George E. Tzelepis

Dysfunction of the Diaphragm

Dysfunction of one or both hemidiaphragms is an underdiagnosed cause of dyspnea. Weakness or paralysis may be seen during mechanical ventilation, after surgery or trauma, with metabolic or inflammatory disorders, and with myopathy, neuropathy, or diseases causing lung hyperinflation.

Functional status and quality of life in long-term survivors of cardiac arrest after cardiac surgery

ObjectiveTo assess long-term survival, functional status, and quality of life in patients who experienced cardiac arrest after cardiac surgery. DesignProspective, observational study. SettingAn 18-bed, adult cardiac surgery intensive care unit in a tertiary teaching center. PatientsTwenty-nine cardiac surgery patients who suffered an unexpected cardiac arrest in the immediate postoperative period. InterventionsThe New York Heart Association classification and a questionnaire based on the Nottingham Health Profile were used to evaluate functional status and quality of life 4 yrs after hospital discharge. Measurements and Main Results Of the 29 patients who experienced cardiac arrest during the first 24 hrs after cardiac surgery, 27 patients (93%) were successfully resuscitated and 23 patients (79%) survived to hospital discharge. Evaluation 4 yrs postdischarge showed that, of the 29 patients, 16 patients (55%) were still alive (long-term survivors). Functional status assessment of long-term survivors revealed that 12 patients (75%) were grouped in New York Heart Association class I, 3 patients (19%) in class II, and 1 patient (6%) in class III. None of them had a neurologic deficit. They all were living independently at home, without need of any nursing care. No patient reported any abnormal emotional reactions, and six patients (38%) had mild sleep disturbances, such as early awaking. Regarding activities of daily living, 20% returned to work, 94% were able to look after their home, 96% had a social life, 63% were sexually active, 81% were involved in their hobbies, and 75% had gone on holidays. ConclusionsCardiac surgery patients who experience an unexpected cardiac arrest in the immediate postoperative period have a 55% chance of being alive 4 yrs postdischarge. The majority of these long-term survivors has a good outcome with respect to functional status and quality of life.

Contribution of Lung Function to Exercise Capacity in Patients with Chronic Heart Failure

Background: The importance of exercise capacity as an indicator of prognosis in patients with heart disease is well recognized. However, factors contributing to exercise limitation in such patients have not been fully characterized and in particular, the role of lung function in determining exercise capacity has not been extensively investigated. Objective: To examine the extent to which pulmonary function and respiratory muscle strength indices predict exercise performance in patients with moderate to severe heart failure. Methods: Fifty stable heart failure patients underwent a maximal symptom-limited cardiopulmonary exercise test on a treadmill to determine maximum oxygen consumption (VO2max), pulmonary function tests and maximum inspiratory (PImax) and expiratory (PEmax) pressure measurement. Results: In univariate analysis, VO2max correlated with forced vital capacity (r = 0.35, p = 0.01), forced expiratory volume in 1 s (r = 0.45, p = 0.001), FEV1/FVC ratio (r = 0.37, p = 0.009), maximal midexpiratory flow rate (FEF25–75, r = 0.47, p < 0.001), and PImax (r = 0.46, p = 0.001), but not with total lung capacity, diffusion capacity or PEmax. In stepwise linear regression analysis, FEF25–75 and PImax were shown to be independently related to VO2max, with a combined r and r2 value of 0.56 and 0.32, respectively. Conclusions: Lung function indices overall accounted for only approximately 30% of the variance in maximum exercise capacity observed in heart failure patients. The mechanism(s) by which these variables could set exercise limitation in heart failure awaits further investigation.

Pattern of breathing during progressive exercise in chronic heart failure.

This descriptive study analyzed serial, individual changes in the exercise pattern of breathing (POB) of patients with stable chronic heart failure (CHF). Twenty-two CHF patients underwent maximal, symptom-limited cardiopulmonary exercise test on a treadmill. Minute ventilation (VE), tidal volume (VT), breathing frequency (f), the ventilatory equivalent for carbon dioxide (VE/VCO2) and estimated dead-space to tidal volume ratio (VD/VT) were continuously recorded. The VE/VCO2 slope was calculated in every subject as the slope of the regression line relating VE to VCO2 during exercising testing. Pattern of breathing was investigated by constructing the individual VT-f relationship for each patient separately. In 16 (73%) patients (group 1), the VT-f plot was initially linear, but subsequently exhibited an inflection point at which VT stopped increasing with further increases in f. In six (27%) patients (group 2) no inflection point was evident on the VT-f relation; in four of these patients the VT-f relation remained linear but shifted to the right throughout testing, and two patients decreased VT before peak exercise achieving high breathing frequencies. Comparing group 1 to group 2 patients, they had higher VEmax (68+/-23 vs. 44+/-10 l/min, P=0.02) and VO2max (17+/-5 vs. 12+/-3 ml/min/kg, P=0.01). In contrast, the two groups did not differ in terms of age, weight, height, diagnosis, ejection fraction or VE/VCO2 slope. In conclusion, patients with CHF adopt variable breathing patterns during exercise; specific patterns are associated with greater impairment in functional capacity.

Inspiratory muscle adaptations following pressure or flow training in humans

Abstract Skeletal muscle adapts differently to training with high forces or with high velocities. The effects of these disparate training protocols on the inspiratory muscles were investigated in ten healthy volunteers. Five subjects trained using high force (pressure) loads (pressure trainers) and five trained using high velocity (flow) loads (flow trainers). Pressure training entailed performing 30 maximal static inspiratory efforts against a closed airway. Flow training entailed performing 30 sets of three maximal dynamic inspiratory efforts against a minimal resistance. Training was supervised and carried out 5 days a week for 6 weeks. Inspiratory flow rates and oesophageal pressure-time curves were measured before and after training. Peak inspiratory pressures during maximal static and dynamic efforts and peak flows during the maximal dynamic efforts were calculated. The time-to-peak pressure and rate of rise in peak pressure during maximal static and dynamic manoeuvres were also calculated before and following training. Maximal static pressure increased in the pressure training group and maximal dynamic pressure increased in the flow training group. Both groups increased the rate of pressure production (dP/dt) during their respective maximal efforts. The post-training decrease in time-to-peak pressure was proportionately greater in the flow trainers than in the pressure trainers. The differences in time-to-peak pressure between the two groups were consistent with the different effects of force and velocity training on the time-to-peak tension of skeletal muscle.

Morbid obesity and hypersomnolence in several members of an ancient royal family.

Recent studies have described an inherited basis for the sleep apnoea syndrome, as suggested by reports of families with multiple affected members.1 We present evidence indicating that several members of the Ptolemys, the royal family that ruled Egypt from 305 to 30 BC, suffered from obesity and sleep disordered breathing. Most of the information was reported by the Greek philosopher and historian Athenaeos (170–230 BC).nnThe family‘s pedigree with all affected members (shaded) is shown in fig 1. Magas I (case 1) was morbidly obese. Athenaeos reported that Magas “was weighted down with monstrous masses of flesh in his last …

Expiratory effort enhancement and peak expiratory flow in humans

Peak expiratory flow (PEF) has previously been considered an effort-dependent, non flow-limited parameter that is constrained by the force–velocity relationship of the respiratory muscles. It has also been assumed that, if the muscles were able to augment the expiratory pressure, the PEF would increase. We tested the validity of this notion in normal volunteers who were able to enhance their expiratory pressure with maneuvers utilizing the stretch-shortening cycle (greater force when contractions were immediately preceded by eccentric contractions). Five healthy volunteers [35 (2)xa0years] performed two successive maximal expiratory flow-volume maneuvers (MEFV) in rapid sequence. MEFV1 was a standard maneuver, whereas MEFV2 included a forceful inspiration to total lung capacity; a strategy designed to augment expiratory pressure via the stretch-shortening cycle. Neither maneuver included a post-inspiratory pause. We measured PEF, esophageal pressure (Pes), and the electromyographic activity of the abdominal muscles. Compared to MEFV1, MEFV2 produced greater activation of the abdominal muscles during inspiration (eccentric contraction), greater peak expiratory Pes, greater rate of rise of Pes, shorter time to PEF, but similar PEF. Our findings directly demonstrate the inability of the augmented expiratory effort to increase PEF and thus support the notion that PEF is determined by a flow-limiting mechanism and not by the velocity of muscle shortening.

Maximal dynamic expiratory pressures with fast and slow inspirations

Maximal dynamic expiratory pressures are higher when forced expiration is preceded by a fast inspiration to total lung capacity (TLC) than when preceded by a slow inspiration and a few seconds pause at TLC. We hypothesized that these pressure differences are due to the stretch-shorten cycle (SSC), which refers to enhancement of muscle force when a concentric muscle contraction is immediately preceded by an eccentric contraction. Seven volunteers [36xa0(2)xa0years; mean (SEM)] performed maximal forced expirations against minimal resistance with fast (F) or slow (S) maneuvers. F maneuvers consisted of a fast inspiration to TLC followed immediately by a fast expiration, whereas S consisted of a slow inspiration to TLC and a 4- to 5-s pause at TLC prior to forced expiration. We measured esophageal pressure (Pes), peak expiratory flow rate (PEFR), and the EMG activity of the transversus abdominis (Tr) by means of intramuscular fine-wire electrodes. The subjects performed several runs of each maneuver in a random order, and runs with the greatest expiratory Pes were analyzed. In comparison with S, F yielded greater Pes [182xa0(15) versus 167xa0(15)xa0cmH2O; P=0.003)] but similar PEFR [9.8xa0(0.7) versus 9.6xa0(0.7)xa0l/s, P>0.05] and EMG activity of the Tr during forced expiration [221xa0(31) versus 208 (34) a.u., P>0.05]. Further analysis revealed significant EMG activity of Tr during end-inspiration (eccentric contraction) with F maneuvers only [73xa0(22) versus 32xa0(17) a.u., P<0.05]. We conclude that the ability of expiratory muscles to generate greater Pes with F maneuvers is related to the sequence of an eccentric contraction, which is followed immediately by concentric contraction in a manner analogous to SSC described in skeletal muscles.

BNP Can Be an All-Cause Mortality Predictor in Sarcoidosis

Introduction: Although plasma BNP level is considered to be a useful biomarker for identifying cardiac involvement in patients with Sarcoidosis (Sarc) few data exist for its predictive role in mortality. Our aim was to investigate the predictive role of BNP on all-cause mortality. Methods: 174 consecutive patients (mean age, 48.95+/- 12. 66 years; male/female, 66/108) with biopsy proven sarcoidosis were prospectively studied. Baseline evaluation included BNP, echocardiography, Holter monitoring with ability to calculate heart rate variability indices and whether was needed cardiac MRI. Also, pulmonary function tests included total lung capacity (TLC) and diffusion lung capacity of oxygen (DLCO) were performed. Results: BNP level of all patients was 24.58±28.2 pg/dl. The baseline BNP was significantly correlated with the age (p=0.0001, r=0.341),left atrium(p=0.0001, r=0.309), interventricular septum(p=0.0001, r=0.280), posterior wall(p=0.001, r=0.240), transmitral A wave(p=0.003, r=0.228), systolic pressure of pulmonary artery(p=0.0001, r=0.382), Forced Expiratory Volume at 1 second(p=0.044, r=-0.153), DLCO(p=0.012, r=-190), the presence of premature ventricular beats(p=0.0001,r=0.281) and the 24hour derived standard deviation of NN, an index of HRV(p=0.001, p=-0.258). During a mean follow-up of 54±20 (range 1-101) months, 15 Sarc patients (36.7%) died. Their baseline BNP was significantly elevated compaired to the alive{ 69.00±48.58 vs 21.45±22,69, p Conclusion: BNP can be used as an additive predictor of all-cause mortality in patients with sarcoidosis.