The myocardial protection allowed great advance in cardiac surgery, decreasing the mortality and making more feasible complex surgeries. Latterly the patient population elected for cardiac procedures has been changing towards elderly patients with ventricular function depressed and myocardial hypertrophy. The myocardial hypertrophy condition represents a great challenge since the beginning of the cardiac surgery. Several techniques have been described to protect the myocardial hypertrophy, however with no satisfactory results. In this manuscript we present the state of the art technique of myocardial protection. 98CRESSONI, ES ET AL -Myocardial protection to the hypertrophied heart: the eternal challenge Bras Cir Cardiovasc 2008; 23(1): 97-107 Rev

Efeitos das cardioplegias sangüínea e cristalóide no miocárdio hipertrófico de coelho: avaliação estrutural e ultra-estruturalEffects of myocardial protection on hypertrophic rabbit hearts: structural and ultra structural analysis Abstract Objective: To experimentally compare the structural and ultrastructural changes in isolated hypertrophied rabbits' hearts submitted to cardiac arrest protected using blood and crystalloid cardioplegia solutions.Method: The study comprised two experimental groups and one control group. In Experimental Group I, cardiac arrest was achieved by the continuous infusion of a tepid blood cardioplegia solution. In Experimental Group II, cardiac arrest was obtained by an intermittent infusion of a cold crystalloid cardioplegia solution. In the Control Group the hearts were submitted to normothermic anoxic arrest for 45 minutes. After the procedures, eight samples of the left ventricle lateral wall were collected and fixed in 10% formaldehyde and 2.5% glutaraldehyde for structural and ultrastructural analysis. Results:The structural and ultrastructural results demonstrated that the hearts submitted to cardiac arrest protected by continuous tepid blood cardioplegia, Group I, were better preserved and with less accentuated cellular alterations compared to those submitted to cardiac arrest protected using intermittent cold crystalloid cardioplegia and the Control Group.Conclusion: Continuous tepid blood cardioplegia was more efficient in the preservation of the structural and ultrastructural integrity of the myocardium when compared to intermittent cold crystalloid cardioplegia.Descriptors: Cardioplegic solutions, pharmacology. Hypertrophy. Cardiac surgical procedures. 25CRESSONI, ES ET AL -Effects of myocardial protection on hypertrophic rabbit hearts: structural and ultra structural analysis Braz J Cardiovasc Surg 2007; 22(1): 24-32 membrane polarized cardioplegia with tetrodotoxin, esmolol and other formulas [15].Thus, the current work aims at evaluating structural and ultrastructural alterations occurring after the use of blood and crystalloid cardioplegic solutions in hypertrophic myocardium of rabbits. METHODNine Norfolk-2000 rabbits variant Botucatu of both genders were utilized with weights ranging from 1850 to 2350 kg, all supplied by the animal house on the Campus of Botucatu -UNESP. The research was approved by the Research Ethics Committee of the Medical School in Botucatu -UNESP. Conditioning of myocardial hypertrophyAfter general anesthesia of the animal using sodium pentobarbital, a crosswise incision was performed in the cervical region, slightly above the sternum. The aortic artery was identified, pericardiotomy was performed and the ascending aorta was isolated and coarctation was provoked using the technique described by Martins et al. [16]. After 5 months with hypertrophic hearts (Figure 1), the animals were euthanized. INTRODUCTIONHypertension is the greatest cause of left ventricle hypertrophy [1], affecting around one third of the hypertensive population [2], leadi...