Uncomplicated type 1 diabetes and preclinical left ventricular myocardial dysfunction: Insights from echocardiography and exercise cardiac performance evaluation

Abstract Objectives Left ventricular (LV) diastolic dysfunction is considered the earliest manifestation of diabetic cardiomyopathy. Whether LV abnormalities identified at rest by echocardiography predict peak exercise LV performance in uncomplicated type 1 diabetes mellitus (DM1) is largely unknown. Research design and methods We evaluated LV size, mass, and functions and peak exercise LV performance in 25 subjects with uncomplicated DM1 (median disease duration 13.5 years, 1–30 years) and in 56 non-DM subjects (24 hypertensive (HT) and 32 normotensive (NT)). Overt coronary heart disease, significant microangiopathy and central autonomic neuropathy were minimized by exclusion criteria. Peak exercise LV stroke index (SVi), cardiac index (COi), LV ejection fraction (EF), LV end-diastolic and end-systolic volumes were assessed noninvasively. No subject was on cardiovascular medications at the time of evaluation. Results In our study, DM1 did not show LV hypertrophy or impaired LV systolic function at rest. Prevalence of diastolic dysfunction was 8% among DM1, 18% among NT and 50% among HT. Pre-exercise heart rate, SVi, COi, and peak exercise blood pressure (BP) and heart rate were comparable among the three groups, but peak exercise LV EF, SVi and COi were lower in DM1 than in HT and NT independent to covariates ( p B =−6.2) and COi ( B =−1.6, both p Conclusions Our study suggests that uncomplicated DM1 may be associated with subnormal LV contractility reserve, which might not be predicted by LV dysfunction evaluated at rest.