Background: Patients with heart failure (HF) suffer from ventilatory abnormalities that are related to poor prognosis.Aim: The aim of the study was to investigate the respiratory drive in HF patients early after left ventricular assist device (LVAD) implantation. Methods: We enrolled eight HF patients after LVAD (HeartMate II) implantation and 8 patients with advanced HF (control group). Patients were evaluated with cardiopulmonary exercise testing, respiratory function tests and transthoracic echocardiographic examination at 1, 3 and 6 months. Respiratory drive was estimated by the mouth occlusion pressure-P0.1 and the P0.1/Pimax ratio.Results: LVAD patients at 1, 3 and 6 months after implantation had significantly improved P0.1/Pimax% ratio (4.17±0.43 vs 3.29±1.0 vs 2.56±0.35 respectively,p<0.01) as well as significantly increased in Pimax. No changes where observed in the HF control group. A significant decrease in LVEDD, LVESD and an improvement in LVEF is also observed during follow up.Conclusions: Our results imply LVAD implantantion induces a progressive and significant improvement of respiratory drive and Left ventricle reverse remodeling during a 6 month follow-up period.

Background Exercise oscillatory ventilation in chronic heart failure has been suggested as a factor related to adverse cardiac events, aggravated prognosis and higher mortality. Exercise training is well known to affect exercise capacity and mechanisms of pathophysiology beneficially in chronic heart failure. Little is known, however, about the exercise training effects on characteristics of exercise oscillatory ventilation in chronic heart failure patients. Design and methods Twenty (out of 38) stable chronic heart failure patients exhibited exercise oscillatory ventilation (age 54 ± 11 years, peak oxygen uptake 15.0 ± 5.0 ml/kg per minute). Patients attended 36 sessions of high intensity interval exercise. All patients underwent cardiopulmonary exercise testing before and after the programme. Assessment of exercise oscillatory ventilation was based on the amplitude of cyclic fluctuations in breathing during rest and exercise. All values are mean ± SD. Results Exercise training reduced ( P < 0.05) the percentage of exercise oscillatory ventilation duration (79.0 ± 13.0 to 50.0 ± 25.0%), while average amplitude (5.2 ± 2.0 to 4.9 ± 1.6 L/minute) and length (44.0 ± 10.9 to 41.0 ± 6.7 seconds) did not change ( P > 0.05). Exercise oscillatory ventilation patients also increased exercise capacity ( P < 0.05). Conclusions A rehabilitation programme based on high intensity interval training improved exercise oscillatory ventilation observed in chronic heart failure patients, as well as cardiopulmonary efficiency and functional capacity.

The objective of this study was to investigate the contribution of left ventricular (LV) diastolic dysfunction to weaning failure, along with the levels of the currently used cardiac biomarkers. Forty-two mechanically ventilated patients, who fulfilled criteria for weaning from mechanical ventilation (MV), underwent a two-hour spontaneous breathing trial (SBT). Transthoracic echocardiography (TTE) was performed before the start of the SBT. The grade of LV diastolic dysfunction was assessed by pulsed-wave Doppler and tissue Doppler imaging at the level of the mitral valve. Haemodynamic and respiratory parameters were recorded. Blood levels of B-type natriuretic peptide (BNP), troponin I, creatine kinase–MB, and myoglobin were measured on MV and at the end of the SBT. Weaning success was defined as the patient's ability to tolerate spontaneous breathing for more than 48 hours. Fifteen patients failed to wean. LV diastolic dysfunction was significantly associated with weaning failure (P <0.001). The grade of diastolic dysfunction was significantly correlated with BNP levels both on MV and at the end of the SBT (P <0.001, r = 0.703 and P <0.001, r = 0.709, respectively). BNP levels on MV were lower in patients who successfully weaned compared to those who did not (361 ± 523 ng/l versus 643 ± 382 ng/l respectively, P=0.008). The presence of diastolic dysfunction was independently associated with weaning failure (odds ratio [OR] 11.23, confidence interval [CI] 1.16–109.1, P=0.037) followed by respiratory frequency/tidal volume (OR 1.05, CI 1.00–1.10, P=0.048). Therefore, assessment of LV diastolic function before the start of weaning could be useful to identify patients at risk of weaning failure.

BACKGROUND:Residents are being increasingly challenged on how best to integrate diagnostic information in making decisions about patient care. The aim of this study is to assess the ability of residents to accurately integrate statistical data from a screening mammography test in order to estimate breast cancer probability and to investigate whether a simple alteration of the representation mode of probabilities into natural frequencies facilitates these computations.METHODS:A multi-institutional randomized controlled study of residents was performed in eight major hospitals in the city of Athens. Residents were asked to estimate the positive predictive value of the screening mammography test given its sensitivity and 1-specificity as well as the prevalence of breast cancer in the relevant population. One version of the scenario was presented in the single-event probability format that is commonly used in the medical literature, while the other used the natural frequency representation. The two questionnaire versions were randomly assigned to the participants.RESULTS:Out of 200 residents, 153 completed and returned the questionnaire (response rate 76.5%). Although more than one-third of the residents reported excellent or close to excellent familiarity with sensitivity and positive predictive value, the majority of responses (79.1%) were incorrect. However, a significantly higher proportion of residents in the natural frequency group (n = 88) selected the correct response compared with residents (n = 65) in the single-event probability group (28.4% vs 10.8%; 95% confidence intervals of the difference between the two proportions = 5.6-29.7%; P < 0.01).DISCUSSION:Residents more often correctly understand test performance accuracy when test characteristics are presented to them as natural frequency representations than the more common approach of presenting single event probabilities. Educators and journal editors should be aware of this facilitative effect.

PURPOSE: Exercise training induces several beneficial effects in patients with chronic heart failure (CHF). This study investigated the effects of high-intensity aerobic interval training (AIT) compared with combined AIT and strength training (COM) on early ventilatory and metabolic recovery pattern after symptom-limited cardiopulmonary exercise testing (CPET) in CHF patients.METHODS: Stable CHF patients (N = 42; 54 +/- 10 years [mean +/- SD], 35 males) participated in an exercise training program for 12 weeks, 3 times per week. Participants were randomly assigned to either AIT (n = 20) or COM group (n = 22). Cardiopulmonary exercise testing was performed before and after completion of the program. Primary measurements included absolute and percentage difference of oxygen uptake, carbon dioxide output, minute ventilation (VE), tidal volume (VT), respiratory rate, and the first-degree slope of oxygen uptake (VO2/t slope) and carbon dioxide output (VCO2/t slope) during the first minute of recovery after maximal exercise.RESULTS: The COM group had a greater improvement in the absolute and the percentage difference of V. E (P=.03 and P=.04, respectively) and respiratory rate (P=.02 and P=.01, respectively) during the first minute of recovery period after exercise compared with the AIT group alone. No significant changes were noted for V T measurements. A significant increase in VCO2/t slope was observed in COM compared with the AIT group (P=.01). There was a trend for a greater increase in VCO2/t slope in the COM group (P=.07).CONCLUSIONS: The addition of strength training to AIT induces significant beneficial effects in terms of ventilatory and metabolic recovery kinetics than AIT alone in CHF patients, possibly indicating greater ventilatory efficiency and metabolic improvement.

AIM To evaluate Quality of life (QoL) in chronic heart failure (CHF) in relation to Neuroticism personality trait and CHF severity. METHODS Thirty six consecutive, outpatients with Chronic Heart Failure (6 females and 30 males, mean age: 54 ± 12 years), with a left ventricular ejection fraction ≤ 45% at optimal medical treatment at the time of inclusion, were asked to answer the Kansas City Cardiomyopathy Questionnaire (KCCQ) for Quality of Life assessment and the NEO Five-Factor Personality Inventory for personality assessment. All patients underwent a symptom limited cardiopulmonary exercise testing on a cycle-ergometer, in order to access CHF severity. A multivariate linear regression analysis using simultaneous entry of predictors was performed to examine which of the CHF variables and of the personality variables were correlated independently to QoL scores in the two summary scales of the KCCQ, namely the Overall Summary Scale and the Clinical Summary Scale. RESULTS The Neuroticism personality trait score had a significant inverse correlation with the Clinical Summary Score and Overall Summary Score of the KCCQ (r = -0.621, P < 0.05 and r = -0.543, P < 0.001, respectively). KCCQ summary scales did not show significant correlations with the personality traits of Extraversion, Openness, Conscientiousness and Agreeableness. Multivariate linear regression analysis using simultaneous entry of predictors was also conducted to determine the best linear combination of statistically significant univariate predictors such as Neuroticism, VE/VCO2 slope and VO2 peak, for predicting KCCQ Clinical Summary Score. The results show Neuroticism (β = -0.37, P < 0.05), VE/VCO2 slope (β = -0.31, P < 0.05) and VO2 peak (β = 0.37, P < 0.05) to be independent predictors of QoL. In multivariate regression analysis Neuroticism (b = -0.37, P < 0.05), the slope of ventilatory equivalent for carbon dioxide output during exercise, (VE/VCO2 slope) (b = -0.31, P < 0.05) and peak oxygen uptake (VO2 peak), (b = 0.37, P < 0.05) were independent predictors of QoL (adjusted R2 = 0.64; F = 18.89, P < 0.001). CONCLUSION Neuroticism is independently associated with QoL in CHF. QoL in CHF is not only determined by disease severity but also by the Neuroticism personality trait.

Purpose The aim of this study is to determine the perceived familiarity of medical residents with statistical concepts, assess their ability to integrate these concepts in clinical scenarios, and investigate their susceptibility to the gambler's fallacy and the conjunction fallacy. Methods A multi-institutional, cross-sectional survey of Greek medical residents was performed. Participants were asked to indicate their familiarity with basic statistical concepts and answer clinically oriented questions designed to assess their biostatistics knowledge and cognitive biases. Univariate, bivariate, and multivariate statistical models were used for the evaluation of data. Results Out of 153 respondents (76.5% response rate), only two participants (1.3%) were able to answer all seven biostatistics knowledge questions correctly while 29 residents (19%) gave incorrect answers to all questions. The proportion of correct answers to each biostatistics knowledge question ranged from 15 to 51.6%. Residents with greater self-reported familiarity were more likely to perform better on the respective knowledge question (all p<0.01). Multivariate analysis of the effect of individual resident characteristics on questionnaire performance showed that previous education outside Greece, primarily during medical school, was associated with lower biostatistics knowledge scores (p<0.001). A little more than half of the respondents (54.2%) answered the gambler's fallacy quiz correctly. Residents with higher performance on the biostatistics knowledge questions were less prone to the gambler's fallacy (odds ratio 1.38, 95% confidence intervals 1.12–1.70, p=0.003). Only 48 residents (31.4%) did not violate the conjunction rule. Conclusions A large number of medical residents are unable to correctly interpret crucial statistical concepts that are commonly found in the medical literature. They are also especially prone to the gambler's fallacy bias, which may undermine clinical judgment and medical decision making. Formalized systematic teaching of biostatistics during residency will be required to de-bias residents and ensure that they are proficient in understanding and communicating statistical information.

Background: Patients with chronic heart failure (CHF) are characterized by exercise intolerance and ventilatory abnormalities that are related to poor prognosis. We hypothesized that CHF patients have increased respiratory drive and abnormal breathing pattern during exercise in relation to disease severity.Materials and methods: The study population consisted of 219 stable CHF patients and 30 healthy control subjects. All subjects underwent a symptom-limited cardiopulmonary exercise testing (CPET), pulmonary function tests, measurement of the maximal inspiratory pressure (P-1max) and respiratory drive (P-0.1).Measurements included peak oxygen uptake (V-o2, peak, ml/kg/min). Respiratory drive was measured by mouth occlusion pressure P-0.1 and P-0.1/P-1max ratio at rest, and by mean inspiratory flow (V-T/T-1) at rest and during exercise. CHF patients were divided into 3 groups according to V-o2 peak (Group A: >20, Group B: 20-16 and Group C: <16 ml/kg/min).Results: CHF patients presented higher P-0.1/P-1max (4.1 +/- 3.6 vs 3.0 +/- 1.5, p = 0.007) and V-T/T-1 at rest (0.48 +/- 0.14 vs 0.41 +/- 0.10, L/s respectively, p = 0.004) and lower V-T/T-1 at peak exercise (2.17 +/- 0.66 vs 2.56 +/- 0.73, L/s, p = 0.009) compared to controls. P-0.1/P-1max was higher in CHF Group C vs B vs A (4.9 +/- 2.9 vs 3.6 +/- 1.8 vs 3.1 +/- 1.8, respectively, p < 0.001), while V-T/T-1 at peak exercise was lower (1.71 +/- 0.43 vs 2.15 +/- 0.52 vs 2.65 +/- 0.64, L/s, respectively, p <0.001).Conclusions: CHF patients present increased respiratory drive at rest and abnormal breathing pattern during exercise in relation to CHF severity. (C) 2013 Elsevier B.V. All rights reserved.

BOOK EuroPRevent 2013 Rome, Italy

BACKGROUND:Pulmonary microcirculation abnormalities are the main determinants of pulmonary arterial hypertension (PAH) pathophysiology. We hypothesized that PAH patients have peripheral tissue microcirculation alterations that might benefit from hyperoxic breathing. We evaluated peripheral muscle microcirculation with near-infrared spectroscopy, before and after hyperoxic breathing.METHODS:Eight PAH subjects, 8 healthy subjects (controls) matched for age, sex, and body mass index, and 16 subjects with chronic heart failure and matched for functional capacity with the PAH subjects underwent near-infrared spectroscopy. Tissue O(2) saturation, defined as the hemoglobin saturation (%) in the microvasculature compartments, was measured on the thenar muscle. Then the 3-min brachial artery occlusion technique was applied before, during, and after 15 min of breathing 100% O(2). We calculated the oxygen consumption rate (%/min), the reactive hyperemia time, and the time needed for tissue O(2) saturation to reach its baseline value after the release of the occlusion.RESULTS:Compared to the controls, the PAH subjects had a significantly lower resting tissue O(2) saturation (65.8 ± 14.9% vs 82.1 ± 4.0%, P = .005), a trend toward a lower oxygen consumption rate (35.3 ± 9.1%/min vs 43.4 ± 19.7%/min, P = .60), and a significantly higher reactive hyperemia time (3.0 ± 0.6 min vs 2.0 ± 0.3 min, P < .001). The PAH subjects also had lower tissue O(2) saturation (P = .08), lower peripheral arterial oxygen saturation (P = .01), and higher reactive hyperemia time (P = .02) than the chronic heart failure subjects. After hyperoxic breathing, the PAH subjects had increased tissue O(2) saturation (65.8 ± 14.9% to 71.4 ± 14.5%, P = .01), decreased oxygen consumption rate (35.3 ± 9.1%/min to 25.1 ± 6.6%/min, P = .01), and further increased reactive hyperemia time (3.0 ± 0.6 min to 4.2 ± 0.7 min, P = .007).CONCLUSIONS:The PAH subjects had substantial impairments of peripheral muscle microcirculation, decreased tissue O(2) saturation (possibly due to hypoxemia), slower reactive hyperemia time, (possibly due to endothelium dysfunction), and peripheral systemic vasoconstriction. Acute hyperoxic breathing improved resting tissue O(2) saturation (an expression of higher oxygen delivery) and decreased the oxygen consumption rate and reactive hyperemia time during reperfusion, possibly due to increased oxidative stress and evoked vasoconstriction.

BACKGROUNDLeft ventricular (LV) remodeling after acute myocardial infarction (AMI) is related to increased morbidity and mortality. The aim of the present study was to examine whether LV deformational and torsional parameters can predict LV remodeling in patients with AMI.METHODSForty-two patients (age 57 ± 14 years) presenting with an anterior ST-elevation AMI and treated with primary percutaneous transluminal coronary angioplasty (PTCA) were included in the study. Four days post MI, LV ejection fraction (EF), LV torsion, longitudinal (4-, 3- & 2-chamber) and circumferential strain of the LV apex were evaluated by conventional and speckle-tracking echocardiography. The echocardiographic study was repeated at 3 months post-AMI and patients with LV remodeling, i.e. an increase >15% in LV end-systolic volume (LVESV), were identified.RESULTSThe 13 patients with LV remodeling had significantly more impaired apical circumferential strain (-7.3 ± 2.2% vs. -18.9 ± 5.2%, p=0.001), EF (42 ± 7% vs. 48.9 ± 6%, p=0.005), LV apical rotation (6.8 ± 4.8° vs. 11.1 ± 4.0°, p=0.027), and LV global longitudinal strain (-9.7 ± 1.9% vs. -12.9 ± 2.9%, p=0.03) on the 4th day post-AMI, in comparison to those without LV remodeling. Apical circumferential strain on the 4th day post-AMI showed the strongest correlation with the LVESV 3 months post-AMI (r=0.76, p=0.001), compared to EF (r=-0.60, p=0.001), global longitudinal strain (r=0.56, p=0.001), and LV apical rotation (r=-0.53, p=0.001). Furthermore, apical circumferential strain demonstrated the highest diagnostic accuracy: area under the receiver operating characteristic (ROC) curve 0.98, with sensitivity 100% and specificity 96% for prediction of LV remodeling, using a cutoff value <-11.0%.CONCLUSIONIn patients with anterior AMI, LV apical circumferential strain in the early post-MI period constitutes a significant prognostic factor for LV remodeling at 3 months. Assessment of this parameter may identify patients at high risk for heart failure development.

Pulmonary microcirculation abnormalities play a central role in pulmonary arterial hypertension (PAH) pathophysiology. We hypothesized that PAH patients also have systemic muscle microcirculation alterations compared to healthy subjects. The aim of this study was to investigate peripheral muscle microcirculation by near-infrared spectroscopy (NIRS) in PAH patients and to test the effects of hyperoxia into their tissue microcirculation.

Background: Patients with heart failure (HF) are characterized by several skeletal muscle abnormalities that are closely related to their exercise intolerance. Aim of this study was to investigate the effects of three different interval exercise training programs on skeletal muscle fiber-type distribution and aerobic capacity of HF patients. Method and Material: The study consisted of 10 HF patients that participated in a rehabilitation program 3 times per week, for a total of 36 sessions. Patients performed cardiopulmonary exercise test (CPET) and percutaneous needle biopsy of the vastus lateralis muscle before and after the completion of the program. Histological measurements included the fiber type distribution and cross section area (CSA) of skeletal muscle fiber. Main CPET measurements included oxygen uptake at peak (VO2p), at anaerobic threshold (AT), peak work (WRp) and the slope of ventilatory equivalent for carbon dioxide output (VE/VCO2slope). Results: After the exercise training program there was a significant increase in the CSA of type I (4509±1184 to 4862±1154 μm2, p

BACKGROUND: Autonomic dysfunction is present early in the course of COPD, and is associated with adverse outcomes. We utilized heart rate recovery, a simple and validated index of autonomic balance, to investigate the effects of exercise training on autonomic dysfunction in patients with COPD. METHODS: We evaluated 45 stable subjects with COPD who participated in a 36-session exercise-based cardiopulmonary rehabilitation program. Subjects underwent maximal cardiopulmonary exercise testing at baseline and after completion of the rehabilitation program. We recorded exercise testing parameters and heart rate during rest, exercise, and recovery. Heart rate recovery was calculated as heart rate at peak exercise minus heart rate at the first minute of recovery. RESULTS: Thirty-nine subjects (age 66.3 ± 7.8 y, 90% male, body mass index 27.1 ± 4.1 kg/m2, FEV1 45.7 ± 18.7%) completed the program. In these subjects, heart rate recovery increased from 16.2 ± 8.0 beats/min to 18.4 ± 8.4 beats/min (P = .01), resting heart rate decreased from 88.0 ± 10.7 beats/min to 83.3 ± 10.5 beats/min (P = .004), and heart rate at anaerobic threshold decreased from 109.0 ± 12.5 beats/min to 105.5 ± 11.7 beats/min (P = .040). In addition, oxygen consumption (V̇O2) increased from 14.3 ± 3.7 mL/kg/min to 15.2 ± 3.8 mL/kg/min at peak exercise, and from 9.7 ± 2.4 mL/kg/min to 10.4 ± 2.6 mL/kg/min at anaerobic threshold (both P = .02), while the V̇O2/t slope increased from –0.32 ± 0.16 mL/kg/min2 to –0.38 ± 0.19 mL/kg/min2 (P = .003). Parameters of ventilatory performance improved also. CONCLUSIONS: In subjects with COPD, exercise-based rehabilitation improves heart rate recovery, modestly though, which indicates a degree of attenuated autonomic dysfunction. Exercise and muscular oxidative capacity, as expressed by V̇O2/t slope, is also improved.

Background. The aim of our study was to investigate the relationship between microcirculatory alterations after open cardiac surgery, macrohemodynamics, and global indices of organ perfusion. Methods. Patients' microcirculation was assessed with near-infrared spectroscopy (NIRS) and the vascular occlusion technique (VOT). Results. 23 patients undergoing open cardiac surgery (11 male/12 female, median age 68 (range 28-82) years, EuroSCORE 6 (1-12)) were enrolled in the study. For pooled data, CI correlated with the tissue oxygen consumption rate as well as the reperfusion rate (r = 0.56, P < 0.001 and r = 0.58, P < 0.001, resp.). In addition, both total oxygen delivery (DO(2), mL/min per m(2)) and total oxygen consumption (VO(2), mL/min per m(2)) also correlated with the tissue oxygen consumption rate and the reperfusion rate. The tissue oxygen saturation of the thenar postoperatively correlated with the peak lactate levels during the six hour monitoring period (r = 0.50, P < 0.05). The tissue oxygen consumption rate (%/min) and the reperfusion rate (%/min), as derived from the VOT, were higher in survivors compared to nonsurvivors for pooled data [23 (4-54) versus 20 (8-38) P < 0.05] and [424 (27-1215) versus 197 (57-632) P < 0.01], respectively. Conclusion. Microcirculatory alterations after open cardiac surgery are related to macrohemodynamics and global indices of organ perfusion.