Congenital Heart Disease
Congenital heart disease refers to a birth defect in the heart. Congenital heart defects are the most common form of birth defects, happening in about 1 out of every 150 births. Symptoms from a congenital heart defect can vary quite a bit, primarily depending on the type of heart defect. Generally speaking, congenital heart defects can be classified in one of three categories. The first category is termed a left to right shunt. In this setting, blood is usually sent through a hole in either the lower or upper wall of the heart, or sometimes through a communication outside the heart, back to the lungs. Examples include a ventricular septal defect, atrial septal defect, or patent ductus arteriosus. In the setting of a small defect, most children won't show any symptoms whatsoever. However, if the defect is large enough, symptoms are usually caused by too much blood flow going to the lungs. The most common symptom in this situation is rapid breathing. This is because some of the water from the bloodstream can leak out into lung tissue, interfering with the exchange of oxygen and carbon dioxide. The child subsequently has to breathe harder to overcome this problem. This often raises the child's metabolic rate, causing slow weight gain and poor growth. Finally, extra lung water and related problems may predispose to more frequent lung infections, for example pneumonia.
Congenital Heart Defect
A congenital heart defect is a birth defect of the heart. Birth defects of the heart are the most common overall birth defects, occurring in about 1 out of every 150 children. Congenital heart defects may include a wide variety of heart defects, for example holes in the walls of the heart, abnormalities of the heart valves, underdevelopment of certain heart chambers, or persistence of normal in utero structures that failed to close after birth.
Patent Ductus Arteriosus
A patent ductus arteriosus (PDA) is an abnormal communication between the aorta and pulmonary artery that allows for oxygenated (red) blood to pass into the lungs. If the amount of blood flowing through the PDA is enough to cause problems, then intervention may be indicated. This most commonly occurs in the setting of a large or moderate size PDA. Indications for intervention in infancy include symptoms unresponsive to medication, elevated blood pressure in the lungs, and significant dilation of the heart due to excess blood flow.
Tetralogy of Fallot
Tetralogy of Fallot is a cyanotic heart defect consisting of a ventricular septal defect, pulmonary valve stenosis, and varying degrees of aortic override and right ventricular hypertrophy. It is most common cyanotic congenital heart defect in children. In the absence of any symptoms or significant cyanosis, surgery for tetralogy of Fallot is usually performed sometime in the first year of life. Often allowing a baby to grow for several months can make the surgery technically easier and allow for a better outcome.
Sinus Node
The sinus node is the pacemaker of the heart. The sinus node is a group of cells in the upper right hand corner of the heart, specifically in the right atrium near the entrance of the superior vena cava. In some instances the cells of the sinus node may traverse a line passing on a course into the lower portion of the right atrium. The sinus node generates electrical impulses that stimulate the heart muscle to contract. The impulses are initially passed through both atrium, then transmitted through the AV node to the ventricles. More information can be found in the article on normal electrical conduction.