful predictor of CHF severity regardless of the presence of β-blocker therapy and of β-blocker daily dose

Predictors of CD34+ cell mobilization and collection in adult men with germ cell tumors: implications for the salvage treatment strategy

BACKGROUND: High-dose chemotherapy with tandem or triple carboplatin and etoposide course is currently the first curative choice for relapsing GCT. The collection of an adequate amount of hematopoietic (CD34(+)) stem cells is a priority. PATIENTS AND METHODS: We analyzed data of patients who underwent HDCT at 2 referral institutions. Chemotherapy followed by myeloid growth factors was applied in all cases. Uni- and multivariable models were used to evaluate the association between 2 prespecified variables and mobilization parameters. Analyses included only the first mobilizing course of chemotherapy and mobilization failures. RESULTS: A total of 116 consecutive patients underwent a mobilization attempt from December 1995 to November 2012. Mobilizing regimens included cyclophosphamide (CTX) 7 gr/m(2) (n = 39), cisplatin, etoposide, and ifosfamide (PEI) (n = 42), paclitaxel, cisplatin, and gemcitabine (TPG) (n = 11), and mixed regimens (n = 24). Thirty-seven percent were treated in first-line, 50% (n = 58) in second-line, 9.5% (n = 11) and 3.4% (n = 4) in third- and fourth-line settings, respectively. Six patients did not undergo HDCT because they were poor mobilizers, 2 in first- and second-line (1.9%), and 4 beyond the second-line (26.7%). In the multivariable model, third-line or later setting was associated with a lower CD34(+) cell peak/μL (P = .028) and a lower total CD34(+)/kg collected (P = .008). The latter was also influenced by the type of mobilizing regimen (P < .001). CONCLUSION: A decline in significant mobilization parameters was found, primarily depending on the pretreatment load. Results lend support to the role of CD34(+) cell mobilization in the therapeutic algorithm of relapsing GCT, for whom multiple HDCT courses are still an option, and potentially a cure

Mineralocorticoid receptor antagonists for heart failure: a real-life observational study

Mineralocorticoid receptor antagonists (MRAs) have been demonstrated to improve outcomes in reduced ejection fraction heart failure (HFrEF) patients. However, MRAs added to conventional treatment may lead to worsening of renal function and hyperkalaemia. We investigated, in a population-based analysis, the long-term effects of MRA treatment in HFrEF patients.Aims Mineralocorticoid receptor antagonists (MRAs) have been demonstrated to improve outcomes in reduced ejection fraction heart failure (HFrEF) patients. However, MRAs added to conventional treatment may lead to worsening of renal function and hyperkalaemia. We investigated, in a population-based analysis, the long-term effects of MRA treatment in HFrEF patients. Methods and results We analysed data of 6046 patients included in the Metabolic Exercise Cardiac Kidney Index score dataset. Analysis was performed in patients treated (n= 3163) and not treated (n= 2883) with MRA. The study endpoint was a composite of cardiovascular death, urgent heart transplantation, or left ventricular assist device implantation. Ten years\u2019survival was analysed through Kaplan\u2013Meier, compared by log-rank test and propensity score matching. At 10 years\u2019follow-up, the MRA-untreated group had a significantly lower number of events than the MRA-treated group (P<0.001). MRA-treated patients had more severe heart failure (higher New York Heart Association class and lower left ventricular ejection fraction, kidney function, and peak VO2). At a propensity-score-matching analysis performed on 1587 patients, MRA-treated and MRA-untreated patients showed similar study endpoint values. Conclusions In conclusion, MRA treatment does not affect the composite of cardiovascular death, urgent heart transplanta- tion or left ventricular assist device implantation in a real-life setting. A meticulous patient follow-up, as performed in trials, is likely needed to match the positive MRA-related benefits observed in clinical trials

Towards a muon collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work

Towards a muon collider

A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work

Erratum: Towards a muon collider

The original online version of this article was revised: The additional reference [139] has been added. Tao Han’s ORICD ID has been incorrectly assigned to Chengcheng Han and Chengcheng Han’s ORCID ID to Tao Han. Yang Ma’s ORCID ID has been incorrectly assigned to Lianliang Ma, and Lianliang Ma’s ORCID ID to Yang Ma. The original article has been corrected

Ladinia e Italia. Discorso inaugurale letto l'11 gennaio 1917 nell'adunanza solenne del R. Istituto lombardo di scienze e lettere

Pavia : Fusi, 1917 Già pubbl. in: Rendiconti del R. Istituto lombardo di scienze e lettere, v. 50 https://galileodiscovery.unipd.it/discovery/fulldisplay?context=L&vid=39UPD_INST:VU1&search_scope=MyInst_and_CI&tab=Everything&docid=alma99000240720020604