Resistance Training After Myocardial Infarction in Rats: Its Role on Cardiac and Autonomic Function

Background: Although resistance exercise training is part of cardiovascular rehabilitation programs, little is known about its role on the cardiac and autonomic function after myocardial infarction. Objective: To evaluate the effects of resistance exercise training, started early after myocardial infarction, on cardiac function, hemodynamic profile, and autonomic modulation in rats. Methods: Male Wistar rats were divided into four groups: sedentary control, trained control, sedentary infarcted and trained infarcted rats. Each group with n = 9 rats. The animals underwent maximum load test and echocardiography at the beginning and at the end of the resistance exercise training (in an adapted ladder, 40% to 60% of the maximum load test, 3 months, 5 days/week). At the end, hemodynamic, baroreflex sensitivity and autonomic modulation assessments were made. Results: The maximum load test increased in groups trained control (+32%) and trained infarcted (+46%) in relation to groups sedentary control and sedentary infarcted. Although no change occurred regarding the myocardial infarction size and systolic function, the E/A ratio (-23%), myocardial performance index (-39%) and systolic blood pressure (+6%) improved with resistance exercise training in group trained infarcted. Concomitantly, the training provided additional benefits in the high frequency bands of the pulse interval (+45%), as well as in the low frequency band of systolic blood pressure (-46%) in rats from group trained infarcted in relation to group sedentary infarcted. Conclusion: Resistance exercise training alone may be an important and safe tool in the management of patients after myocardial infarction, considering that it does not lead to significant changes in the ventricular function, reduces the global cardiac stress, and significantly improves the vascular and cardiac autonomic modulation in infarcted rats.

Gender-Based Differences in Cardiac Remodeling and ILK Expression after Myocardial Infarction

Background: Gender can influence post-infarction cardiac remodeling. Objective: To evaluate whether gender influences left ventricular (LV) remodeling and integrin-linked kinase (ILK) after myocardial infarction (MI). Methods: Female and male Wistar rats were assigned to one of three groups: sham, moderate MI (size: 20-39% of LV area), and large MI (size: ≥40% of LV area). MI was induced by coronary occlusion, and echocardiographic analysis was performed after six weeks to evaluate MI size as well as LV morphology and function. Real-time RT-PCR and Western blot were used to quantify ILK in the myocardium. Results: MI size was similar between genders. MI resulted in systolic dysfunction and enlargement of end-diastolic as well as end-systolic dimension of LV as a function of necrotic area size in both genders. Female rats with large MI showed a lower diastolic and systolic dilatation than the respective male rats; however, LV dysfunction was similar between genders. Gene and protein levels of ILK were increased in female rats with moderate and large infarctions, but only male rats with large infarctions showed an altered ILK mRNA level. A negative linear correlation was evident between LV dimensions and ILK expression in female rats with large MI. Conclusions: Post-MI ILK expression is altered in a gender-specific manner, and higher ILK levels found in females may be sufficient to improve LV geometry but not LV function.

Obesity Preserves Myocardial Function During Blockade of the Glycolytic Pathway

Background: Obesity is defined by excessive accumulation of body fat relative to lean tissue. Studies during the last few years indicate that cardiac function in obese animals may be preserved, increased or diminished. Objective: Study the energy balance of the myocardium with the hypothesis that the increase in fatty acid oxidation and reduced glucose leads to cardiac dysfunction in obesity. Methods: 30-day-old male Wistar rats were fed standard and hypercaloric diet for 30 weeks. Cardiac function and morphology were assessed. In this paper was viewed the general characteristics and comorbities associated to obesity. The structure cardiac was determined by weights of the heart and left ventricle (LV). Myocardial function was evaluated by studying isolated papillary muscles from the LV, under the baseline condition and after inotropic and lusitropic maneuvers: myocardial stiffness; postrest contraction; increase in extracellular Ca2+ concentration; change in heart rate and inhibitor of glycolytic pathway. Results: Compared with control group, the obese rats had increased body fat and co-morbities associated with obesity. Functional assessment after blocking iodoacetate shows no difference in the linear regression of DT, however, the RT showed a statistically significant difference in behavior between the control and the obese group, most notable being the slope in group C. Conclusion: The energy imbalance on obesity did not cause cardiac dysfunction. On the contrary, the prioritization of fatty acids utilization provides protection to cardiac muscle during the inhibition of glycolysis, suggesting that this pathway is fewer used by obese cardiac muscle.

Impact of Intensive Physiotherapy on Cognitive Function after Coronary Artery Bypass Graft Surgery

Background: Coronary artery bypass graft (CABG) is a standard surgical option for patients with diffuse and significant arterial plaque. This procedure, however, is not free of postoperative complications, especially pulmonary and cognitive disorders. Objective: This study aimed at comparing the impact of two different physiotherapy treatment approaches on pulmonary and cognitive function of patients undergoing CABG. Methods: Neuropsychological and pulmonary function tests were applied, prior to and following CABG, to 39 patients randomized into two groups as follows: Group 1 (control) - 20 patients underwent one physiotherapy session daily; and Group 2 (intensive physiotherapy) - 19 patients underwent three physiotherapy sessions daily during the recovery phase at the hospital. Non-paired and paired Student t tests were used to compare continuous variables. Variables without normal distribution were compared between groups by using Mann-Whitney test, and, within the same group at different times, by using Wilcoxon test. The chi-square test assessed differences of categorical variables. Statistical tests with a p value ≤ 0.05 were considered significant. Results: Changes in pulmonary function were not significantly different between the groups. However, while Group 2 patients showed no decline in their neurocognitive function, Group 1 patients showed a decline in their cognitive functions (P ≤ 0.01). Conclusion: Those results highlight the importance of physiotherapy after CABG and support the implementation of multiple sessions per day, providing patients with better psychosocial conditions and less morbidity.

Impact of Atrial Fibrillation Ablation on Left Ventricular Filling Pressure and Left Atrial Remodeling

Background:Left ventricular (LV) diastolic dysfunction is associated with new-onset atrial fibrillation (AF), and the estimation of elevated LV filling pressures by E/e' ratio is related to worse outcomes in patients with AF. However, it is unknown if restoring sinus rhythm reverses this process.Objective:To evaluate the impact of AF ablation on estimated LV filling pressure.Methods:A total of 141 patients underwent radiofrequency (RF) ablation to treat drug-refractory AF. Transthoracic echocardiography was performed 30 days before and 12 months after ablation. LV functional parameters, left atrial volume index (LAVind), and transmitral pulsed and mitral annulus tissue Doppler (e' and E/e') were assessed. Paroxysmal AF was present in 18 patients, persistent AF was present in 102 patients, and long-standing persistent AF in 21 patients. Follow-up included electrocardiographic examination and 24-h Holter monitoring at 3, 6, and 12 months after ablation.Results:One hundred seventeen patients (82.9%) were free of AF during the follow-up (average, 18 ± 5 months). LAVind reduced in the successful group (30.2 mL/m2 ± 10.6 mL/m2 to 22.6 mL/m2 ± 1.1 mL/m2, p < 0.001) compared to the non-successful group (37.7 mL/m2 ± 14.3 mL/m2 to 37.5 mL/m2 ± 14.5 mL/m2, p = ns). Improvement of LV filling pressure assessed by a reduction in the E/e' ratio was observed only after successful ablation (11.5 ± 4.5 vs. 7.1 ± 3.7, p < 0.001) but not in patients with recurrent AF (12.7 ± 4.4 vs. 12 ± 3.3, p = ns). The success rate was lower in the long-standing persistent AF patient group (57% vs. 87%, p = 0.001).Conclusion:Successful AF ablation is associated with LA reverse remodeling and an improvement in LV filling pressure.

Right Ventricular Doppler Echocardiographic Study of Indeterminate Form of Chagas Disease

Background: Patients with indeterminate form of Chagas disease/cardiac normality (ICD/CN) exhibited normal electrocardiograms and chest X-rays; however, more sophisticated tests detected some degree of morphological and functional changes in the heart. Objective: To assess the prevalence of systolic and diastolic dysfunction of the right ventricle (RV) in patients with ICD/CN. Methods: This was a case–control and prevalence study. Using Doppler two-dimensional echocardiography (2D), 92 patients were assessed and divided into two groups: group I (normal, n = 31) and group II (ICD/CN, n = 61). Results: The prevalence of RV systolic dysfunction in patients in groups I and II was as follows: fractional area change (0.0% versus 0.6%), mobility of the tricuspid annulus (0.0% versus 0.0%), and S-wave tissue Doppler (6.4% versus 26.0%, p = 0.016). The prevalence of global disorders such as the right myocardial performance index using tissue Doppler (16.1% versus 27.8%, p = 0.099) and pulsed Doppler (61.3% versus 68%, p = 0.141) and diastolic disorders such as abnormal relaxation (0.0% versus 6.0%), pseudonormal pattern (0.0% versus 0.0%), and restrictive pattern (0.0% versus 0.0%) was not statistically different between groups. Conclusion: The prevalence of RV systolic dysfunction was estimated to be 26% (S wave velocity compared with other variables), suggesting incipient changes in RV systolic function in the ICD/CN group.

Chronic Stress Improves NO- and Ca2+ Flux-Dependent Vascular Function: A Pharmacological Study

Background: Stress is associated with cardiovascular diseases. Objective: This study aimed at assessing whether chronic stress induces vascular alterations, and whether these modulations are nitric oxide (NO) and Ca2+ dependent. Methods: Wistar rats, 30 days of age, were separated into 2 groups: control (C) and Stress (St). Chronic stress consisted of immobilization for 1 hour/day, 5 days/week, 15 weeks. Systolic blood pressure was assessed. Vascular studies on aortic rings were performed. Concentration-effect curves were built for noradrenaline, in the presence of L-NAME or prazosin, acetylcholine, sodium nitroprusside and KCl. In addition, Ca2+ flux was also evaluated. Results: Chronic stress induced hypertension, decreased the vascular response to KCl and to noradrenaline, and increased the vascular response to acetylcholine. L-NAME blunted the difference observed in noradrenaline curves. Furthermore, contractile response to Ca2+ was decreased in the aorta of stressed rats. Conclusion: Our data suggest that the vascular response to chronic stress is an adaptation to its deleterious effects, such as hypertension. In addition, this adaptation is NO- and Ca2+-dependent. These data help to clarify the contribution of stress to cardiovascular abnormalities. However, further studies are necessary to better elucidate the mechanisms involved in the cardiovascular dysfunction associated with stressors. (Arq Bras Cardiol. 2014; [online].ahead print, PP.0-0)

Subclinical Ventricular Dysfunction Detected by Speckle Tracking Two Years after Use of Anthracycline

Background: Heart failure is a severe complication associated with doxorubicin (DOX) use. Strain, assessed by two-dimensional speckle tracking (2D-STE), has been shown to be useful in identifying subclinical ventricular dysfunction. Objectives: a) To investigate the role of strain in the identification of subclinical ventricular dysfunction in patients who used DOX; b) to investigate determinants of strain response in these patients. Methods: Cross-sectional study with 81 participants: 40 patients who used DOX ±2 years before the study and 41 controls. All participants had left ventricular ejection fraction (LVEF) ≥55%. Total dose of DOX was 396mg (242mg/ms2). The systolic function of the LV was evaluated by LVEF (Simpson), as well as by longitudinal (εLL), circumferential (εCC), and radial (εRR) strains. Multivariate linear regression (MLR) analysis was performed using εLL (model 1) and εCC (model 2) as dependent variables. Results: Systolic and diastolic blood pressure values were higher in the control group (p < 0.05). εLL was lower in the DOX group (-12.4 ±2.6%) versus controls (-13.4 ± 1.7%; p = 0.044). The same occurred with εCC: -12.1 ± 2.7% (DOX) versus -16.7 ± 3.6% (controls; p < 0.001). The S’ wave was shorter in the DOX group (p = 0.035). On MLR, DOX was an independent predictor of reduced εCC (B = -4.429, p < 0.001). DOX (B = -1.289, p = 0.012) and age (B = -0.057, p = 0.029) were independent markers of reduced εLL. Conclusion: a) εLL, εCC and the S’ wave are reduced in patients who used DOX ±2 years prior to the study despite normal LVEF, suggesting the presence of subclinical ventricular dysfunction; b) DOX was an independent predictor of reduced εCC; c) prior use of DOX and age were independent markers of reduced εLL.

top-down function of prestimulus EEG alpha activity

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2007

Assessment of Autonomic Function by Phase Rectification of RRInterval Histogram Analysis in Chagas Disease

Background:In chronic Chagas disease (ChD), impairment of cardiac autonomic function bears prognostic implications. Phase‑rectification of RR-interval series isolates the sympathetic, acceleration phase (AC) and parasympathetic, deceleration phase (DC) influences on cardiac autonomic modulation.Objective:This study investigated heart rate variability (HRV) as a function of RR-interval to assess autonomic function in healthy and ChD subjects.Methods:Control (n = 20) and ChD (n = 20) groups were studied. All underwent 60-min head-up tilt table test under ECG recording. Histogram of RR-interval series was calculated, with 100 ms class, ranging from 600–1100 ms. In each class, mean RR-intervals (MNN) and root-mean-squared difference (RMSNN) of consecutive normal RR-intervals that suited a particular class were calculated. Average of all RMSNN values in each class was analyzed as function of MNN, in the whole series (RMSNNT), and in AC (RMSNNAC) and DC (RMSNNDC) phases. Slopes of linear regression lines were compared between groups using Student t-test. Correlation coefficients were tested before comparisons. RMSNN was log-transformed. (α < 0.05).Results:Correlation coefficient was significant in all regressions (p < 0.05). In the control group, RMSNNT, RMSNNAC, and RMSNNDCsignificantly increased linearly with MNN (p < 0.05). In ChD, only RMSNNAC showed significant increase as a function of MNN, whereas RMSNNT and RMSNNDC did not.Conclusion:HRV increases in proportion with the RR-interval in healthy subjects. This behavior is lost in ChD, particularly in the DC phase, indicating cardiac vagal incompetence.

Function and regulation of death-associated protein kinase1 (DAPK) in colon cancer cells and macrophage-like cell line : identifcation of p38 as a novel DAPK interacting partner during TNFα-mediated apoptosis in colon cancer

DAPK, Apoptosis, p38, macrophages, survival

Methodological Gaps in Left Atrial Function Assessment by 2D Speckle Tracking Echocardiography

Abstract The assessment of left atrial (LA) function is used in various cardiovascular diseases. LA plays a complementary role in cardiac performance by modulating left ventricular (LV) function. Transthoracic two-dimensional (2D) phasic volumes and Doppler echocardiography can measure LA function non‑invasively. However, evaluation of LA deformation derived from 2D speckle tracking echocardiography (STE) is a new feasible and promising approach for assessment of LA mechanics. These parameters are able to detect subclinical LA dysfunction in different pathological condition. Normal ranges for LA deformation and cut-off values to diagnose LA dysfunction with different diseases have been reported, but data are still conflicting, probably because of some methodological and technical issues. This review highlights the importance of an unique standardized technique to assess the LA phasic functions by STE, and discusses recent studies on the most important clinical applications of this technique.

Advancing the understanding of brain function with multivariate pattern analysis

Magdeburg, Univ., Fak. für Naturwiss., Diss., 2009