In modern heart surgery, we usually must stop the heart to operate upon it. Their are chiefly two reasons for this; the first is that it is easier to perform delicate maneuvers on a still heart, and the second is that we must open the heart in cases where we work on the valves or other interior structures. The heart, a muscular organ, receives its own blood supply from the coronary arteries which arise from the aorta just as it leaves the heart. So what we do is to place the patient on cardiopulmonary bypass (the heart-lung machine) and drain blood from the heart down to a pump that puts oxygen into the blood. The blood is then returned to the aorta into the patient's body. At this point no blood is passing through the patient's own heart and lungs. We place a clamp on the aorta above the coronary arteries and instill a medicine into the aorta that flows down the coronaries and paralyzes the heart. Just as you have heard of the terms paraplegia and quadriplegia, this medicine is called cardioplegia, because it paralyzes the heart.
While the heart is still and not beating, it consumes very little energy and requires very little oxygen or nutrition. And the cardioplegia is usually cold, chilling the heart and reducing its energy consumption even further. But there is a limit to how long you can do this. Eventually you must restore blood supply to the heart, for even the best cardioplegia cannot replace the function of blood. This presents real challenges with difficult operations. Thirty or forty minutes of stopping the heart is of minor concern. Three or four hours can result in a very weakened heart. Therefore, the cardioplegia solution often has other agents in it to give the heart muscle cells nutrition and protection during this period of semi-starvation. And the whole strategy of how we stop the heart with cardioplegia is called myocardial protection.
We didn't always have cardioplegia. Modern heart surgery was invented in the 1950's, and cardioplegia didn't arrive on the scene until the late 1970's. And the first decade or so after that was spent refining and developing the chemistry of myocardial protection. And early on, occasionally it simply didn't work. When that happened, the heart was very, very weak at the end of the procedure. In the worst cases, when the clamp was removed, the heart would contract once into a tight ball of muscle and then never work or beat again. That condition was called stone heart. I saw a case of this one time, over twenty years ago, when I was in training. A stone heart is always fatal.
Yet all of us, in our natural state, have hearts of stone. The most beautiful message I have read on this was from Charles Spurgeon, entitled, "The Stony Heart Removed," and delivered May 25, 1962. He describes in great detail the natural qualities of our stony hearts, their hardness and coldness and resistance to change. The heart of man can be warmed for a while, but then returns to its natural cold state. As he says, "Such is the heart of man. It is warm enough towards sin; it grows hot as coals of juniper, towards its own lusts; but naturally the heart is as cold as ice towards the things of God. You may think you have heated it for a little season under a powerful exhortation, or in presence of a solemn judgment, but how soon it returns to its natural state!"
We cannot perform open heart surgery upon ourselves. Likewise, we cannot change our hearts of stone by our human efforts. Only God can do this by Christ's work through the Holy Spirit. As God told Ezekiel in 36:26 (and similarly in 11:19), "I will take away the stony heart out of your flesh, and I will give you an heart of flesh." To quote Spurgeon again, "But while such a thing would be impossible apart from God, it is certain that God can do it. Oh, how the Master delighteth to undertake impossibilities!"
The person who has received Christ as their Savior is assured of getting this operation. And as I have done thousands of heart operations, I have seen hearts in all sizes and shapes, and all conditions, with some operations easy and some difficult. While God could instantaneously soften the heart of all believers, in His sovereign will He takes longer with some than others, and the pain and recovery will be difficult in those cases. I am one of those, and daily heart surgery is no fun.
We must also, along with the Father, attend to our myocardial protection. As the prophet Jeremiah tells us in 17:9, "The heart is deceitful above all things, and desperately wicked; who can know it?" Our natural hearts tend towards sin and lusts, and we must protect our hearts from such things. Proverbs 4:23 advises us, "Above all else, guard your heart, for everything you do flows from it." These same sins and lusts that the heart desires damage it, scarring it and leaving it cold and callous. We must pray diligently for God to work with us to guard our hearts and protect them from temptation.
In heart surgery, a stone heart is incurable. Not so for God and our hardened hearts. He can and will cure us. The coronary arteries that provide blood and nourishment for our hearts encircle it like a crown, and that is where the name "coronary" comes from, from the Latin word "corona" or crown. When we give myocardial protection into that crown of arteries, we are able to perform life-saving heart surgery, the gift of physical life. And if we protect our hearts from sin, what happens? James tells us in 1:12, "Blessed is the man who endures temptation,; for when he is approved, he will receive the crown of life, which the Lord has promised to those who love Him," the gift of spiritual life.
