Differences in pulmonary function and exercise capacity in patients with idiopathic dilated cardiomyopathy and idiopathic pulmonary arterial hypertension.
OBJECTIVE
We observed the pulmonary function and exercise capacity of idiopathic dilated cardiomyopathy (IDCM) and idiopathic pulmonary arterial hypertension (IPAH) patients using cardiopulmonary exercise testing (CPX). We evaluated and compared the two groups.


BACKGROUND
Pulmonary abnormalities and decreased exercise capacity are common in IDCM and IPAH. Little is known about the differences in these two syndromes.


METHODS
Sixty-three patients were involved the study, 23 with IDCM and 40 with IPAH. All patients underwent pulmonary function testing at rest and CPX.


RESULTS
Patients with IPAH had a higher peak respiratory frequency (32.40 ± 7.88 vs 29.60 ± 6.50 b/min), peak dead space volume/tidal volume (29.33 ± 4.55 vs 26.30  ± 3.31%), peak end-tidal partial pressure of O2 (125.18 ± 5.88 vs 115.17 ± 6.06 mm Hg), peak minute ventilation/CO2 production (50.14 ± 13.26 vs 33.50 ± 6.80 L/min/L/min), and a lower peak oxygen uptake (1262.70 ± 333.34 vs 742.76 ± 194.72 ml/min), peak minute ventilation (38.20 ± 13.07 vs 45.33 ± 12.31 L), peak oxygen uptake/heart rate (5.11 ± 1.47 vs 9.43 ± 2.79 ml/b) and peak end-tidal partial pressure of CO2 (23.73 ± 5.39 vs 35.30 ± 5.45 mm Hg) during exercise.


CONCLUSIONS
Compared to IDCM, patients with IPAH had worse pulmonary function and exercise capacity resulting from severe ventilation/perfusion mismatching and gas exchange abnormalities.
State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100037, China.
Wei-Hua
WH
Liu
State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100037, China.
Qin
Q
Luo
State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100037, China. Electronic address: fuwailiu@hotmail.com.
Zhi-Hong
ZH
Liu
State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100037, China.
Qing
Q
Zhao
State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100037, China.
Qun-Ying
QY
Xi
State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100037, China.
Zhi-Hui
ZH
Zhao
D000328:Adult; D002311:Cardiomyopathy, Dilated / Q000503:physiopathology*; D005080:Exercise Test; D017079:Exercise Tolerance; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics; D055815:Young Adult
Cardiopulmonary exercise testing; Dilated cardiomyopathy; Pulmonary arterial hypertension; Pulmonary function; Right heart failure