THE ROLE of OXIDATIVE STRESS and LIPID PEROXIDATION IN VENTRICULAR REMODELING INDUCED BY TOBACCO SMOKE EXPOSURE AFTER MYOCARDIAL INFARCTION

OBJECTIVE: To evaluate the roles of oxidative stress and lipid peroxidation in the ventricular remodeling that is induced by tobacco smoke exposure after myocardial infarction.METHODS: After induced myocardial infarction, rats were allocated into two groups: C (control, n=25) and ETS (exposed to tobacco smoke, n=24). After 6 months, survivors were submitted to echocardiogram and biochemical analyses.RESULTS: Rats in the ETS group showed higher diastolic (C = 1.52 +/- 0.4 mm(2), ETS = 1.95 +/- 0.4 mm(2); p=0.032) and systolic (C = 1.03 +/- 0.3, ETS = 1.36 +/- 0.4 mm(2)/g; p=0.049) ventricular areas, adjusted for body weight. The fractional area change was smaller in the ETS group (C = 30.3 +/- 10.1 %, ETS = 19.2 +/- 11.1 %; p=0.024) and E/A ratios were higher in ETS animals (C = 2.3 +/- 2.2, ETS = 5.1 +/- 2.5; p=0.037). ETS was also associated with a higher water percentage in the lung (C = 4.8 (4.3-4.8), ETS = 5.5 (5.3-5.6); p=0.013) as well as higher cardiac levels of reduced glutathione (C = 20.7 +/- 7.6 nmol/mg of protein, ETS = 40.7 +/- 12.7 nmol/mg of protein; p=0.037) and oxidized glutathione (C = 0.3 +/- 0.1 nmol/g of protein, ETS = 0.9 +/- 0.3 nmol/g of protein; p=0.008). No differences were observed in lipid hydroperoxide levels (C = 0.4 +/- 0.2 nmol/mg of tissue, ETS = 0.1 +/- 0.1 nmol/mg of tissue; p=0.08).CONCLUSION: In animals exposed to tobacco smoke, oxidative stress is associated with the intensification of ventricular re-remodeling after myocardial infarction.

Exposure time and ventricular remodeling induced by tobacco smoke exposure in rats

Background: We investigated the effects of length of exposure to tobacco smoke on the cardiac remodeling process induced by exposure to cigarette smoke in rats.Material/Methods: Rats were separated into 4 groups: nonsmoking (NS) 2 (n=25; control animals not exposed to tobacco smoke for 2 months), smoking (S)2 (n=22; rats exposed to smoke from 40 cigarettes/d for 2 months), NS6 (n=18; control animals not exposed to tobacco smoke for 6 months), and S6 (n=25; rats exposed to smoke from 40 cigarettes/d for 6 months). All animals underwent echocardiographic, isolated heart, and morphometric studies. Data were analyzed with a 2-way analysis of variance.Results: No interaction among the variables was found; this suggests that length of exposure to tobacco smoke did not influence the effects of exposure to smoke. Values for left ventricular diastolic diameter/body weight and left atrium/body weight were higher (p=0.023 and p=0.001, respectively) in smoking (S2 and S6) than in nonsmoking animals (NS2 and NS6). Left ventricular mass index was higher (p=0.048) in smoking than in nonsmoking animals. In the isovolumetrically beating ventricle, peak systolic pressure was higher (p=0.034) in smoking than in nonsmoking animals. Significantly higher values were found for left ventricular weight (p=0.017) and right ventricular weight (p=0.001) adjusted for body weight in smoking as opposed to nonsmoking animals. Systolic pressure was higher (p=0.001) in smoking (128 +/- 14 mm Hg) than in nonsmoking animals (112 +/- 11 mm Hg).Conclusions: Length of exposure to cigarette smoke did not influence cardiac remodeling caused by exposure to sm oke in rats.

Heart Failure After Myocardial Infarction: Clinical Implications and Treatment

Heart failure is a frequent complication of myocardial infarction. Several factors, such as recurrent myocardial ischemia, infarct size, ventricular remodeling, stunned myocardium, mechanical complications, and hibernating myocardium influence the appearance of left ventricular systolic dysfunction after myocardial infarction. Importantly, its presence increases the risk of death by at least 3- to 4-fold. The knowledge of the mechanisms and clinical features are essential for the diagnosis and treatment of left ventricular dysfunction and heart failure after myocardial infarction. Therefore, this review will focus on the clinical implications and treatment of heart failure after myocardial infarction.

Myocardial contractility of the isovolumetrically beating isolated rat heart

Several indexes of myocardial contractility have been proposed to assess ventricular function in the isovolumetrically beating isolated heart. However, the conclusions reached on the basis of these indexes may be influenced by ventricular geometry rather than contractility itself. The objective of the present study was to assess the performance of widely used contractility indexes in the isovolumetrically beating isolated heart in two experimental models of hypertrophy, the spontaneously hypertensive rat (SHR) and infrarenal aortocava fistula. Compared to normotensive controls (N = 8), SHRs with concentric hypertrophy (N = 10) presented increased maximum rate of ventricular pressure rise (3875 ± 526 vs 2555 ± 359 mmHg/s, P < 0.05) and peak of isovolumetric pressure (187 ± 11 vs 152 ± 11 mmHg, P < 0.05), and decreased developed stress (123 ± 20 vs 152 ± 26 g/cm², P < 0.05) and slope of stress-strain relationship (4.9 ± 0.42 vs 6.6 ± 0.77 g/cm²/%). Compared with controls (N = 11), rats with volume overload-induced eccentric hypertrophy (N = 16) presented increased developed stress (157 ± 38 vs 124 ± 22 g/cm², P < 0.05) and slope of stress-strain relationship (9 ± 2 vs 7 ± 1 g/cm²/%, P < 0.05), and decreased maximum rate of ventricular pressure rise(2746 ± 382 vs 3319 ± 352 mmHg, P < 0.05) and peak of isovolumetric pressure (115 ± 14 vs 165 ± 13 mmHg/s, P < 0.05). The results suggested that indexes of myocardial contractility used in experimental studies may present opposite results in the same heart and may be influenced by ventricular geometry. We concluded that several indexes should be taken into account for proper evaluation of contractile state, in the isovolumetrically beating isolated heart.

Heart transplantation experiences: a phenomenological approach

Aim. The aim of this study was to understand the heart transplantation experience based on patients' descriptions.Background. To patients with heart failure, heart transplantation represents a possibility to survive and improve their quality of life. Studies have shown that more quality of life is related to patients' increasing awareness and participation in the work of the healthcare team in the post-transplantation period. Deficient relationships between patients and healthcare providers result in lower compliance with the postoperative regimen.Method. A phenomenological approach was used to interview 26 patients who were heart transplant recipients. Patients were interviewed individually and asked this single question: What does the experience of being heart transplanted mean? Participants' descriptions were analysed using phenomenological reduction, analysis and interpretation.Results. Three categories emerged from data analysis: (i) the time lived by the heart recipient; (ii) donors, family and caregivers and (iii) reflections on the experience lived. Living after heart transplant means living in a complex situation: recipients are confronted with lifelong immunosuppressive therapy associated with many side-effects. Some felt healthy whereas others reported persistence of complications as well as the onset of other pathologies. However, all participants celebrated an improvement in quality of life. Health caregivers, their social and family support had been essential for their struggle. Participants realised that life after heart transplantation was a continuing process demanding support and structured follow-up for the rest of their lives.Conclusion. The findings suggest that each individual has unique experiences of the heart transplantation process. To go on living participants had to accept changes and adapt: to the organ change, to complications resulting from rejection of the organ, to lots of pills and food restrictions.Relevance to clinical practice. Stimulating a heart transplant patients spontaneous expression about what they are experiencing and granting them the actual status of the main character in their own story is important to their care.

Pressão arterial e freqüência cardíaca avaliadas pela MAPA em primigestas durante o trabalho de parto e puerpério imediato

OBJETIVO: analisar os valores da pressão arterial e da freqüência cardíaca durante o trabalho de parto e puerpério imediato de primigestas normais. MÉTODOS: foram incluídas no estudo 60 parturientes, às quais foi aplicada a monitorização ambulatorial da pressão arterial (MAPA) com uso do aparelho modelo SpaceLabs 90207, durante o trabalho de parto e nas primeiras 12 horas após o mesmo. A pressão arterial e a freqüência cardíaca foram registradas a cada 15 minutos durante o trabalho de parto e na primeira hora após o parto, e a cada 30 minutos até a 12ª hora após o parto. Esses parâmetros foram avaliados em três momentos do trabalho de parto (com dilatação cervical até 7 cm, entre 8 cm e dilatação total e durante o período expulsivo) e em dois momentos do puerpério (na primeira e décima segunda hora). Primeiramente os resultados foram analisados sem levar em consideração o tipo de procedimento anestésico, e depois, dividindo-os em grupos conforme o tipo de procedimento realizado: anestesia local, analgesia peridural lombar e anestesia subaracnóidea. Para comparação dentro de cada grupo foram realizados análise de variância (ANOVA) e teste t de Student pareado e, entre os grupos, o teste t não-pareado. Foi considerado o limite de significância estatística de 5%. RESULTADOS: quando os resultados foram avaliados sem levar em consideração o procedimento anestésico, os valores médios da pressão arterial sistólica, registrados durante o trabalho de parto, foram significativamente mais elevados que no puerpério. Durante o trabalho de parto esses valores foram significativamente mais elevados nos períodos de dilatação final e expulsivo que no período de dilatação inicial e, na 12ª hora, inferiores ao da primeira hora após o parto. Os valores médios da pressão arterial diastólica registrados durante o trabalho de parto foram significativamente mais altos que no puerpério. Estes valores não apresentaram alteração durante os diferentes períodos do trabalho de parto ou durante as primeiras doze horas do puerpério. A freqüência cardíaca aumentou progressivamente durante o trabalho de parto, diminuindo nas primeiras 12 horas após o parto. Quando a pressão arterial e a freqüência cardíaca foram avaliadas conforme o tipo de procedimento anestésico empregado, ambas mostraram-se com mesmo comportamento na anestesia local e peridural, embora naquelas submetidas à anestesia subaracnóidea, tanto a pressão arterial sistólica como a diastólica não apresentaram alteração durante o trabalho de parto. CONCLUSÕES: o trabalho de parto determinou aumento da pressão arterial sistólica e da freqüência cardíaca. Durante o trabalho de parto os valores das pressões arteriais sistólica e diastólica foram mais altos que nas primeiras 12 horas do puerpério, havendo queda significativa entre a primeira e a décima segunda hora do mesmo. Diferentes procedimentos anestésicos não interferiram nos valores das pressões arteriais sistólica e diastólica ou da freqüência cardíaca, durante o trabalho de parto e nas primeiras doze horas após o parto.