Myocardium tissue changes caused by electrical transthoracic discharges in rats

<p>Abstract</p> <p>Background</p> <p>Cardiomyocytes cytoarchitecture changes caused by transthoracic countershocks have been focused recently. We aimed to evaluate the effects of electrical discharge application in the mitochondria structure in atrial myocardium of rats.</p> <p>Methods</p> <p>An electrical cardioverter was adapted to small rodent animals for our research. Electrical discharges were applied to the precordial region of 30 albino rats: (1) control group - animals that remained on resting period and were afterwards sacrificed; (2) electrical discharge group - animals that remained on resting period, followed by ten electrical discharges of 300 mV and sacrificed, and; (3) electrical post-discharge group - animals that remained on a resting period and received ten electrical discharges like the electrical discharge group, but were sacrificed seven days subsequently. We examined liver, adrenal and left atrium tissue fragments of the three groups.</p> <p>Results</p> <p>It was observed in control and post-discharge groups a normal cellular structure aspect with preserved architecture of cardiomyocytes and continuous sarcoplasmic membrane integrity. On the other hand, cardiac muscle fibers with mitochondrial edema and lysis occurred in the discharge group. Glycogen and adrenal lipids were not depleted in all groups.</p> <p>Conclusion</p> <p>These data suggest that transthoracic electrical discharges induce mitochondrial injuries in atrial cardiac cells of rats.</p

Signal averaged electrocardiogram in top deficient athletes

Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL

Increase in systolic blood pressure during exercise testing after heart transplantation: correlation with the clinical condition and ventricular function assessed by dobutamine stress echocardiography

OBJECTIVE: Patients who underwent heart transplantation (HTX) experience a reduction in the elevation that is usual in systolic blood pressure during exercise testing. Of unknown origin, this phenomenon varies in frequency and intensity. The aim of this study was to analyze the relationship between systolic blood pressure increase (delta SBP) and clinical aspects, as well as variables measured during exercise testing (ET) and dobutamine stress echocardiography (DSE) in patients in the late post-transplantation course. METHODS: Forty-five men, mean age 49.04 ± 10.19, underwent clinical assessment, ET and DSE 40.91 ± 27.46 months after heart transplantation. Left ventricular wall motion score index and ejection fraction were assessed. Delta SBP < 35mmHg during ET was considered abnormal (SBC,1995). RESULTS: No significant correlation was found between delta SBP and post-transplantation time, graft ischemic time, history of rejection, diltiazem dosage, oxygen uptake, ejection fraction, and wall motion score index (WMSI). Delta SBP was normal in 17 patients (Group I) and abnormal in 28 (Group II). Patients of both groups did not differ significantly in regard to clinical features and ET and DSE results. CONCLUSION: Unlike other populations, no correlation was found between delta SBP during exercise testing and clinical condition or left ventricular function in heart transplant patients. Pathophysiological factors associated with delta SBP reduction during exercise testing remain unknown.OBJETIVO: Em pacientes submetidos a transplante cardíaco (TxC) descreve-se redução da elevação da pressão arterial durante o teste ergométrico (TE). Este fenômeno, cuja origem é desconhecida, ocorre em freqüência e intensidade variáveis. O objetivo deste estudo foi verificar a relação entre o incremento da pressão arterial sistólica (deltaPAS) e aspectos clínicos, bem como as variáveis aferidas no TE e ecocardiograma sob estresse pela dobutamina (EED), em pacientes na fase tardia após TxC. MÉTODOS: Quarenta e cinco homens, 49,04±10,19 anos, 40,91±27,46 meses pós-TxC submeteram-se a avaliação clínica, TE e EED . Avaliou-se o índice de contratilidade segmentar e a fração de ejeção de ventrículo esquerdo. Consideraram-se anormais deltaPAS<35mmHg no TE (SBC,1995). RESULTADOS: Não houve correlação significativa entre deltaPAS e o tempo de evolução do transplante, tempo de isquemia do enxerto, antecedentes de rejeição, dose de diltiazem, consumo de oxigênio estimado, fração de ejeção e índice de contratilidade segmentar. O deltaPAS foi normal em 17 casos (Grupo I) e anormal em 28 pacientes (Grupo II). Não houve diferenças significativas entre os pacientes de ambos os grupos em relação aos aspectos clínicos e aos resultados do TE e EED. CONCLUSÃO: Ao contrário de outras populações, os autores não detectaram correlações entre deltaPAS e o quadro clínico e a função ventricular esquerda em pacientes com TxC. Os fatores associados à redução do deltaPAS no TE pós-TxC permanecem desconhecidos.Universidade Federal de São Paulo (UNIFESP) EPMUNIFESP, EPMSciEL

Electrical transthoracic discharges in albine rats: ultrastructural changes in atrial myocardium

Objective: Morphological myocardial tissue cytoarchitecture alterationsafter transthoracic countershocks were extensively studied. The aim ofthe present study was to evaluate the electrical discharge applicationeffects to the atrium subcellular level. Methods: An electrical cardioverterwas adapted to small rodent animals for this study. Electrical dischargeswere applied to the precordial region of 30 rats. Three groups with tenanimals each were randomly constituted. Animals were divided into acontrol group - animals that remained on resting period and wereafterwards sacrificed; an electrical discharge group - animals thatremained on resting period, followed by ten electrical discharges of 300mV and sacrificed; and an electrical post-discharge group - animals thatstayed on a resting period and received ten electrical discharges like theelectrical discharge group, but were sacrificed seven days subsequently.Liver, adrenal and left atrium tissue fragments of all groups were examined.Results: In the control and in the post-discharge groups a normal cellularstructure aspect with preserved architecture of cardiomyocytes andcontinuous sarcoplasmic membrane integrity were observed. However,cardiac muscle fibers with mitochondrial edema and lysis occurred inthe discharge group. In all experimental groups hepatic glycogen andadrenal lipids were not depleted. Conclusion: Results evidenced that thealarm reaction did not occur immediately after the countershocks althoughatrium myocardial ultrastructure presented severe injury signals. Thepresent investigation was helpful, since important information should beconsidered in clinical application field on myocardial protectionproceedings before and after application of transthoracic countershockdischarges

Índice tornozelo-braquial e hipertrofia ventricular na hipertensão arterial

O Índice Tornozelo-Braquial (ITB) é marcador de doença arterial obstrutiva periférica. Raros relatos correlacionam esse índice com hipertrofia ventricular esquerda (HVE), capacidade funcional (CF) e escore de risco coronariano de Framingham (ERCF). O objetivo do trabalho foi verificar a correlação entre ITB, HVE, CF e ERCF em homens com hipertensão arterial (HA). Estudo prospectivo e transversal de pacientes do sexo masculino (n = 40), com idade média de 57,92 ± 7,61 anos, sem complicações cardiovasculares. Essa população foi submetida às medidas de ITB, ecocardiograma (ECO), teste ergométrico (TE) e exames laboratoriais. O ITB (direito e esquerdo) foi considerado anormal quando a relação entre a maior média das pressões sistólicas dos tornozelos e dos braços foi inferior ou igual a 0,9 ou superior a 1,3 mmHg. A HVE foi identificada pelo ECO transtorácico; e a CF, pelo TE. Amostras sanguíneas periféricas foram colhidas para o cálculo do ERCF. Valores normais de ITB foram encontrados em 33 pacientes (82,5%), os quais foram incluídos no Grupo I; sete pacientes (17,5%) com ITB anormal constituíram o Grupo II. Os índices de massa do índice de massa do ventrículo esquerdo (IMVE) ao ECO foram de 111,18 ± 34,34 g/m² (Grupo I) e de 150,29 ± 34,06 g/m2 (Grupo II) (p = 0,009). A prevalência de HVE foi de 4% (Grupo I) e de 35,3% (Grupo II) (p = 0,01), constatando-se diferenças significativas entre os grupos. Quanto à CF no TE, não se registrou diferença entre os grupos. Em relação ao ERCF, a média do Grupo I foi inferior à média do Grupo II: 13,18 ± 2,11 versus 15,28±1,79 (p = 0,019). Em HA, a presença de HVE definida pelo IMVE esteve mais presente nos casos com ITB anormal, identificando maior risco cardiovascular

How much do the benefits cost? Effects of a home-based training programme on cardiovascular fitness, quality of life, programme cost and adherence for patients with coronary disease

Objective: To evaluate cost, adherence and effects on cardiovascular function and quality of life of a home-based cardiac rehabilitation programme for patients with coronary disease.Design: A randomized, prospective controlled trial.Setting: Department of Rehabilitation, University Hospital, Brazil.Subjects: Thirty-nine low-risk patients were assigned to a home exercise training group (n=19) or a control group (n=20).Interventions: the home group performed home-based training for three months with biweekly telephone monitoring.Main outcome measures: the aerobic capacity and the quality of life (Medical Outcomes Study 36-Item Short Form Survey (SF-36)) of all patients were evaluated before and after the three-month period. Adherence was evaluated weekly. Programme cost was estimated using the Brazilian Classification of Medical Procedures.Results: After training, the home group had higher peak Vo(2) from 28.8 (6.4) to 31.7 (8.1) mL/kg per minute, peak heart rate from 135 (22) to 143 (20) bpm, work rate from 4780 (2021) to 7103 (3057) kpm/min and exercise time from 11.5 (1.9) to 13.6 (2.3) minutes (P <= 0.05). the control group showed reduction in peak Vo(2) from 28.6 (6.6) to 26.8 (7.2) mL/kg per minute, peak Vo(2) pulse from 15.5 (3.9) to 14.3 (3.8) mL/bpm and exercise time from 11.5 (2.3) to 11.4 (2.7) minutes (P<0.05). the home group reported improvements in all domains of SF-36. the control group showed improvement in only three domains of SF-36. in the home group the average cost per patient was US$502.71 and the adherence achieved 100%.Conclusion: the programme seems to provide an efficient low-cost approach to cardiac rehabilitation in low-risk patients.Universidade Federal de São Paulo, Dept Cardiol, Paulista Sch Med, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Cardiol, Paulista Sch Med, BR-04024002 São Paulo, BrazilWeb of Scienc