Cem Koz

Cardiac Autonomic Functions in Obese Children

Objective: The autonomic nervous system is assumed to have a role in the pathophysiology of obesity. In this study, we evaluated the autonomic system by measuring heart rate variability (HRV) in obese children. Methods: Thirty-two obese and 30 healthy children (mean ages: 11.6±2.0 years and 11.0±2.9 years, respectively) were enrolled in the study. Obesity was defined as a body mass index higher than 97th percentile for age- and gender-specific reference values. All participants were free of any disease and none of them was receiving any medication. Twenty-four-hour ambulatory electrocardiographic recordings were obtained and the time-domain and frequency-domain indices of HRV were analyzed. The study group was evaluated with respect to insulin resistance by HOMA-IR values. Results: A significant decrease in calculated HRV variables was observed in obese children as compared to controls. The HRV alteration was found in both time-domain and frequency-domain parameters. The subgroup analysis of the study group revealed a significant decrease in all investigated HRV parameters in the insulin-resistant obese children compared to the non-insulin-resistant obese ones. Conclusions: Our results indicate that HRV is decreased in obese children, which implies parasympathetic withdrawal and sympathetic predominance. A marked decrease in HRV was observed in insulin-resistant obese children compared to their non-insulin-resistant counterparts. We propose that autonomic imbalance pertaining especially to insulin resistance may be involved in the pathogenesis of obesity in pediatric patients Conflict of interest:None declared.

Conventional and non-conventional coronary risk factors in male premature coronary artery disease patients already having a low Framingham risk score

Background — Individual risk factors and, more importantly, global risk assessment tools such as the Framingham risk score have been used successfully for risk prediction especially in older patients. However, there is paucity of data about the coronary heart disease prediction in premature coronary artery disease patients with a low Framingham risk score. Methods and results — We recruited 102 consecutive young patients without hypertension and diabetes mellitus in the study. All subjects had had chest pain and underwent coronary angiography since non-invasive diagnostic test results suggested ischaemia. Forty-five patients having at least one coronary lesion independent of severity were included in the study group.The remaining fifty-seven subjects without any coronary lesion were used as control group. Conventional and non-conventional risk factors were evaluated both in patients and control subjects. Framingham risk score and absolute 10-year hard CHD events risk were also calculated for each individual. The coronary heart disease group had a significantly higher smoking frequency as compared to the control group. They also had higher plasma levels of triglycerides, apolipoprotein B and apo B/A1 ratio but a smaller LDL particle size.We failed to find any independent CHD predictor after logistic regression analysis. However, individual ROC curve analysis of risk factors revealed that apolipoprotein B, triglycerides and apo B/A1 ratio have the highest area under the curve for coronary artery disease prediction. Conclusions — The Framingham risk score may underestimate the true risk of an individual. Incorporating non-conventional risk factors such as apolipoprotein B and apo B/apo A1 ratio may provide valuable information in these patients.

Evaluation of plasma adiponectin levels in young men with coronary artery disease

Objective — In this study, we investigated the relation between plasma adiponectin levels and other risk factors in a young patient population. Material and results — We enrolled consecutively 69 young patients (<45years) with coronary artery disease in the study group. The patient enrollment period was between February 2003 and November 2004.The control group consisted of 42 age- and sex-matched healthy subjects.Anthropometric, lipid and other variables including adiponectin, fasting glucose and plasma insulin levels were measured in all subjects. Appropriate statistical analyses were performed to determine the differences between the groups, the relation between adiponectin and other parameters and independent factors that predict CAD. There was a statistically significant difference between the groups in terms of lipid parameters (triglycerides, total cholesterol, HDL and LDL cholesterol). Mean plasma adiponectin levels were significantly lower in the patients (P<0.05).Among the risk factors adiponectin had a significant negative association with the plasma triglyceride level (P<0.01). Logistic regression analysis revealed triglycerides and adiponectin as independent predictors of CAD.The areas under the ROC curves of adiponectin and triglycerides were not different (P>0.05). Conclusion — We found a decreased plasma adiponectin level in young male patients with coronary artery disease. It may be a novel marker of atherosclerosis in young men.

Echocardiographic, electrocardiographic, and clinical correlates of recurrent transient ischemic attacks: a follow-up study.

Background: Transient ischemic attack (TIA) is presumed to be of cardiovascular origin. The aim of the study was to evaluate the electrocardiographic, echocardiographic, and clinical signs for predicting TIA recurrence. Methods: A total of 100 consecutive patients presenting with a first episode of TIA without atrial fibrillation, previous stroke, and uncontrolled diabetes or hypertension were enrolled in the study. The electrocardiographic, echocardiographic, and clinical parameters were obtained in those patients. The patients received a follow-up of bimonthly visits and were grouped according to the presence (or lack) of TIA recurrence in the follow-up period. Results: Of these patients, 23 experienced recurrent TIA and 72 did not; 5 patients dropped out. Independent risk factors evaluated for TIA recurrence were aortic diameter, left atrial diameter, P-wave dispersion, hyperlipidemia, absence of lipid lowering, and warfarin treatment. Conclusion: Careful electrocardiographic and echocardiographic evaluation of patients with TIA may help assess the outcome of patients and guide therapeutic interventions.

Brain natriuretic peptide and the severity of aortic regurgitation: is there any correlation?

We aimed to evaluate the correlation between aortic regurgitation severity and brain natriuretic (BNP) levels as a marker for left ventricular dysfunction. Sixty consecutive male patients (mean age 22 ± 3 years) with isolated chronic aortic regurgitation were enrolled in the study together with a control group of 30 age-matched healthy volunteers (group A). Patients were classified with regard to aortic regurgitation vena contracta width as follows: group B, < 3 mm, mild (n = 16); group C, ≥ 3 and < 6 mm, moderate (n = 26); group D, ≥ 6 mm, severe (n = 18). BNP measurements were performed with a fluorescence immunoassay kit. BNP levels were increased in patients with aortic regurgitation, and severity of regurgitation had a significant influence on BNP levels. This effect can be explained by the volume loading effect of aortic regurgitation.

Left atrial functions after myocardial infarction.

Acute myocardial infarction results in not only left ventricular but also left atrial dysfunction. Left atrial function is important for optimal filling of the left ventricle. In this study, we aimed at evaluating left atrial functions 6 months after acute myocardial infarction in three different patient groups (thrombolytic therapy, primary percutaneous intervention, or no reperfusion strategies). Between October 2002 and May 2003, 48 patients with ST elevation myocardial infarction who were either administered thrombolytic therapy (group T, n = 16), underwent primary angioplasty (group A, n = 20), or underwent no reperfusion therapy (group C, n = 12) at our unit were enrolled into the study. Echocardiography was performed in these patients 6 months after acute myocardial infarction. Left atrial contractility was assessed by atrial ejection force. Left atrial contribution was assessed by atrial fractional shortening and left atrial volume was calculated. The left atrial volume was significantly higher in group C (P < 0.05), but there was no significant difference between groups A and T (P > 0.05). Patients in group C had significantly lower atrial ejection force values compared with the other groups (P < 0.05). Atrial fractional shortening was not significantly different among the three groups (P > 0.05). Atrial ejection force, which is an indicator of left atrial contractility, is better with either angioplasty or thrombolysis. Left atrial volume is higher in patients who were not treated with reperfusion strategies. Further studies are needed to explain the mechanism involved.

Utility of myocardial performance index measured by left ventricular catheterization.

Background — Myocardial performance index (MPI) is a valuable index of global ventricular performance. It is almost always measured by Doppler echocardiography. The purposes of this study were (1) to compare MPI measured by catheterization (MPIc) and that measured by Doppler echocardiography (MPId), and (2) to compare it with the functional status. Materials and methods — The study included 80 patients who had undergone left heart catheterization. The MPIc was measured from the pressure recordings obtained at left ventricle and aorta. Results — Mean MPId and MPIc were 0.40 ± 0.12 and 0.42 ± 0.12, respectively. Mean left ventricular end diastolic pressure (LVEDP) was 13 ± 5 mm Hg. Mean heart rate was 77 ± 11 beats/min. Mann-Whitney U test revealed that MPIc could discriminate between the functional statuses of the patients. The regression analysis revealed that there is a good correlation between MPIc and MPId, LVEDP or heart rate.There was no significant difference between MPIc and MPId (p > 0.05). Conclusion — The present data show that (1) the MPIc has a strong correlation with MPId; (2) it is a good discriminator of functional status. It may provide an additional information regarding the left ventricular performance in patients who underwent the cardiac catheterization.

Impedance cardiographic monitoring during pericardiocentesis: comparison with echocardiography

Objective — Thoracic impedance cardiography (TIC) is a noninvasive method which has proved to be useful in monitoring the haemodynamic status of the patients. In this study, we evaluated the TIC findings in patients with pericardial effusion and cardiac tamponade. Methods and results — The study consisted of patients with pericardial effusion with (group A) or without (group B) cardiac tamponade (CT).The stroke volume, cardiac output and ejection fraction was measured by both echocardiography and TIC.The measurements were done at baseline in both groups and following pericardiocentesis in group A.The variables were compared by linear regression analysis, paired sample’s t test and chi-square test.The study included 32 patients. Group A consisted of 16 patients and group B of 14 patients.Two patients were excluded from comparisons because of insufficient quality of the echocardiographic examination. There were no significant differences between group A and B with regard to demographic features. Both echocardiographic and TIC measurements at baseline revealed decreased cardiac output, EDV and SV in group A and EF was not different. Linear regression analysis revealed that echocardiography and TIC were in significant correlation with regard to cardiac output, enddiastolic volume, stroke volume (p < 0.01) but not ejection fraction (p = 0.8910).The correlation was also present after pericardiocentesis. Conclusions — TIC can be safely used in patients with pericardial effusion. It provides suggestive data for the diagnosis of CT and can be used as a means of monitoring the results of the pericardiocentesis.

Letter by Baysan et al Regarding Article, “A New Parameter of Pulsed-Wave Tissue Doppler Imaging: IVRa”

Dear Editor: We read the article “A new parameter of pulsed-wave tissue Doppler imaging: IVRa” with great enthusiasm.1 The authors proposed a novel marker for the evaluation of diastolic functions that also affected by left ventricular geometry. However, this interesting study brought new questions into our minds. Edvardsen et al. reported in their animal study that myocardial velocity pattern during isovolumic relaxation phase was dominated by a negative velocity spike.2 Therefore, they suggested net elongation of the left ventricle as the cause of this event. In this study, the authors reported bidirectional velocity during isovolumic phase. We thought that the authors should provide their opinions about the positive velocity (IVRa) detected during isovolumic period. Does it cause by active contraction or merely a reflection of tethering-translational movements?

Nomogram for Mitral Valve Area Assessment

Dear Editor, We have read the article by Uzun et al. titled “A nomogram for measurement of mitral valve area by proximal isovelocity surface area method.”1 The use of nomogram for complex calculations is very advantageous in terms of requiring less time. It has been used in many instances such as measuring body surface area and body mass index in medical area. The measurement of mitral valve area is still a challenge for echocardiographers because each method has its own limitations. The proximal isovelocity surface area method has the potential to overcome many of these limitations.2–4 Although the deviations in measurement of radius and the need for angle correction has been proposed by many other authors, we think that the most important limitation for the use of this method seems to be the complexity of the method. It should be kept in mind that the radius is measured correctly if the echocardiographer uses this method and compares it with others (as reference methods) when there is no limitation for other methods. The need for angle correction is with a great extent alleviated by the nomogram proposed by Uzun et al. However, we have some comments about the proportion of aliasing velocity (Val) and maximum velocity (Vmax). The authors have used the proportion of 1:8 for Val:Vmax. The nomogram has been drawn according to this proportion. We think that dividing a number by eight is still complex and may necessitate calculator. The nomogram would be simpler if they had used the proportion of 1:10. The process of dividing by 10 only includes shifting the comma to the left by one digit. Everybody can make this modification without using a calculator. Another problem is the adjustment of aliasing velocity. The authors have not mentioned