Physical activity is increased by a 12-week semiautomated telecoaching programme in patients with COPD: a multicentre randomised controlled trial.

RATIONALE: Reduced physical activity (PA) in patients with COPD is associated with a poor prognosis. Increasing PA is a key therapeutic target, but thus far few strategies have been found effective in this patient group. OBJECTIVES: To investigate the effectiveness of a 12-week semiautomated telecoaching intervention on PA in patients with COPD in a multicentre European randomised controlled trial. METHODS: 343 patients from six centres, encompassing a wide spectrum of disease severity, were randomly allocated to either a usual care group (UCG) or a telecoaching intervention group (IG) between June and December 2014. This 12-week intervention included an exercise booklet and a step counter providing feedback both directly and via a dedicated smartphone application. The latter provided an individualised daily activity goal (steps) revised weekly and text messages as well as allowing occasional telephone contacts with investigators. PA was measured using accelerometry during 1 week preceding randomisation and during week 12. Secondary outcomes included exercise capacity and health status. Analyses were based on modified intention to treat. MAIN RESULTS: Both groups were comparable at baseline in terms of factors influencing PA. At 12 weeks, the intervention yielded a between-group difference of mean, 95% CI (lower limit - upper limit; ll-ul) +1469, 95% CI (971 to 1965) steps/day and +10.4, 95% CI (6.1 to 14.7) min/day moderate PA; favouring the IG (all p≤0.001). The change in 6-min walk distance was significantly different (13.4, 95% CI (3.40 to 23.5) m, p<0.01), favouring the IG. In IG patients, an improvement could be observed in the functional state domain of the clinical COPD questionnaire (p=0.03) compared with UCG. Other health status outcomes did not differ. CONCLUSIONS: The amount and intensity of PA can be significantly increased in patients with COPD using a 12-week semiautomated telecoaching intervention including a step counter and an application installed on a smartphone. TRIAL REGISTRATION NUMBER: NCT02158065.

Simulation analysis of air flow and turbulence statistics in a rib grit roughened duct.

The implementation of variable artificial roughness patterns on a surface is an effective technique to enhance the rate of heat transfer to fluid flow in the ducts of solar air heaters. Different geometries of roughness elements investigated have demonstrated the pivotal role that vortices and associated turbulence have on the heat transfer characteristics of solar air heater ducts by increasing the convective heat transfer coefficient. In this paper we investigate the two-dimensional, turbulent, unsteady flow around rectangular ribs of variable aspect ratios by directly solving the transient Navier-Stokes and continuity equations using the finite elements method. Flow characteristics and several aspects of turbulent flow are presented and discussed including velocity components and statistics of turbulence. The results reveal the impact that different rib lengths have on the computed mean quantities and turbulence statistics of the flow. The computed turbulence parameters show a clear tendency to diminish downstream with increasing rib length. Furthermore, the applied numerical method is capable of capturing small-scale flow structures resulting from the direct solution of Navier-Stokes and continuity equations.

Analysis of the effectiveness and the cost of hospitalization of patients with atrial fibrillation.

Introduction: Hospitalizations of patients with atrial fibrillation (AF) lead to an explosion of expenditure on the public health system or private health expenses in family budgets. This study aims to estimate the duration and the cost of hospitalization for the public health system or the private cost to patients hospitalized after an AF episode. Material and Methods: Two hundred thirty-five consecutive patients (141 men and 94 women with an average age of 71.91 ± 12.2 years) who presented with AF to the Emergency Department of the General Hospital of Veroia during a single year were studied. We assessed the possible causes of arrhythmia, the duration and outcome of hospitalization, and the cost of hospitalization. We estimated the total cost by adding the price of the drugs used to cardiovert and the money spent on the patient's hospitalization. Results: The average hospitalization time was 2.37 ± 1.17 days, and the average cost of hospitalization (total cost) was € 488.22 ± 170.34. There was a significant correlation between the severity of the episode and the total cost (r =0.78, p<0.0001), with 87.6 % of the total cost (€ 427.76 ± 135.86) being related to the cost of hospitalization (imaging, laboratory, hospitalization) and the rest to the drug therapy cost. Amiodarone (97 patients, 41.1 %), flecainide (52 patients, 22 %), propafenone (68 patients, 28.8 %), vernakalant (two patients, 0.8 %), and quinidine (eight patients, 3.4 %) were utilized. Conclusion: The average cost of hospital care in patients with AF is significantly related to the severity of the episode. Effective drug therapy to reduce AF-provoking factors, such as antihypertensive therapy, combined with cardiovascular disease prevention in general, could reduce the morbidity and costs of AF-related hospitalizations. HIPPOKRATIA 2023, 27 (1):18-21.

Prescribing and adjusting exercise training in chronic respiratory diseases - Expert-based practical recommendations.

BACKGROUND: International guidelines recommend endurance (ET) and strength training (ST) in patients with chronic respiratory diseases (CRDs), but only provide rough guidance on how to set the initial training load. This may unintentionally lead to practice variation and inadequate training load adjustments. This study aimed to develop practical recommendations on tailoring ET and ST based on practices from international experts from the field of exercise training in CRDs. METHODS: 35 experts were invited to address a 64-item online survey about how they prescribe and adjust exercise training. RESULTS: Cycling (97%) and walking (86%) were the most commonly implemented ET modalities. Continuous endurance training (CET, 83%) and interval endurance training (IET, 86%) were the frequently applied ET types. Criteria to prescribe IET instead of CET were: patients do not tolerate CET due to dyspnoea at the initial training session (79%), intense breathlessness during initial exercise assessment (76%), and/or profound exercise-induced oxygen desaturation (59%). For ST, most experts (68%) recommend 3 sets per exercise; 62% of experts set the intensity at a specific load that patients can tolerate for a range of 8 to 15 repetitions per set. Also, 56% of experts advise patients to approach local muscular exhaustion at the end of a single ST set. CONCLUSIONS: The experts´ practices were summarized to develop practical recommendations in the form of flowcharts on how experts apply and adjust CET, IET, and ST in patients with CRDs. These recommendations may guide health care professionals to optimize exercise training programs in patients with CRDs.

Strategies of muscle training in very severe COPD patients.

There is strong evidence that exercise training, constituting the cornerstone of pulmonary rehabilitation, improves exercise tolerance, dyspnoea sensations, functional capacity and quality of life in patients with severe chronic obstructive pulmonary disease. However, intolerable sensations of breathlessness and/or peripheral muscle discomfort may prevent such patients from tolerating high-intensity exercise levels for sufficiently long periods of time to obtain true physiological training effects. Accordingly, the major issue that arises is the selection of the appropriate training strategy, which is tailored to the cardiovascular, pulmonary and peripheral muscle limitations of the individual patient and is aimed at maximising the effect of exercise conditioning. Within this context, the present article explores the application of strategies that optimise exercise tolerance by reducing dyspnoea sensations, namely noninvasive mechanical ventilation, oxygen and/or heliox supplementation. Administration of heliox or oxygen during exercise also increases peripheral muscle oxygen delivery, thereby delaying the onset of peripheral muscle fatigue. Particular emphasis is also given to interval exercise and resistance-muscle training as both modalities allow the application of intense loads on peripheral muscles with tolerable levels of dyspnoea sensations. In patients with profound muscle weakness and intense breathlessness upon physical exertion, execution of short bouts of interval or local muscle strength conditioning, along with oxygen breathing, may constitute a feasible and effective approach to pulmonary rehabilitation.

Effect of portable noninvasive ventilation on thoracoabdominal volumes in recovery from intermittent exercise in patients with COPD.

We previously showed that use of portable noninvasive ventilation (pNIV) during recovery periods within intermittent exercise improved breathlessness and exercise tolerance in patients with COPD compared with pursed-lip breathing (PLB). However, in a minority of patients recovery from dynamic hyperinflation (DH) was better with PLB, based on inspiratory capacity. We further explored this using Optoelectronic Plethysmography to assess total and compartmental thoracoabdominal volumes. Fourteen patients with COPD (means ± SD) (FEV1: 55% ± 22% predicted) underwent, in a balanced order sequence, two intermittent exercise protocols on the cycle ergometer consisting of five repeated 2-min exercise bouts at 80% peak capacity, separated by 2-min recovery periods, with application of pNIV or PLB in the 5 min of recovery. Our findings identified seven patients showing recovery in DH with pNIV (DH responders) whereas seven showed similar or better recovery in DH with PLB. When pNIV was applied, DH responders compared with DH nonresponders exhibited greater tidal volume (by 0.8 ± 0.3 L, P = 0.015), inspiratory flow rate (by 0.6 ± 0.5 L/s, P = 0.049), prolonged expiratory time (by 0.6 ± 0.5 s, P = 0.006), and duty cycle (by 0.7 ± 0.6 s, P = 0.007). DH responders showed a reduction in end-expiratory thoracoabdominal DH (by 265 ± 633 mL) predominantly driven by reduction in the abdominal compartment (by 210 ± 494 mL); this effectively offset end-inspiratory rib-cage DH. Compared with DH nonresponders, DH responders had significantly greater body mass index (BMI) by 8.4 ± 3.2 kg/m2, P = 0.022 and tended toward less severe resting hyperinflation by 0.3 ± 0.3 L. Patients with COPD who mitigate end-expiratory rib-cage DH by expiratory abdominal muscle recruitment benefit from pNIV application.NEW & NOTEWORTHY Compared with the pursed-lip breathing technique, acute application of portable noninvasive ventilation during recovery from intermittent exercise improved end-expiratory thoracoabdominal dynamic hyperinflation (DH) in 50% of patients with COPD (DH responders). DH responders, compared with DH nonresponders, exhibited a reduction in end-expiratory thoracoabdominal DH predominantly driven by the abdominal compartment that effectively offset end-expiratory rib cage DH. The essential difference between DH responders and DH nonresponders was, therefore, in the behavior of the abdomen.

Interval versus constant-load exercise training in adults with Cystic Fibrosis.

BACKGROUND: The efficacy of interval exercise (IE) compared to constant-load exercise (CLE) training remains unsettled in adults with Cystic Fibrosis (CF). METHODS: Twenty-four adults with CF were randomised to 30-min IE (100 % peak work capacity (WRpeak) for 30-s alternated with 40 % WRpeak for 30-s; n = 12) or 30-min CLE (70 % WRpeak; n = 12) training, 3 times weekly, for 12 weeks. Isometric quadriceps muscle strength was assessed using a strain gauge Myometer. RESULTS: The magnitude of improvement in quadriceps muscle strength was greater (p = 0.037) in the IE (by 32 ±â€¯13 Nm) compared to the CLE (by 23 ±â€¯12 Nm) groups. Maximum inspiratory and expiratory mouth pressures were significantly improved only in the IE group (by 30 ±â€¯10 cmH2O; p = 0.009 and 13 ±â€¯4 cmH2O; p = 0.007, respectively). Arterial oxygen saturation during training was higher (p = 0.002) for IE (94 ±â€¯1%) compared to CLE (91 ±â€¯1%), whereas dyspnoea scores were lower (p = 0.001) for IE (3.8 ±â€¯0.7) compared to CLE (5.9 ±â€¯0.8) CONCLUSIONS: IE is superior to CLE in improving peripheral and respiratory muscle strength and preferable to CLE because it is associated with lower exercise-induced arterial oxygen desaturation and breathlessness.

Effect of pulmonary rehabilitation on muscle remodelling in cachectic patients with COPD.

It is known that non-cachectic patients with chronic obstructive pulmonary disease (COPD) respond well to pulmonary rehabilitation, but whether cachectic COPD patients are capable of adaptive responses is both important and unknown. 10 cachectic and 19 non-cachectic COPD patients undertook high-intensity cycling training, at the same relative intensity, for 45 min x day(-1), 3 days x week(-1) for 10 weeks. Before and after rehabilitation vastus lateralis muscle biopsies were analysed morphologically and for the expression of muscle remodelling factors (insulin-like growth factor (IGF)-I, myogenic differentiation factor D (MyoD), tumour necrosis factor (TNF)-alpha, nuclear factor (NF)-kappaB and myostatin) and key components of ubiquitin-mediated proteolytic systems (muscle ring finger protein (MURF)-1 and Atrogin-1). Rehabilitation improved peak work-rate and the 6-min walk distance similarly in non-cachectic (18+/-3% and 42+/-13 m, respectively) and cachectic (16+/-2% and 53+/-16 m, respectively) patients, but quality of life only improved in non-cachectic COPD. Mean muscle fibre cross-sectional area increased in both groups, but significantly less in cachectic (7+/-2%) than in non-cachectic (11+/-2%) patients. Both groups equally decreased the proportion of type IIb fibres and increased muscle capillary/fibre ratio. IGF-I mRNA expression increased in both groups, but IGF-I protein levels increased more in non-cachectic COPD. MyoD was upregulated, whereas myostatin was downregulated at the mRNA and protein level only in non-cachectic patients. Whilst rehabilitation had no effect on TNF-alpha expression, it decreased the activation of the transcription factor NF-kappaB in both groups by the same amount. Atrogin-1 and MURF-1 expression were increased in cachectic COPD, but it was decreased in non-cachectic patients. Cachectic COPD patients partially retain the capacity for peripheral muscle remodelling in response to rehabilitation and are able to increase exercise capacity as much as those without cachexia, even if they exhibit both quantitative and qualitative differences in the type of muscle fibre remodelling in response to exercise training.

Exercise-induced skeletal muscle deoxygenation in O-supplemented COPD patients.

This study was designed to assess quadriceps oxygenation during symptom-limited and constant-load exercise in patients with chronic obstructive pulmonary disease (COPD) and healthy age-matched controls. Thirteen male COPD patients [FEV(1): 43 +/- 5% predicted (mean +/- SEM)] and seven healthy male controls performed an incremental exercise test at peak work rate (WR) and a constant-load test at 75% peak WR on a cycle ergometer. Quadriceps hemoglobin saturation (StO2) was measured by continuous-wave near-infrared spectrophotometry throughout both exercise tests. StO2 is the ratio of oxygenated hemoglobin to total hemoglobin and reflects the relative contributions of tissue O2 delivery and tissue O2 utilization. Oxygen was supplemented to all patients in order to maintain arterial O2 saturation normal (> 95%). The StO2 decreased during symptom-limited exercise, reaching the nadir at peak WR. The decrease in StO2 was greater (P < 0.05) in healthy subjects (from 74 +/- 2% to 38 +/- 6%) compared with that in COPD patients (from 61 +/- 5% to 45 +/- 4%). However, when StO2 was normalized relative to the WR, the slope of change in StO2 during exercise was nearly identical between COPD patients and healthy subjects (0.47 +/- 0.10%/W and 0.51 +/- 0.04%/W, respectively). During constant-load exercise, the kinetic time constant of StO2 desaturation after the onset of exercise (i.e., equivalent to time to reach approximately 63% of StO2 decrease) was not different between COPD patients and healthy subjects (19.0 +/- 5.2 and 15.6 +/- 2.5 s, respectively). In O2-supplemented COPD patients, peripheral muscle oxygenation for a given work load is similar to that in healthy subjects, thus suggesting that skeletal muscle O2 consumption becomes normal for a given O2 delivery in COPD patients

Chest wall volume regulation during exercise in COPD patients with GOLD stages II to IV.

The present study investigated how end-expiratory ribcage and abdominal volume regulation during exercise is related to the degree of dynamic chest wall hyperinflation in patients with different spirometric severity of chronic obstructive pulmonary disease (COPD) based on the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. In total, 42 COPD patients and 11 age-matched healthy subjects were studied during a ramp-incremental cycling test to the limit of tolerance (W(peak)). Volume variations of the chest wall (at end expiration (EEV(cw)) and end inspiration) and its compartments (ribcage (V(rc)) and abdominal (V(ab))) were computed by optoelectronic plethysmography. At W(peak), only patients in GOLD stages III and IV exhibited a significant increase in EEV(cw) (increase of 454+/-509 and 562+/-363 mL, respectively). These patients did not significantly reduce end-expiratory V(ab), whereas patients in GOLD stage II resembled healthy subjects with significantly reduced end-expiratory V(ab) (decrease of 287+/-350 mL). In patients, the greater the increase in EEV(cw) at W(peak), the smaller the reductions in end-expiratory V(ab) and the greater the increase in end-expiratory V(rc). In chronic obstructive pulmonary disease patients with different spirometric disease severity, greater degrees of exercise-induced dynamic chest wall hyperinflation were accompanied by lower degrees of end-expiratory abdominal volume displacement and larger increases in end-expiratory ribcage volume.

Clinical features, follow-up, and reprogramming of patients with pacemaker in a secondary care center.

INTRODUCTION: During recent years, several recommendations and guidelines regarding cardiac pacing have been published in the literature. However, only a few studies have examined the implementation of these guidelines in clinical practice. The current study aimed to record and evaluate the effects of the mainstream studies, and the experience gathered by all patients who have been followed-up at the pacemaker Unit of Veroia Hospital, which is a secondary care center. METHODS AND RESULTS: Epidemiological, clinical, and electrocardiographic data were collected and studied for patients with a permanent pacemaker that have been followed-up in our hospital from 2002 to 2017. The total number of patients of the study was 3,902 (2,164 men; 55.45 %) with a mean age of 73.4 ± 12.6 years. Third degree atrioventricular (AV) block was the most common cause of pacing. Dysfunction of the sinus node involved the majority of cases with bradycardia-tachycardia syndrome. At 18 patients, the cause of permanent pacemaker implantation was carotid sinus syndrome and at 13 of them, cardio-vascular type of neurocardiogenic syncope. Dizziness and syncope were the most common symptoms. Dual-chamber pacing was the most common type of pacing, which has been increasing in recent years. In follow-up visits, the most frequent examinations concerned battery condition, as the stimulation and sensing threshold. Reprogramming of the device was required in 1,434 patients (36.75 %), especially during the first year after implantation. CONCLUSION: Pacing indications have been unchanged during all the years of the study and have been based on confirmed bradycardia and major symptoms. Reprogramming of the device was needed in an increased number of patients. HIPPOKRATIA 2018, 22(2): 75-79.

Vernakalant versus ibutilide for immediate conversion of recent-onset atrial fibrillation.

BACKGROUND: The pharmacological cardioversion of recent-onset atrial fibrillation (AF) is a challenge for the clinician. The aim of the study was to compare the efficacy, the safety, and the overall cost of intravenous (iv) administration of vernakalant, which is a relatively new atrial-selective antiarrhythmic agent, versus ibutilide, in cardioversion of recent-onset AF. METHODS: We enrolled in this study 78 patients (56 men, 22 women; mean age 63.72 ± 6.67 years) who presented with recent-onset AF. Cardioversion was attempted in 36 patients (group A: 24 men, 12 women; mean age 62.44 ± 7.24 years) by iv administration of vernakalant (3 mg/kg over 10 min and if needed after 15 min, a second dose 2 mg/kg over 10 min) while in 42 patients (group B: 32 men, 10 women; mean age 64.81 ± 6 years) iv ibutilide was administered (1 mg over 10 min and if needed after 10 min, a second dose 1 mg over 10 min). RESULTS: AF was successfully converted in 52.78 % of (n =19) patients of group A vs 52.38 % of (n =22) patients of group B (p =0.58), with an average time of conversion 11.8 ± 4.3 min for group A patients vs 33.9 ± 20.25 min for group B patients (p <0.0001). The average length of hospital stay for patients of group A was 17.64 ± 15.96 hours vs 41.09 ± 17.6 hours for patients of Group B (p <0.0001). In one patient of group A, the administration of vernakalant was discontinued due to hypotension while two other patients reported dysgeusia during their hospitalization. In three patients of group B, the administration of ibutilide was discontinued due to development of nonsustained ventricular tachycardia, which resolved with discontinuation of the drug. The cost of administered drugs was estimated at 488.22 ± 170.34 € for patients of group A vs 142.43 ± 54.45 € for patients of group B (p <0.0001), however, hospitalization costs were significantly lower in patients of group A (258.5 8± 124.73 € over 414.43 ± 100.32; p =0.002). CONCLUSION: There was no significant difference in the efficiency of converting recent-onset AF between vernakalant and ibutilide. Although vernakalant is an expensive drug, we recorded fewer side effects and more rapid restoration, which reduced the overall cost of hospitalization of these patients. HIPPOKRATIA 2017, 21(2): 67-73.

Exercice-induced bronchoconstriction among athletes: Assessment of bronchial provocation tests.

Diagnosis of exercise-induced bronchoconstriction (EIB) requires the use of bronchial provocation tests (BPTs). We assessed exercise-induced respiratory symptoms (EIRS), EIB and asthma in athletes and evaluated the validity of BPTs in the diagnosis of EIB. Rhinitis and atopy were also assessed. Athletes with (n=55) and without previous asthma diagnosis (n=145) were tested by skin prick tests, lung function and eNO measurements. EIRS were recorded and EIB was assessed by methacholine (Mch), eucapnic voluntary hyperpnoea (EVH), mannitol and exercise test. EIRS were highly reported and history of asthma was common among athletes. A high prevalence of atopy (48.7%) and allergic rhinitis (30.5%) was found. Athletes with asthma had a higher response rate to Mch and to EVH, as compared with athletes without a previous asthma diagnosis (P=0.012 and P=0.017 respectively). Report of EIRS, rhinitis and atopy were not associated with a positive BPT response. Screening athletes for EIB using BPTs is suggested, irrespective of reported EIRS or a previous asthma diagnosis.

Atrial fibrillation causing ST elevation myocardial infarction due to coronary embolism: case report and review of the literature.

BACKGROUND: Atrial fibrillation is a rare but important nonatherosclerotic cause of ST elevation myocardial infarction. CASE DESCRIPTION: We report the case of a 69 years old woman who presented to our hospital with ST elevation myocardial infarction and permanent atrial fibrillation and eventually treated with thrombus aspiration from the left descending coronary artery. CONCLUSION: We have to notice the importance of the appropriate antithrombotic treatment in atrial fibrillation to prevent systemic embolism. In selected cases with ST elevation myocardial infarction due to coronary embolism, aspiration thrombectomy with or without balloon dilatation or stenting can be safely performed. Hippokratia 2016, 20(2):160-162.

Detection of crackle events using a multi-feature approach.

The automatic detection of adventitious lung sounds is a valuable tool to monitor respiratory diseases like chronic obstructive pulmonary disease. Crackles are adventitious and explosive respiratory sounds that are usually associated with the inflammation or infection of the small bronchi, bronchioles and alveoli. In this study a multi-feature approach is proposed for the detection of events, in the frame space, that contain one or more crackles. The performance of thirty-five features was tested. These features include thirty-one features usually used in the context of Music Information Retrieval, a wavelet based feature as well as the Teager energy and the entropy. The classification was done using a logistic regression classifier. Data from seventeen patients with manifestations of adventitious sounds and three healthy volunteers were used to evaluate the performance of the proposed method. The dataset includes crackles, wheezes and normal lung sounds. The optimal detection parameters, such as the number of features, were chosen based on a grid search. The performance of the detection was studied taking into account the sensitivity and the positive predictive value. For the conditions tested, the best results were obtained for the frame size equal to 128 ms and twenty-seven features.

Dissection of the right coronary artery following blunt cardiac injury.

BACKGROUND: Coronary artery dissection is a rare complication of blunt thoracic trauma which can become rapidly lethal necessitating prompt diagnosis and treatment. Most reported cases of coronary artery injury, including dissection, involve the left anterior descending coronary artery, given its anatomical location in relation to the impact. DESCRIPTION OF CASE: A 72-year-old male, who was involved in a vehicular accident, sustained blunt thoracic trauma which resulted in isolated right coronary artery dissection and acute myocardial infarction. The culprit lesion was found in coronary angiography in the proximal right coronary artery and was successfully repaired with percutaneous coronary intervention and one drug-eluting stent placement. CONCLUSION: Traumatic dissection of coronary arteries must be suspected in blunt thoracic trauma. It can be treated with interventional management and results in a fairly good prognosis. Hippokratia 2015; 19 (3): 278-280.

Detection of wheezes using their signature in the spectrogram space and musical features.

In this work thirty features were tested in order to identify the best feature set for the robust detection of wheezes. The features include the detection of the wheezes signature in the spectrogram space (WS-SS) and twenty-nine musical features usually used in the context of Music Information Retrieval. The method proposed to detect the signature of wheezes imposes a temporal Gaussian regularization and a reduction of the false positives based on the (geodesic) morphological opening by reconstruction operator. Our dataset contains wheezes, crackles and normal breath sounds. Four selection algorithms were used to rank the features. The performance of the features was asserted having into account the Matthews correlation coefficient (MCC). All the selection algorithms ranked the WS-SS feature as the most important. A significant boost in performance was obtained by using around ten features. This improvement was independent of the selection algorithm. The use of more than ten features only allows for a small increase of the MCC value.

Hemodynamic effects of high intensity interval training in COPD patients exhibiting exercise-induced dynamic hyperinflation.

Dynamic hyperinflation (DH) has a significant adverse effect on cardiovascular function during exercise in COPD patients. COPD patients with (n = 25) and without (n = 11) exercise-induced DH undertook an incremental (IET) and a constant-load exercise test (CLET) sustained at 75% peak work (WRpeak) prior to and following an interval cycling exercise training regime (set at 100% WRpeak with 30-s work/30-s rest intervals) lasting for 12 weeks. Cardiac output (Q) was assessed by cardio-bio-impedance (PhysioFlow, enduro, PF-O7) to determine Q mean response time (QMRT) at onset (QMRT(ON)) and offset (QMRT(OFF)) of CLET. Post-rehabilitation only those patients exhibiting exercise-induced DH demonstrated significant reductions in QMRT(ON) (from 82.2 ± 4.3 to 61.7 ± 4.2 s) and QMRT(OFF) (from 80.5 ± 3.8 to 57.2 ± 4.9 s ). These post-rehabilitation adaptations were associated with improvements in inspiratory capacity, thereby suggesting that mitigation of the degree of exercise-induced DH improves central hemodynamic responses in COPD patients.