Patients with early diabetic heart disease demonstrate a normal myocardial response to dobutamine.
OBJECTIVE
We sought to use quantitative markers of the regional left ventricular (LV) response to stress to infer whether diabetic cardiomyopathy is associated with ischemia.


BACKGROUND
Diabetic cardiomyopathy has been identified in clinical and experimental studies, but its cause remains unclear.


METHODS
We studied 41 diabetic patients with normal resting LV function and a normal dobutamine echo and 41 control subjects with a low probability of coronary disease. Peak myocardial systolic velocity (Sm) and early diastolic velocity (Em) in each segment were averaged, and mean Sm and Em were compared between diabetic patients and controls and among different stages of dobutamine stress.


RESULTS
Both Sm and Em progressively increased from rest to peak dobutamine stress. In the diabetic group, Sm was significantly lower than in control subjects at baseline (4.2 +/- 0.9 cm/s vs. 4.7 +/- 0.9 cm/s, p = 0.012). However, Sm at a low dose (6.0 +/- 1.3), before peak (8.4 +/- 1.8), and at peak stress (8.9 +/- 1.8) in diabetic patients was not significantly different from that of controls (6.3 +/- 1.4, 8.9 +/- 1.6, and 9.6 +/- 2.1 cm/s, respectively). The Em (cm/s) in the diabetic group (rest: 4.2 +/- 1.2; low dose: 5.0 +/- 1.4; pre-peak: 5.3 +/- 1.1; peak: 5.9 +/- 1.5) was significantly lower than that of controls (rest: 5.8 +/- 1.5; low dose: 6.6 +/- 1.5; pre-peak: 6.9 +/- 1.3; peak: 7.3 +/- 1.7; all p < 0.001). However, the absolute and relative increases in Sm or Em from rest to peak stress were similar in diabetic and control groups.


CONCLUSIONS
Subtle LV dysfunction is present in diabetic patients without overt cardiac disease. The normal response to stress suggests that ischemia due to small-vessel disease may not be important in early diabetic heart muscle disease.
Fang
Zhi You
ZY
University of Queensland, Brisbane, Australia.
Najos-Valencia
Ofelia
O
Leano
Rodel
R
Marwick
Thomas H
TH
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D003324:Coronary Artery Disease / Q000209:etiology / Q000503:physiopathology*; D048909:Diabetes Complications; D003925:Diabetic Angiopathies / Q000175:diagnosis*; D004280:Dobutamine / Q000494:pharmacology*; D025401:Echocardiography, Stress; D005260:Female; D006321:Heart / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000209:etiology*; D016277:Ventricular Function, Left / Q000187:drug effects
D000318:Adrenergic beta-Agonists; D004280:Dobutamine