Document Detail

Relationship between exercise hyperpnea, hemodynamics, and blood gases before and during glyceryl trinitrate infusion in patients with exercise-induced elevation of pulmonary artery wedge pressure.
MedLine Citation:
PMID:  9294669     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: The mechanisms underlying the excessive ventilatory response to exercise in patients with cardiac failure are still not fully understood. HYPOTHESIS: This study was undertaken to investigate the mechanisms behind exercise hyperpnea in patients with exercise-induced left ventricular dysfunction. METHODS: In 18 patients, aged 57-82 years, all with atherosclerotic lumbar aorta aneurysm and pulmonary artery wedge pressure (PAWP) > 25 mmHg during supine exercise, ventilation (V), central hemodynamics, and arterial and venous blood gases were examined during supine rest and exercise, before and during infusion of glyceryl trinitrate (GTN). RESULTS: Before GTN, exercise PAWP was 32.2 +/- 6.1 mmHg and V/V O2 was 33.8 +/- 7.7 l/l (130% of predicted). With GTN, exercise PAWP was markedly reduced to 15.3 +/- 3.8 mmHg (p < 0.001), whereas V/V O2 was only marginally reduced to 32.3 +/- 3.0 l/l (124% of predicted) (p < 0.05). Exercise physiologic dead space (VD/VT) declined from 0.31 +/- 0.16 to 0.26 +/- 0.17 (p < 0.05), while PaCO2 was reduced from 5.20 +/- 0.31 to 5.10 +/- 0.24 kPa (p < 0.05). PvO2 and cardiac output (CO), however, were unchanged below normal. CONCLUSION: The data show that exercise-induced hyperpnea was not substantially reduced by rapid normalization of PAWP and could not be related to preservation of normal PaCO2 in the presence of high VD/VT. The persistence of exercise hyperpnea and reduced PvO2 after GTN is consistent with augmented ventilatory stimuli from hypoxia-induced metabolic abnormalities in the skeletal muscles, or/and persistently reduced CO, due to changes in the integrated superior command of ventilation and circulation.
L H Jørgensen; E Thaulow; H E Refsum
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Clinical cardiology     Volume:  20     ISSN:  0160-9289     ISO Abbreviation:  Clin Cardiol     Publication Date:  1997 Sep 
Date Detail:
Created Date:  1997-10-20     Completed Date:  1997-10-20     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7903272     Medline TA:  Clin Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  773-7     Citation Subset:  IM    
Department of Clinical Physiology, Ullevål Hospital, Oslo, Norway.
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MeSH Terms
Aged, 80 and over
Blood Gas Analysis
Exercise / physiology*
Exercise Test
Heart Failure / drug therapy,  physiopathology*
Hemodynamics / drug effects,  physiology*
Hyperventilation / physiopathology*
Infusions, Intravenous
Middle Aged
Nitroglycerin / administration & dosage*
Pulmonary Wedge Pressure / physiology*
Vasodilator Agents / administration & dosage*
Reg. No./Substance:
0/Vasodilator Agents; 55-63-0/Nitroglycerin

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