Myocardium – ABC CARDIOL

IJCS

Review Article

Current Role of Myocardial Blood Flow Quantification with PET/CT in the Management of Coronary Artery Disease

Raffaele Giubbini et al. Elisa Milan

Abstract

The ability to measure myocardial blood flow (MBF) offers significant advantages in interpreting the phenomena underlying myocardial ischemia. Nuclear cardiology using hybrid positron emission tomography/computed tomography (PET/CT) systems allows accurate measurement of MBF using noninvasive techniques. Short- or very short-lived radiopharmaceuticals are now available, as well as standardized analytical models and software for clinical use. The incremental value of quantitative measurement of MBF in the pathophysiologic assessment of ischemic heart disease compared with anatomic variables or qualitative or semi-quantitative assessment by single-photon emission computed tomography (SPECT) with gamma-emitting tracers will be analyzed. The clinical role of MBF, myocardial flow reserve (MFR), and coronary flow capacity (CFC) will be clarified. However, the widespread availability of this technology is limited by the need for on-site cyclotron tracer production or the purchase of expensive radionuclide generators. The ability to obtain quantitative measurements using newer SPECT with cadmium-zinc-telluride technology and technetium-labeled tracers may offer the possibility of extending MBF measurement to most nuclear cardiology units in the near future.

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Original Article

Predictors of 30-Day Hospital Readmission Following CABG in a Multicenter Database: A Cross-Sectional Study

Rene Augusto Gonçalves e Silva et al. Gabrielle Barbosa Borgomoni Fabiane Letícia de Freitas Adnaldo da Silveira Maia … Cleóstones Farias do Vale Junior Eva da Silva Pereira Leonardy Guilherme Ibrahim Silvestre Luís Roberto Palma Dallan Luiz Augusto Lisboa Luís Alberto Oliveira Dallan Fabio Biscegli Jatene Omar Asdrúbal Vilca Mejia grupo de estudos REPLICCAR

Abstract

Background:

The analysis of indicators such as hospital readmission rates is crucial for improving the quality of services and management of hospital processes.

Objectives:

To identify the variables correlated with hospital readmission up to 30 days following coronary artery bypass grafting (CABG).

Methods:

Cross-sectional cohort study by REPLICCAR II database (N=3,392) from June 2017 to June 2019. Retrospectively, 150 patients were analyzed to identify factors associated with hospital readmission within 30 days post-CABG using univariate and multivariate logistic regression. Analysis was conducted using software R, with a significance level of 0.05 and 95% confidence intervals.

Results:

Out of 3,392 patients, 150 (4,42%0 were readmitted within 30 days post-discharge from CABG primarily due to infections (mediastinitis, surgical wounds, and sepsis) accounting for 52 cases (34.66%). Other causes included surgical complications (14/150, 9.33%) and pneumonia (13/150, 8.66%). The multivariate regression model identified an intercept (OR: 1.098, p<0.00001), sleep apnea (OR: 1.117, p=0.0165), cardiac arrhythmia (OR: 1.040, p=0.0712), and intra-aortic balloon pump use (OR: 1.068, p=0.0021) as predictors of the outcome, with an AUC of 0.70.

Conclusion:

4.42% of patients were readmitted post-CABG, mainly due to infections. Factors such as sleep apnea (OR: 1.117, p=0.0165), cardiac arrhythmia (OR: 1.040, p=0.0712), and intra-aortic balloon pump use (OR: 1.068, p=0.0021) were predictors of readmission, with moderate risk discrimination (AUC: 0.70).

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Case Report

Acute Myocarditis as the Initial Presentation of Desmoplakin Mutation – Broadening the Differential Diagnosis

Hideki Koike et al. Amr Idris Justin Berger Victor Y. Cheng … Jay Sengupta João L. Cavalcante

Introduction

Genetic cardiomyopathy related to desmoplakin (DSP) mutation can start its clinical manifestation with chest pain symptoms, along with transient troponin elevation configuring first manifest as acute myocarditis, sometimes in a relapsing pattern. It is clear that the revised Task Force criteria for genetic cardiomyopathy will miss many cases, particularly those with left-sided dominance. This case reports highlights to understand that genetic cardiomyopathy, particularly with DSP mutation, can present with acute myocarditis and to understand that cardiovascular magnetic resonance (CMR) imaging could raise the possibility of arrhythmogenic cardiomyopathy and predict ventricular tachyarrhythmias despite preserved LVEF.

[…]

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Original Article

Overexpression of the PTEN Gene in Myocardial Tissues of Coronary Bypass Surgery Patients

Reyhan Tahtasakal et al. Elif Funda Sener Nesrin Delibasi Zuhal Hamurcu … Ecmel Mehmetbeyoglu Keziban Korkmaz Bayram Isin Gunes Dincer Goksuluk Omer Naci Emirogullari

Abstract

Background:

Coronary artery disease is a complex disorder that causes death worldwide. One of the genes involved in developing this disease may be PTEN.

Objectives:

This study aimed to investigate the PTEN gene and protein expression in tissue and blood samples taken from coronary bypass surgery patients.

Methods:

Molecular studies were performed at Erciyes University Genome and Stem Cell Center (GENKOK). Right atrial appendage and blood samples were taken from the central vein of 22 coronary bypass surgery patients before starting and ending cardiopulmonary bypass. PTEN expression was determined using quantitative real-time PCR and western blot analysis. The significance level was accepted as p<0.05.

Results:

There was no significant difference in the PTEN gene expression in blood samples taken before and after cardiopulmonary bypass. However, a substantial increase in both protein and gene expression levels of P-PTEN and PTEN was observed in the tissue samples. Myocardial expression of the PTEN gene was significantly increased at the end of the cardiopulmonary bypass. PTEN gene expression in the post-cardiopulmonary bypass period was increased when compared to the pre-bypass period, but it was insignificant when compared to healthy controls.

Conclusion:

This study first revealed the role of the PTEN gene by analyzing both mRNA and protein expression in coronary bypass patients, appearing in both myocardial tissue and blood samples. Increased levels of PTEN may be a marker in myocardial tissue for patients with coronary artery disease.

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Review Article

Left Atrial Strain in the Analysis of LV Diastolic Function: Ready to Use?

Antonio Amador Calvilho Júnior et al. Jorge Eduardo Assef João Moron Saes Braga Andrea de Andrade Vilela … Antonio Tito Paladino Filho Gustavo Nishida

Abstract

Left atrial (LA) dilation is a common indicator of diastolic dysfunction, and its analysis through a volume calculation reflects the cumulative effects of the left ventricular (LV) filling pressures. However, an increase in LA volume is not exclusive to diastolic dysfunction, which has also been observed in other clinical conditions. Thus, the evaluation of the LA strain enables a functional study of this chamber, adding to the morphological analysis through the volume calculation.

The LA strain, measured using the speckle tracking technique, brings information on the reservoir, conduction, and contractile functions of the LA, and is related to the LV function. Moreover, the changes in the LA strain precede the volumetric changes by nearly a decade, and correlate inversely with the degree of LA fibrosis – this has an important relationship with the diastolic dysfunction and its grading system. Albeit insufficient to explain its totality, LA fibrosis can partially justify the functional changes of this heart chamber and can favor the use of this variable as a complement to the current protocols for the analysis of the diastolic function.

Although further study is still warranted to establish other clinical applications, the LA strain stands out in the analysis of diastolic dysfunction and can be considered ready to use, offering a great potential to improve the evaluation of the overall cardiac function.

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Review Article

My Approach to Right Ventricular Longitudinal Strain with Automated 2D and 3D Software

Lucas Arraes de França et al. Lucas Velloso Dutra

Abstract

Right ventricular strain analysis has emerged as an important diagnostic tool in the detection of early right ventricular systolic dysfunction not detected by conventional echocardiography techniques. Furthermore, it is capable of providing additional diagnostic and prognostic information to the traditional parameters for evaluating right ventricular systolic function in various pathologies. The echocardiography method of choice for its assessment is longitudinal strain derived from speckletracking. This method has been shown to be more sensitive for small changes in systolic function when compared to tricuspid annular plane systolic excursion, tissue Doppler imaging of the tricuspid annular s’ wave, and right ventricular fractional area change. Advances in artificial intelligence and software with automated analysis have been introduced to this scenario with the aim of making the method simpler and quicker to apply, with lower inter- and intra-observer variability. The objective of this review article is to demonstrate the technique step by step, from image optimization and acquisition to interpretation of results, with illustrative figures of selected cases.

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Original Article

Body Surface Potential Mapping during Ventricular Depolarization in Rats after Acute Exhaustive Exercise

Alexey G. Ivonin et al. Svetlana L. Smirnova Irina M. Roshchevskaya

Abstract

Background

Exhaustive physical exercise can cause substantial changes in the electrical properties of the myocardium.

Objective

To evaluate, using body surface potential mapping, the electrical activity of the heart in rats during ventricular depolarization after acute exhaustive exercise.

Methods

Twelve-week-old male rats were submitted to acute treadmill exercise at 36 m/min until exhaustion. Unipolar electrocardiograms (ECGs) from the torso surface were recorded in zoletil-anesthetized rats three to five days before (Pre-Ex), 5 and 10 minutes after exhaustive exercise (Post-Ex 5 and Post-Ex 10, respectively) simultaneously with ECGs in limb leads. The instantaneous body surface potential maps (BSPMs) were analyzed during ventricular depolarization. P values <0.05 were considered statistically significant.

Results

Compared with Pre-Ex, an early completion of the second inversion of potential distributions, an early completion of ventricular depolarization, as well as a decrease in the duration of the middle phase and the total duration of ventricular depolarization on BSPMs were revealed at Post-Ex 5. Also, compared with Pre-Ex, an increase in the amplitude of negative BSPM extremum at the R-wave peak on the ECG in lead II (R_II-peak) and a decrease in the amplitude of negative BSPM extremum at 3 and 4 ms after R_II-peak were showed at Post-Ex 5. At Post-Ex 10, parameters of BSPMs did not differ from those at Pre-Ex.

Conclusion

In rats, acute exhaustive exercise causes reversible changes in the temporal and amplitude characteristics of BSPMs during ventricular depolarization, most likely related to alterations in the excitation of the main mass of the ventricular myocardium.

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Case Report

Heart failure in pregnancy – another possibility beyond peripartum cardiomyopathy

Antonio José Lagoeiro Jorge et al. Deborah Luz Diniz Martins Diane Xavier de Ávila Otávio Souza de Martino … Mário Luiz Ribeiro Daniel Gama das Neves Wolney de Andrade Martins

Abstract

Non-compacted myocardium is a rare primary genetic cardiomyopathy described as an abnormality in endomyocardial morphogenesis where there is interruption of myocardial fiber compaction, generating a loose trabecular tissue. It is manifested with heart failure, embolism and ventricular arrhythmia. This is the case of systemic non-compacted cardiomyopathy in a 22-year-old woman, who had recently given birth and has type 1 diabetes mellitus.

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Original Article

Cardiac Autonomic Nervous System Remodeling May Play a Role in Atrial Fibrillation: A Study of the Autonomic Nervous System and Myocardial Receptors

Ítalo Martins de Oliveira et al. Evilásio Leobino da Silva Júnior Yasmin de Oliveira Martins Hermano Alexandre Lima Rocha … Maurício Ibrahim Scanavacca Paulo Sampaio Gutierrez

Abstract

Background

The primary factors that originate and perpetuate atrial fibrillation (AF) are electrical and anatomical substrate alterations. However, the central mechanisms governing AF perpetuation have not been elucidated yet, which is reflected on the modest results of the treatment in patients with long persistent AF.

Objective

To evaluate if human intrinsic cardiac autonomic nervous system (ICANS) remodeling, including nervous system fibers and muscarinic and β-adrenergic receptors, play a role in permanent AF.

Methods

Heart necropsy samples from thirteen patients with heart disease and permanent AF and thirteen controls without AF were used. By using immunoperoxidase and histomorphometry quantification, we identified the following: the density of all fibers of the ICANS, sympathetic and parasympathetic fibers; and the percentage of myocardium positive for β-adrenergic receptors 1, 2 and 3; G protein-coupled receptor kinase-5 (GRK-5); and muscarinic receptors M1 to M5. The results were compared using ANOVA and nested ANOVA and were adjusted according to the left atrium volume for all variables, and β-blocker use to evaluate the expression of β-receptors and GRK-5.

Results

There was an overall increase in the density of fibers of the ICANS (p=0.006), especially in atrial sympathetic nerve fibers (p=0.017). Only M1 muscarinic receptors were increased (5.87 vs 2.35, p=0.032). For adrenergic receptors, the results were positive for increased expression of β-3 (37.41 vs 34.18, p=0.039) and GRK-5 (51.16 vs 47.66; p<0.001). β-blocker use had no impact on β-receptor expression.

Conclusion

Increased ICANS innervation and remodeling receptor expression in regions prone to triggering AF may play a role in permanent AF.

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Editorial

Heart and Skeletal Muscles: Linked by Autonomic Nervous System

Claudio Gil Araujo et al. Jari Antero Laukkanen

The autonomic nervous system (ANS) plays a fundamental role in maintaining cell homeostasis and human life. The functionality of the heart and skeletal muscles is partially modulated by sympathetic and parasympathetic branches of the ANS both in resting and exercising conditions.

Substantial literature attests to the fact that objective indices of muscle strength reflect health status. It is well-established that heart failure is typically accompanied by skeletal muscle abnormalities that contributed to the exercise intolerance and poor health-related quality of life usually seen in these patients.^, Indeed, while a decrease in muscle mass and strength is naturally seen with ageing, especially after the fifth decade of life, this is especially more relevant in middle-aged and older patients with heart failure.

[…]

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Original Article

Functional Effects of Hyperthyroidism on Cardiac Papillary Muscle in Rats

Fabricio Furtado Vieira et al. Robson Ruiz Olivoto Priscyla Oliveira da Silva Julio Cesar Francisco Rosalvo Tadeu Hochmuller Fogaça

Abstract

Background:

Hyperthyroidism is currently recognized to affect the cardiovascular system, leading to a series of molecular and functional changes. However, little is known about the functional influence of hyperthyroidism in the regulation of cytoplasmic calcium and on the sodium/calcium exchanger (NCX) in the cardiac muscle.

Objectives:

To evaluate the functional changes in papillary muscles isolated from animals with induced hyperthyroidism.

Methods:

We divided 36 Wistar rats into a group of controls and another of animals with hyperthyroidism induced by intraperitoneal T3 injection. We measured in the animals’ papillary muscles the maximum contraction force, speed of contraction (+df/dt) and relaxation (-df/dt), contraction and relaxation time, contraction force at different concentrations of extracellular sodium, post-rest potentiation (PRP), and contraction force induced by caffeine.

Results:

In hyperthyroid animals, we observed decreased PRP at all rest times (p < 0.05), increased +df/dt and -df/dt (p < 0.001), low positive inotropic response to decreased concentration of extracellular sodium (p < 0.001), reduction of the maximum force in caffeine-induced contraction (p < 0.003), and decreased total contraction time (p < 0.001). The maximal contraction force did not differ significantly between groups (p = 0.973).

Conclusion:

We hypothesize that the changes observed are likely due to a decrease in calcium content in the sarcoplasmic reticulum, caused by calcium leakage, decreased expression of NCX, and increased expression of a-MHC and SERCA2.

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Artigo Original

Influence of Term of Exposure to High-Fat Diet-Induced Obesity on Myocardial Collagen Type I and III

Danielle Cristina Tomaz da Silva et al. Ana Paula Lima-Leopoldo André Soares Leopoldo Dijon Henrique Salomé de Campos … André Ferreira do Nascimento Sílvio Assis de Oliveira Junior Carlos Roberto Padovani Antonio Carlos Cicogna

BACKGROUND:

Obesity is a risk factor for many medical complications; medical research has shown that hemodynamic, morphological and functional abnormalities are correlated with the duration and severity of obesity.

OBJECTIVE:

Present study determined the influence of term of exposure to high-fat diet-induced obesity on myocardial collagen type I and III.

METHODS:

Thirty-day-old male Wistar rats were randomly distributed into two groups: a control (C) group fed a standard rat chow and an obese (Ob) group alternately fed one of four palatable high-fat diets. Each diet was changed daily, and the rats were maintained on their respective diets for 15 (C₁₅ and Ob₁₅) and 30 (C₃₀ and Ob₃₀) consecutive weeks. Obesity was determined by adiposity index.

RESULTS:

The Ob₁₅ group was similar to the C₁₅ group regarding the expression of myocardial collagen type I; however, expression in the Ob₃₀ group was less than C₃₀ group. The time of exposure to obesity was associated with a reduction in collagen type I in Ob₃₀ when compared with Ob₁₅. Obesity did not affect collagen type III expression.

CONCLUSION:

This study showed that the time of exposure to obesity for 30 weeks induced by unsaturated high-fat diet caused a reduction in myocardial collagen type I expression in the obese rats. However, no effect was seen on myocardial collagen type III expression.

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Artigo Original

Influence of long-term obesity on myocardial gene expression

Ana Paula Lima-Leopoldo et al. André Soares Leopoldo Danielle Cristina Tomaz Silva André Ferreira do Nascimento … Dijon Henrique Salomé de Campos Renata de Azevedo Melo Luvizotto Silvio Assis de Oliveira Júnior Carlos Roberto Padovani Célia Regina Nogueira Antonio Carlos Cicogna

BACKGROUND: Several authors have shown that deterioration of cardiac function is associated with the degree and duration of obesity. It is necessary to establish the gene expression patterns after prolonged periods of obesity. OBJECTIVE: This study tested the hypothesis that increased duration of exposure to obesity leads to a reduction in the mRNA levels of proteins involved in regulation of myocardial Ca2+ homeostasis. In addition, this study verified whether the decrease in mRNA expression was caused by a reduction in thyroid hormone. METHODS: Thirty-day-old male Wistar rats were distributed in two groups: control (C) and obese (Ob). The C group was fed a standard diet and the Ob was fed with high-fat diets for 15, 30 and 45 weeks. Obesity was defined by adiposity index. The gene expression was assessed by quantitative real-time PCR. RESULTS: The adiposity index was higher in the Ob compared to the C after all periods. While obesity at 15 and 45 weeks resulted in a reduction in mRNA of sarcoplasmic reticulum Ca2+- ATPase (SERCA2a), Na+/Ca2+ exchanger (NCX), and calsequestrin (CSQ), L-type Ca2+ channels, ryanodine receptor, SERCA2a, phospholamban (PLB), NCX, and CSQ expression were increased compared to the C after 30 weeks. There was no significant association between T3 levels and mRNA expression. CONCLUSIONS: Our data indicate that obesity over the short and long periods of time may promote alteration in gene expression of Ca2+ homeostasis regulatory proteins without influence by thyroid hormone.

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Artigo Original

Upregulation of mRNA myocardium calcium handling in rats submitted to exercise and food restriction

Mário Mateus Sugizaki et al. Ana Paula Lima Leopoldo Sandro José Conde Dijon Salome Campos … Ricardo Damato André Soares Leopoldo André Ferreira do Nascimento Silvio de Assis Oliveira Júnior Antonio Carlos Cicogna

BACKGROUND: Chronic exercise and food restriction (FR) have directionally opposite changes in transcription of molecular structures of calcium handling and thyroid hormone (TH) status. OBJECTIVE: Evaluate the association of chronic exercise and FR on serum thyroid hormones and gene transcription of molecular structures of intracellular calcium transients and thyroid receptors in myocardium of rats. METHODS: Male Wistar Kyoto rats, divided into two groups: control (C, n = 7), FR (R50, n = 7), chronic exercise (EX, n = 7) and chronic exercise + FR (EX50, n = 7). FR was of 50% and exercise was swimming (1 hour/day, 5 days/week, during 12 weeks). Serum concentrations of T3, T4 and TSH were determined. The mRNA gene expression of the sarcoplasmatic reticulum calcium pump (SERCA2a), phospholamban (PLB), Na+/Ca+2 exchanger (NCX), calcium channel L-type (L-channel), ryanodine (RYR), calsequestrin (CQS) and HT receptor (TRα1 and TRβ1) of the myocardium was performed by PCR real-time. RESULTS: FR reduced serum levels of T4 and TSH and TRα1 mRNA and increased the expression of PLB, NCX and L-channel. Exercise increased the TRβ1 receptor, L-channel and NCX. The association of exercise and FR reduced plasma T4 and TSH, TRβ1 mRNA increase, SERCA2a, NCX and PLB, and there was a significant correlation of TRβ1 with CQS and NXC. CONCLUSION: Chronic exercise and food restriction increased the mRNA of transient Ca2+ proteins; however, TH-receptor axis cannot participate in the transcription of mRNA of myocardial calcium transient proteins.

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Artigo Original

Effects of the corticosteroids in the lesions by radiofrequency on rats' thigh in different age groups

Mieko Okada et al. Sérgio de Araújo Marcello Franco Angelo de Paola Guilherme Fenelon

BACKGROUND: The corticosteroids limit the late growth of the lesions by radiofrequency (RF) on the rats’ infants’ thighs, but the effects on the pubescent and adult rats are unknown. OBJECTIVE: Evaluate the effects of the corticosteroids in the healing of the lesions by RF on the rats’ thighs muscles in different age groups. METHODS: Ablation was performed on the thigh muscle of 30 rats (1 lesion per animal): infants (30 days old, weight 73 g, n = 10), pubescents (60 days old, weight 230 g, n = 10) and 10 adults (90 days old, 310 g, n = 10), subdivided in control and treated groups, that received Hydrocortisone (10 mg/kg IM post-RF) and Betametasone (3.5 mg/kg IM, twice a week, for 29 days). The rats were sacrificed 60 days after the ablation for hystopathological and planimetric analysis with specified software (ImageJ®). RESULTS: In the infant, pubescent and adult groups, the weight gain in the follow up did not differ between the control and the treated ones. In the control group, the lesions of the infants and pubescents were superior (p = 0.01) to the adults’. The treatment reduced the size of the lesion in the infants (5.58+0.61 mm² vs 4.02+0.23 mm²; p < 0.01) and pubescents (5.20+0.47 mm² vs 4.16+0.48 mm²; p < 0.01), but not in the adults (4.44+0.50 mm² vs 4.79+0.53 mm², p = NS). Infant and pubescent treated groups presented lower collagen deposition and less fibrotic bands invading the healthy tissue from the central fibrosis area, and forming lesions with remarkably more reduced dimensions than their controls. There were no differences in the adult groups. CONCLUSION: The corticosteroids seem to reduce the late growth of lesion, in addition to attenuate the fibrotic proliferation in the infant and pubescent rats.

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Artigo Original

Scintigraphy for the detection of myocardial damage in the indeterminate form of Chagas disease

Ivana Moura Abuhid et al. Enio Roberto Pietra Pedroso Nilton Alves de Rezende

BACKGROUND: Non-invasive cardiological methods have been used for the identification of myocardial damage in Chagas disease. OBJECTIVE: To verify whether the rest/stress myocardial perfusion scintigraphy is able to identify early myocardial damage in the indeterminate form of Chagas disease. METHODS: Eighteen patients with the indeterminate form of Chagas Disease and the same number of normal controls, paired by sex and age, underwent rest/stress myocardial scintigraphy using sestamibi-99mTc, aiming at detecting early cardiac damage. RESULTS: The results did not show perfusion or ventricular function defects in patients at the indeterminate phase of Chagas disease and in the normal controls, except for a patient who presented signs of ventricular dysfunction in the myocardial perfusion scintigraphy with electrocardiographic gating. CONCLUSION: The results of this study, considering the small sample size, showed that the rest/stress myocardial scintigraphy using sestamibi-99mTc is not an effective method to detect early myocardial alterations in the indeterminate form of Chagas disease.

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Artigo Original

Different levels of Hsp72 in female rat myocardium in response to voluntary exercise and forced exercise

Stéphano Freitas Soares Melo et al. Wellington Lunz Elizabeth Pacheco Batista Fontes Cristina Maria Ganns Chaves Dias … Miguel Araujo Carneiro Júnior Anselmo Gomes de Moura Ricardo Junqueira Del Carlo Antonio Jose Natali

BACKGROUND: Physical exercise induces hemodynamic stress. OBJECTIVE: To evaluate if voluntary running and forced running induced different levels of stress protein (Hsp72) in the myocardium of female Wistar rats. METHODS: Female rats were randomly assigned to the following groups: forced treadmill running group (FR; n= 6), voluntary running group (VR; n=6) and control group (C; n=6). VR group animals had free access to running wheels, and those from FR group underwent a running program on a treadmill (18 m/min, 60 min/day, 5 days/wk) for 8 weeks. Left ventricle (LV) and right ventricle (RV) fragments were collected at sacrifice, and the relative immunoblot contents of stress protein (Hsp72) were determined. RESULTS: VR animals ran on average 4.87 km/wk, and FR rats ran 4.88 km/wk. Animals from VR and FR groups had less body weight gain (p0.05) among VR, FR and C groups (4.54 ± 0.79 mg/g vs 4.94 ± 0.89 mg/g vs 4.34 ± 0.87 mg/g, respectively). FR group animals had levels of Hsp72 (p<0.05) higher than those from VR, both in LV (287.45 ± 35.86 % vs 135.59 ± 5.10 %, respectively) and RV (241.31 ± 25.83 % vs 137.91 ± 45.20 %, respectively). CONCLUSION: Voluntary running and forced running induced different levels of Hsp72 in the myocardium of female Wistar rats.

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Artigo Original

The myocardium in tetralogy of Fallot: a histological and morphometric study

Maria Cecília Knoll Farah et al. Cláudia Regina Pinheiro de Castro Valéria Mello Moreira Arlindo de Almeida Riso … Antonio Augusto Barbosa Lopes Vera Demarchi Aiello

BACKGROUND: Patients with Tetralogy of Fallot frequently develop ventricular dysfunction in the postoperative period. The histological basis of this functional alteration has been scarcely studied. OBJECTIVE: To evaluate myocardial remodeling in anatomical specimens, comparing the subepicardial and subendocardial regions, especially because the subendocardial region is easily approached by means of endomyocardial biopsy. METHODS: Transmural sections of myocardium from the right ventricular (RV) inflow tract, anterior wall and infundibulum, and from the left ventricular (LV) free wall were evaluated regarding the degree of cardiomyocyte hypertrophy, vascularization and interstitial fibrosis were analyzed. RESULTS: The mean diameter of subendocardial cardiomyocytes is similar to that of subepicardial cardiomyocytes in all regions, except for the RV infundibulum, in which subendocardial cardiomyocytes are significantly larger in relation to those of the subepicardium (p=0.007). The amount of interstitial collagen is in the upper limits of normal and was similar in the subendocardial layers in comparison with the subpericardial layer of each region; however, it was greater in the inflow tract and RV anterior wall than in the LV lateral wall. The numerical density of subendocardial capillaries was similar to that of the subepicardium and was lower than the mean minus two standard deviations of normal in all regions and layers, except for the infundibulum, in which the subepicardium showed normal values and the subendocardium showed values lower than the mean minus two standard deviations. CONCLUSION: The postnatal myocardial changes in Tetralogy of Fallot are homogeneously distributed in the subepicardial and subendocardial halves of the ventricular walls, except for the infundibulum, which has peculiar remodeling characteristics and, therefore, is not representative of the other ventricular regions and layers for morphometric studies.

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Artigo Original

Spironolactone effects on myocardium changes induced by thyroid hormone in rats

Maria Luiza Mendonça Pereira Fernandes et al. Eloísa Amália Vieira Ferro Marcelo Emilio Beletti Elmiro Santos Resende

BACKGROUND: To study the possible role of aldosterone on thyroid hormone-induced myocardium hypertrophy, using spironolactone. OBJECTIVE: To evaluate morphological changes in the myocardium induced by thyroid hormone and the possible effects of spironolactone use on these alterations. METHODS: Forty Wistar rats were studied. The animals were allocated to four groups and were given: the vehicle used for dilution of the thyroid hormone (C); sodium levothyroxin at 50 µg/rat/day (H); spironolactone, 0.3 mg/kg/day (S); or thyroid hormone plus spironolactone (HS), at the same doses mentioned above, for 28 consecutive days. All the animals were weighed, had blood drawn for hormonal measurements and underwent ECG at the start and the end of the experiment. At the end of experiment all animals were euthanized, the weight of the left ventricle (LV) was determined and LV slices were obtained for morphological analysis. RESULTS: There was an increase in T3 levels, decrease of body weight and higher heart rate in the animals from group H. The LV weight was significantly higher in the H e HS groups. The histometric analyses that measured the diameter of the myocytes showed higher values in group H and a progressive decrease in groups HS, S and C, with a significant difference among all the groups. The addition of spironolactone decreased the transversal myocyte hypertrophy by 14.6%. CONCLUSION: Rats treated with thyroid hormone present cardiac hypertrophy with increased LV weight and greater myocyte diameter. Spironolactone, when associated with thyroid hormone, can partially prevent this hypertrophy through mechanisms that are yet to be determined.

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Artigo Original

Clinical, electrocardiographic and echocardiographic findings in significant cardiac amyloidosis detected only at necropsy: comparison with cases diagnosed in life

Paulo Sampaio Gutierrez et al. Fábio Fernandes Charles Mady Maria de Lourdes Higuchi

BACKGROUND: Currently, many cases of heart amyloidosis still fail to be diagnosed. OBJECTIVE: To disclose factors related to the difficulty in attaining the diagnosis of cardiac amyloidosis. METHODS: We compared the clinical, electrocardiographic and echocardiographic data of 17 patients in whom amyloidosis was diagnosed only at the necropsy (group I) with data from 9 patients in whom the disease was diagnosed in life (group II). The quantitative variables were compared by t-test and qualitative ones by Fisher’s exact test. Significance was set at p<0.05. RESULTS: The two groups showed differences regarding age (group I: 75.29 ± 11.61, group II: 58.67 ± 11.07 years), association with other cardiac disease (group I: 52.94%, group II: 0%), low voltage at the ECG (group I: 17.65%, group II: 66.67%), and diastolic dysfunction at the echocardiogram (group I: 7.69%, group II: 62.50%). Some degree of left ventricular thickening was found in 75% of necropsy cases and 100% of controls (p=0.23), but wall thickness was lower in group I (free left ventricular wall: 1.20 ± 0.28 cm versus 1.53 ± 0.18cm in group II, p=0.01). Systolic dysfunction was present in 57.89% of the cases, without significant difference between the groups. CONCLUSION: Amyloidosis is diagnosed when the clinical, ECG, and echocardiogram patterns are "typical", but most of the cases fail to be diagnosed, especially in elderly people, due to the association with other cardiac diseases, lack of diastolic dysfunction at the echocardiogram and only a slightly thickened ventricular wall.

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Artigo Original

Ultrasonic tissue characterization in acute coronary syndromes

Antonio Pazin-Filho et al. Gustavo Jardim Volpe Minna Moreira Dias Romano Gerson Antonio Tavares Júnior … André Schmidt Benedito Carlos Maciel

BACKGROUND: Ultrasonic tissue characterization (UTC), as evaluated through integrated backscatter, has the potential to detect precocious structural damage to myocardial tissue. In acute coronary syndromes (ACS) this technique is attracting attention due to its potential to evaluate myocardial viability. OBJECTIVE: To evaluate the role of UTC in the emergency department. METHODS: We studied 28 individuals, classified in three groups: Group I (13; 52.2±15.5 years) with patients admitted with chest pain who have negative evaluation for acute coronary syndrome; Group II (9; 54.2±10.0 years) with acute myocardial infarction in right coronary artery territory; and Group III (6; 62.1±9.1 years) with acute myocardial infarction in the anterior descendent branch territory. For each individual, we analyzed four segments in the short axis view at the papillary muscle level (1 – anterior; 2 – anterior-lateral; 3 – inferior e 4 – septal), for the following parameters: corrected coefficient, amplitude, delay index and IBS pattern. RESULTS: The acute myocardial isquemic process in its initial phase was not detected by the corrected coefficient or by the IBS amplitude. The sincronicity parameters (delay index and IBS pattern), more sensible, were partially able to identify changes in more extension regions of myocardial infarction. CONCLUSION: More studies should be conducted to evaluate these parameters in the early phase of acute coronary syndromes.

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Artigo Original

Influences of rich in saturated and unsaturated fatty acids diets in rat myocardium

Matheus Fécchio Pinotti et al. Maeli Dal-Pai Silva Mário Mateus Sugizaki Yeda Santana Diniz Novelli … Lea Sílvia Sant'ana Flávio Ferrari Aragon Carlos Roberto Padovani Ethel Lourenzi Barbosa Novelli Antonio Carlos Cicogna

OBJECTIVES: To study the influence of saturated (SFA) and unsaturated fatty acid (UFA) rich diets on mechanical function, morphology and oxidative stress in rat myocardium. METHODS: Male, 60-day-old Wistar rats were fed a control (n=8), a SFA (n=8), or a UFA-rich diet (n=8) for sixty days. Mechanical function was studied in isolated left ventricle papillary muscle under isometric and isotonic contractions, in basal conditions (1.25mM calcium chloride) and after 5.2mM calcium chloride and beta-adrenergic stimuli with 1.0µM isoproterenol. Left ventricle fragments were used to study oxidative stress and morphology under light and electron microscopy. RESULTS: SFA and UFA-rich diets did not change myocardium mechanical function. Both diets caused oxidative stress, with high lipid hydroperoxide and low superoxide-dismutase concentrations. UFA rich diet decreased catalase expression and SFA rich diet decreased the amount of myocardial glutathione-peroxidase. Both diets promoted light ultrastructural injuries such as lipid deposits and cell membrane injuries. CONCLUSION: Results suggest that SFA and UFA rich diets do not alter isolated muscle mechanical function, but promote light myocardial morphological injuries and oxidative stress.

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The role of storage of interstitial myocardial collagen on the overlife rate of patients with idiopathic and chagasic dilated cardiomyopathy

Vera Lopes Nunes et al. Felix José Alvarez Ramires Walace de Souza Pimentel Fábio Fernandes … Barbara Maria Ianni Charles Mady

OBJECTIVE: To find out whether there is a correlation between a myocardial structural marker and the overlife rate of patients with dilated cardiomyopathy. METHODS: Using endomyocardial biopsy and 2D-echocardiogram, we studied nine patients with no changes in myocardial structure (control) and 45 patients with severe dilated cardiomyopathy of idiopathic etiology (IDCM) and of Chagasic etiology (CDCM). We analyzed the correlation between the quantity of interstitial myocardial collagen (ICVF) and the overlife rates of these patients. We also evaluated the difference in ICVF between these groups and whether fibrosis interfered on the geometry and function of the myocardium. RESULTS: We observed that ICVF was 15 times higher in cardiomyopathy patients than in the control group, but there was no difference in ICVF between CDCM and IDCM (*p < 0.001) patients. There was no correlation between ICVF and the overlife rate in cardiomyopathy patients (IDCM p = 0.249, and CDCM p = 0.587). We observed a significant correlation between ICVF and left ventricular ejection fraction (LVEF) only for IDCM. There was no correlation between ICVF and left ventricular diastolic diameter in either etiology. CONCLUSION: There was no difference in myocardial fibrosis between patients with CDCM or IDCM, and there was no correlation between fibrosis and the prognosis either for IDCM or CDCM. There was a correlation between myocardial fibrosis and LVEF only for IDCM.

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Morphometry of human myocardium in senile individuals

José Antonio Cardoso et al. Ana Elisa Toscano Tetsuo Tashiro Cláudio Antonio Ferraz de Carvalho Sílvia Regina Arruda de Moraes

OBJECTIVE: To carry out a quantitative assessment in human myocardium cells of senile individuals, in right, left and septal ventricular regions. METHODS: Five hearts from corpses of individuals without heart diseases, of both sexes, with age between 67 and 87 years old were used. The following parameters were assessed: myocyte unit cross section area (myoc. a o); myocyte unit perimeter length (myoc. l o); myocyte unit volume (myoc. v o); myocyte volumetric density (myoc. Vv); number of myocytes per volume unit (Nmm ^³myoc.). The t-test of Student was used in statistic analysis. RESULTS: The analysis of differences (p < 0.05) among right (RV), left (LV) and septal (S) ventricular regions of human heart showed that myoc. a o values were lower in RV (1.51 ± 0.10 µm²) and in S (1.55 ± 0.07 µm²) in relation to LV (1.84 ± 0.24 µm²). Values of myoc. l o were also shown lower in S (5.11 ± 0.46 µm) comparing to LV (6.2 ± 0.97 µm). Likewise, myoc. v o and myoc. Vv showed lower values in RV (88.75 ± 25.37 µm ³; 0.39 ± 0.03%) in relation to LV (122.41 ± 16.31 µm ³; 0.41 ± 0.01%). CONCLUSION: Results obtained show that there may be changes in dimensions of left ventricular wall myocyte cell during senescent stage. However, those differences are subtle and seem to mean the adjustment of tissue to functional changes that install along life.

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