Diastolic function and functional capacity after a single session of continuous positive airway pressure in patients with compensated heart failure.
OBJECTIVE
The effects of acute continuous positive airway pressure therapy on left ventricular diastolic function and functional capacity in patients with compensated systolic heart failure remain unclear.


METHODS
This randomized, double-blind, placebo-controlled clinical trial included 43 patients with heart failure and a left ventricular ejection fraction <0.50 who were in functional classes I-III according to the New York Heart Association criteria. Twenty-three patients were assigned to continuous positive airway pressure therapy (10 cmH2O), while 20 patients received placebo with null pressure for 30 minutes. All patients underwent a 6-minute walk test (6MWT) and Doppler echocardiography before and immediately after intervention. Clinicaltrials.gov: NCT01088854.


RESULTS
The groups had similar clinical and echocardiographic baseline variables. Variation in the diastolic function index (e') after intervention was associated with differences in the distance walked in both groups. However, in the continuous positive airway pressure group, this difference was greater (continuous positive airway pressure group: Δ6MWT = 9.44+16.05×Δe', p = 0.002; sham group: Δ6MWT = 7.49+5.38×Δe'; p = 0.015). There was a statistically significant interaction between e' index variation and continuous positive airway pressure for the improvement of functional capacity (p = 0.020).


CONCLUSIONS
Continuous positive airway pressure does not acurately change the echocardiographic indexes of left ventricle systolic or diastolic function in patients with compensated systolic heart failure. However, 30-minute continuous positive airway pressure therapy appears to have an effect on left ventricular diastolic function by increasing functional capacity.
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu (UNESP), Botucatu, SP, Brazil.
Marjory Fernanda
MF
Bussoni
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu (UNESP), Botucatu, SP, Brazil.
Gabriel Negretti
GN
Guirado
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu (UNESP), Botucatu, SP, Brazil.
Luiz Shiguero
LS
Matsubara
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu (UNESP), Botucatu, SP, Brazil.
Meliza Goi
MG
Roscani
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu (UNESP), Botucatu, SP, Brazil.
Bertha Furlan
BF
Polegato
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu (UNESP), Botucatu, SP, Brazil.
Suzana Tanni
ST
Minamoto
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu (UNESP), Botucatu, SP, Brazil.
Silméia Garcia Zanati
SG
Bazan
Departamento de Clínica Médica, Faculdade de Medicina de Botucatu (UNESP), Botucatu, SP, Brazil.
Beatriz Bojikian
BB
Matsubara
D000328:Adult; D000368:Aged; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D003971:Diastole / Q000502:physiology*; D004311:Double-Blind Method; D015150:Echocardiography, Doppler / Q000379:methods; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D054143:Heart Failure, Systolic / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016277:Ventricular Function, Left / Q000502:physiology*