Autonomic function and specific right atrial functions - Is there a relationship? Correlations from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study.

INTRODUCTION: Similarly to the ventricles, the atria are under sympathetic/parasympathetic neural regulation. Accordingly, correlations were investigated between Ewing's standard cardiovascular reflex tests (SCRTs) and three-dimensional speckle-tracking echocardiography (3DSTE)-derived right atrial (RA) volumes and strains in healthy subjects. MATERIALS AND METHODS: The study comprised 45 healthy adults, but 5 subjects were excluded due to inferior image quality for 3DSTE-derived RA assessments. The remaining 40 individuals being in sinus rhythm had a mean age of 35.1 ± 3.5 years (20 men). Two-dimensional, Doppler, 3DSTE and SCRTs were performed in all cases. RESULTS: RA maximum volume and total and passive RA stroke volumes correlated with the Valsalva ratio. Active RA stroke volume and emptying fraction showed correlations with 30/15 ratio. Peak global and mean segmental RA circumferential (CS) and longitudinal strains (LS) showed correlation with the Valsalva ratio. At atrial contraction, global RA-LS and mean segmental RA-CS showed correlations with the Valsalva ratio. Moreover, mean segmental RA-CS correlated with 30/15 ratio and mean segmental RA radial strain showed correlations with systolic blood pressure in response to standing. Autonomic neuropathy score correlated with peak global RA-LS. CONCLUSIONS: Autonomic function parameters have significant associations with specific RA functions in healthy adults, making the latter possible indicators of autonomic dysregulation.

Correlations between vegetative autonomic function and specific left atrial functions in healthy adults: Insights from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study.

INTRODUCTION: The functioning of the left atrium (LA) is partly controlled by the neural system. It was purposed to evaluate correlations between the result of Ewing's 5 standard cardiovascular reflex tests (SCRTs) characterizing autonomic function and LA volumetric and functional features as assessed by three-dimensional speckle-tracking echocardiography (3DSTE) in healthy individuals. MATERIALS AND METHODS: The current study comprised 18 healthy volunteers being in sinus rhythm (mean age: 35 ± 12 years, 10 men). Measurement of blood pressure, ECG, 5 SCRTs, two-dimensional Doppler echocardiography and 3DSTE were performed. These parameters were in normal ranges in all cases. RESULTS: From LA volumetric parameters, only systolic total atrial emptying fraction (r = 0.559, p = 0.037) and early diastolic passive atrial emptying fraction (r = 0.539, p = 0.047) correlated with systolic blood pressure response to standing representing sympathetic autonomic function. From LA strains, peak mean segmental LA radial strain (RS) (r = -0.532, p = 0.050), global and mean segmental LA circumferential strain (CS) (r = 0.662, p = 0.010 and r = 0.635, p = 0.015, respectively) representing systolic LA function correlated with Valsalva ratio representing parasympathetic autonomic function. Global LA-RS (r = -0.713, p = 0.040) and LA-CS (r = 0.657, p = 0.011) and mean segmental LA-CS (r = 0.723, p = 0.003) at atrial contraction representing end-diastolic atrial contraction showed correlations with Valsalva ratio, as well. Peak global and mean segmental LA-CS (r = 0.532, p = 0.050 and r = 0.530, p = 0.050) and the same strains at atrial contraction (r = 0.704, p = 0.005 and r = 0.690, p = 0.006) representing systolic function and end-diastolic atrial contraction correlated with systolic blood pressure response to standing representing both parasympathetic and sympathetic autonomic functions. CONCLUSIONS: Significant correlations between features of vegetative autonomic function represented by Ewing's 5 SCRTs and specific LA functions represented by 3DSTE-derived LA volume-based functional properties and strains could be demonstrated in healthy adults.

Perspectives on weight control in diabetes - Tirzepatide.

Tirzepatide, a once-weekly glucose-dependent insulinotropic polypeptide (GIP)/glucagon-like peptide-1 (GLP-1) receptor agonist (GIP/GLP-1 RA) improves glycemic control. Besides improvement of glycemic control, tirzepatide treatment is associated with significantly more weight loss as compared to potent selective GLP-1 receptor agonists as well as other beneficial changes in cardio-metabolic parameters, such as reduced fat mass, blood pressure, improved insulin sensitivity, lipoprotein concentrations, and circulating metabolic profile in individuals with type 2 diabetes (T2D). Some of these changes are partially associated with weight reduction. We review here the putative mechanisms of GIP receptor agonism contributing to GLP-1 receptor agonism-induced weight loss and respective findings with GIP/GLP-1 RAs, including tirzepatide in T2D preclinical models and clinical studies. Subsequently, we summarize the clinical data on weight loss and related non-glycemic metabolic changes of tirzepatide in T2D. These findings suggest that the robust weight loss and associated changes are important contributors to the clinical profile of tirzepatide for the treatment of T2D diabetes and serve as the basis for further investigations including clinical outcomes.

Increased Short-Term Beat-to-Beat QT Interval Variability in Patients with Impaired Glucose Tolerance.

Prediabetic states and diabetes are important risk factors for cardiovascular morbidity and mortality. Determination of short-term QT interval variability (STVQT) is a non-invasive method for assessment of proarrhythmic risk. The aim of the study was to evaluate the STVQT in patients with impaired glucose tolerance (IGT). 18 IGT patients [age: 63 ± 11 years, body mass index (BMI): 31 ± 6 kg/m2, fasting glucose: 6.0 ± 0.4 mmol/l, 120 min postload glucose: 9.0 ± 1.0 mmol/l, hemoglobin A1c (HbA1c): 5.9 ± 0.4%; mean ± SD] and 18 healthy controls (age: 56 ± 9 years, BMI: 27 ± 5 kg/m2, fasting glucose: 5.2 ± 0.4 mmol/l, 120 min postload glucose: 5.5 ± 1.3 mmol/l, HbA1c: 5.4 ± 0.3%) were enrolled into the study. ECGs were recorded, processed, and analyzed off-line. The RR and QT intervals were expressed as the average of 30 consecutive beats, the temporal instability of beat-to-beat repolarization was characterized by calculating STVQT as follows: STVQT = Σ|QTn + 1 - QTn| (30x√2)-1. Autonomic function was assessed by means of standard cardiovascular reflex tests. There were no differences between IGT and control groups in QT (411 ± 43 vs 402 ± 39 ms) and QTc (431 ± 25 vs 424 ± 19 ms) intervals or QT dispersion (44 ± 13 vs 42 ± 17 ms). However, STVQT was significantly higher in IGT patients (5.0 ± 0.7 vs 3.7 ± 0.7, P < 0.0001). The elevated temporal STVQT in patients with IGT may be an early indicator of increased instability of cardiac repolarization during prediabetic conditions.

Complex evaluation of left atrial dysfunction in patients with type 1 diabetes mellitus by three-dimensional speckle tracking echocardiography: results from the MAGYAR-Path Study.

OBJECTIVE: Changes in left atrial (LA) function can be observed in type 1 diabetes mellitus (T1DM). Three-dimensional (3-D) speckle tracking echocardiography (STE) seems to be a promising tool for volumetric and functional evaluation of LA. The objective of the present study was to compare 3DSTE-derived LA volumetric and strain parameters between T1DM patients and matched healthy controls. METHODS: This prospective study consists of 17 subcutaneous insulin pump-treated non-obese patients with T1DM (mean age: 33.5±8.2 years, 8 males). To exclude possible cardiovascular disease, patients with complaints of chest pain, dyspnea, or signs of cerebrovascular disease or peripheral artery disease were not included. Their results were compared with 20 age-matched and gender-matched healthy controls (mean age: 36.9±11.0 years, 9 males). Independent sample Student t-test and Fisher's exact test were used for comparisons. Bland-Altman method was used for evaluating intraobserver and interobserver correlations. RESULTS: Anemia and impaired renal function were not confirmed in T1DM patients. Calculated LA maximum and minimum volumes and LA volume before atrial contraction were significantly increased in T1DM patients. Total atrial stroke volume was increased (23.6±6.9 mL vs. 19.6±4.6 mL, p=0.04), whereas mean segmental circumferential peak strain was decreased (28.9%±11.4% vs. 37.3%±12.5%, p=0.04). Segmental basal longitudinal and area strains were increased, whereas segmental superior circumferential and area strains and midatrial 3-D strain were decreased in T1DM. CONCLUSION: Both 3DSTE-derived volumetric and strain analysis confirmed alterations in LA function, suggesting early LA remodeling in patients with T1DM.

Increased Short-Term Beat-To-Beat Variability of QT Interval in Patients with Acromegaly.

Cardiovascular diseases, including ventricular arrhythmias are responsible for increased mortality in patients with acromegaly. Acromegaly may cause repolarization abnormalities such as QT prolongation and impairment of repolarization reserve enhancing liability to arrhythmia. The aim of this study was to determine the short-term beat-to-beat QT variability in patients with acromegaly. Thirty acromegalic patients (23 women and 7 men, mean age±SD: 55.7±10.4 years) were compared with age- and sex-matched volunteers (mean age 51.3±7.6 years). Cardiac repolarization parameters including frequency corrected QT interval, PQ and QRS intervals, duration of terminal part of T waves (Tpeak-Tend) and short-term variability of QT interval were evaluated. All acromegalic patients and controls underwent transthoracic echocardiographic examination. Autonomic function was assessed by means of five standard cardiovascular reflex tests. Comparison of the two groups revealed no significant differences in the conventional ECG parameters of repolarization (QT: 401.1±30.6 ms vs 389.3±16.5 ms, corrected QT interval: 430.1±18.6 ms vs 425.6±17.3 ms, QT dispersion: 38.2±13.2 ms vs 36.6±10.2 ms; acromegaly vs control, respectively). However, short-term beat-to-beat QT variability was significantly increased in acromegalic patients (4.23±1.03 ms vs 3.02±0.80, P<0.0001). There were significant differences between the two groups in the echocardiographic dimensions (left ventricular end diastolic diameter: 52.6±5.4 mm vs 48.0±3.9 mm, left ventricular end systolic diameter: 32.3±5.2 mm vs 29.1±4.4 mm, interventricular septum: 11.1±2.2 mm vs 8.8±0.7 mm, posterior wall of left ventricle: 10.8±1.4 mm vs 8.9±0.7 mm, P<0.05, respectively). Short-term beat-to-beat QT variability was elevated in patients with acromegaly in spite of unchanged conventional parameters of ventricular repolarization. This enhanced temporal QT variability may be an early indicator of increased liability to arrhythmia.

Changes in mitral annular morphology and function in young patients with type 1 diabetes mellitus-results from the three-dimensional speckle tracking echocardiographic MAGYAR-Path Study.

BACKGROUND: Alterations in mitral annular size and function could be demonstrated in cardiomyopathies and ischaemic heart disease. The present study was designed to evaluate mitral annulus (MA) morphology and function in young type 1 diabetes mellitus (T1DM) patients by three-dimensional speckle tracking echocardiography (3DSTE) and to compare their results to matched healthy controls. METHODS: The study comprised 18 patients with T1DM (mean age: 33.0±8.0 years). Their results were compared to that of 20 age- and gender-matched healthy controls (mean age: 37.8±10.9 years). Complete two-dimensional (2D) Doppler echocardiography and 3DSTE have been performed in all cases. RESULTS: No significant differences could be demonstrated in demographic and standard echocardiographic parameters between the groups. Significantly enlarged diastolic MA diameter (2.87±0.27 mm vs. 2.58±0.32 mm, P=0.01), MA diameter index 1.61±0.20 cm/m(2) vs. 1.30±0.39 cm/m(2), P=0.008, and MA area index (4.81±0.88 cm(2)/m(2) vs. 3.91±1.35 cm(2)/m(2), P=0.03) could be demonstrated in T1DM together with augmented MA fractional shortening (28.64±9.63% vs. 20.35±12.50%, P=0.05). CONCLUSIONS: Early alterations in MA size and function could be demonstrated in young patients with T1DM by 3DSTE.

Investigation of cardiac autonomic and peripheral sensory neuropathy in diabetic and nondiabetic patients with hypertension.

Peripheral sensory function and cardiac autonomic neuropathy were studied in 18 nondiabetic and 10 type-2 diabetic hypertensives compared with 11 healthy controls. All the patients were treated with antihypertensive drugs. Cardiac autonomic neuropathy using Ewing method was detected in all patient groups. The current perception threshold values on peroneal nerve at 250 Hz in nondiabetic group and at 250 Hz and at 5 Hz in diabetic group were found increased compared with the controls. In conclusion, so-called typical complications of diabetes can be observed in nondiabetic hypertensives also. Our data might support the essential role of vascular factors in the development of neuropathy.

Correlations between Arteriograph-derived pulse wave velocity and aortic elastic properties by echocardiography.

INTRODUCTION: There is an increased scientific interest on the evaluation of parameters characterizing aortic elasticity. The current study was designed to compare two characteristics of aortic distensibility: Arteriograph-derived pulse wave velocity (PWV) and augmentation index standardized to 80 per minutes heart rate (AIx80) and aortic elastic properties by echocardiography. METHODS: The study comprised 21 adult healthy volunteers. In all cases, systolic and diastolic ascending aortic diameters were recorded during transthoracic echocardiography in M-mode at a level 3 cm above the aortic valve from a parasternal long-axis view. Using forearm blood pressure values, the following aortic elastic properties were calculated: aortic strain, distensibility and stiffness index. All patients were examined by Arteriograph at the same time, as well. RESULTS: The Arteriograph-derived AIx80 and PWV correlated with aortic strain (R = -0·495, P = 0·023 and R = -0·527, P = 0·014, respectively) and aortic stiffness index (R = 0·454, P = 0·039 and R = 0·608, P = 0·003, respectively). Aortic distensibility did not correlated with AIx80 (R = -0·344, P = 0·127), only with PWV (R = -0·593, P = 0·005, respectively). DISCUSSION: Low to moderate correlations could be demonstrated between Arteriograph-derived PWV and aortic elastic properties by echocardiography.

Correlations between aortic stiffness and parasympathetic autonomic function in healthy volunteers.

Cardiovascular autonomic dysfunction and alterations in vascular elasticity are known complications of several disorders, including diabetes mellitus, hypertension, hypercholesterolemia, aging, and chronic kidney disease. The current study was designed to test whether a relationship existed between pulse wave velocity (PWV), augmentation index (AIx), aortic elastic properties, and cardiovascular autonomic function in healthy volunteers. The study comprised 25 healthy volunteers, whose aortic strain, distensibility, and stiffness index were measured by echocardiography, whereas PWV and AIx were evaluated by Arteriograph (TensioMed, Budapest, Hungary) in all cases. Autonomic function was assessed by means of 5 standard cardiovascular reflex tests. We found that heart rate response to deep breathing, as the most reproducible cardiovascular reflex test to characterize parasympathetic function, showed low to moderate correlations with PWV (r = -0.431, p = 0.032), aortic strain (r = 0.594, p = 0.002), distensibility (r = 0.407, p = 0.043), and stiffness index (r = -0.453, p = 0.023). Valsalva ratio and autonomic neuropathy score (ANS) correlated with PWV (r = -0.557, p = 0.004 and r = -0.421, p = 0.036, respectively) and AIx (r = -0.461, p = 0.020 and r = -0.385, p = 0.057, respectively), while ANS correlated with even aortic stiffness index (r = -0.457, p = 0.022). Cardiovascular reflex tests mainly characterizing sympathetic function had no correlation with aortic stiffness parameters (p = NS for all correlations). Correlations exist between parameters characterizing aortic elasticity and parasympathetic autonomic function, as shown by standard cardiovascular reflex tests in healthy volunteers.

Cardiovascular autonomic dysfunction in primary Sjögren's syndrome.

OBJECTIVE: To assess the occurrence and clinical significance of a cardiovascular autonomic nervous system dysfunction in primary Sjögren's syndrome (pSS). METHODS: Fifty-one pSS patients participated in this case-control study. Heart rate and blood pressure variability measurements, spontaneous baroreflex sensitivity examinations and cardiovascular reflex tests were performed. RESULTS: The results of the heart rate and blood pressure variability measurements and also the baroreflex sensitivity parameters of the pSS patients peaked in the lowest percentile ranges of a database on 559 healthy control subjects (P < 0.05). In three of the five cardiovascular reflex tests, the frequencies of abnormal results were significantly higher among the patients than among the controls (P < 0.05), and the median autonomic neuropathy score was also elevated (3 vs 0 in the controls; P < 0.0001). CONCLUSION: Signs of an autonomic nervous system dysfunction involving the cardiovascular system can be discerned in the majority of pSS patients.

Effect of pioglitazone compared with metformin on glycemic control and indicators of insulin sensitivity in recently diagnosed patients with type 2 diabetes.

Pioglitazone, a thiazolidinedione, improves glycemic control primarily by increasing peripheral insulin sensitivity in patients with type 2 diabetes, whereas metformin, a biguanide, exerts its effect primarily by decreasing hepatic glucose output. In the first head-to-head, double-blind clinical trial comparing these two oral antihyperglycemic medications (OAMs), we studied the effect of 32-wk monotherapy on glycemic control and insulin sensitivity in 205 patients with recently diagnosed type 2 diabetes who were naive to OAM therapy. Subjects were randomized to either 30 mg pioglitazone or 850 mg metformin daily with titrations upward to 45 mg (77% of pioglitazone patients) and 2550 mg (73% of metformin patients), as indicated, to achieve fasting plasma glucose levels of less than 7.0 mmol/liter (126 mg/dl). Pioglitazone was comparable to metformin in improving glycemic control as measured by hemoglobin A1C and fasting plasma glucose. At endpoint, pioglitazone was significantly more effective than metformin in improving indicators of insulin sensitivity, as determined by reduction of fasting serum insulin (P = 0.003) and by analysis of homeostasis model assessment for insulin sensitivity (HOMA-S; P = 0.002). Both OAM therapies were well tolerated. Therefore, pioglitazone and metformin are equally efficacious in regard to glycemic control, but they exert significantly different effects on insulin sensitivity due to differing mechanisms of action. The more pronounced improvement in indicators of insulin sensitivity by pioglitazone, as compared with metformin monotherapy in patients recently diagnosed with type 2 diabetes who are OAM-naive, may be of interest for further clinical evaluation.

Investigation of auditory brainstem function in diabetic patients.

We performed brainstem auditory evoked potential (BAEP) examinations in 15 patients with long-standing type 1 diabetes mellitus. We applied cardiovascular reflex tests for assessment of autonomic neuropathy. The aim of our investigation was to compare the BAEP results of this patient group with those of controls and to look for the possible correlation between alteration of the auditory brainstem function and cardiovascular autonomic neuropathy. Analysis of the latencies (waves I, II, III, and V) and the interpeak latencies (I-III and I-V) of BAEP revealed a significant difference between those of diabetics and those of healthy controls. The amplitudes of waves I, III, and V were definitely lower in comparison with amplitudes of healthy controls. We observed a positive correlation between the overall autonomic score and the latencies (waves III and V) and interpeak latencies (I-III, I-V). These data support the hypothesis that long-standing diabetes mellitus and diabetic neuropathy might be revealed as a cause of certain dysfunctions of the central auditory pathways.