Diurnal characteristics of heart rate variability in patients with sarcoidosis.

BACKGROUND: The aim of this study was to evaluate autonomic nervous system function by measuring heart rate variability (HRV) in patients with sarcoidosis without known cardiac manifestations. PATIENTS AND METHODS: The study comprised 61 participants, including 31 patients with sarcoidosis without known cardiac manifestations and 30 healthy volunteers. All participants underwent echocardiographic examination, 12-channel electrocardiography (ECG), and 24-h Holter monitoring. HRV parameters were determined and compared between the groups. RESULTS: There were no differences between groups with regard to age, body mass index, systolic and diastolic blood pressure, or heart rate at the time of admission. In the time domain analyses, the 24-h, daytime, and night-time standard deviations of all normal-to-normal R­R interval (SDNN) values were significantly lower in patients with sarcoidosis than those in the controls. The frequency domain analyses showed that 24-h and daytime low-frequency (LF) values, 24-h, daytime, and night-time high-frequency (HF) values were significantly lower in the patient group compared with the control group, whereas the night-time LF/HF ratio was significantly higher. CONCLUSION: Although Holter ECG is not a diagnostic tool for cardiac sarcoidosis, the HRV parameters, especially the night-time LF/HF values, may demonstrate increased sympathetic activation in patients with sarcoidosis.

Aortic elastic properties : effects of carvedilol versus nebivolol.

OBJECTIVES: The aim of this study was to compare the effects of the new generation ß-blocker anti-hypertensive drugs carvedilol and nebivolol on aortic elastic properties which are important indicators of hypertension-related morbidity and mortality. METHODS: A total of 50 patients who had been diagnosed with stage 1 hypertension according to the Joint National Committee (JNC) VII criteria and who had not received any anti-hypertensive treatment were enrolled in this study. Patients were randomized to receive either 25 mg/day carvedilol (n=25) or 5 mg/day nebivolol (n=25) for 3 months at the beginning of the study. Three patients (1 in the carvedilol group, 2 in the nebivolol group) who did not attend 3 month follow-up measurements were excluded from the study. The study was completed with 47 patients (25 women; mean age: 49 ± 9 years). The aortic elastic parameters such as aortic strain (AS), aortic distensibility (AD), and aortic stiffness index (ASI) were measured by echocardiography. RESULTS: Carvedilol and nebivolol provided a similar decline in both systolic and diastolic blood pressures (-12/-7 mmHg, p<0.0001 and -12/-7 mmHg, p=0.002, respectively). Both carvedilol and nebivolol induced a significant decrease in heart rate (-15 bpm, p<0.0001, -17 bpm, p<0.0001, respectively). Even though the heart rate at the end of the treatment was lower for the nebivolol group, the rate of decrease of heart rates between carvedilol and nebivolol groups was not statistically significant (p=0.074). Both groups demonstrated improvements in the diastolic functions of the left ventricle where certain values showed more improvement for the nebivolol group. Both groups showed improvements in AS and AD rates compared to basal rates; however, these improvements were not statistically significant. Although the improvement rates in AS, AD, and ASI were higher in the nebivolol group compared to the carvedilol group, the differences were not statistically significant (p=0.091, p=0.095, p=0.259, respectively). CONCLUSION: Both carvedilol and nebivolol induced a decrease in blood pressure and heart rate and showed an improvement in left ventricular diastolic functions. It was observed that both drugs did not cause deterioration in the aortic elastic properties but a slight improvement was seen. However, this improvement was not statistically significant. The improvement was more explicit in the nebivolol group. It may be concluded that nebivolol is slightly superior to carvedilol in reducing heart rate and improving left ventricular diastolic functions. However, further long-term studies with larger sample sizes should be performed in order to better define the effects of both drugs.

Assessment of left ventricular systolic and diastolic dyssynchrony with tissue Doppler echocardiography in patients with heart failure and narrow QRS complex.

AIM: Cardiac dyssynchrony is a well known entity in patients with wide QRS complex (>120 ms). Dyssynchrony may also cause ventricular dysfunction in heart failure patients with narrow QRS complexes. In the study, the presence and extent of cardiac dyssynchrony were investigated in patients with heart failure both with narrow and wide QRS complexes using tissue Doppler echocardiography (TDE). METHODS: Forty-nine patients with heart failure, were included to the study. The first group of 30 patients with a QRS duration of <120 ms (23M; mean age, 64±10.1 years) and the second group consisted of 19 patients with a QRS duration of >120 ms (12M; mean age, 65±11.6 years). In order to examine cardiac synchronization, TDE was performed. Systolic and diastolic intraventricular dyssynchrony and interventricular dyssynchrony were calculated. In order to define systolic and diastolic dyssynchrony, intraventricular delay was accepted as >60 ms, and interventricular delay was accepted as >40 ms. RESULTS: Left ventricular systolic dyssynchrony was detected in 18 patients (60%) within the narrow QRS group and in 18 patients (94%) within the wide QRS group. Interventricular dyssynchrony was detected in 17 patients (56%) within the narrow QRS group and in 18 patients (94%) within the wide QRS group. For systolic dyssynchrony, correlations existed between intraventricular delay and QRS duration (r=0.48), left ventricular end diastolic diameter (r=0.62), left ventricular end systolic diameter (r=0.61), and EF (r=-0.63). Similarly, correlations existed between interventricular delay and QRS duration (r=0.58), left ventricular end diastolic diameter (r=0.65), left ventricle end systolic diameter (r=0.64), and EF (r=-0.64). CONCLUSION: The present study suggested that systolic or diastolic dyssynchrony exists despite normal levels of QRS duration.

Effects of impaired fasting glucose on aortic elasticity.

The pathophysiology of atherosclerosis development in patients with diabetes mellitus (DM) is similar to that in nondiabetics. However, atherosclerosis develops earlier and runs a rapid course in patients with diabetes. Aortic stiffness, strain and distensibility are the parameters used to assess an increase in arterial stiffness and can be measured by invasive and non-invasive methods.Aortic elastic properties were compared among patients with normal oral glucose tolerance test but impaired fasting glucose and healthy individuals. The study group consisted of 50 subjects with impaired fasting glucose who had no known risk factors for atherosclerosis. The control group was composed of the same number of volunteers.It was found that aortic strain and distensibility were reduced (8.78±4.3 vs. 10.65±2.6 p<0.01 and 4.1±2.1 vs. 5.1±1.7 p<0.01 respectively) and aortic stiffness index was significantly increased (6.9±3.2 vs. 5.01±1.6, p<0.0001) in patients with impaired fasting glucose compared to those in the control group.It was demonstrated that aortic elasticity was impaired in those with impaired fasting glucose, which indicates that these patients should be kept under close follow-up for cardiovascular events.