Effects of lowered dialysate sodium on left ventricle function and brain natriuretic peptide in maintenance of hemodialysis patients.

INTRODUCTION: Impaired diastolic flow is characterized by decreased left ventricular (LV) filling diastole, abnormal LV distensibility, or delayed relaxation. B-Type natriuretic peptide (BNP) is an indicator of various cardiovascular diseases and body volume status. The aim of this study was to determine whether the lowering of dialysate sodium (Na) levels is effective on LV systolic and diastolic parameters and BNP in the maintenance of hemodialysis patients. MATERIALS AND METHODS: The study included 49 chronic hemodialysis patients. Left atrium (LA) diameter and LV ejection fraction, LV systolic and diastolic diameter, deceleration time (DT), pulmonary artery pressure (PAP), inferior vena cava diameter (IVCD), early diastolic transmitral flow ( E) and late diastolic transmitral flow ( A) velocities, E/ A ratio, isovolumic relaxation time, peak early diastolic velocity ( E'), late diastolic velocity ( A') of tissue Doppler mitral annulus, and flow propagation velocity of mitral inflow ( Vp) were measured before and 6 months after hemodialysis with low Na dialysate. RESULTS: Six months after low Na hemodialysis, a decrease was observed in echocardiographic parameters such as PAP and IVCD ( p < 0.05, p < 0.001, and p < 0.001, respectively). However, a significant difference was not observed in LA diameter. In LV diastolic measurement of E and A waves, E/ A ratio, DT, Vp, septal E' and A', and lateral E' and A' exhibited significant improvement by low Na HD. BNP level was significantly reduced ( p < 0.001). CONCLUSIONS: Lowered dialysate Na concentration improves PAP, IVCD, and LV diastolic properties assessed by mitral inflow filling, tissue Doppler velocity, and mitral inflow velocity propagation.

Two markers in predicting the cardiovascular events in patients with polycystic ovary syndrome: increased P-wave and QT dispersion.

OBJECTIVE: Polycystic ovary syndrome (PCOS) is a prevalent disease with many potential long-term cardiovascular risks. P-wave dispersion (Pdis) and QT dispersion (QTdis) have been shown to be noninvasive electrocardiographic predictors for development of cardiac arrhythmias. In this study we aimed to search Pdis and QTdis parameters in patients with PCOS. PATIENTS AND METHODS: The study included 82 patients with PCOS and 74 age- and sex-matched healthy controls. Baseline 12-lead electrocardiographic and transthoracic echocardiographic measurements were evaluated. P-wave maximum duration (Pmax), P-wave minimum duration (Pmin), Pdis, QT interval, heart rate-corrected QT dispersion and QTdis were calculated by two cardiologists. RESULTS: Patients wirh PCOS had significantly higher QT dispersion (49.5 ± 14.1 vs. 37.9 ± 12.6 ms, p < 0.001), and P wave dispersion (54.2 ± 11.4 vs. 45.9 ± 10.1 ms, p < 0.001) than the controls. Serum testosterone and estradiol levels was correlated with the Pdis (r = 0.677, p < 0.001 and r = 0.415, p < 0.001 respectively) and QTdis (r = 0.326, p < 0.001 and r = 0.321, p < 0.001 respectively). CONCLUSIONS: Pdis and QTdis are simple and useful electrocardiographic markers which may be used in the prediction of the risk of adverse cardiovascular events in PCOS patients.

A new echocardiographic parameter of arterial stiffness in end-stage renal disease.

BACKGROUND: Cardiovascular disease is the leading cause of death among patients with end-stage renal disease (ESRD). Arterial stiffness is an independent predictive parameter of overall and cardiovascular mortality in these patients. However, the defined procedures for the measurement of arterial stiffness are time consuming and not practical in daily practice. METHODS: The study population included 50 patients with ESRD who were treated with hemodialysis (HD; n=23) or peritoneal dialysis (PD; n=27) and 70 age- and sex-matched control subjects. Aortofemoral pulse wave velocity (PWV), carotid intima-media thickness (CIMT), and color M-mode propagation velocity of the descending aorta (aortic propagation velocity, APV) were measured. RESULTS: Compared to the control group, the patients with ESRD had significantly lower APV (46.4 ± 12.4 vs. 58.5 ± 8.5, p < 0.01) and higher PWV (10.5 ± 2.5 vs. 9.2 ± 1.2, p < 0.01) and CIMT (0.66 ± 0.15 vs. 0.43 ± 0.06, p < 0.01) measurements. There were significant correlations between APV and CIMT (r = - 0.769, p < 0.001), APV and PWV (r = - 0.682, p < 0.001), and PWV and CIMT (r = 0.564, p < 0.001). There were no significant differences in APV and PWV between the PD and HD patients. CONCLUSION: Arterial stiffness is an important indicator of atherosclerosis and arterial aging in patients with ESRD. The measurement of APV is an easy and practical new echocardiographic method and may be used to identify arterial stiffness in these patients.

A novel echocardiographic method as an indicator of endothelial dysfunction in patients with coronary slow flow.

BACKGROUND: To improve clinical outcomes, noninvasive imaging modalities have been proposed to measure and monitor atherosclerosis. Endothelial dysfunction is considered the first stage in the development of atherosclerosis. Brachial artery flow-mediated dilatation (FMD) has been impaired in patients with coronary slow flow (CSF). Recently, color M-mode derived propagation velocity of descending thoracic aorta (aortic propagation velocity-AVP) was shown to be an ultrasonographic marker for atherosclerosis. AIM: To assess endothelial function in patients with CSF and the correlation of AVP with FMD. MATERIALS AND METHODS: FMD and AVP were measured in 90 patients with CSF and 39 patients having normal coronary arteries (NCA) detected by coronary angiography. RESULTS: Compared to patients with normal coronary arteries patients having CSF had significantly lower AVP (39.1±8.4 vs. 53.7±12.7 cm/s, p < 0.001) and FMD (5.6±3.2 vs. 17.6±4.4 %, p < 0.001) measurements. There were significant correlations between AVP and FMD (r = 0.524, p < 0.001). CONCLUSIONS: Transthoracic echocardiographic determination of color M-mode propagation velocity of descending aorta is a simple practical method and correlates well with coronary slow flow and brachial endothelial function.

Word recall in schizophrenia: a connectionist model.

OBJECTIVE: The authors examined word recall of patients with schizophrenia by using an experimental paradigm generated from connectionist models of memory. METHOD: Schizophrenic patients and normal comparison subjects first studied and then recalled a list of 32 words of equal difficulty. Both the connectivity (associative strength) and the network size (number of associates) of the words varied in such a way that the list contained equal proportions of four types of words: 1) high connectivity-small network size, 2) low connectivity-small network size, 3) high connectivity-large network size, and 4) low connectivity-large network size. RESULTS: The schizophrenic patients recalled fewer words and showed a particularly pronounced effect of the connectivity of the to-be-remembered words. For the patients, regardless of network size, recall improved substantially for words of high connectivity and declined dramatically for words of low connectivity. By contrast, the comparison subjects showed the expected effects, with the best recall for words of high connectivity-small network size, followed by words of low connectivity-small network size, then by words of high connectivity-large network size, and finally by words of low connectivity-large network size. CONCLUSIONS: Schizophrenia may be characterized by faulty modulation of associative links within a putative lexicon that is thought to be widely distributed across frontal and temporal lobes.

Auditory mismatch negativity in schizophrenia: topographic evaluation with a high-density recording montage.

OBJECTIVE: The mismatch negativity, a negative component in the auditory event-related potential, is thought to index automatic processes involved in sensory or echoic memory. The authors' goal in this study was to examine the topography of auditory mismatch negativity in schizophrenia with a high-density, 64-channel recording montage. METHOD: Mismatch negativity topography was evaluated in 23 right-handed male patients with schizophrenia who were receiving medication and in 23 nonschizophrenic comparison subjects who were matched in age, handedness, and parental socioeconomic status. The Positive and Negative Syndrome Scale was used to measure psychiatric symptoms. RESULTS: Mismatch negativity amplitude was reduced in the patients with schizophrenia. They showed a greater left-less-than-right asymmetry than comparison subjects at homotopic electrode pairs near the parietotemporal junction. There were correlations between mismatch negativity amplitude and hallucinations at left frontal electrodes and between mismatch negativity amplitude and passive-apathetic social withdrawal at left and right frontal electrodes. CONCLUSIONS: Mismatch negativity was reduced in schizophrenia, especially in the left hemisphere. This finding is consistent with abnormalities of primary or adjacent auditory cortex involved in auditory sensory or echoic memory.