Exercise training without ventricular remodeling in patients with moderate to severe left ventricular dysfunction early after acute myocardial infarction.
BACKGROUND
The purpose of this study was to determine whether or not patients with moderate to severe left ventricular (LV) dysfunction benefit from exercise training starting early after acute myocardial infarction (AMI) without deteriorating LV remodeling.


METHODS
We investigated changes in exercise capacity and LV end-diastolic dimension (LVDd by two-dimensional echocardiography) before and after exercise training in 126 patients after AMI. Patients were divided into three groups according to LV ejection fraction (EF) at the beginning of exercise training: 74 patients with LVEF>/=45% (Group H), 35 patients with 35%</=LVEF<45% (Group M), and 17 patients with LVEF<35% (Group L). Exercise training was prescribed at a moderate intensity (50-60% of heart rate reserve or Karvonen's equation). Exercise capacity was assessed by peak work rate (WR) and peak oxygen uptake (VO(2)) by upright cardiopulmonary exercise test before and after 3 months of exercise training. LVDd was measured before and at 27+/-10 months of follow-up period.


RESULTS
At the baseline, Group L had a significantly lower LVEF (H 55+/-7 vs. M 40+/-3 vs. L 30+/-3%, P<0.05), significantly greater LVDd (49+/-6 vs. 52+/-7 vs. 56+/-6 mm, P<0.05), and a higher incidence of anterior infarction (P<0.01) compared with Groups H and M, whereas there were no difference in age, sex, coronary risk factors, the incidence of multivessel disease, prior myocardial infarction, peak WR or peak VO(2) among the three groups. After 3 months of exercise training, exercise capacity increased significantly (all P<0.01) in all groups. The magnitudes of the increases in peak VO(2) (%Deltapeak VO(2): 18+/-20 vs. 15+/-19 vs. 18+/-17%, NS) and peak WR (%Deltapeak WR: 17+/-17 vs. 16+/-14 vs. 15+/-13%, NS) were similar among the three groups. In addition, there was no significant correlation between %Deltapeak VO(2) and baseline LVEF. No increase in LVDd was observed in any group at follow-up (H 48+/-5 to 49+/-4 mm vs. M 53+/-8 to 52+/-8 mm vs. L 57+/-5 to 57+/-7 mm, NS in each group).


CONCLUSIONS
Patients with moderate to severe LV dysfunction benefit from exercise training starting early after AMI without deteriorating LV remodeling, with a similar magnitude of improvement in exercise capacity to that in patients with mild LV dysfunction.
Otsuka
Yoritaka
Y
Department of Medicine, Division of Cardiology, National Cardiovascular Center, Fujishirodai 5-7-1, Suita, 565-8565, Osaka, Japan.
Takaki
Hiroshi
H
Okano
Yoshiaki
Y
Satoh
Toru
T
Aihara
Naohiko
N
Matsumoto
Takahiro
T
Yasumura
Yoshio
Y
Morii
Isao
I
Goto
Yoichi
Y
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D015331:Cohort Studies; D004452:Echocardiography; D005081:Exercise Therapy / Q000379:methods*; D017079:Exercise Tolerance; D005260:Female; D006334:Heart Function Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000534:rehabilitation*; D011336:Probability; D011379:Prognosis; D018570:Risk Assessment; D012494:Sampling Studies; D012720:Severity of Illness Index; D013318:Stroke Volume; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000534:rehabilitation; D020257:Ventricular Remodeling