Altered diaphragm position and function in patients with chronic heart failure

Background: Breathlessness is a common symptom experienced by patients with chronic heart failure (CHF) but its etiology remains controversial. Variou s molecular and histological adaptations have been reported for the diaphra gm in CHF but their functional consequences are poorly described. Aims: Thi s study aims to determine the position and function of the diaphragm in CHF patients. Methods: The diaphragm position was measured, relative to the re nal pelvis, by ultrasound in 20 CHF patients and ninety controls matched fo r age and body mass. The extent and velocity of diaphragm movement was also measured during quiet breathing and sniffing. Results: Al the end of expir ation, the diaphragm was significantly nearer to the renal pelvis in CHF pa tients (89.3 +/- 16.8 vs. 96.3 +/- 19.2 mm, P < 0.05) and also moved furthe r during quiet breathing (18.2 <plus/minus> 4.4 vs. 12.7 +/- 4.6 mm, P < 0. 001) and sniffing (23.9 <plus/minus> 7.4 vs. 18.2 +/- 5.7 mm, P < 0.005). V elocity of diaphragm movement was also increased in CHF patients during qui et breathing (26.5 <plus/minus> 8.2 vs. 15.9 +/- 6.1 mm s(-1) P < 0.001). C onclusions: These data demonstrate that the position and function of the di aphragm is altered in CHF. (C) 2001 European Society of Cardiology. Al righ ts reserved.