All in situ hearts receive some noncoronary collateral flow so that intermittent replenishment of cardioplegia is needed to maintain the primary goals of hypothermia for cardiac myocyte metabolic demand reduction, washout of accumulated metabolites, counteraction of acidosis, and provision of a cardioprotective composition to lower perfusion injury before the next period of planned ischemia is initiated. Several experimental studies favor the use of blood cardioplegia over crystalloid solutions when comparing release of cardiac enzymes and metabolic response . from the Oslo Heart Center conducted the largest prospectively randomized single center trial comparing postoperative outcomes of cold blood versus cold crystalloid cardioplegic regimens (1440 CABG patients  and 345 aortic valve patients ).
All patients were gender, age, and perioperative risk matched and no statistical significant differences were seen regarding perioperative and postoperative parameters (Table 3).
The institution of cardioplegic arrest ensures that myocardial oxygen consumption (MVO2) is significantly reduced, as is the ATP depletion characteristic of severe ischemia [7–9].
ink a lot of us are guilty of focussing on how far we have to go or what we "lack" rather than focussing on our strengths and achievements.
We can be so focussed on what we're "not" and where we want to be that we fail to notice what we've already achieved.
This is reflected in the clinical setting by higher perfusion volumes rather than higher perfusion pressures required to induce cardiac arrest. from UCLA in Los Angeles on human freshly explanted hearts it became obvious that all regions of the heart can be homogenously perfused in a retrograde fashion .
However, when collecting the effluents using colored microspheres % escaped from the left and right coronaries, respectively .
Factors influencing operative risk include age Figure 1: (a) Action potential for cardiac myocytes and (b) ion flux occurring during each cardiac myocyte action potential.
Nernst equation on the right-hand side illustrating membrane potential changes upon modification of the extracellular KThe action potential (AP) is the result of an orchestrated activation of various voltage-gated channels located in the cell membrane (Figure 1).
Blood cardioplegia is mixed in a ratio of 1 : 4 (1 part of crystalloid solution and 4 parts of blood); crystalloid solutions may be of intracellular type (Custadiol) or extracellular type (Plegisol). Modes of application range from antegrade versus retrograde versus antegrade plus retrograde, intermittent versus single shot, cold (with or without additional warm induction) versus warm.
Thereby antegrade and retrograde refer to the route of application: antegrade application follows anatomical routes and normal coronary circulation via insertion of a cardioplegia line into the aortic root below the aortic cross-clamp, whereas retrograde perfusion is achieved via direct intubation of the coronary sinus.
Even in patients with higher operative risk (female sex, age 5), no statistically significant differences could be demonstrated [11, 12].  from the Toronto University compared 34 trials with a total of 5,044 patients.