Impact of Improved Glycemic Control on Cardiac Function in Type 2 Diabetes Mellitus

Abstract

Background— Patients with type 2 diabetes mellitus are at risk of heart failure. Specific therapeutic interventions for diabetic heart disease are still elusive. We aimed to examine the impact of improved glycemic control on left ventricular (LV) function in these patients. Methods and Results— A total of 105 subjects with type 2 diabetes mellitus (aged 54±10 years) and poor glycemic control received optimization of treatment for blood glucose, blood pressure, and cholesterol to recommended targets for 12 months. LV systolic and diastolic function, measured by LV global longitudinal strain (GLS) and septal e′ velocities, were compared before and after optimization. At baseline, patients had impaired LV systolic (GLS −14.9±3.2%) and diastolic function (e′ 6.2±1.7 cm/s). After 12 months, glycated hemoglobin (HbA1c) decreased from 10.3±2.4% to 8.3±2.0%, which was associated with significant relative improvement in GLS of 21% and septal e′ of 24%. There was a progressively greater improvement in GLS as patients achieved a lower final HbA1c. Patients achieving an HbA1c of <7.0% had the largest improvement. The 15 patients whose HbA1c worsened experienced a decline in GLS. Patients who improved their HbA1c by ≥1.0% had a significantly higher relative improvement in e′ than those who did not (32% versus 8%; P =0.003). Baseline GLS, decrease in body mass index, and treatment with metformin were additional independent predictors of GLS improvement. Conclusions— Improvements in glycemic control over a 12-month period led to improvements in LV systolic and diastolic function. This may have long-term prognostic implications.

Impact of glycemic control on aortic stiffness, left ventricular mass and diastolic longitudinal function in type 2 diabetes mellitus

“…LV diastolic dysfunction is an early manifestation of diabetic heart disease [1, 20, 21], and a subclinical impairment of diastolic function is associated with higher glucose levels [3, 19, 21]. Chronic increase in plasma glucose levels has been shown to negatively influence LV diastolic performance through different mechanisms, including alteration in mitochondrial energy metabolism and increment in myocardial oxidative stress [10, 11], LV mass increase and changes in myocardial composition [7, 8], acceleration of large artery stiffening and consequent increase in vascular load [12–14].…”

“…In addition, e′ velocity has been shown to be inversely related to serum concentration of procollagen type I carboxy-terminal propeptide [17], which is considered a marker of myocardial collagen content [18]. Previous studies have reported reduced e′ velocity of mitral annulus in asymptomatic T2DM patients [19, 20] as well as an association between e′ velocity and poor glycemic control [19, 21]. They have also demonstrated an inverse relationship between e′ velocity and LV mass or arterial stiffness [22, 23] and a direct association between diastolic e′ and systolic s′ longitudinal velocities [23].…”

The Effect of Metformin on Diastolic Function in Patients Presenting with ST-Elevation Myocardial Infarction

“…Also in dogs with pacing induced heart failure, metformin treatment improved diastolic function as indicated by a reduced left ventricular end-diastolic pressure [29]. In patients with diabetes, improvements of glycemic control, including the use of metformin, was associated with improvements of diastolic function as measured by septal e’ [45]. Also in the setting of stable coronary artery disease, metformin use in diabetic patients was associated with improved left ventricular diastolic function as measured by mean e’ and IVRT [28].…”

Cardiac dysfunction in type II diabetes: a bittersweet, weighty problem, or both?

“…Studies have suggested poor glycaemic control was associated with LV diastolic dysfunction, manifest as either lower e’ velocities or raised LV filling pressure; and/or more impaired LV systolic function with lower systolic strain [2, 8, 9]. Furthermore, we have recently demonstrated that improving glycaemic control in such patients resulted in improvement in LV systolic and diastolic function [30]. The largest improvements in the aforementioned study were seen in patients with the largest reduction in HbA1c levels, and in those with the lowest HbA1c levels at the end of the study.…”