Angiotensin-converting enzyme inhibitors in preventing remodeling and development of heart failure after acute myocardial infarction: results of the German multicenter study of the effects of captopril on cardiopulmonary exercise parameters (ECCE).

Early action of angiotensin-converting enzyme (ACE) inhibitors after myocardial infarction (MI) has been shown in large scale clinical trials to reduce mortality over the first weeks. However, the mechanisms involved are yet unclear and several trials showed a tendency toward a small, albeit unexpected, rise in cardiogenic shock or mortality. Since cardiopulmonary exercise testing (CPX) has become a "gold standard" in assessing the severity of heart failure, we studied--after finishing a pilot trial--the effect of captopril versus placebo in 208 patients who were individually titrated (titrated dose, mean 46/69 mg/day after 7 days/4 weeks, respectively) in order to preserve their blood pressure in the acute phase of myocardial infarction; we followed the development of congestive heart failure (CHF) over 4 weeks by measuring oxygen consumption. After 4 weeks, overall oxygen consumption at the anaerobic threshold (VO2-AT; 13.7 vs 13.1), maximal oxygen consumption (VO2max 19.3 vs 18.9 mL/kg per min) and exercise duration (896 vs 839 sec) showed a nonsignificant difference in favor of the captopril group. The predefined, categorized, combined endpoint of severe heart failure or death (heart failure necessitating ACE inhibition, VO2max < 10 mL/kg per min, or death) was significantly reduced in the captopril group (n = 7/104) versus placebo (n = 18/104; p = 0.03). Differences were mainly caused by fewer CHF events (delta n = 10). We conclude that ACE inhibition with individualized dose titration markedly reduces the 4-week incidence of severe heart failure or death; > 10 patients per 100 treated gained major benefits from this therapy.

[Rickettsiosis of the typhus fever type. Its joint appearance with a left-ventricular thrombus and single-vessel coronary disease]. / Rickettsiose vom Fleckfiebertyp. Gemeinsames Auftreten mit einem linksventrikulären Thrombus und einer koronaren Ein-Gefäss-Krankheit.

A 44-year-old German fell ill in Libya, where he had been living for 10 years, with high fever, rigor and a nonitching centrifugally spreading macular rash, which had spared the head, hands and soles. In addition, a systolic cardiac murmur was heard. The Weil-Felix reaction had a titre rising within 3 days from 1:160 to 1:640, confirming the diagnosis of rickettsial disease, the total clinical picture indicating typhus. On treatment with chloramphenicol (1 g three times daily i.v.) the fever subsided within 5 days. On the ninth day treatment was changed to oral doxycyclin, 200 mg daily for 3 weeks. Echocardiography surprisingly revealed a floating thrombus, about 4 x 8 cm, attached to the hypo- and even akinetic apex of the left ventricle. In addition there was single-vessel coronary disease. Since the segmental contraction abnormality persisted after the typhus had been cured, a causal connection with the rickettsial disease is unlikely. The thrombus was removed at the time of a aortocoronary bypass operation: his course has been unremarkable since then.

[Cardiopulmonary capacity of patients with congenital heart defects in childhood, adolescence and adulthood]. / Kardiopulmonale Leistungsfähigkeit bei Patienten mit angeborenen Herzfehlern im Kindes-, Adoleszenten- und Erwachsenenalter.

Cardiopulmonary exercise capacity is a significant criterion of life quality. The evaluation of the exercise capacity is important to answer patient-questions concerning every day activity, choice of profession, sports-activity etc. We performed cardiopulmonary exercise testing in 38 patients (age 33.6 +/- 12.0 years, 18 women, 20 men) with different congenital heart disease (5 after surgical repair of tetralogy of fallot, 2 after Mustard-operation in transposition of the great arteries (TGA), 1 single ventricle, 14 atrial septal defect (ASD), 8 ventricular septal defect (VSD), 8 pulmonary valve stenosis (PS)) during outpatient routine control. All tests were performed on upright bicycle with continuous ramp program of 20 Watt increase/minute. Ventilatory values as O2-uptake, CO2-production, minute ventilation (VE) were measured breath-by-breath. Max. VO2 was reduced as average value for every patient group (tetralogy of fallot 60.2 +/- 20.3% pred., TGA 53.0 +/- 0.0% pred., single ventricle 35% pred., closed ASD 71.9 +/- 23.8% pred., ASD 62.7 +/- 30.0% pred., VSD 64.1 +/- 11.7% pred., PS 73.2 +/- 16.0% pred.). Anaerobic threshold was reduced in tetralogy of fallot (35.9 +/- 12.2% pred. max. VO2) and in single ventricle (28.3% pred. max. VO2). In comparison with clinical classification of exercise capacity we found for max. VO2 differences in 23/38 patients. 22/23 patients reported no exercise limitation but had reduced max. VO2. One patient had a normal max. VO 2 but complaints of exercise dyspnoea. For anaerobic threshold 18/38 patients had discrepancies in objective and subjective estimation of their exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cardiopulmonary exercise capacity in VVI stimulation in patients with high grade AV block]. / Kardiopulmonale Belastbarkeit unter VVI-Stimulation bei Patienten mit höhergradigen AV-Blockierungen.

VVI-pacemaker patients with high-grade atrioventricular block were subjected to cardiopulmonary exercise testing. An interindividual comparison was made between patients with intermittent intrinsic rhythm (n = 9) and patients with permanent VVI-stimulation (n = 15). Patients with intermittent sinus rhythm on exercise had no significant increase in exercise capacity as quantified by the O2-uptake at the anaerobic threshold. An intermittent sinus rhythm is of no relevance to therapeutic decisions, such as choosing the appropriate pacing mode. Exercise capacity is determined by multiple, partly peripheral factors.

[Predictive value of ergospirometry in preoperative assessment of risk factors before lung resections]. / Prädiktiver Wert der Spiroergometrie in der präoperativen Abschätzung von Risikopatienten vor Lungenresektionen.

Surgical resection for lung cancer provides the only real chance for cure. However, there is a high risk of postoperative complications including death for patients with pulmonary dysfunction. Therefore preoperative identification of patients at risk is necessary. Apart from history and physical examination three tests are currently used: 1. resting lung function (RFL), 2. invasive measurement of pulmonary vascular resistance (PVR) and 3. exercise testing with measurement of oxygen consumption (VO2). Main studies in the literature report the probability of abnormal tests for prediction of pulmonary complications (positive predictive value) and the probability of normal tests for prediction of uneventful outcome (negative predictive value) as follows: [table: see text] In conclusion, the "ideal" test predictive for morbidity and mortality after lung resection has not been found. The positive predictive values of RLF and PVR are disappointing, while the negative predictive values are acceptable. Measurement of VO2 is simple, noninvasive and might predict survivable morbidity, as suggested in the literature. Obviously, additional studies are necessary.

[Non-invasive measurement of stroke volume in steady-state and unsteady-state workload with CO2 rebreathing]. / Nichtinvasive Messung des Herzzeitvolumens während Steady-State- und Unsteady-state-Belastungen mittels CO2-Rückatmung.

During steady-state exercise the noninvasive measurement of cardiac output using CO2-rebreathing has been found to be reliable and reproducible. In contrast, reliability of cardiac output measurement during unsteady state exercise is unclear. The ability to determine cardiac output (CO) noninvasively during steady state and unsteady state exercise was assessed in nine healthy students aged 25.7 +/- 7.4 years. Two cycle ergometer exercise tests were performed, one maximal unsteady state test with 25 watts increment of workload per minute, and also one steady state test at 25, 50, and 75 percent of max. VO2. CO was measured using the equilibrium CO2-rebreathing technique during unloaded cycling in both tests, at 75 and 150 watts in the unsteady state test and at all workloads during steady state exercise. Mean max. VO2 was 31.4 +/- 5.9 ml/kg/min and mean VO2 at the anaerobic threshold 24.5 +/- 7.2 ml/kg/min, respectively. During unsteady state exercise the CO2/workload slope was linear (r = 0.973), as with steady state exercise (r = 0.976). There was no difference concerning the slopes of both curves, but the elevation of VO2 with unsteady state exercise was lower, compared to steady state (p < 0.005). The relationships of CO/VO2 during unsteady and steady state exercise were best expressed by linear equations: CO = 7.49 x VO2 + 2.35 (r = 0.866) and CO = 8.24 x VO2 + 1.4 (r = 0.852), respectively. Similar to VO2/workload, both regressions did not have different slopes, but did have different elevations (p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical experiences with four newly developed, surface modified stimulation electrodes]. / Klinische Erfahrungen mit vier neuartigen, oberflächenbehandelten Stimulationselektroden.

Newly developed pacing electrodes with so-called porous surfaces promise a significantly improved post-operative pacing and sensing threshold. We therefore investigated four newly developed leads (ELA-PMCF-860 n = 10; Biotronik-60/4-DNP n = 10, CPI-4010 n = 10, Intermedics-421-03-Biopore n = 6) connected to two different pacing devices (Intermedics NOVA II, Medtronic PASYS) in 36 patients (18 men, 18 women, age: 69.7 +/- 9.8 years) suffering from symptomatic bradycardia. The individual electrode maturation process was investigated by means of repeated measurements of pacing threshold, electrode impedance in acute, subacute, and chronic phase, as well as energy consumption and sensing behavior in the chronic phase. However, with the exception of the 4010, the investigated leads showed largely varying values of the pacing threshold with individual peaks occurring from the second up to the 13th week. All leads had nearly similar chronic pacing thresholds (PMCF 0.13 +/- 0.07; DNP 0.25 +/- 0.18; Biopore 0.15 +/- 0.05; 4010 0.14 +/- 0.05 ms). Impedance measurements revealed higher, but not significantly different values for the DNP (PMCF 582 +/- 112, DNP 755 +/- 88, Biopore 650 +/- 15, 4010 718 +/- 104 Ohm). Despite differing values for pacing threshold and impedance, the energy consumption in the chronic phase during threshold-adapted, but secure stimulation (3 * impulse-width at pacing threshold) were comparable.

[Treatment of hydrofluoric acid burns]. / Therapie der Flusssäureverätzung.

A chemical-plant worker sustained hydrofluoric acid burns during cleaning procedures. Intra-arterial perfusion and intralesional injections of calcium gluconate solution prevented progression of the burns into deeper tissue layers.

Noninvasive control of the early postimplantation period.

Modern programmable pacemakers often incorporate features that allow one to perform a series of diagnostic maneuvers to aid in postimplantation surveillance. These features often include noninvasive measurements of thresholds, lead impedance, and intracardiac electrogram recognition via telemetry circuits. Interindividual differences in these measurements are so great that one must utilize individual comparisons for longitudinal studies of reliability. While these devices allow "fine tuning" of individual units, they require major time-consuming efforts and add to the total device costs.

[Activity-initiated rate-adapted pacemaker therapy. Clinical results]. / Aktivitätsgesteuerte frequenzadaptierende Schrittmachertherapie. Klinische Ergebnisse.

In a prospective study of 23 patients the clinical effects of rate-adapted activity-sensed (by mechanical resonance oscillations) pacing (Activitrax system) were tested over a mean period of 8.1 +/- 3.8 months. This form of pacemaker treatment was used when, after exercise and on long-term ECG monitoring, the spontaneous heart rate had not exceeded 85 beats per min and there had been symptoms of decreased exercise tolerance. Lasting improvement in physical exercise tolerance was achieved in 11 of 17 patients after changing from fixed-rate to rate-adapted pacing. Treadmill ergometry, randomised in the fixed-rate or rate-adapted mode, brought about a significant rise in exercise tolerance (P greater than 0.01). Contrary to results after external influences, insufficient rate increases in five patients in the course of static stress was of clinical significance and thus narrow the indications for this type of pacing.

[Chronic right heart failure after implantation of a cava filter]. / Chronische Rechtsherzbelastung nach Implantation eines Kavasperrfilters.

HISTORY AND CLINICAL FINDINGS: A 39-year-old woman complained of dyspnoea and increasing abdominal pressure sensation. A Greenfield filter had been implanted into her inferior vena cava (IVC) 4 years previously because of pulmonary embolism from a deep vein thrombosis after a hysterectomy with abscess formation. Physical examination revealed neck vein congestion, jaundiced sclerae, a tense abdominal wall, ascites and a soft machinery murmur in the paraumbilical region. INVESTIGATIONS: Transaminase activities were slightly raised (GOT 38 U/I, GPT 20 U/I), but total bilirubin and direct bilirubin were markedly elevated (2.9 mg/dl and 1.1 mg/dl, respectively). There was no evidence of cholestasis or decreased liver synthesis. Ultrasound showed marked dilatation of the IVC and hepatic veins, and echocardiography revealed right ventricular enlargement with grade II tricuspid regurgitation. Calculated pulmonary arterial systolic pressure averaged 50 mmHG. Colour-coded Doppler sonography demonstrated an aorto-caval shunt at the level of the filter in the IVC and penetration of a filter strut into the aortic lumen. TREATMENT AND COURSE: After removing the ascitic fluid by fluid and sodium restriction, and administration of an aldosterone antagonist and a loop diuretic, the A-V fistula was closed surgically and the filter removed. Three months after operation she was put on phenprocoumon (Quick value 20-30%). At the latest outpatient examination, 6 months after the operation, she was free of symptoms. CONCLUSION: As filter implantation in the IVC may produce severe complications, indications for it need to be demonstrated by further studies of its efficacy.

[Methodologic aspects of modern, computerized ergospirometry (CPX): ramp program, constant workload test and CO2 rebreathing method]. / Methodische Aspekte der modernen, computerisierten Ergospirometrie (CPX): Rampenprogramm, konstanter Belastungstest und CO2-Rückatmungsmethode.

The cardiopulmonary exercise testing (CPX) is a non-invasive method for the evaluation of the cardiopulmonary exercise capacity. Based upon the recent technical progress in gas analysers and personal computers today it is possible to perform CPX with acceptable time consumption, high practicability and high reproducibility of the results in many clinical areas. CPX is realized on a bike or on a treadmill. In bicycle CPX a ramp program (increase of x watts per minute) or a constant workload test (p.e. with 75% of the watts at anaerobic threshold) are performed. Furthermore, an estimation of the cardiac output using CO2-rebreathing method can be realized during a ramp program or a constant workload test. In this paper, also the CPX parameters of the ramp program, the constant workload test and the CO2-rebreathing method are defined and explained. The normal values of CPX are dependent of age, sex, body weight and exercise program. This should be kept in mind in interpreting the measured CPX data. Additionally, the performance of a routine CPX will be reported. Furthermore, the accuracy of the CPX parameters and the potential influences on the data will be discussed. Finally, problems during measurements and their analysis will be clarified.

[Methodologic and clinical comparison of four different ergospirometry systems]. / Methodischer und klinischer Vergleich von vier verschiedenen Ergospirometriesystemen.

The clinician who uses cardio-pulmonary exercise testing (CPX) systems relies on the technical informations from the device producers. In this paper, the practicability, the accuracy and the safety of four different, available CPX systems are compared in the clinical area, using clinically orientated criteria. The exercise tests were performed in healthy subjects, in patients with cardiac and/or pulmonary disease as well as in young or old people. The comparison study showed, that there were partially large differences in device design and measurement accuracy. Furthermore, our investigation demonstrated that beneath repetitive calibrations of the CPX systems a frequent validation of the devices by means of a metabolic simulator is necessary. Problems in calibration can be caused by an inadequate performance or by unclean calibration gases. Problems in validation can be due to incompatibility of the CPX device and the validator. The comparison study of the four different systems showed that in the future standards for CPX testing should be defined.

[Cardiopulmonary capacity in patients with coronary heart disease]. / Kardiopulmonale Leistungsfähigkeit bei Patienten mit koronarer Herzkrankheit.

Cardiopulmonary exercise testing (CPX) allows a non-invasive control of the cardiopulmonary exercise capacity. In this study, we wanted to investigate if the CPX can be securely, practicably, and accurately performed in patients with invasively documented coronary heart disease (CHD). Furthermore, we wanted to find out the clinical value of CPX in CHD diagnosis. The CPX measurements (symptom-limited; ramp program with 20 Watts increase/min; semi-supine position; continuous registration of the cardio-circulatory parameters (HR, RR, ECG), of the gas exchange parameters (O2, CO2) and of the ventilation) in 101 patients have shown that CPX is secure, accurate, and practicable. The day-to-day reproducibility is high (r > 0.8). The respiratory anaerobic threshold can be manually evaluated by means of the PET O2 criterion in 95% of the cases. The CCS-classification of angina pectoris could not accurately describe the cardiopulmonary exercise capacity as compared to the Weber-classification. The disadvantage of the Weber-classification is that it does not respect the age-, sex- and weight-dependent differences of the normal values. Our own data and results from the literature demonstrate that the anaerobic threshold, the maximum VO2 and the maximum O2-pulse are the more reduced the more coronary arteries are involved, the more reduced the left ventricular function is. But, nevertheless, the range of values shows large overlaps so that an exact differentiation, based upon these parameters, is not possible. Patients with similar functional results or degree of reduced exercise capacity have different morphological alterations. Most patients demonstrated typical ischemic cascade with anaerobic threshold, ST-segment alterations, angina pectoris and, finally, reduced max. VO2. In conclusion, CPX does not replace the traditional methods of non-invasive and invasive ischemia detection, but enables secure, practicable, and accurate measurements of the individual cardiopulmonary exercise capacity and the interaction between muscles, heart, circulation, and lungs. Possibly, CPX can be used in the near future for identifying CHD patients with low, medium or high risk.

[Effect of a single blood donation on ergo-spirometrically determined cardiopulmonary performance capacity of young healthy probands]. / Einfluss einer einmaligen Blutspende auf die ergospirometrisch bestimmte kardiopulmonale Leistungsfähigkeit bei jungen gesunden Probanden.

Autologous blood donation is an established method for an effective reduction of the blood-transfusion-associated infectious diseases (hepatitis, HIV infections, etc.) in elective surgical procedures. The aim of the study was to investigate the effects of a blood donation of 450 ml on the cardiopulmonary exercise capacity in 16 apparently healthy young subjects. The 24 cardiopulmonary exercise tests were performed on a bicycle ergometer (Ergoline 900) in a semisupine position, using a ramp program (+20 watt/min) 1-7 days before and 2 days after blood donation. By means of continuous breath-by-breath measurements of the gas exchange (VO2, VCO2) and ventilation parameters (minute ventilation VE), as well as of the routine parameters (heart rate, blood pressure, work rate) during incremental exercise the respiratory anaerobic threshold VO2AT, the maximum VO2 (VO2max and the maximal working capacity (max. WR) were determined. Serum hemoglobin concentration was significantly (p < 0.0005) reduced from 14.5 +/- 1.0 to 13.0 +/- 1.4 g/dl after blood donation. The ventilatory anaerobic threshold (before: 68.5 +/- 17.0; after: 52.0 +/- 20.3% pred. max. VO2), the max. VO2 (before: 124.2 +/- 21.3; after: 110.2 +/- 23.2% pred. max. VO2) and max. WR (before: 287.1 +/- 75.6; after 265.5 +/- 76.2 watt) fell significantly (VO2AT: p < 0.0005; max. VO2: p < 0.0005; max. WR: p < 0.025). Heart rate and minute ventilation showed a steeper increase (dHR/dWR: before: 0.31 +/- 0.06; after: 0.34 +/- 0.05 beats/min/watt; dVE/dWR: before: 0.29 +/- 0.05; after: 0.31 +/- 0.05 l/watt) in relation to the increase in WR after blood donation as compared to the test before.(ABSTRACT TRUNCATED AT 250 WORDS)

[Local vascular complications in heart catheter studies]. / Lokale Gefässkomplikationen bei Herzkatheteruntersuchungen.

Over a period of 30 months (1. 1. 89-30. 6. 91) 3516 patients who had either a diagnostic (2718) or therapeutic (798) heart catheterization were followed for local vascular complications. 774 patients were investigated prospectively. The following complications were observed in declining frequency: 1. relevant haematoma, 2. pseudoaneurysm, 3. arteriovenous fistula, 4. arterial thrombosis/dissection, 5. venous thrombosis, 6. rupture of the vessel, 7. local infection. The total complication rate was 2.22%. With prospective investigation it was significantly higher (3.23%) than with retrospective investigation (1.93%). The complication rate was also significantly higher in therapeutical procedures (3.76%) than in diagnostic catheterizations (1.76%). Factors associated with a significantly higher incidence of local vascular complications were age (p < 0.01), female gender (p < 0.025), manifest arterial hypertension (p < 0.005), aortic regurgitation (p < 0.1), peri-interventional medication with acetylsalicylic acid and full dose heparin (p < 0.001), full dose heparin alone (p < 0.001) or fibrinolysis-therapy (p < 0.025). Relevant technical factors were: duration of the procedure, duration of the placement of the catheter-sheath, French size of the catheter, left femoral access, arterial and venous access at one extremity. In about half of the cases the treatment of the complications was conservative, in the other half it was surgical (51%). In relation to all surgically treated patients the percentage of emergency operations was 25%, the percentage of reoperations was 15%.

Cardiopulmonary exercise testing (CPX) and transthoracic bioimpedance measurements: new tools for an "old disease" (congestive heart failure).

The purpose of the study was to examine the cardiovascular and cardiopulmonary exercise capacity in patients with symptomatic congestive heart failure more exactly than with conventional investigations, using the simultaneous non-invasive determination of the gas exchange parameters (ergospirometry, CPX) and of the hemodynamic (transthoracic bioimpedance). The reproducibility of the data were measured with each method with repeated tests under the same conditions in healthy subjects and patients with myocardial failure. Therefore we tested 15 patients with documented congestive heart failure repeatedly on a bicycle (semi-supine, +15 watts/min, symptom-limited). The ergospirometric (VO2, VCO2, RER = VCO2/VO2, max. VO2, VO2AT, VE, RR) and the bioimpedance-parameters (CI, SVI, HR) were measured simultaneously during rest and exercise. According to Wasserman et al. we used the VO2AT and the max. VO2 to assign the patients to the different Weber classes: Weber A: greater than 20 ml/min/kg max. VO2, greater than 14 ml/min/kg VO2AT; Weber B: 16 to 20 ml/min/kg max. VO2, 11 to 14 8 to 11 ml/min/kg VO2AT; Weber D: 6 to 10 ml/min/kg max. ml/min/kg VO2AT; Weber C: 10 to 16 ml/min/kg max. VO2, 8 to 11 ml/min/kg VO2AT; Weber D: 6 to 10 ml/min/kg max. VO2, 4 to 8 ml/min/kg VO2AT: Weber E: less than 6 ml/min/kg max. VO2, less than 4 ml/min/kg VO2AT. The V-slope-method according to Beaver et al. allowed for the determination of the anaerobic threshold in 13/15 patients. 2/15 patients didn't reach the anaerobic threshold. Oscillations of the gas exchange parameters due to Cheyne-Stokes-breathing were found in 9/15 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of different body-exercise modes on the rate response of the temperature-controlled pacemaker Nova MR.

In order to evaluate the effect of different modes of physical exercise on the rate response of the temperature-controlled Nova MR, parameters such as temperature behaviour and correlation of work load to pacing rate were investigated using different types and protocols of stress testing. This study considered 21 patients (age: 66 +/- 12 y). The indications for the Nova MR were AV block (n: 14) and sick sinus syndrome (n: 7). The patients performed two different types of exercise (treadmill n: 13, bicycle n: 14) based on different protocols. We registered the surface ECG, pacing rate, exercise time, and (via data transmission by the RX 2000 programmer) blood temperature and pacing rate. An adequate rate response could be achieved with all the different types of exercise and protocols using more sensitive program settings. The type of stress testing used to adjust or evaluate the Nova MR seems to be secondary, although cycling as compared with treadmill exercise resulted in a slightly weakened reaction of temperature and pacing rate. Our investigations revealed a good correlation between work load and pacing rate independent of the type of stress testing. The initial DIP (48%) is not a constant phenomenon and showed inter- and intraindividual variations. Impressive psychological influences also exhibited an effect on temperature and pacing rate, sometimes preventing a DIP response. During exercise at lower work loads (under 50 watts, shorter than 3-4 min) the rate response of the Nova MR--without any detected DIP--is often delayed due either to a decrease or to a late and flat increase in temperature. An additional fast-reacting sensor could be advantageous in triggering the initial rate response in such cases.

[Comparison of four different methods for respiratory determination of the anaerobic threshold in normal people, and heart- and lung patients]. / Vergleich der vier verschiedenen Methoden zur respiratorischen Bestimmung der anaeroben Schwelle bei Normalpersonen, Herz- und Lungenkranken.

We analyzed 128 cardiopulmonary exercise tests (CPX), performed in normal subjects (n = 31), in patients with coronary artery disease (n = 41), with chronic heart failure before (n = 14) and after (n = 14) application of oral PDE-inhibitors and in patients with HIV-infection on a bicycle-ergometer in semi-supine position using a ramp-program (dependent on study-population with 15, 20 or 35 Watt/min increases) with respect to the ability to determine the respiratory anaerobic threshold non-invasively, using the main criteria described by Wasserman et al.: the V-slope-method according to Beaver, the increase of the ventilatory equivalent for O2 (VE/VO2), the increase of the end-tidal PO2 (PETO2) and the increase of the respiratory quotient (RQ) during exercise. In the different study-populations we calculated the detection rates of the AT for each criteria separately. The typical changes in the end-tidal PO2 (124/128 = 96.9%) and the V-slope-method (119/128 = 92.9%) were the most reliable parameters to detect the anaerobic threshold. The characteristic changes of the ventilatory equivalent for O2 (VE/VO2) and of the respiratory quotient (RQ) we found in 100/128 (= 78.1%) and in 107/128 (= 83.6%) of the tests respectively. 86/128 tests (67.2%) showed typical changes in all four mentioned criteria. In another 24/128 tests (19.8%) three of four criteria were fulfilled. Therefore, our investigations showed that in 110/128 cases (85.9%) the AT could be determined by typical changes by means of at least three of the four described parameters. In 15/128 (11.7%) tests only two of four criteria were fulfilled.(ABSTRACT TRUNCATED AT 250 WORDS)