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Abnormalities of the cardiovascular response to cold pressor test in type 1 diabetes. Correlation with blood glucose
Insights
Type 1 diabetics without heart disease show abnormal cardiovascular responses to stress, even with normal ejection fraction. Cardiac function abnormalities correlate with recent blood glucose control, highlighting the impact of glycemic fluctuations on heart health.
Area of Science:
- Cardiology
- Endocrinology
- Diabetology
Background:
- Type 1 diabetes (T1D) is associated with cardiovascular complications.
- Subclinical cardiac dysfunction may precede overt heart disease in T1D.
- The impact of glycemic control on cardiac function in T1D requires further investigation.
Purpose of the Study:
- To compare left-ventricular (LV) function in T1D patients without clinical heart disease to matched controls.
- To assess the cardiovascular response to cold pressor test (CPT) in T1D patients.
- To investigate the correlation between glycemic control (hemoglobin A1c) and cardiac function post-CPT.
Main Methods:
- Echocardiography was used to assess LV function (ejection fraction, filling volumes).
- A cold pressor test (CPT) was administered to evaluate cardiovascular stress response.
- Cardiac function parameters post-CPT were analyzed in relation to hemoglobin A1c levels.
Main Results:
- Diabetics had normal LV ejection fraction but a trend towards smaller left ventricles.
- Cardiovascular response to CPT was abnormal in T1D patients.
- Cardiac function post-CPT correlated with hemoglobin A1c levels, with recent glycemic control showing stronger association.
Conclusions:
- Abnormal cardiovascular response to stress can be present in T1D patients even with normal LV ejection fraction.
- Cardiac function abnormalities post-CPT correlate with glycemic control, particularly recent blood glucose levels.
- These findings suggest cardiac function fluctuates with recent glycemic control in T1D.
Abstract:
Left-ventricular (LV) function in type 1 diabetics without clinical heart disease was compared with that found in matched normal subjects. Although diabetics had a normal LV ejection fraction (66% +/- 6%), they showed a trend toward smaller left ventricles. Their cardiovascular response to a cold pressor test was abnormal and cardiac function after the cold pressor test correlated with hemoglobin A1c levels: Average hemoglobin A1c was inversely related to ejection fraction and early filling volume and directly related to the ratio of pre-ejection period to ejection time (PEP/LVET) after a cold pressor test. Hemoglobin A1c at the time of study correlated more closely with PEP/LVET after cold pressor test than did the six-month average hemoglobin A1c level, suggesting that cardiac function fluctuates with recent changes in blood glucose control. Thus, even when diabetics have a normal LV ejection fraction, an abnormal cardiovascular response to stress may still be present, and such abnormalities correlate with blood glucose control.