Ventilation and Gas Exchange during Exercise in Severe Chronic Heart Failure<sup>1,</sup><sup>2</sup>

Rubin, Stanley A.; Brown, Harvey V.

doi:10.1164/arrd.1984.129.2p2.s63

Cited by 77 publications

(24 citation statements)

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“…In patients with CCF during exercise the PETCO~ is typically 6-8 mmHg less than it would be in normal controls [26]. It is not clear if this reduction represents a true difference in CaCOz or if it is a result of the pulmonary abnormalities that occur in cardiac failure [34]. If the equation used to derive the Pacoz from the PETCO~ [35] is corrected assuming values of VD/VT greater than the 0.2 typically found in normal subjects (see Fig.…”

Section: Discussionmentioning

confidence: 99%

Non-invasive Measurement of Cardiac Output and Ventricular Ejection Fractions in Chronic Cardiac Failure: Relationship to Impaired Exercise Tolerance

et al. 1997

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1. The role of cardiac output limitation in the pathophysiology of exercise in patients with chronic failure remains undefined. During steady-state submaximal exercise, oxygen uptake is similar in patients and control subjects, but it is not known if cardiac output is also similar. We wished to determine if the reduced exercise tolerance of patients with chronic cardiac failure during such exercise is related to reduced cardiac output, or to peripheral factors. 2. Ten male patients with stable chronic failure and ten age-matched male normal controls were studied at rest and during exercise. Each subject performed a familiarization exercise test, a symptom-limited maximal exercise test and two submaximal exercise tests. Cardiac output was measured by a carbon dioxide rebreathing method. We also measured oxygen consumption, ventilation, Borg score of perceived exertion and venous lactate concentration, and ejection fractions. 3. As expected, patients had lower peak oxygen consumption [median (range) 1.18 (0.98-1.76) versus 1.935 (1.53-2.31) l/min; P < 0.001], lower peak venous lactate concentration but a similar overall level of perceived exertion. At the same submaximal workload, patients and control subjects had similar oxygen consumption [0.67 (0.59-0.80) versus 0.62 (0.52-0.82) l/min] and cardiac output [6.92 (5.79-9.76) versus 7.3 (5.99-10.38) l/min] but the patients had a greater perceived level of exertion [Borg score: 4 (1-6) versus 3 (1-5); P < 0.005], higher venous lactate concentration [1.6 (1-3.3) versus 1.14 (0.7-1.7) mmol/l; P < 0.05] and higher heart rate [106 (89-135) versus 87 (69-112) beats/ min; P < 0.005]. 4. During submaximal exercise at a similar absolute workload, patients with cardiac failure have a similar oxygen uptake and cardiac output but greater anaerobiosis and increased fatigue when compared with normal subjects. These findings appear to relate predominantly to changes that occur in the periphery rather than abnormalities of central cardiac function.

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Section: Discussionmentioning

confidence: 99%

Non-invasive Measurement of Cardiac Output and Ventricular Ejection Fractions in Chronic Cardiac Failure: Relationship to Impaired Exercise Tolerance

et al. 1997

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“…4,61112,15,17 However, few have studied the other major respiratory gas exchange-CO2 output (Vco2) and transport.3'7 Vco2 is linked to both the circulation through the Fick equation and respiration through the level of ventilation. In the present study, we sought to examine both hemodynamics and ventilation to understand their relation in CO2 gas transport.…”

Section: Discussionmentioning

confidence: 99%

“…4,8,9 Plasma CO2 content (Cp) was calculated from the standard formula derived from the Henderson-Hasselbach equation:…”

Section: Calculationsmentioning

confidence: 99%

Respiratory and circulatory analysis of CO2 output during exercise in chronic heart failure.

1991

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Background. The output of carbon dioxide (Vco2) is controlled by both hemodynamics and ventilation. To understand Vco2 in patients who have chronic heart failure (CHF), we studied 14 patients who had New York Heart Association functional class III failure by measurements of hemodynamics, ventilation, and arterial and venous blood gases at rest and at 50 W of cycle ergometry exercise.Methods and Results. Fick principle analysis ofVco2 showed that because of a limited increase in cardiac output, CHF patients widened their venoarterial CO2 content difference from 4.9±3.5 ml/dl at rest to 11.1±4.0 ml/dl with exercise (p<0.05). This increase in CO2 content difference was achieved with no change in venous CO2 content (from 54.3+±3.3 ml/dl at rest to 54.5 +4.8 ml/dl at exercise,p=NS); however, there was a decrease of arterial CO2 content (from 49.4±3.7 ml/dl at rest to 43.4±2.3 ml/dl with exercise, p<0.05). Modeling of the CO2 tension-content relation showed that there would have been a small, nonproportional increase of venous CO2 content as venous CO2 tension increased from 43.2±+1.8 mm Hg at rest to 55.3+±4.2 mm Hg during exercise (p<0.05); however, the development of metabolic acidosis during exercise entirely blunted the increase of CO2 content. In contrast, both the shape of the tension-content relation and the acidosis of exercise further influenced the decrease of arterial

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“…arterial hypoxaemia is not a typical finding in CHF [41]. Therefore, the correlations between D L (or D M ) and markers of exercise capacity might not reveal a causal relationship but reflect a common determinant, namely poor haemodynamic response to exercise with high left ventricular filling pressures and consecutive increased pulmonary capillary pressures.…”

Section: Respiratory Gas Exchange Parametersmentioning

confidence: 99%

Exercise Tolerance Measurements in Pulmonary Vascular Diseases and Chronic Heart Failure

Piepoli

2009

Respiration

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The hallmark symptoms of heart failure are dyspnoea and fatigue during exercise. In recent years, the physiologic response to progressive exercise using direct measures of ventilation and gas exchange, commonly termed the ‘cardiopulmonary exercise test’ (CPET), has evolved into an important clinical tool in the management of patients with heart failure. CPET provides a global assessment of the integrated response to exercise involving the pulmonary, cardiovascular, haematopoietic, neuropsychological and skeletal muscle systems. This information cannot be obtained through investigation of the individual organ system in isolation. The noninvasive, dynamic physiologic overview permits the evaluation of both submaximal and peak exercise responses providing the physician with relevant information for clinical decision making. The use of CPET in the management of chronic heart failure patients is increasing, with the understanding that resting pulmonary and cardiac function testing cannot reliably predict exercise performance and functional capacity and that, furthermore, overall health status and prognosis are better predicted by indices of exercise tolerance than by resting measurements.

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Ventilation and Gas Exchange during Exercise in Severe Chronic Heart Failure^1,²

Cited by 77 publications

References 0 publications

Non-invasive Measurement of Cardiac Output and Ventricular Ejection Fractions in Chronic Cardiac Failure: Relationship to Impaired Exercise Tolerance

Non-invasive Measurement of Cardiac Output and Ventricular Ejection Fractions in Chronic Cardiac Failure: Relationship to Impaired Exercise Tolerance

Respiratory and circulatory analysis of CO2 output during exercise in chronic heart failure.

Exercise Tolerance Measurements in Pulmonary Vascular Diseases and Chronic Heart Failure

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Ventilation and Gas Exchange during Exercise in Severe Chronic Heart Failure1,2

Cited by 77 publications

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Non-invasive Measurement of Cardiac Output and Ventricular Ejection Fractions in Chronic Cardiac Failure: Relationship to Impaired Exercise Tolerance

Non-invasive Measurement of Cardiac Output and Ventricular Ejection Fractions in Chronic Cardiac Failure: Relationship to Impaired Exercise Tolerance

Respiratory and circulatory analysis of CO2 output during exercise in chronic heart failure.

Exercise Tolerance Measurements in Pulmonary Vascular Diseases and Chronic Heart Failure

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Ventilation and Gas Exchange during Exercise in Severe Chronic Heart Failure^1,²