[Levosimendan for preventing low output syndrome in pediatric patients with correction of tetralogy of Fallot]. / Levosimendán para prevenir el síndrome de bajo gasto en pacientes pediátricos con corrección de tetralogía de Fallot.

Background: Tetralogy of Fallot is one of the most frequent cyanotic heart diseases in our country, occupying the second place reported by the national health program 2007- 2012 and its prevalence is around 11%. Patients undergoing correction for tetralogy of Fallot are considered patients with a prolonged ischemic time and a high risk of presenting low cardiac output syndrome. Objective: To compare levosimendan with milrinone to prevent low cardiac output syndrome in patients undergoing tetralogy of Fallot correction. Material and methods: Randomized controlled open, prospective, longitudinal and comparative clinical trial. The sample size consisted of 19 patients, with a 95% confidence level. Group 1: levosimendan 0.1 mcg/kg/min from anesthetic induction. Group 2: conventional management with milrinone 0.5 mcg/kg/min. Results: When comparing the final measurements, it can be observed that the mean arterial pressure of the intervention group (levosimendan) was statistically significant (p = 0.04), both in the intraoperative measurement and in the final measurement. When comparing uresis, we found that the intervention group had a greater amount of uresis (p = 0.03). Regarding lactate, both in the intraoperative measurement (p = 0.002) and in the final measurement (p = 0.02), a lower amount was found in the intervention group. Conclusions: The results in favor of the use of levosimendan were reported, demonstrating the prevention of low cardiac output syndrome.

Introducción: la tetralogía de Fallot es una de las cardiopatías cianóticas más frecuentes de nuestro país, pues ocupa el segundo lugar reportado por el Programa Nacional de Salud 2007-2012 y su prevalencia se sitúa aproximadamente en 11%. Los pacientes sometidos a corrección de tetralogía de Fallot se consideran pacientes con un tiempo de isquemia prolongado y con riesgo alto de presentar síndrome de bajo gasto cardiaco. Objetivo: comparar levosimendán con milrinona para prevenir el síndrome de bajo gasto cardiaco en pacientes operados de corrección de tetralogía de Fallot. Material y métodos: ensayo clínico aleatorizado, controlado, abierto, prospectivo, longitudinal y comparativo. El tamaño de la muestra se estimó en 19 pacientes, con un nivel de confianza del 95%. En el grupo 1 se empleó 0.1 mcg/kg/min de levosimendán desde la inducción anestésica; en el grupo 2 se usó el manejo convencional con milrinona de 0.5 mcg/kg/min. Resultados: al comparar las mediciones finales se pudo observar que la presión arterial media del grupo de intervención (levosimendán) fue estadísticamente significativa (p = 0.04), tanto en la medición transoperatoria como en la medición final. Al comparar la uresis encontramos que el grupo con intervención tuvo mayor cantidad de uresis (p = 0.03). En cuanto al lactato, tanto en la medición transoperatoria (p = 0.002) como en la medición final (p = 0.02) se encontró una menor cantidad en el grupo de intervención. Conclusiones: se reportaron los resultados a favor del uso del levosimendán, pues se demostró que previene el síndrome de bajo gasto cardiaco.

Prophylactic intra-aortic balloon pump in high-risk patients undergoing coronary artery bypass surgery: a meta-analysis of randomized controlled trials.

OBJECTIVES: The aim of this study was to assess the efficacy of a prophylactic intra-aortic balloon pump (IABP) in high-risk patients undergoing coronary artery bypass graft surgery. METHODS: MEDLINE, EMBASE, CENTRAL/CCTR, SciELO, LILACS, Google Scholar, and reference lists of relevant articles were searched. We included only randomized controlled trials. Assessments for eligibility, relevance, and study validity and data extraction were performed in duplicate using prespecified criteria. Meta-analysis was carried out using fixed-effect and random-effect models. RESULTS: Seven publications fulfilled our eligibility criteria. There was no important statistical heterogeneity or publication bias among included studies. In total, 177 patients received prophylactic IABP and 168 did not. Overall relative risk (RR) for hospital mortality in patients treated with prophylactic IABP was 0.255 [95% confidence interval (CI), 0.122-0.533; P<0.001; same results for both effect models]. Pooled RR for postoperative low cardiac output syndrome was 0.206 (95% CI, 0.109-0.389; P<0.001) for the fixed-effect model and 0.219 (95% CI, 0.095-0.504; P<0.001) for the random-effect model. Patients treated with prophylactic IABP presented an overall difference in means for length of intensive care unit stay and hospital stay, which was lower than that in the control group (P<0.001 for both effect models). Only 7.4% (13/177) of patients who received prophylactic IABP developed complications at an insertion site, with no IABP-related death. CONCLUSION: This meta-analysis supports the use of prophylactic IABP in high-risk patients to reduce hospital mortality.

Uso profiláctico de esteroides en niños con cardiopatías congénitas, operados con apoyo de circulación extracorpórea. Estudio clínico controlado / Prophylactic use of steroids in children with congenital heart disease, operated with extracorporeal circulation support. Controlled clinical study

El beneficio del uso de corticosteroides, con el fin de reducir las complicaciones asociadas con la respuesta inflamatoria sistémica, desencadenada en niños con cardiopatías congénitas (CC), durante la cirugía cardíaca bajo circulación extracorpórea (CEC), continua siendo un tema controversial a pesar de su introducción en la práctica clínica desde hace seis décadas. Pacientes y Métodos: Estudio clínico controlado, prospectivo, aleatorio, doble ciego, realizado en 104 niños (edad 06 meses a 8 años) con CC complejas, ASA III, dirigido a evaluar el impacto de la administración de MPS 30mg/kg iv (n 63), en la modulación del estrés quirúrgico en comparación con un grupo placebo (n 41). Inclusión: Todos los niños de 6 meses a 8 años, programados para cirugía bajo CEC, mayo 2010 a mayo 2011. Consentimiento informado. Exclusión: asma bronquial, insuficiencia adrenal, infecciones, tratamiento previo con esteroides o inmunosupresores. Parámetros basal y a las 24 horas del post-operatorio (PO): leucocitosis, interleuquina 6 (IL-6), proteína C reactiva (PCR), cortisol sérico y glicemia en ayunas. Evolución clínica: duración de la ventilación mecánica (VM), estancia en UCI, requerimiento de inotrópicos, hemoderivados, sangrado, días en hospitalización e incidencia del síndrome de respuesta inflamatoria sistémica (SRIS), falla multiorgánica (FMO), síndrome de bajo gasto (SBG), disfunción ventricular y síndrome de fuga capilar (SFC).Protocolos de anestesia general balanceada y perfusión homogéneos, se utilizó bombas de rodillo, oxigenadores de membrana y hemoderivados leucodepletados. No se administró insulina, aprotinina, ni etomidato. Resultados: Homogénea distribución de ambos grupos de tratamiento por tipo de CC (cianógenas y no cianógenas), con similar riesgo quirúrgico y características peri-operatorias. La incidencia del SRIS fue del 34%, FMO 26%, SBG 15%, SFC14%, sin diferencia entre los grupos CTR y MPS, lo cual indica que la MPS no se asoció a la reducción del riesgo a presentar complicaciones en el PO. No hubo diferencias entre los grupos CTR y MPS en la formula y recuento leucocitario a las 24h, pero si reducción de IL-6 y PCR, al 5to día se observó linfopenia más prolongada, lo cual sugiere modulación de la respuesta inflamatoria. La administración de MPS no se asoció a hiperglicemia, ni sangrado gástrico, con relación al CTR. Sin embargo fue mayor la incidencia de infecciones y el uso de antibióticos de alto espectro en el PO. El 63% de los pacientes tratados con MPS respondió a las 24h del PO con reducción de la cortisolemia (MPS-RESPONDEDORES) (p 0,003), mientras que el 38% no respondió a la acción supresora hipofisiaria del esteroide exógeno (MPS-NO RESPONDEDORES). Los pacientes del subgrupo MPS-NO RESPONDEDORES con relación al grupo CTR y subgrupo MPS-RESPONDEDORES, permanecieron mayor cantidad de horas con soporte inotrópico, ventilatorio, fue mayor la estancia en UCI y hospitalización y más elevado el riesgo a presentar SBG y falla cardiaca. Conclusiones: En nuestras condiciones, la pauta de administración de MPS 30 mg/kg iv durante la inducción anestésica, no fue eficaz en prevenir el SRIS, FMO, SBG, SFC, ni su uso se asoció a mejor evolución clínica en el PO, lo contrario hubo mayor riesgo a presentar infecciones en el PO y a permanecer hospitalizados más de 15 días.

Randomized trial of milrinone versus placebo for prevention of low systemic blood flow in very preterm infants.

OBJECTIVE: To assess the effectiveness of early prophylactic milrinone versus placebo for prevention of low systemic blood flow in high-risk preterm infants. STUDY DESIGN: Double-blind randomized placebo controlled trial of milrinone (loading dose 0.75 microg/kg/min for 3 hours then maintenance 0.2 microg/kg/min until 18 hours after birth) versus placebo. Infants born <30 weeks gestational age and <6 hours of age were eligible and were monitored with serial echocardiography, head ultrasound scanning, and continuous invasive blood pressure. Primary outcome was maintenance of superior vena cava (SVC) flow > or =45 mL/kg/min through the first 24 hours. The exit criterion was hypotension unresponsive to volume and inotropes. RESULTS: Ninety infants were enrolled, equal proportions maintained SVC flow > or =45 mL/kg/min after treatment commenced. No significant difference was observed in SVC flow, right ventricular output, and blood pressure during the first 24 hours; or grades 3 to 4 periventricular/intraventricular hemorrhage and death. Heart rate was higher and constriction of the ductus was slower in the infants randomized to milrinone. CONCLUSIONS: Milrinone did not prevent low systemic blood flow during the first 24 hours in very preterm infants, and no adverse effects were attributable to milrinone. Use of a preventative treatment with rescue model allowed comparison of an inotrope with placebo in this high-risk group of infants.

Cardiac sympathetic activity pre and post resynchronization therapy evaluated by 123I-MIBG myocardial scintigraphy.

BACKGROUND: Imaging with (123)I-metaiodobenzylguanidine (MIBG) is used for the assessment of cardiac sympathetic activity (CSA). We analyzed CSA before and after cardiac resynchronization therapy (CRT), and correlated these data with CRT response. METHODS AND RESULTS: Thirty patients with chronic heart failure and classic indications for CRT were prospectively studied before and at least 3 months after CRT. The variables analyzed were: QRS width, left-ventricular ejection fraction (LVEF), left-ventricular end-diastolic diameter (LVEDD), heart/mediastinum MIBG uptake ratio (H/M), and washout rate (WR). After CRT, patients were divided into two groups: group 1 (21 patients), responders improving to functional class (FC) I or II; and group 2 (9 patients), nonresponders remaining in FC III or IV. After CRT, only group 1 showed favorable changes in QRS width (P =.003), LVEF (P =.01), LVEDD (P =.04), and H/M ratio (P =.003). The H/M ratio and WR were associated with CRT response (P =.005 and P =.04, respectively). The H/M ratio was the only independent predictor of CRT response (P =.01). Receiver operating characteristic curves showed that the optimal H/M ratio cutoff point was 1.36 (sensitivity, 75%; specificity, 71%). CONCLUSIONS: Improvement in CSA correlated with a positive CRT response. Lower MIBG uptake before therapy was associated with CRT nonresponse. The H/M ratio could be helpful in selecting patients for CRT.

The nonpeptide angiotensin-(1-7) receptor Mas agonist AVE-0991 attenuates heart failure induced by myocardial infarction.

The nonpeptide AVE-0991, which has been reported as a selective ligand for the angiotensin-(1-7) [ANG-(1-7)] receptor Mas, has actions similar to those attributed to the cardioprotective product of the renin-angiotensin system, ANG-(1-7). In this study, we evaluated the cardiac effects of AVE-0991 in normal and infarcted male Wistar rats. Myocardial infarction was induced by left coronary artery ligation. At the end of the treatment, the Langendorff technique was used to analyze cardiac function. Left ventricle serial sections were dyed with Gomori trichrome stain to quantify the infarcted area. In normal hearts, AVE-0991 produced a significant decrease in perfusion pressure and an increase in systolic tension, rate of tension rise and fall (+/-dT/dt), and heart rate. These effects were completely blocked by the perfusion of the hearts with a solution containing the selective ANG-(1-7) antagonist A-779. N(G)-nitro-l-arginine methyl ester treatment abolished the AVE-0991-induced vasodilation in isolated hearts. AVE-0991 significantly attenuated the decrease in systolic tension (sham operated, 13.00 +/- 1.02 g; infarction, 7.18 +/- 0.66 g; AVE treated, 9.23 +/- 1.05 g, n = 5), +dT/dt, -dT/dt, and heart rate induced by myocardial infarction. Infarction-induced vasoconstriction was completely prevented by AVE-0991 treatment. Furthermore, AVE-0991 significantly decreased the infarcted area (6.98 +/- 1.01 vs. 3.94 +/- 1.04 mm(2) in AVE-treated rats). These data indicate that the compound AVE-0991 produces beneficial effects in isolated perfused rat hearts involving the ANG-(1-7) receptor Mas and the release of nitric oxide. In addition, our results indicate that AVE-0991 attenuates postischemic heart failure.

Non-pharmacological management of patients hospitalized with heart failure at a teaching hospital.

OBJECTIVE: To describe non-pharmacological management of patients admitted with heart failure (HF) in a teaching hospital. METHODS: A cohort longitudinal study of patients diagnosed with HF according to the Boston score. Within the first 72 hours of admission, the nursing staff of the HF clinic conducted structured interviews and medical chart reviews. RESULTS: Two hundred and eighty-three admissions of 239 patients (age = 64 +/- 15 years) were evaluated; approximately 50% of the patients were male and 37% had heart failure of ischemic etiology Non-pharmacological measures included salt restriction in 97%, urine output monitoring in 85%, fluid balance in 75%, weight monitoring in 61%, and fluid restriction in only 25% of the patients. However, they were often not carried out by the team in charge (p < 0.01 for all comparisons). Irregular use of prescribed drugs in the week prior to admission was 22% and 21% in non-readmitted and readmitted patients, respectively (p = 1.00). Readmitted patients (n = 38) had severe systolic dysfunction, more previous hospitalizations, and longer duration of HF symptoms, as compared to those non-readmitted; in addition they had better knowledge related to self-care (p values < 0.05). In the multivariate analysis, only duration of symptoms remained as an independent predictor of re-admissions. CONCLUSION: Our data suggest that, even at a teaching hospital, important gaps exist between prescribing non-pharmacological measures for HF patients and their being carried out. Readmitted patients seem to have good understanding of their condition; this finding, however, is significantly associated with HF severity and time of onset.

Manejo não-farmacológico de pacientes hospitalizados com insuficiência cardíaca em hospital universitário / Non-pharmacological management of patients hospitalized with heart failure at a teaching hospital

OBJETIVO: Descrever o manejo não-farmacológico de pacientes internados com insuficiência cardíaca (IC) em um hospital universitário. MÉTODOS: Estudo de coorte longitudinal de pacientes com IC diagnosticados pelo escore de Boston. Durante as 72 horas iniciais de internação, enfermeiras da clínica de IC realizaram entrevistas padronizadas e revisões de prontuários. RESULTADOS: Foram avaliadas 283 internações de 239 pacientes (idade = 64 ± 15 anos), aproximadamente 50 por cento sexo masculino e 37 por cento de etiologia isquêmica. O padrão de prescrição dos diferentes cuidados não-farmacológicos foi restrição de sal em 97 por cento, controle de diurese em 85 por cento, balanço hídrico em 75 por cento, controle de peso em 61 por cento e restrição hídrica em apenas 25 por cento das internações. Embora os cuidados referidos estivessem nas prescrições, freqüentemente não eram realizados pela equipe responsável (p < 0,01 para todas as comparações). O uso irregular dos fármacos prescritos na semana anterior à hospitalização ocorreu em 22 por cento e 21 por cento dos pacientes sem e com re-internações, respectivamente (p = 1,00). Os pacientes com reinternações (n = 38) apresentaram disfunção sistólica grave, mais hospitalizações prévias e tempo prolongado de sintomas de IC, quando comparados aos não-reinternados, além de terem conhecimento mais adequado de aspectos relacionados com autocuidado (todos valores de p < 0,05). Na análise multivariada, apenas tempo de doença sintomática permaneceu como preditor independente de reinternações. CONCLUSÃO: Nossos dados indicam que mesmo em hospital universitário há importantes lacunas relativas à prescrição e realização de medidas não-farmacológicas de autocuidado na IC. Demonstramos que pacientes que reinternam aparentam bom conhecimento da doença; esse achado, entretanto, está relacionado de forma importante com a gravidade e o tempo de evolução da IC.

OBJECTIVE: To describe non-pharmacological management of patients admitted with heart failure (HF) in a teaching hospital. METHODS: A cohort longitudinal study of patients diagnosed with HF according to the Boston score. Within the first 72 hours of admission, the nursing staff of the HF clinic conducted structured interviews and medical chart reviews. RESULTS: Two hundred and eighty-three admissions of 239 patients (age = 64 ± 15 years) were evaluated; approximately 50 percent of the patients were male and 37 percent had heart failure of ischemic etiology Non-pharmacological measures included salt restriction in 97 percent, urine output monitoring in 85 percent, fluid balance in 75 percent, weight monitoring in 61 percent, and fluid restriction in only 25 percent of the patients. However, they were often not carried out by the team in charge (p < 0.01 for all comparisons). Irregular use of prescribed drugs in the week prior to admission was 22 percent and 21 percent in non-readmitted and readmitted patients, respectively (p = 1.00). Readmitted patients (n = 38) had severe systolic dysfunction, more previous hospitalizations, and longer duration of HF symptoms, as compared to those non-readmitted; in addition they had better knowledge related to self-care (p values < 0.05). In the multivariate analysis, only duration of symptoms remained as an independent predictor of re-admissions. CONCLUSION: Our data suggest that, even at a teaching hospital, important gaps exist between prescribing non-pharmacological measures for HF patients and their being carried out. Readmitted patients seem to have good understanding of their condition; this finding, however, is significantly associated with HF severity and time of onset.

Pilot study of milrinone for low systemic blood flow in very preterm infants.

OBJECTIVES: To examine the hemodynamic effects of milrinone given prophylactically to very preterm infants at high risk of low superior vena cava (SVC) flow and to investigate the preliminary efficacy and safety of an optimal dose. STUDY DESIGN: This was a prospective, open-label study in two stages. The first involved dose escalation in two cohorts. Milrinone infusions of 0.25 microg/kg per minute (n = 8) and then 0.5 microg/kg per minute (n = 11) were administered from 3 to 24 hours of age. Population pharmacokinetic modeling was used to develop an optimized dose regimen. Ten infants then were loaded with 0.75 microg/kg per minute for 3 hours, followed by 0.2 microg/kg per minute maintenance until 18 hours of age. Infants were monitored for blood pressure, serial echocardiograms, and blood milrinone levels. The primary outcome was maintenance of SVC flow greater than 45 mL/kg per minute through the first 24 hours. RESULTS: Low SVC flow developed in 36% of babies at both 0.25 microg/kg per minute and 0.5 microg/kg per minute of milrinone. Blood levels on these two regimens were slow to reach the target range and accumulated above this range by 24 hours. At 0.75 to 0.2 microg/kg per minute, no infant had SVC flow below 45 mL/kg per minute, compared with 61% in historic control subjects. Four infants needed an additional inotrope to support blood pressure. Blood levels were within the target range in 9 of 10 babies. CONCLUSIONS: We used population pharmacokinetic modeling to develop an optimal dosing regimen for milrinone. The efficacy and safety in this novel preventative approach to circulatory support is encouraging but inconclusive. We do not recommend the use of milrinone in preterm infants outside a research setting.

Uso profiláctico de la milrinona en el postoperatorio inmediato de la cirugía correctiva de la transposición de grandes arterias / Prophylactic use of milrinone in immediate postoperatory of surgical correction for transposition of the great arteries

Objetivo: en las primeras horas del postoperatorio de la corrección quirúrgica de la transposición de grandes arterias, suele aparecer una caída del gasto cardíaco. Con el fin de disminuir su impacto en un grupo de neonatos con extrema labilidad hemodinámica, presentamos nuestra experiencia clínica preliminar con el empleo profiláctico de milrinona. Material y métodos: seis neonatos consecutivos portadores de transposición de grandes arterias y sometidos a corrección quirúrgica recibieron, antes de la separación de la circulación extracorpórea, una infusión intravenosa a dosis media (0,54 µg/kg/min) sin previa realización de dosis carga. Se analizaron la mortalidad intrahospitalaria, la presencia de signos clínicos y hemodinámicos de bajo gasto cardíaco y la aparición de efectos adversos ligados a la milrinona. Resultados: no hubo mortalidad, ni presencia de síndrome de bajo gasto cardíaco, así como tampoco detectamos efectos colaterales debido al fármaco en estudio. Conclusiones: la milrinona, utilizada de acuerdo a nuestro protocolo, se reveló eficaz y confiable para evitar la caída del gasto cardíaco en 6 neonatos consecutivos sometidos a la cirugía correctiva de la transposición de grandes arterias.

Uso profiláctico de la milrinona en el postoperatorio inmediato de la cirugía correctiva de la transposición de grandes arterias / Prophylactic use of milrinone in immediate postoperatory of surgical correction for transposition of the great arteries

Objetivo: en las primeras horas del postoperatorio de la corrección quirúrgica de la transposición de grandes arterias, suele aparecer una caída del gasto cardíaco. Con el fin de disminuir su impacto en un grupo de neonatos con extrema labilidad hemodinámica, presentamos nuestra experiencia clínica preliminar con el empleo profiláctico de milrinona. Material y métodos: seis neonatos consecutivos portadores de transposición de grandes arterias y sometidos a corrección quirúrgica recibieron, antes de la separación de la circulación extracorpórea, una infusión intravenosa a dosis media (0,54 µg/kg/min) sin previa realización de dosis carga. Se analizaron la mortalidad intrahospitalaria, la presencia de signos clínicos y hemodinámicos de bajo gasto cardíaco y la aparición de efectos adversos ligados a la milrinona. Resultados: no hubo mortalidad, ni presencia de síndrome de bajo gasto cardíaco, así como tampoco detectamos efectos colaterales debido al fármaco en estudio. Conclusiones: la milrinona, utilizada de acuerdo a nuestro protocolo, se reveló eficaz y confiable para evitar la caída del gasto cardíaco en 6 neonatos consecutivos sometidos a la cirugía correctiva de la transposición de grandes arterias. (AU)

Reanimación cardiopulmonar cerebral / Cerebral cardiopulmonary resuscitation

The guidelines, recomendations and complications of cardiopulmonary and brain resuscitation are analized

La insuficiencia cardiaca como complicación de la hipertensión arterial: características epidemiológicas, clínicas y ecocardiográficas / Heart failure as a complication of hypertension: clinical, epidemiological and echocardiographic features

El tratamiento farmacológico de la hipertensión arterial primaria ha reducido la incidencia de la IC, que era la complicación más frecuente en su historia natural. Sin embargo, como aún persiste, se estudiaron su incidencia, factores pronósticos y caracteres clínico y ecocardiográfico en una cohorte de 837 hipertensos seguidos 16 años con terapia farmacológica a base de diuréticos (solos 23%, asociados 47%), betabloqueadores (solos 32%, asociados 47%) y vasodilatadores, antagonistas del Ca++ e inhibidores de la ECA (solos 5% y asociados 9%). Treinta y ocho pacientes desarrollaron IC en el seguimiento (tasas 9,6% a 7 años, 8,2% a 12 años y 6,1% a 16 años, diferencias no significativas), 15 fallecieron (tasa 1,9% a 16 años). Los factores pronósticos significativos (según modelo de riesgos proporcionales de Cox) fueron grado de avance lesional (OMS) al ingreso, PA diastólica promedio intraterapia y número de antecedentes mórbidos preexistentes, de los cuales la diabetes y la enfermedad coronaria fueron los más relevantes y significativos (en 7 de 10 coronarios, el compromiso coronario fue directamente responsable de la IC). La HTA apareció como causa única de IC en el 58%, asociada a enfermedad coronaria en el 26,5%, a insuficiencia renal en el 13,3% y a aneurisma disecante aórtico 2,5%. De los 16 pacientes con evolución ecocardiográfica anual (7años), la mitad desarrolló dilatación del VI con disfunción sistólica y la otra mitad mantuvo hipertrofia concéntrica con cámara normal y disfunción diastólica

The intraaortic counterpulsation balloon in cardiac surgery. The importance of opportune indication.

The results with the use of this device in patients who develop Low Cardiac Output Syndrome after cardiac surgery with extracorporeal circulation are analyzed. Special emphasis is given to the development of the opportune indication of this procedure, on the basis of a comparison of the results of the first few years to the most recent ones. Finally, the advantages of the prophylactic use of the Intraaortic Balloon Pump are commented.

Protection of the immature myocardium. An experimental evaluation of topical cooling, single-dose, and multiple-dose administration of St. Thomas' Hospital cardioplegic solution.

Low cardiac output in infants after cardiac operations continues to be a problem, yet little experimental work has been done to evaluate the various methods of protecting the immature myocardium. In this study, we have used an isolated working heart model to test three methods of myocardial protection in 3- to 4-week-old rabbit hearts: (1) topical cooling, (2) single-dose cardioplegia plus topical cooling, and (3) multiple-dose cardioplegia plus topical cooling. Myocardial temperature was maintained at 10 degrees C during ischemia, and St. Thomas' Hospital solution was used for cardioplegia. Sets of 18 hearts were subjected to 60, 90, or 120 minutes of ischemia, and within each set six hearts were protected by all three methods. After 90 and 120 minutes of ischemia, the percent recovery of aortic flow (expressed as mean +/- standard error of the mean) was lower in hearts protected with multiple-dose cardioplegia plus topical cooling (61.5% +/- 4.8%, 50.7% +/- 14.2%) than in those protected with topical cooling (92.4% +/- 5.7%, 94.3% +/- 12.8%) or single-dose cardioplegia plus topical cooling (86.4% +/- 5.3%, 90.2 +/- 3.6%). However, adenosine triphosphate, creatine phosphate, and glycogen levels were adequately preserved in all groups. Both topical cooling and single-dose cardioplegia provide effective protection for the immature rabbit heart during ischemia, but multiple-dose cardioplegia plus topical cooling results in inadequate preservation of hemodynamic function, despite adequate preservation of myocardial high-energy phosphate stores.