Abstract 12997: Reduced Exercise Capacity Attributable to Latent Left Ventricular Diastolic Dysfunction Unmasked by Invasive Exercise Testing in Diabetic Patients After Acute Myocardial Infarction
Introduction: Left ventricular (LV) diastolic dysfunction has been reported to be associated with reduced exercise capacity in patients with diabetes mellitus (DM). However, the relation between exercise capacity and diastolic dysfunction remains unclear in DM patients after acute myocardial infarction (AMI).
Hypothesis: We hypothesized that latent LV diastolic dysfunction, a potential cause of reduced exercise capacity, may be unmasked by exercise testing in patients with DM after AMI.
Methods: A total of 25 male patients after AMI were enrolled prospectively and divided into those with DM (n=13) and those without DM (n=12). All underwent an invasive hemodynamic exercise test on a supine cycle ergometer (work rate 60 W) with simultaneous hemodynamic measurements using a conductance catheter and micro-tip manometer to analyze LV pressure-volume loops. A symptom-limited cardiopulmonary exercise test (CPX) was performed to measure exercise capacity (peak oxygen uptake, PVO2) on a separate day.
Results: There was no significant difference between non-DM and DM groups in clinical characteristics including age (Non-DM 60.4 vs DM 63.0years, NS), body mass index, prevalence of hypertension, peak CK, and medications, except for HbA1c (5.2 vs 6.8%, p=0.002). Likewise, there was no difference in hemodynamic variables at rest such as LV ejection fraction (LVEF, 50 vs 49%, NS), stroke volume (SV, 97 vs 86ml, NS), minimal LV pressure (MinP, 6.6 vs 7.5mmHg, NS), LV end-diastolic pressure (EDP, 16.4 vs 17.3mmHg, NS), and LV Stiffness index ([EDP-MinP]/SV, 0.15 vs 0.19mmHg/ml, NS) between the two groups. However, at 60W exercise, MinP (11.1 vs 16.0mmHg, p=0.03) and Stiffness index (0.27 vs 0.38mmHg/ml, p=0.039) were significantly higher and SV (137 vs 111ml, p=0.02) was significantly smaller in DM than in non-DM group. PVO2 assessed by CPX (23.6 vs 19.6 ml/kg/min, p=0.003) was significantly lower in DM than in non-DM group. Furthermore, PVO2 correlated not with LVEF (r=0.15, NS) but with Stiffness index at 60W significantly (r=-0.45, p=0.03).
Conclusions: These findings indicate that latent LV diastolic dysfunction undetected at rest is unmasked by exercise testing, and may be responsible for reduced exercise capacity in DM patients after AMI.
Author Disclosures: M. Hieda: None. S. Yasuno: None. N. Nagaya: None. H. Takaki: None. Y. Goto: None.
- © 2014 by American Heart Association, Inc.