Search PubMed⌕ Search

Biomedical subjects

T Onat

Publications and source records attributed to T Onat.

32 records · Page 2Linked to original sources
PubMedDate not supplied

Echocardiographic study on the origin of the innocent flow murmurs.

To investigate the origin of the pulmonary systolic ejection innocent flow murmur (IFM), echocardiographic examinations were undertaken in 30 children with IFM and in a control group consisting of 28 healthy children without murmur. Compared to the controls, the diameters of the left ventricular outflow tract (LVOT) and aortic valve annulus and aortic valve area tended to be smaller, whereas stroke volume (SV) and cardiac output were slightly greater in children with IFM, but they were not statistically significant. Mean fractional shortening was significantly higher in children with IFM. Peak flow velocity of LVOT, right ventricular outflow tract, aorta, and pulmonary artery, mean velocity and velocity time integral of the aortic and pulmonary flow, and maximal acceleration of the aortic flow were all significantly higher in the IFM group compared to the controls. The variables of left-sided flow velocities in the same individuals with IFM were significantly higher compared to those derived from the right heart. The ratios of the SV to the LVOT diameter and to the aortic valve area were found to be significantly greater. It was concluded that IFM originates from higher blood flow velocities in the region of LVOT and aortic valve annulus, and that the increased flow velocity results from the larger SV passing through the relatively narrow LVOT and aortic valve in children with IFM.

Blood Flow Velocity↗
PubMedDate not supplied

Regression of right ventricular dominance in the electrocardiogram after birth: a longitudinal follow-up of a healthy cohort from birth to 3 years.

To establish the incidence and course of right ventricular (RV) conduction delay during the regression of right ventricular dominance, 12 serial ECGs were recorded at regular intervals until age 36 months in a cohort of 43 normal neonates. Additionally, ECGs were recorded similarly in 6 infants from the age of 1 month and in 7 from 2 months. The right precordial R waves were classified according to their amplitudes and their occurrence before or after the S wave. QR duration and its ratio to QRS were measured in right and left chest leads. The incidence of notched R waves, which is very rare in neonates, increased after the first month and occurred before the peak of R. Thereafter, the height of the notch decreased and then occurred after the peak of R. This turned into an r' (after the S wave) and finally the amplitude of r' decreased further and evolved into a notched S pattern. An rSR' or qRS pattern in the right precordial leads was never observed. An abnormal incomplete right bundle branch block during infancy can be distinguished from physiological right ventricular conduction delay by the unvarying amplitude of the R' wave, preceded by an S wave.

Aging↗
PubMedDate not supplied

The natural course of isolated ventricular septal defect during adolescence.

Serial changes in patients with isolated VSD during adolescence have not previously been investigated. Hemodynamic status, diameter of the defect, and growth were studied yearly in 106 children with VSD. The mean duration of the follow-up was 13.16 years and ranged in 80% of subjects from 7 to 19 years (1395 patients years). The mean ages at pre- and postpuberty were 8.62 and 16.67, respectively. The presented longitudinal study, in which losses due to death and operation were minimal (4%), ideally reflected the natural history of VSD. Although weight showed retardation during prepuberty, this lag was caught up by the end of adolescence. Stature showed no retardation in pre- and postpuberty. Cardiothoracic ratio decreased significantly from a mean of 0.48 to 0.44 and showed normal variation. Although the mean defect diameter at prepuberty was 5.33 mm, this decreased to 2.7 postpubertally. The individual decrease (1.7 +/- 2.34 mm) was significant (t = 5.349, p < 1/10(5)). The defect closed spontaneously in 24 (22.6%). In the 75 patients without pulmonary hypertension and with mild left-to-right shunting, 52 remained in the same class and spontaneous closure was observed in 23. In the 24 patients with moderate to severe left-to-right shunt, this decreased in 23 and only one remained stable. The 2 patients (1.9%) with Eisenmenger syndrome remained stable and 1 died. Aortic regurgitation developed in 10 patients (9.4%); however, this was of mild degree in most of them. No infective endocarditis was observed. It is concluded that patients with VSD should be followed closely through adolescence, because the diameter of the defect, as well as left-to-right shunting, can decrease, and it is concluded that the spontaneous closure of the defect is to be expected in a considerable 23%, and aortic prolapse or mild regurgitation may develop in approximately 10%.

Adolescent↗
PubMedDate not supplied

Regression of right ventricular pressure in ventricular septal defect in infancy: a longitudinal color-flow Doppler echocardiographic study.

To determine the course of right ventricular pressure (RVP) in patients with isolated ventricular septal defect (VSD) and factors influencing it, unselected 148 infants were followed-up longitudinally with color-Doppler echocardiography from a median age of 1 month for 201 patient-years. The patients were divided into three groups by absolute echographic size of VSD: group I, </=4.0 mm; group II, >4 to </=7 mm; group III, >7 mm. Sixty percent belonged to group I. Muscular defects dominated in group I, perimembranous defects dominated in group II, and those with outlet extensions dominated in group III. Peak systolic RVP was obtained by Doppler-estimated difference between systolic brachial artery and peak gradient across the VSD. Initial RVP ranged between 15 and 95 mmHg and increased in parallel to the size of defect. According to the regression equations RVP decreased in general by 0.17 mmHg per month. This correlated significantly with the size of the defect. In group I, the rate of decrease was very fast and is best expressed by a log function of time (r = -0.67, r(2) = 0.45). In groups II and III the rate of decrease was less steep and had a greater variability. RVP normalized in 100% in those of group I and in 90% of group II, at median ages of 0.17 and 0.33 years, respectively. Median Q(p):Q(s) values were 1.5, 2.2, and 3.0 in groups I-III, respectively. The outcome depended on the size of VSD. Spontaneous closure was observed in 51% of group I, 10% of group II, and none of group III. The rate was higher in muscular defects. Congestive heart failure was present in 53% and 100% in groups II and III, respectively. Death rate was 2.03%, all in patients with large defects. It is concluded that the temporal course of RVP with time can be estimated fairly well by the regression equation presented in relation to the initial size of the VSD.

Angiocardiography↗
PubMedDate not supplied

Catalase/superoxide dismutase (SOD) and catalase/paraoxonase (PON) ratios may implicate poor glycemic control.

BACKGROUND: Previous studies suggest that elevated oxidative stress implicates poor glycemic control resulting in the development of diabetic complications. By evaluating the relationship between paraoxonase (PON) and antioxidant enzyme activities and glycemic control in diabetic patients with and without complications, we investigated whether there is a role of PON and/or antioxidant status in glycemic control. METHODS: A total of 107 patients with type 2 diabetes mellitus (DM) was included in the study. Seventy-five patients had complications including microangiopathy, proliferative retinopathy, and/or nephropathy while 32 had no complications. The control group consisted of 29 age- and sex-matched healthy persons. Serum superoxide dismutase (SOD) and catalase activities were measured according to Sun and Goth, respectively. Basal and salt-stimulated paraoxonase activities and arylesterase activity were determined using the method of Eckerson et al. RESULTS: There was an increase in the catalase activity and a decrease in the basal and salt-stimulated PON activity of patients when compared with controls, while no significant difference was observed in SOD activity. PON phenotypes had no effect on any parameter in patient and control groups. The ratio of catalase/SOD was 2.44 +/- 7.10 and 0.17 +/- 0.09 in diabetics and controls, respectively (p = 0.004); this was associated with an elevation in HbA1c levels. On the other hand, catalase/PON ratio was also enhanced in diabetic patients (2.8 +/- 5.2), showing a relationship with HbA1c levels compared to controls (0.29 +/- 0.3, p = 0.000). CONCLUSIONS: The data of this study reveal that enhanced catalase/SOD and catalase /PON ratios that are correlated with HbA1c levels are observed in diabetic patients; thus, these ratios may be used as markers of poor glycemic control and as risk factors in the development of diabetic complications.

Adult↗
PubMedDate not supplied

Long-term prognosis of acute rheumatic carditis with combined aortic and mitral regurgitation.

Thirty-one patients with acute rheumatic carditis associated with aortic (AR) and mitral regurgitation (MR) who received corticosteroid anti-inflammatory therapy for an average of nine weeks were followed up for 332 patient-years (mean: 10.71 years). The age of onset was 9.34 (1 SD = +/- 1.94) years. The patients were classified according to degree of left ventricular volume overloading (LVH), duration of pre-treatment interval and regularity of penicillin prophylaxis. The probability of the yearly disappearance of MR, AR and both lesions were calculated for the total group and in relation to affecting subgroups. The mean yearly rate of disappearance of AR was 2 percent after a 10 percent probability in the first year. This rate was 6.83 percent per year for MR, and it increased to 10.15 percent per year in the patients in whom therapy was initiated in less than three weeks, and decreased to 3.14 percent in the patients in whom therapy was initiated after three weeks. The disappearance of both AR and MR was observed in only two patients (about 1% per year); MS developed in two patients (6.45%) and the mortality rate was 3.2 percent in 332 patient-years (0.0001/year).

Adolescent↗
PubMedDate not supplied

Long-term prognosis of rheumatic mitral regurgitation: presentation of yearly prognostic regressions in relation to affecting factors.

Acute rheumatic isolated mitral regurgitation was followed up in 86 children for 730 patient-years. The grade of severity of regurgitation was classified according to degree of left ventricular enlargement, which was based on an original method of correction of cardiothoracic ratio on the chest x-ray, taking into consideration the diaphragmatic level, and electrocardiographic criteria for age. A combination of both quantitative estimations, after the regression of a detectable pericardial effusion reduced false-positive radiologic and false-negative electrocardiographic results. Linear regressions of percentage of yearly disappearance of MR were presented in relation to the grades of severity; the mean yearly rate of disappearance of 5.8% increased to 9.08% in mild, and decreased to 1.84% in severe regurgitation. The effect of other beneficial factors such as the shortness of the pretreatment interval and regularity of prophylaxis could be demonstrated by keeping the grade of severity of regurgitation constant. Thus, chances for recovery in reported years after onset, up to ten years, can readily be calculated from the presented regressions with regard to the appropriate subgroups.

Adolescent↗