Determinants of the heart rate variability in type 1 diabetes mellitus.

Background: Evaluation of heart rate variability (HRV) detects the early subclinical alterations of the autonomic nervous system. Thus, impaired HRV is the earliest subclinical marker of cardiac autonomic neuropathy (CAN) in type 1 diabetes mellitus (T1DM). Objectives: We aimed to explore the HRV parameters in asymptomatic T1DM patients and compare them with the results obtained in healthy subjects. Potential associations between HRV parameters and the established risk factors for CAN and cardiovascular diseases were also investigated. Methods: Seventy T1DM patients (38 ± 12 years, 46 females) and 30 healthy subjects were enrolled into the study. For HRV analysis, beat-to-beat heart rate was recorded for 30 min. The less noisy 5-min segment of the recording was analyzed by Bittium Cardiac Navigator HRV analysis software. Time domain, frequency domain, and nonlinear indices were calculated. Results: Regarding ratio of low to high frequency component (LF/HF), no differences were found between the two populations (p = 0.227). All the further, time domain, frequency domain, and nonlinear HRV indices were significantly lower in T1DM patients (each p < 0.001). In multiple linear models, disease duration remained the only independent predictor of LF/HF ratio (p = 0.019). HbA1c was found to be significant independent predictor of all further time domain (SDNN, p < 0.001; rMSSD, p < 0.001), frequency domain (VLF, p < 0.001; LF, p = 0.002; HF, p = 0.006; Total Power, p = 0.002), and nonlinear indices (SD1, p = 0.006; SD2, p = 0.007), alone, or in combination with other factors, such as age or body mass index. Conclusion: Asymptomatic T1DM patients have significantly reduced overall HRV as compared with healthy subjects, indicating subclinical CAN. Quality of the glycemic control is important determinant of HRV among T1DM patients. This relationship is independent of other risk factors for CAN or cardiovascular diseases.

Quality of glycemic control has significant impact on myocardial mechanics in type 1 diabetes mellitus.

The potential associations between disease duration, glycemic control, and the echocardiographic markers of the myocardial mechanics were investigated in asymptomatic T1DM patients. Seventy T1DM patients (38.2 ± 11.7 years, 46 female) and 30 healthy volunteers were investigated. Besides the conventional and tissue Doppler measurements, left ventricular global longitudinal (GLS) and circumferential (GCS) strain as well as left and right atrial strain parameters were measured with 2D speckle tracking technique. Median HbA1c level was 7.4 (1.8)%. Even when added age and hypertension to the model, current HbA1c level remained independent predictor of left ventricular GLS (p = 0.002), GCS (p < 0.001), mitral e' (p = 0.018), tricuspid e' (p = 0.018) and left (p = 0.039) and right atrial conduit strain (p = 0.047) in multiple linear regression models. Correlations between disease duration and the echocardiographic variables lost their significance in multiple models. In patients with a combination of HbA1c ≤ 7.4% and no hypertension, echocardiographic findings did not differ from those in healthy volunteers. Patients with HbA1c > 7.4% and no hypertension and especially patients with coexisting hypertension and HbA1c > 7.4%, exhibited significantly impaired myocardial mechanics. Quality of glycemic control has a significant impact on myocardial mechanics in T1DM patients. Regarding disease duration this relationship was not proved.

Prognostic value of right atrial stiffness in systemic sclerosis.

OBJECTIVES: We hypothesised that right atrial (RA) size and mechanics may have prognostic role in systemic sclerosis (SSc) patients without manifest pulmonary arterial hypertension (PAH), thus we aimed to investigate the prognostic power of RA volume, strain and stiffness parameters alone and when added to the echocardiographic marker of RV longitudinal systolic function. METHODS: Seventy SSc patients (57±12 years) were enrolled into our follow-up study. They underwent standard echocardiographic and tissue Doppler measurements at baseline. In addition to maximal RA volume index, RA reservoir, conduit and contractile strain were measured with 2D speckle tracking technique. RA stiffness was calculated as ratio of TriE/e' to reservoir strain. Survival was assessed after 5 years. All-cause mortality was chosen as outcome. Sequential χ2 analysis was used to evaluate the incremental prognostic benefit of adding RA volume, strain or stiffness to tricuspid S (TriS). RESULTS: During the follow-up period of 4.7±0.9 years, 6 patients (8.6%) died. When added to TriS in sequential Cox model, RA stiffness significantly improved the diagnostic performance of the model (Δχ2= 3.950; p=0.047) and remained independent predictor of the outcome (HR 2.460 (1.005-6.021); p=0.049). Vmax index and strain parameters did not show incremental prognostic value over TriS. Using ROC analysis, RA stiffness ≥0.156 was the best predictor of mortality (sensitivity=83.3%, specificity =89.1%, AUC=0.859). CONCLUSIONS: RA stiffness is associated with all-cause mortality in SSc patients without PAH independent of and incremental to the RV longitudinal systolic function. It may be proposed as non-invasive marker for identifying patients with high mortality risk.

Galectin-3 and sST2: associations to the echocardiographic markers of the myocardial mechanics in systemic sclerosis - a pilot study.

BACKGROUND: Progressive cardiac fibrosis is the central aspect of the myocardial involvement in systemic sclerosis (SSc). We hypothesized that circulating biomarkers of the cardiac fibrosis may be useful in the early diagnosis of the cardiac manifestation in this disease. Thus, we investigated the potential correlations between the levels of galectin-3, soluble suppression of tumorigenicity-2 (sST2) and the echocardiographic markers of the myocardial mechanics in SSc patients. METHODS: Forty patients (57.3 ± 13.7 years, 36 female) were investigated. In addition to the conventional echocardiography, tissue Doppler and speckle tracking-derived strain techniques were used to assess the function of both ventricles and atria. To estimate the correlations between galectin-3 and sST2 levels and the echocardiographic variables, partial correlation method was used with age as correcting factor. RESULTS: In age adjusted analysis galectin-3 level showed significant correlation with left ventricular global longitudinal strain (r = 0.460, p = 0.005); grade of left ventricular diastolic dysfunction (r = 0.394, p = 0.013); septal e' (r = - 0.369, p = 0.021); septal E/e' (r = 0.380, p = 0.017) and with the grade of mitral regurgitation (r = 0.323, p = 0.048). No significant correlation was found between sST2 levels and the echocardiographic variables. CONCLUSIONS: Galectin-3 levels, but not sST2 levels show significant correlation with the parameters of the left ventricular systolic and diastolic function. Galectin-3 may be a useful biomarker for the screening and early diagnosis of SSc patients with cardiac involvement.

Diastolic Dysfunction Is a Contributing Factor to Exercise Intolerance in COPD.

Right ventricular (RV) systolic failure is rare in patients with COPD, but they often develop RV diastolic dysfunction. Left ventricular (LV) diastolic dysfunction is also common in this population. Nevertheless, data are scarce regarding the effect of diastolic dysfunction on the functional capacity in patients with COPD. We investigated the correlation between echocardiographic parameters of RV and LV diastolic function and the exercise capacity in COPD, by using conventional echocardiographic methods and tissue Doppler imaging. 65 patients with COPD (61 ± 9 years) in stages GOLD II-IV were investigated. Functional capacity was measured with 6-minute walk test (6MWT). Right (RA) and left atrial (LA) area index were measured; collapsibility index inferior vena cava was calculated. Parameters of the mitral and tricuspid inflow (E, A) as well as annular systolic (S), early- (e') and late- (a') diastolic myocardial longitudinal velocities were measured. E/A, E/e' and e'/a' ratios were calculated. 6MWT distance was 330 ± 76 m. LV diastolic dysfunction was found in 48 (74%) patients. LV and RV filling pressures were elevated in 28 (43%) and in 29 (45%) patients, respectively. In the left heart, LA area index showed significant correlation with the functional capacity (r = -0.319; p = 0.011). In stepwise multiple linear regression analysis tricuspid e'/a' (r = 0.611; p = 0.000), collapsibility index (r = 0.505; p = 0.000), RA area index (r = -0.445; p = 0.000) and body surface area (r = 0.314; p = 0.011) were independent predictors of 6MWT distance. Right ventricular diastolic function and filling pressure have strong influence on the functional capacity in patients with COPD.