Standardization of an isolated pig heart preparation with parabiotic circulation: methodological considerations

In the present study we standardized an experimental model of parabiotic circulation of isolated pig heart. The isolated heart was perfused with arterial blood from a second animal as support and submitted to regional ischemia for 30 min, followed by total ischemia for 90 min and reperfusion for 90 min. Parameters for measurement of ventricular performance using different indices measured directly or indirectly from intraventricular pressure were defined as: maximum peak pressure, final diastolic pressure, pressure developed, first derivative of maximum pressure (dP/dt max), first derivative of minimum pressure (dP/dt min), systolic stress of the left ventricle (sigmas), and maximum elastance of the left ventricle. Isolated hearts subjected to regional and global ischemia presented significant worsening of all measured parameters. Less discriminative parameters were dP/dt max and dP/dt min. Elastance was the most sensitive parameter during the reperfusion period, demonstrating an early loss of ventricular function during reperfusion. The model proved to be stable and reproducible and permitted the study of several variables in the isolated heart, such as ischemia and reperfusion phenomena, the effects of different drugs, surgical interventions, etc. The model introduces an advantage over the classical models which use crystalloid solutions as perfusate, because parabiotic circulation mimics heart surgery with extracorporeal circulation.64965

Standardization Of An Isolated Pig Heart Preparation With Parabiotic Circulation: Methodological Considerations.

In the present study we standardized an experimental model of parabiotic circulation of isolated pig heart. The isolated heart was perfused with arterial blood from a second animal as support and submitted to regional ischemia for 30 min, followed by total ischemia for 90 min and reperfusion for 90 min. Parameters for measurement of ventricular performance using different indices measured directly or indirectly from intraventricular pressure were defined as: maximum peak pressure, final diastolic pressure, pressure developed, first derivative of maximum pressure (dP/dt max), first derivative of minimum pressure (dP/dt min), systolic stress of the left ventricle (sigmas), and maximum elastance of the left ventricle. Isolated hearts subjected to regional and global ischemia presented significant worsening of all measured parameters. Less discriminative parameters were dP/dt max and dP/dt min. Elastance was the most sensitive parameter during the reperfusion period, demonstrating an early loss of ventricular function during reperfusion. The model proved to be stable and reproducible and permitted the study of several variables in the isolated heart, such as ischemia and reperfusion phenomena, the effects of different drugs, surgical interventions, etc. The model introduces an advantage over the classical models which use crystalloid solutions as perfusate, because parabiotic circulation mimics heart surgery with extracorporeal circulation.36649-5

Review of natural fibre-reinforced hybrid composites

Natural fibre-reinforced hybrid composites which contain one or more types of natural reinforcement are gaining increasing research interest. This paper presents a review of natural fibre-reinforced hybrid composites. Both thermoplastic and thermoset composites reinforced by hybrid/synthetic fibres or hybrid/hybrid fibres are reviewed. The properties of natural fibres, the properties and processing of composites are summarised

Standardization of an isolated pig heart preparation with parabiotic circulation: methodological considerations

In the present study we standardized an experimental model of parabiotic circulation of isolated pig heart. The isolated heart was perfused with arterial blood from a second animal as support and submitted to regional ischemia for 30 min, followed by total ischemia for 90 min and reperfusion for 90 min. Parameters for measurement of ventricular performance using different indices measured directly or indirectly from intraventricular pressure were defined as: maximum peak pressure, final diastolic pressure, pressure developed, first derivative of maximum pressure (dP/dt max), first derivative of minimum pressure (dP/dt min), systolic stress of the left ventricle (sigmas), and maximum elastance of the left ventricle. Isolated hearts subjected to regional and global ischemia presented significant worsening of all measured parameters. Less discriminative parameters were dP/dt max and dP/dt min. Elastance was the most sensitive parameter during the reperfusion period, demonstrating an early loss of ventricular function during reperfusion. The model proved to be stable and reproducible and permitted the study of several variables in the isolated heart, such as ischemia and reperfusion phenomena, the effects of different drugs, surgical interventions, etc. The model introduces an advantage over the classical models which use crystalloid solutions as perfusate, because parabiotic circulation mimics heart surgery with extracorporeal circulation

[high Output Heart Failure Due To Coronary Fistula].

A 45 year-old woman complaining of heart failure symptoms (New York Heart Association--class III) and a non typical thoracic pain was submitted to a transthoracic echocardiogram which showed a very dilated coronary artery and a fistula to the right atrium. The angiograms confirmed the same findings. She underwent open heart surgery which confirmed the diagnosis. Fistula ligation was then undertaken. She remains symptom-free three years after the operation.7051-

[use Of A Thin Retrocardiac Drain After Open Heart Surgery. Description Of The Technique].

To describe a technique with a thin drainage system placed behind the heart, avoiding reoperation caused by tamponade due to pericardial effusion in patients who undergo open heart surgery. We studied 59 patients, average age of 50 years. Twenty-six (44%) patients had undergone CABG, 25 (42%) valvar procedures and 8 (14%) different procedures. The control group were 20 patients, average age 44 years. Nine (45%) underwent CABG, 6 (30%) valvar procedures and 5 (25%) other procedures. Every patient was submitted to echocardiographic study to verify presence of pericardial effusion after operation. There was one patient with pericardial effusion with 8mm in the study group. Six patients showed pericardial effusion in the control group. The control group had mean drainage flow of 320 +/- 110ml and average permanence time was 45 +/- 10h. The study group had mean drainage flow of 410 +/- 122ml, the average permanence time was 46 +/- 10h. There was statistic difference between both groups when we compared the frequency of pericardial effusion. This drainage system reduces pericardial effusion comparing with the literature and causes little discomfort to the patient. The fixed rule to remove the drains did not present more discomfort to the patient and there were no complications related to its permanence.68181-