Intraoperative transesophageal echocardiographic assessment of left ventricular Tei index in congenital heart disease.

Background: Use of the Tei index has not been described to assess myocardial function before or after surgery in pediatric patients. This study was designed to evaluate the left ventricular (LV) function using the Tei index pre‑ and post‑cardiopulmonary bypass in patients with lesion that result in a volume loaded right ventricle (RV). Methods: Retrospective data on 55 patients who underwent repair of a cardiac defect were analyzed. Patients with volume overload RV (n = 15) were compared to patients without volume overload but with other cardiac defects (n = 40). We reviewed pre‑ and post‑operative LV myocardial performance index (Tei index). Tei index was obtained from transesophageal Doppler echocardiogram. Results: Patients with right heart volume overload, the mean preoperative Tei index was 0.6, with a postoperative mean decrease of 0.207 (P = 0.014). Patients without right heart volume overload, the mean preoperative Tei was 0.48 with no significant postoperative change (P = 0.82). Conclusion: Pre‑ and post‑operative transesophageal echocardiogram assessment provides an easy and quick way of evaluating LV function intra‑operatively using LV Tei index. Preoperative LV Tei index was greater in the RV volume overload defects indicating diminished LV global function. This normalized in the immediate postoperative period, implying an immediate improvement in LV function. In patients without right heart volume load, consist of other cardiac defects, demonstrated no changes in the pre‑ and post‑operative LV Tei. This implies that LV function was similar after the surgery.

Myocardial Performance Index in Patients of Acute Coronary Syndrome.

Evaluation of ventricular systolic and diastolic functions is an essential part of echocardiographic evaluation in a patient of acute coronary syndrome (ACS). Both systolic and diastolic functions change as disease progresses. There are many limitations of the echocardiographic indices of LV functions used routinely in patients of acute coronary syndrome. Tei Chuwa devised a reliable index of myocardial performance (The Tei Index/ Myocardial Perfomance Index). It is a reliable index for evaluation of LV systolic and diastolic performance in acute coronary syndrome. Materials and Methods: 75 patients of acute coronary syndrome and 25 controls were studied. All patients admitted with the complaints of ischemic chest pain were included in the study. An informed consent was taken from all patients. Detailed history and physical examination were carried out and baseline investigations were done. Tei index was calculated from the ratio of time intervals: a-b/b, derived with the aid of pulse doppler echocardiography. Its relationship was studied with acute coronary syndrome and complications after ACS. Results: The Cardiac Output was not significantly different from controls in UA; but it was significantly deranged in STEMI (p<0.001) and NSTEMI (p <0.001). MPI was significantly different in all the three groups from controls. The t and p values of MPI of various groups on comparison with controls were t=9.0, p<0.001; t=12.5, p<0.001; t=18, p< 0.001 for UA, STEMI and NSTEMI respectively. The MPI of STEMI patients was 0.64±0.08 that of NSTEMI patients was 0.57±0.059, that of UA was 0.48±0.06 and that of controls was 0.39±0.04. The correlation showed that MPI was more strongly related to complications as compared to other echocardiographic parameters. Conclusion: MPI is a non-geometric doppler index, that combines systolic and diastolic performance of left ventricle. As compared to controls, MPI was found to be deranged in patients of acute coronary syndrome. when recorded within 24 hours of admission, myocardial performance index was a sensitive and independent predictor of in-hospital events.

Phenylephrine postconditioning increases myocardial injury: Are alpha-1 sympathomimetic agonist cardioprotective.

Objective: We studied effects of phenylephrine (PHE) on postischemic functional recovery and myocardial injury in an ischemia-reperfusion (I-R) experimental model. Materials and Methods: Rat hearts were Langendorff-perfused and subjected to 30 min zero-fl ow ischemia (I) and 60 min reperfusion (R). During R PHE was added at doses of 1 μM (n = 10) and 50 μM (n = 12). Hearts (n = 14) subjected to 30 and 60 min of I-R served as controls. Contractile function was assessed by left ventricular developed pressure (LVDP) and the rate of increase and decrease of LVDP; apoptosis by fl uorescent imaging targeting activated caspase-3, while myocardial injury by lactate dehydrogenase (LDH) released during R. Activation of kinases was measured at 5, 15, and 60 min of R using western blotting. Results: PHE did not improve postischemic contractile function. PHE increased LDH release (IU/g); 102 ± 10.4 (Mean ± standard error of mean) control versus 148 ± 14.8 PHE (1), and 145.3 ± 11 PHE (50) hearts, (P < 0.05). PHE markedly increased apoptosis. Molecular analysis showed no effect of PHE on the activation of proapoptotic c-Jun N-terminal kinase signaling; a differential pattern of p38 mitogen activated protein kinase (MAPK) activation was found depending on the PHE dose used. With 1 μM PHE, p-p38/total-p38 MAPK levels at R were markedly increased, indicating its detrimental effect. With PHE 50 μM, no further changes in p38 MAPK were seen. Activation of Akt kinase was decreased implying involvement of different mechanisms in this response. Conclusions: PHE administration during reperfusion does not improve postischemic recovery due to exacerbation of myocardial necrosis and apoptosis. This fi nding may be of clinical and therapeutic relevance.

Myocyte renewal and ventricular remodelling

Remaining young at heart is a desirable but elusive goal. Unbeknown to us, however, myocyte regeneration may accomplish just that. Continuous cell renewal in the adult myocardium was thought to be impossible, but multipotent cardiac stem cells may be able to renew the myocardium and, under certain circumstances, can be coaxed to repair the broken heart after infarction

Introduction to seismocardiography

Seismocardiography is a new noninvasive technique for recording cardiac vibrations. It is a form of displacement cardiology, a field that includes apexocardiography, kinetocardiography, ballistocardiography and cardiokymography

Estimulador elétrico de corrente para estudos fisiológicos / Electric current stimulator for physiological studies

Com o objetivo de contribuir ao estudo da atividade elétrica e contrátil do músculo cardíaco foi desenvolvido um estimulador elétrico capaz de produzir pulsos mono e bipolares de corrente, na faixa de 1 micronA a 5 mA, com duraçäo variável de 50 microns a 500 ms e frequência estimulatória variável de 0,1 Hz a 2 KHz. Além disso, o instrumento permite o controle externo do intervalo entre pulsos. Uma entrada especial para acoplamento de um gerador de funçöes permite a estimulaçäo com qualquer forma de pulso de corrente. A calibraçäo do instrumento pode ser feita sem necessidade de acoplamento à preparaçäo biológica. A saída para estimulaçäo é isolada por acoplamento optico e alimentada por conversor DC/DC. Os testes efetuados em bancada revelaram que o instrumento possui resposta linear na faixa de -5 a 5 mA, tempo de subida ao degrau de 17 microns e sua curva de regulaçäo obedece as condiçöes impostas no projeto. Com base nestes resultados e na aplicaçäo a experimentos biológicos concluiu-se que o instrumento desenvolvido é perfeitamente adequado para a estimulaçäo do tecido cardíaco isolado

Regional wall thickening dynamics as an index of regional myocardial function

Angiogramas roentgen biplanares de ventrículos esquerdos caninos, isolados e mantidos funcionando metabolicamente, foram analisados em termos da taxa de aumento de espessura da parede durante a fase sistólica do ciclo cardíaco. A pressäo de enchimento de átrio esquerdo, a resistência à saída de fluxo na aorta, a frequência cardíaca e o fluxo coronariano foram controlados independentemente. Valores para o pico da taxa de aumento de espessura da parede, normalizado para valores instantâneos de espessuras de paredes, foram similares para paredes livres nas partes anterior e lateral de todos os ventrículos sob condiçöes hemodinâmicas similares. A taxa de aumento de espessura de parede variou linearmente e com a frequência cardíaca de estado permanante e fluxo arterial de coronária. Pouca mudança ocorreu na taxa de aumento da expessura da parede para uma faixa considerável de pressöes de enchimento mas houve uma consistente, porém pequena, diminuiçäo nesta taxa para valores elevados da resistência ao fluxo de saída da aorta. Os resultados levam a concluir que a taxa de aumento da espessura da parede ventricular é um bom indicador do estado inotrópico e/ou perfusäo regional do miocárdio