But pumping is not the real, or at least not the first problem, Dr. Kapuku says. Like loosening the belt to eat a big meal, the heart must relax to fill with blood. In fact, the heart is relaxed two-thirds of the time and a healthy left ventricle which pumps blood to the body should fill with blood during the early stage of relaxation. Scientists such as Dr. Kapuku say the true dysfunction of congestive heart failure occurs when that begins to change. When the heart muscle relaxes, differences in pressure between the upper and lower chambers should move the blood into the lower chamber, the left ventricle. The atrium, the upper, collecting chamber, then contracts. In very early heart failure, the heart also begins to rely on the contraction of the atrium to finish filling the left ventricle. Dr. Kapuku was among the first to demonstrate this abnormal filling is one of the earliest expressions of heart malfunction and that this phenomenon may occur behind the faade of normal pump function and cardiac structure.
Many risk factors for cardiovascular disease, such as high blood pressure, obesity and inactivity, contribute to the decline of heart tissue, turning strong, flexible muscle stiff and fibrous. "When you have a mild increase in blood pressure, the pump function is still good, sometimes even exaggerated, but at that time, you can already figure out the heart is starting to depend more on the atrial contribution than the early filling. So how do you reverse that? By lowering blood pressure," says Dr. Kapuku. That may mean taking antihypertensive medications at these early signs of trouble. Measures such as weight loss and exercise also may help stop the cascade that ultimately leads to a failing heart.
He's focusing his studies on adolescents because of mounting evidence, from centers such as the Georgia Preventi
Contact: Toni Baker
Medical College of Georgia