Influence of etiology on ventilatory expired gas and prognosis in heart failure.
BACKGROUND
Mechanisms leading to heart failure (HF) are numerous. Etiology-based differences are, however, frequently not taken into account when assessing results of an exercise test. The purpose of this investigation is to: (1) compare subject characteristics and ventilatory expired gas measures demonstrating clinical value between subjects with ischemic and non-ischemic HF. (2) Examine the prognostic value of HF etiology.


METHODS
71 subjects (44 male/27 female) diagnosed with compensated HF underwent exercise testing with ventilatory expired gas analysis. Mean age and ejection fraction (EF) were 51.3% (+/-12.8) and 27.0% (+/-12.5%) for the entire group. HF etiology was ischemic in 30 subjects (16 male/14 female) and non-ischemic in 41 (28 male/13 female).


RESULTS
Age (57.5+/-10.7 vs. 46.7+/-12.5, p<0.001), minute ventilation-carbon dioxide production (VE/VCO2) slope (39.5+/-9.1 vs. 32.6+/-7.7, p=0.001), and duration of phase 1 kinetics in seconds (46.0+/-23.0 vs. 30.0+/-15.6, p=0.001) were significantly higher while peak oxygen consumption (VO2) in ml O2 kg(-1) min(-1) (12.5+/-4.7 vs. 16.0+/-5.2, p=0.006) and partial pressure of end-tidal CO2 (P(ET)CO2) in mm Hg at rest (32.1+/-4.8 vs. 36.1+/-8.0, p=0.02) and peak exercise (31.7+/-4.3 vs. 36.2+/-5.9, p=0.001) were significantly lower in the ischemic group. Difference in EF did not reach statistical significance (28.4% +/-12.5%-ischemic vs. 26.1%+/-12.5%-non-ischemic, p=0.44). Ischemic etiology was additionally a significant predictor of cardiac-related events (p=0.04).


CONCLUSIONS
These findings demonstrate noninvasive indicators of cardiac function and prognosis is poorer in subjects with ischemic HF etiology. Consideration of HF etiology may therefore be prudent, particularly when considering prognosis.
Arena
Ross
R
Department of Physical Therapy, Virginia Commonwealth University, Medical College of Virginia, Health Sciences Campus, Box 980224, Richmond, VA 23298-0224, USA. raarena@vcu.edu
Tevald
Michael
M
Peberdy
Mary Ann
MA
D002245:Carbon Dioxide / Q000378:metabolism; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000503:physiopathology; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D011379:Prognosis; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology*; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology
D002245:Carbon Dioxide