Document Detail

Diaphragm strength in chronic heart failure.
MedLine Citation:
PMID:  10430724     Owner:  NLM     Status:  MEDLINE    
Reduced respiratory muscle strength has been reported in chronic heart failure (CHF) in several studies. The data supporting this conclusion come almost exclusively from static inspiratory and expiratory mouth pressure maneuvers (MIP, MEP), which many subjects find difficult to perform. We therefore performed a study using measurements that are less dependent on patient aptitude and also provide specific data on diaphragm strength. In 20 male patients and 15 control subjects we measured MIP and MEP as well as esophageal and transdiaphragmatic pressure during maximal sniffs (Sn Pes, Sn Pdi) and cervical magnetic phrenic nerve stimulation (Tw Pdi). In a subgroup the response to paired phrenic nerve stimulation (pTw Pdi) at interpulse intervals from 10 to 200 ms (5 to 100 Hz) was also determined. As expected, MIP was significantly reduced in the CHF group (CHF, 69.5 cm H(2)O; control, 96.7 cm H(2)O; p = 0.01), but differences were much less marked for Sn Pes (CHF, 95.2 cm H(2)O; control, 104.8 cm H(2)O; p = 0.20) and MEP (CHF, 109.1 cm H(2)O; control, 135.7 cm H(2)O; p = 0.09). Diaphragm strength was significantly reduced (Sn Pdi: CHF, 123.8 cm H(2)O; control 143.5 cm H(2)O; p = 0.04. Tw Pdi: CHF, 21.4 cm H(2)O; control, 28.5 cm H(2)O; p = 0.0005). Paired phrenic nerve stimulation suggested a trend to increased twitch summation at 5 to 20 Hz in CHF, although this did not reach significance. We conclude that mild reduction in diaphragm strength occurs in CHF, possibly because of an increased proportion of slow fibers, but overall strength of the respiratory muscles remains well preserved.
P D Hughes; M I Polkey; M L Harrus; A J Coats; J Moxham; M Green
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of respiratory and critical care medicine     Volume:  160     ISSN:  1073-449X     ISO Abbreviation:  Am. J. Respir. Crit. Care Med.     Publication Date:  1999 Aug 
Date Detail:
Created Date:  1999-08-30     Completed Date:  1999-08-30     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  9421642     Medline TA:  Am J Respir Crit Care Med     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  529-34     Citation Subset:  AIM; IM    
Department of Cardiology and Respiratory Muscle Laboratory, Royal Brompton Hospital and National Heart and Lung Institute, London, UK.
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MeSH Terms
Diaphragm / physiopathology*
Dyspnea / physiopathology*
Electric Stimulation
Heart Failure / physiopathology*
Inspiratory Capacity / physiology
Middle Aged
Phrenic Nerve / physiopathology
Plethysmography, Whole Body
Respiratory Mechanics / physiology*
Respiratory Muscles / physiopathology*
Ventricular Function, Left / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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