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[Existence of asymptomatic changes in left ventricular function in the diabetic. Noninvasive study]
Insights
Diabetes significantly impairs left ventricular function, causing prolonged relaxation and reduced contractility, independent of complications. These cardiac changes may stem from metabolic disorders or microangiopathy.
Area of Science:
- Cardiology
- Diabetology
- Biomedical Engineering
Context:
- Diabetes mellitus is a global health concern associated with cardiovascular complications.
- Assessing subclinical cardiac dysfunction in diabetics is crucial for early intervention.
- Noninvasive cardiovascular techniques are vital for evaluating diabetic cardiomyopathy.
Purpose:
- To investigate left ventricular (LV) diastolic and systolic function in diabetic patients without ischemic cardiopathy.
- To determine if observed cardiac abnormalities correlate with diabetes duration, complications, or type.
- To explore potential underlying mechanisms, such as metabolic disorders or myocardial microangiopathy.
Summary:
- Diabetic patients (n=49) exhibited prolonged isovolumetric relaxation time (IVRT) and reduced ejection fraction (EF) slope compared to controls (n=32).
- A high Weissler index (PEP/LVET ratio) indicated impaired myocardial contractility in diabetics, unrelated to preload/afterload.
- Increased septal and posterior wall thickness were observed in diabetics with retinopathy and NIDD, respectively.
Impact:
- Identifies specific left ventricular functional abnormalities in diabetes, distinct from ischemic cardiopathy and hypertension.
- Suggests that metabolic derangements and/or myocardial microangiopathy are potential causes of diabetic cardiomyopathy.
- Highlights the importance of echocardiography in detecting early cardiac dysfunction in diabetic populations.
Abstract:
49 diabetics (D) (26 IDD and 23 NIDD) were compared to 32 controls (C). Absence of ischemic cardiopathy (IC) was confirmed by routine investigations and noninvasive cardiovascular techniques, including an exercise ECG using 12 leads and a thallium 201 scintigraphy. Our results show: a) a prolonged mean isovolumetric relaxation time (IVRT) as studied by the M mode echocardiography and phonomechanography: D = 0,10 sec +/- 0,04; C = 0,05 sec +/- 0,02; p less than 0,0001; b) a reduced mean EF slope: D = 97,48 +/- 37,08 mm / sec; C = 125,68 +/- 34,35; p less than 0,005; c) a high mean Weissler index (ratio of PEP to LVET): D = 40 +/- 0,08; C = 33 +/- 0,05; p less than 0,01. IVRT and EF slope abnormalities are related to increased myocardial stiffness and impaired LV compliance. In the absence of changes in preload and afterload, the high Weissler index reflects impaired contractility of the myocardium. These abnormalities are related neither to the duration of diabetes nor to the presence or severity of the complications. With the M mode echocardiography, mean diastolic and systolic thickness of the septum is greater in D with retinopathy than in C (p less than 0,005 and p less than 0,03 respectively); mean diastolic and systolic thickness of the posterior wall is greater in NIDD than in C (p less than 0,001 and p less than 0,025). We conclude that there is evidence of left ventricular functional abnormalities specific to diabetes and unrelated to IC and hypertension. Our findings support the hypothesis that they may be due to metabolic disorders and/or myocardial microangiopathy.