Open-heart surgery is one of medicine's modern miracles that saves lives. But, as reader Roger-Anne Gardner of Symsonia writes, the first few weeks after surgery can be challenging - not only physically, but also emotionally. "There's something about the fact that someone has literally held your heart and life in their hands," she said.

Patients may experience depression after their procedure, but the reasons for this phenomenon are unclear.

One theory focuses on the technique used in open-heart surgery. During a coronary artery bypass graft (CABG), blood is rerouted through a new vein or artery grafted around diseased sections of your coronary arteries. The chest usually is cut open, and a heart-lung bypass machine is used to circulate blood and add oxygen.

Many who have studied depression after CABG think that the heart-lung machine may play a role by affecting the brain in two ways: 1. Platelets tend to clump and may cause very small "plugs" in tiny brain blood vessels. 2. The cannula placed through the aortic wall to return blood from the heart-lung machine back into the patient's circulation could dislodge a plaque from the aorta if one is there, and that plaque could travel to the brain.

Anesthesia also could contribute to post-surgical depression. When a patient undergoes CABG, he must be anesthetized deeply and for a long period of time. During this time, the body cools and the heart is actually stopped while the blood is shunted away. Perhaps the anesthesia or hypothermia during the operation alters brain chemistry.

Another reason could involve the psychological aspect. The heart commonly is referred to in spiritual and emotional terms. For instance, "I love you with all of my heart" is a saying that rings emotional bells for us. Just the thought of the heart being tampered with may cause many to feel upset.

If you are facing open-heart surgery, you can take some pre-emptive steps to minimize or avoid depression.

* Be informed. Know that the possibility of depression exists, and discuss this with your physician. Certain factors make you more eligible to experience depression. Pre-existing depression, age and medical factors other than your heart condition may contribute. Gender does not seem to matter.

* Stay aware. Depression may occur as early as three to five days after the surgery or may not appear until after you have left the hospital.

* Remain connected. Cardiac rehabilitation programs are not just about exercise. The hospital does testing to show the level of a patient's depression. Your physician, clergy or a counselor can be of great assistance if you're struggling.

* Get going! Exercise and activity are key ingredients to beating depression. Follow the advice of your cardiac rehab caregivers.