Cardiovascular autonomic neuropathy contributes to left ventricular diastolic dysfunction in subjects with Type 2 diabetes and impaired glucose tolerance undergoing coronary angiography
ABSTRACT Left ventricular diastolic dysfunction is considered a precursor of diabetic cardiomyopathy, while diabetic cardiovascular autonomic neuropathy is associated with an increased risk of mortality. This study aimed to evaluate the association between left ventricular diastolic dysfunction and cardiovascular autonomic neuropathy, both diagnosed according to the current guidelines.
We evaluated 145 patients referred for an elective coronary angiography, 52 of whom had Type 2 diabetes and 48 had impaired glucose tolerance, while 45 subjects had normal glucose tolerance. Cardiovascular autonomic neuropathy was diagnosed using autonomic function tests, while left ventricular diastolic dysfunction was verified by tissue Doppler imaging echocardiography.
Cardiovascular autonomic neuropathy was diagnosed in 15 (28.8%) patients with Type 2 diabetes and in six (12.5%) individuals with impaired glucose tolerance. The rates of left ventricular diastolic dysfunction were 81 and 33% in patients with and without cardiovascular autonomic neuropathy, respectively (P < 0.001). In the cardiovascular autonomic neuropathy group (n = 21), early diastolic relaxation velocity (Em) was significantly reduced (5.4 ± 0.9 vs. 7.3 ± 2.1 cm/s; P < 0.001) and the E/Em ratio was significantly higher (13.6 ± 4.6 vs. 10.3 ± 3.4 cm/s, P < 0.001) as compared with the group without cardiovascular autonomic neuropathy (n = 79). These findings remained significant after adjustment for age, sex, coronary artery disease, hypertension and HbA(1c) . A severe form of left ventricular diastolic dysfunction was observed in 33 and 15% of patients with and without cardiovascular autonomic neuropathy, respectively (P = 0.001).
Cardiovascular autonomic neuropathy is associated with a higher prevalence and a more severe form of left ventricular diastolic dysfunction in patients with diabetes or impaired glucose tolerance undergoing coronary angiography. Because both cardiovascular autonomic neuropathy and left ventricular diastolic dysfunction are associated with increased cardiovascular morbidity and mortality, screening for patients with left ventricular diastolic dysfunction and cardiovascular autonomic neuropathy with diabetes or impaired glucose tolerance may identify those at high risk.
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ABSTRACT: Cardiovascular autonomic neuropathy (CAN) is one of the major complications of Diabetes Mellitus (DM) seen in a significant number of patients, which is often ignored and is also least frequently diagnosed. It can be diagnosed by performing five standard non-invasive bedside autonomic function tests based on Cardiovascular reflexes, which are quite cumbersome. Studies have revealed an increase in mortality in the diabetic patients with CAN due to silent cardiac ischemia, sudden cardiac death, arrhythmias. The precursor of diabetic cardiomyopathy is Left ventricular diastolic dysfunction (LVDD). In the present study we are studying the association between LVDD and CAN, in order to identify high mortality risk patients by performing 2D Echo and looking at LVDD instead of performing the cumbersome bedside cardiovascular autonomic function tests. To study the association between LVDD and CAN in patients with Type 2 DM. This study is a cross-sectional observational study with a sample size of 100. Both outpatients and inpatients between 35 y and 65 y of age with Type 2 DM coming to Department of General Medicine, KIMS hospital, Bangalore were studied from November 2011 to October 2013.Patients with macrovascular complications, Hypertension, congenital & acquired heart diseases etc. were excluded from the study. The standard five autonomic function tests based on cardiovascular reflexes and 2D Echo were performed. Individual scores for each of the five tests were added to produce Ewing's score. Ewing's score of >2.5 is positive for CAN. Chi-square/ Fisher Exact test has been. There was a significant association between individual non-invasive bedside tests of Ewing's score and LVDD. Significant association was also seen between LVDD and positive Ewing's score. Positive Ewing's score is strongly associated with LVDD in patients with Type 2 DM in this study .This suggests that patients with LVDD have CAN and hence, are at increased risk of sudden cardiac death. As bedside tests are cumbersome, patients with LVDD on 2D Echo can be concluded to have CAN.
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ABSTRACT: We investigated the relation between diabetic autonomic neuropathy (DAN) and left ventricular (LV) function in 59 patients with type 2 diabetes mellitus (T2DM) free of coronary artery disease (CAD) or hypertension. Diabetic autonomic neuropathy was established by ≥2 abnormal autonomic nervous function tests. Left ventricular systolic and diastolic functions were assessed by resting radionuclide ventriculography. Compared with non-DAN patients (n = 24), patients with DAN (n = 35) had an increased adjusted atrial contribution to ventricular filling (A/V%, 30.1% ± 8.2% vs 26.5% ± 5.1%; P = .031), suggestive of diastolic dysfunction (DD). There were no differences between the 2 groups in peak filling rate, first 1/3 filling fraction, ejection fraction, cardiac output, and cardiac index. Patients with diabetic autonomic neuropathy had an increased heart rate (77.8 ± 6.3 vs 69.3 ± 3.3 bpm; P < .0001) and a higher rest LV workload (10 072 ± 1165 vs 8606 ± 1075 bpm mm Hg; P < .0001). Patients with DAN T2DM without CAD or hypertension have DD, increased A/V index, and a higher LV working load than non-DAN patients.Angiology 11/2013; 65(10). DOI:10.1177/0003319713510966 · 2.37 Impact Factor
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ABSTRACT: Cardiac autonomic dysfunction has prognostic significance in patients with coronary artery disease. This investigation aimed to assess changes in autonomic modulation induced by dobutamine stress in the presence and absence of myocardial ischaemia. Three hundred and fourteen individuals underwent dobutamine stress echocardiography to detect or exclude myocardial ischaemia. Simultaneous autonomic and haemodynamic data were obtained using a plethysmographic device. Total power spectral density and associated low frequency (LF) and high frequency (HF) power spectral components in absolute (ms(2) ) and normalised units (nu) were determined. Participants were categorised as non-ischaemic (NI) or ischaemic (IS) responders. There were no significant differences in LFnu or HFnu between groups at baseline. At peak stress, LFnu decreased from baseline in NI (43 ± 1.8 to 40 ± 1.8%), but increased from baseline in IS responders (39.5 ± 2 to 56 ± 2%, p<0.05). In contrast, HFnu increased in NI patients (57 ± 1.8 to 60 ± 1.8%) but decreased in IS responders (60.5 ± 2 to 44 ± 2%, p<0.05). Those with a high ischaemic burden (>3 ischaemic left ventricular [LV] segments) had a greater increase in LFnu (41 ± 4.8 to 65 ± 3.2% vs 44.8 ± 3.8 to 57.7 ± 3.1%, p<0.05) and greater decrease in HFnu (59 ± 4.8 to 35 ± 3.2% vs 55.2 ± 3.8 to 42.3 ± 3.1%, p<0.05) compared to patients with a low ischaemic burden (1-3 ischaemic LV segments) respectively, at peak stress. In the absence of myocardial ischaemia, dobutamine stress is associated with a residual predominance of parasympathetic over sympathetic activity. Under conditions of ischaemia, there is a directionally opposite autonomic response with a significant residual increase of sympathetic over parasympathetic modulation. This response is augmented as the burden of ischaemia is increased. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.The Journal of Physiology 02/2015; 593(9). DOI:10.1113/JP270063 · 4.54 Impact Factor