The term “native heart” refers to a person’s original, biological heart. This designation becomes relevant in medical discussions, particularly when advanced heart conditions necessitate therapies like heart transplantation.
What is the Native Heart?
The term is employed when this original heart is experiencing severe dysfunction or failure. Conditions such as end-stage heart failure, where the heart can no longer pump enough blood to meet the body’s needs, lead to its use.
Various underlying diseases can cause the native heart to fail. These include coronary artery disease, where plaque buildup narrows the arteries supplying the heart muscle, and cardiomyopathy, which involves damage to the heart muscle. Other causes may include severe valvular heart disease, congenital heart defects, or persistent abnormal heart rhythms. When these conditions progress, the native heart’s ability to sustain life becomes impaired.
The Native Heart and Transplantation
During orthotopic heart transplantation, the native heart is surgically removed. This procedure replaces the diseased native heart with a healthy heart from a deceased donor. The removal of the native heart is a necessary step to create space for the new organ and to eliminate the source of the patient’s cardiac dysfunction.
The surgical process begins by connecting the patient to a cardiopulmonary bypass machine, which temporarily takes over the functions of the heart and lungs, circulating oxygenated blood. Once on bypass, the major blood vessels connected to the native heart, including the aorta, pulmonary artery, superior vena cava, and inferior vena cava, are clamped and divided. The left and right atria are also separated, making way for the implantation of the donor heart.
Life After Native Heart Removal
After the native heart has been removed and a donor heart is implanted, the patient’s body undergoes significant physiological adjustments. The transplanted heart begins to function as the primary pump, restoring adequate blood flow and oxygen delivery to the body’s tissues. One immediate change is that the new heart is denervated, meaning it is disconnected from the recipient’s autonomic nervous system. This denervation leads to a higher resting heart rate, typically between 90 to 110 beats per minute, and alters how the heart responds to stress or exercise, as it relies more on circulating hormones like catecholamines rather than direct nerve signals.
To prevent the recipient’s immune system from recognizing the donor heart as foreign and attacking it, patients must take immunosuppression medications for the remainder of their lives. These medications, which often include calcineurin inhibitors, antimetabolites, and glucocorticoids, work to dampen the immune response. While these drugs are effective in preventing rejection, they also increase the risk of infections and can have other side effects, necessitating careful monitoring. Long-term care for heart transplant recipients involves regular follow-up appointments, frequent heart biopsies, especially in the first year, and continuous monitoring of medication levels to maintain a delicate balance between preventing rejection and minimizing adverse effects.