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Biomedical subjects

Beatriz Bojikian Matsubara

Publications and source records attributed to Beatriz Bojikian Matsubara.

10 recordsLinked to original sources
PubMed2008

Cardiac hemangioma of the right atrium.

Primary cardiac tumors are rare, with an incidence range between 0.001% and 0.030% at autopsy. Recent technical advances have facilitated diagnosis and surgical treatment of such lesions. Patients with a resectable tumor usually have a good prognosis, but patients with an unresectable tumor may have a poor prognosis. This report shows a case of right atrial hemangioma growing like an extracardiac mass, with cardiac tamponade the only clinical presentation.

Adult↗
PubMed2006

Myocardial dysfunction with increased ventricular compliance in volume overload hypertrophy.

The aim this study was to evaluate systolic and diastolic function in volume overload induced myocardial hypertrophy in rats. Volume overload myocardial hypertrophy was induced in thirteen male Wistar rats by creating infrarenal arteriovenous fistula (AVF). The results were compared with a SHAM operated group (n=11). Eight weeks after surgery, tail-cuff blood pressure was recorded, then rats were sacrificed for isolated heart studies using Langendorff's preparation. AVF rats presented increased left and right ventricular weights, compared to controls. The increased normalized ventricular volume (V0/LVW, 0.141+/-0.035 mL/g vs. 0.267+/-0.071 mL/g, P<0.001) in the AVF group indicated chamber dilation. Myocardial hydroxyproline concentration remained unchanged. There was a significant decrease in +dP/dt (3318+/-352 mm Hg s(-1) vs. 2769+/-399 mm Hg s(-1); P=0,002), end-systolic pressure-volume relation (246+/-56 mm Hg mL(-1) vs. 114+/-63 mm Hg mL(-1); P<0,001), and -dP/dt (1746+/-240 mm Hg s(-1) vs. 1361+/-217 mm Hg s(-1), P<0.001) in the AVF group, which presented increased ventricular compliance (DeltaV(25): SHAM=0.172+/-0.05 mL vs. AVF=0.321+/-0.072 mL, P<0.001) with preserved myocardial passive stiffness (Strain(25): SHAM=13.5+/-3.0% vs. AVF=12.3+/-1.9%, P>0.05). We conclude that volume-overload induced hypertrophy causes myocardial systolic and diastolic dysfunction with increased ventricular compliance. These haemodynamic features help to explain the long-term compensatory phase of chronic volume overload before transition to overt congestive heart failure.

Animals↗
PubMed2006

[Myocardial remodeling in chronic pressure or volume overload in the rat heart].

OBJECTIVE: To compare cardiac structural changes in experimental pressure and volume overload models. METHODS: The study analysis included renovascular hypertensive rats (RVH, n = 8), normotensive rats with volume overload caused by an aortocaval fistula (ACF, n = 10) and control rats (CONT, n = 8). After four weeks, tail cuff blood pressure (SBP) was recorded. Rats were killed, the hearts were excised and the right and left ventricles (RV&LV) were weighed (RVW&LVW). Using histological sections, myocyte cross sectional areas (MA). LV wall thickness (LVWT) LV cavity diameter (LVD), normalized LVWT (LVWT/LVD) and collagen volume fraction (CVF) were measured. The comparisons were made using the ANOVA and Tukey test for a significance level of 5%. RESULTS: Tail cuff blood pressure (mmHg) was higher in the RVH group (RVH = 187 +/- 22; CONT = 125 +/- 10; ACF = 122 +/- 6, p < 0.05). LV hypertrophy was observed in the RVH and ACF groups. The ACF group presented a significant increase in size of LVD, compared to CONT and RVH. The absolute and normalized ventricular wall thickness were similar among the groups. The RVH group presented a significant increase in CVF compared to CONT group and ACF group. CONCLUSION: Cardiac remodeling patterns following volume or pressure overload are distinct, suggesting that their implications on ventricular dysfunction are not interchangeable.

Animals↗
PubMed2005

[Clinical characteristics associated with unfavorable outcomes in peripartum myocardiopathy].

OBJECTIVE: To assess the clinical characteristics of women with a previous diagnosis of peripartum myocardiopathy and to study the characteristics associated with unfavorable outcomes. METHODS: Clinical, obstetric, and echocardiographic variables were studied in 12 patients with peripartum myocardiopathy, assessed at diagnosis and at a current appointment, when they were divided into 2 groups: FG (n = 6, without cardiac alterations) and UG (n = 6, with cardiomegaly and persistent ventricular dysfunction). The comparisons were made using the Student t test and Fisher's exact test (P < 0.05). RESULTS: At diagnosis, mean age of the patients (8 Caucasian and 4 black/non-Caucasian) was 24+/-7.4 years, all in Functional Class IV (NYHA) and 8 reporting gestational hypertension or preeclampsia. Mean follow-up time was 25 months. Ten patients developed Functional Class I/II. Comparison between the groups demonstrated that UG had lower left ventricular ejection fractions (0.30+/-0.05 vs. 0.58+/-0.09; P < 0.001) and greater LV systolic diameter (58+/-5 mm vs. 46+/-3 mm; P < 0.001) at diagnosis. An unfavorable outcome was more frequent among non-Caucasian women (P = 0.01). In the current evaluation, UG had lower relative wall thickness (0.13+/-0.02 vs. 0.17+/-0.02; P < 0.05) and greater LV mass (283+/-90 g vs. 186+/-41 g; P < 0.05). CONCLUSION: Patients with previous peripartum myocardiopathy had unfavorable outcomes associated with black race, and stronger initial cardiac alterations; a favorable outcome was associated with a reduction in myocardial mass and an increase in relative ventricular wall thickness.

Adolescent↗
PubMed2004

Guide of internet sites for the study of cardiology.

OBJECTIVE: To increase the offer of didactic resources for medical students, physicians, and health care professionals, stimulating the use of the Internet for academic purposes or cardiological updating. METHOD: Electronic addresses with academic content in the areas of anatomy, biophysics, physiology, semiology, electrocardiography, and image diagnosis were researched and selected. The selection criteria included the following: relevance of the content, neatness of presentation, and richness of animation resources. The sites obtained were classified in regard to their contents and academic level. RESULTS: The sites obtained were as follows: 5 sites of anatomy and anatomical pathology, one of biophysics, 3 of physiology, 8 of semiology, 7 of image diagnosis, and 2 of electrocardiography. The sites were also organized according to academic level to provide an alternative access. The set of addresses resulted in a simplified and hierarchic guide of contents for the study of cardiac morphology and image diagnosis in cardiology. CONCLUSION: The resulting list of sites is an example of the potential of the Internet as a learning instrument to be used in association with other conventional pedagogical methods.

Cardiology↗
PubMed2004

Improved systolic ventricular function with normal myocardial mechanics in compensated cardiac hypertrophy.

There is still controversy about the relation between changes in myocardial contractile function and global left ventricular (LV) performance during stable concentric hypertrophy. To clarify this, we analyzed LV function in vivo and myocardial mechanics in vitro in rats with pressure overload-induced cardiac hypertrophy. Male Wistar rats (70 g) underwent ascending aortic stenosis for 8 weeks (group AAS, n = 9). LV performance was assessed by transthoracic echocardiography under anesthesia. Myocardial function was studied in isolated papillary muscle preparations during isometric contraction. The data were compared with age- and sex-matched sham-operated rats (group C, n = 9). LV weight-to-body weight ratio (C: 2.13 +/- 0.14 mg/g; AAS: 3.24 +/- 0.44 mg/g), LV relative wall thickness (C: 0.18 +/- 0.02; AAS: 0.33 +/- 0.09), and LV fractional shortening (C: 54 +/- 5%; AAS: 70 +/- 8%) were increased in group AAS (P < 0.05). Echocardiographic analysis also indicated a significant association (r = 0.74; P < 0.001) between the percent fractional shortening index and LV relative wall thickness. The performance of AAS isolated muscle revealed that active tension (C: 6.6 +/- 1.7 g/mm2; AAS: 6.5 +/- 1.5 g/mm2) and maximum rate of tension development (C: 69 +/- 21 g/mm2/s; AAS: 69 +/- 18 g/mm2/s) were not significantly different from group C (P > 0.05). In conclusion, compensated pressure-overload myocardial hypertrophy is associated with preserved myocardial function and increased ventricular performance. The improved LV function might be due to the ventricular remodeling characterized by an increased relative wall thickness.

Animals↗
PubMed2003

Ventricular remodeling induced by retinoic acid supplementation in adult rats.

Retinoic acid (RA) plays a role in regulating cardiac geometry and function throughout life. The aim of this study was to analyze the cardiac effects of RA in adult rats. Wistar rats were randomly allocated to a control group (n = 18) receiving standard rat chow and a group treated with RA (n = 14) receiving standard rat chow supplemented with RA for 90 days. All animals were evaluated by echocardiography, isolated papillary muscle function, and morphological studies. Whereas the RA-treated group developed an increase in both left ventricular (LV) mass and LV end-diastolic diameter, the ratio of LV wall thickness to LV end-diastolic diameter remained unchanged when compared with the control group. In the isolated papillary muscle preparation, RA treatment decreased the time to peak developed tension and increased the maximum velocity of isometric relengthening, indicating that systolic and diastolic function was improved. Although RA treatment produced an increase in myocyte cross-sectional area, the myocardial collagen volume fraction was similar to controls. Thus our study demonstrates that small physiological doses of RA induce ventricular remodeling resembling compensated volume-overload hypertrophy in rats.

Animals↗
PubMed2003

Influence of fluid volume variations on the calculated value of the left ventricular mass measured by echocardiogram in patients submitted to hemodialysis.

The left ventricular mass (LVM) measurement is of major importance for renal patients, as ventricular hypertrophy is an important prognostic index. The echocardiogram of the ventricular mass is larger before than it is after hemodialysis, which can confuse data interpretation. The aim of this work is to study the influence of alterations in fluid volume on the variations in measurements of ventricular mass observed during the course of a hemodialysis. Sixteen patients with chronic renal insufficiency in hemodialysis were evaluated at the Dialysis Unit of the University Hospital-UNESP, Botucatu, São Paulo State. The left ventricular mass was calculated from echocardiograms taken before and after hemodialysis and simultaneous ultra-filtration (12 patients: UF GROUP) and before and after hemodialysis isovolemic phase with sequential ultra-filtration (10 patients: ISO GROUP). Six of these patients were submitted to measurements of left ventricular mass before and after hemodialysis in both isovolemic and simultaneous ultra-filtration procedures. In the UF group, there was significant reduction in the following parameters before and after dialysis: diastolic diameter from 54.0 +/- 6.0mm to 45.6 +/- 7.6mm; left ventricular mass from 342 +/- 114 g to 265 +/- 117 g; and its respective index (IMVE) from 214 +/- 68 g/m2 to 168 +/- 71 g/m2. The ISO group showed no statistically significant variation. The behavior of the variables of six patients submitted to both observations confirm these results. In conclusion, the variations in echocardiogram measurements of the left ventricula mass relating to hemodialysis appear to be induced by alterations of the volemic condition.

Adolescent↗
PubMed2002

Volume overload influence on hypertrophied myocardium function.

The aim of this study was to demonstrate that hypertrophied cardiac muscle is more sensitive to volume-overload than normal cardiac muscle. We assessed the mechanical function of isolated left ventricular papillary muscle from male spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto rats (WKY) submitted to volume overload caused by aortocaval fistula (ACF) for 30 days. Muscles were perfused with Krebs-Henseleit solution at 28 degrees C and studied isometrically at a stimulation rate of 0.2 Hz. The ACF increased the right and left ventricular weight-to-body weight ratio in WKY rats; it also promoted right ventricular hypertrophy and further increased the basal hypertrophy in the left ventricle from SHR. The arterial systolic pressure was greater in SHR than in WKY rats, and decreased with ACF in both groups. Developed tension (DT) and maximum rate of DT (+dT/dt) were greater in the SHR-control than in the WKY-control (P < 0.05); the time from peak tension to 50% relaxation (RT 1/2) was similar in these animals. ACF did not change any parameters in the SHR group and increased the resting tension in the WKY group. However, the significant difference observed between myocardial contraction performance in WKY-controls and SHR-controls disappeared when the SHR-ACF and WKY-controls were compared. Furthermore, RT 1/2 increased significantly in the SHR-ACF in relation to the WKY-controls. In conclusion, the data lead us to infer that volume-overload for 30 days promotes more mechanical functional changes in hypertrophied muscle than in normal cardiac muscle.

Animals↗