Excessive ventilation after acute myocardial infarction and its improvement in 4 months.
The relationship between ventilation (VE) and CO2 output (VCO2) is fitted linearly. The steeper gradient implies excessive ventilation. Through an evaluation of the VE-VCO2 slopes, this study investigated whether patients with acute myocardial infarction (AMI) have excessive ventilation and whether it improved in 4 months. The VE-VCO2 slopes were determined in exercise tests at 1 and 4 months in 131 patients with AMI. Patients were divided into 3 groups according to the 1 month VE-VCO2 slope value: (i) normal (<30); (ii) intermediate (30-32); and (iii) excessive (>32). In the normal group (n=76), at 4 months, the slope decreased in 10, increased in 5 and remained unchanged in 61 patients; in the intermediate (n=31) group, 9, 2 and 20; and in the excessive (n=24) group, 15, 3 and 6, respectively, showing that the slope reduction was greater in the excessive group (p<0.01). The slope correlated with age and acute phase heart failure. The percent reduction of the slope did not correlate with these parameters. In conclusion, a substantial fraction of patients with AMI have excessive ventilation that improves in 4 months. The improvement is greater in patients with greater excessive ventilation but is not associated with an improvement in exercise capacity nor hemodynamics.
Satoh
T
T
Department of Medicine, National Cardiovascular Center, Osaka, Japan. tsatoh@cpnet.med.keio.ac.jp
Okano
Y
Y
Takaki
H
H
Matsumoto
T
T
Yasumura
Y
Y
Aihara
N
N
Goto
Y
Y
D000208:Acute Disease; D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000378:metabolism; D015444:Exercise; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000378:metabolism / Q000534:rehabilitation*; D012123:Pulmonary Ventilation; D013997:Time Factors
D002245:Carbon Dioxide