AV Node
The AV node is a group of specialized conducting cells found in the middle of the heart. The AV node is responsible for transmitting electrical pulses from the sinus node and the top part of the heart through to the bottom part of the heart. Second degree AV block refers to a condition where the transmission of electrical impulses through the AV node is slower than expected, with occasional times where impulses are not transmitted at all.
Arterial Switch Operation
In transposition of the great arteries (see Fig. 1), the aorta arises from the right ventricle and the pulmonary artery from the left ventricle. Deoxygenated, or blue blood, returning from the body is sent directly back out to the body again. Likewise, oxygenated, or red blood returning from the lungs is sent right back out to the lungs. Mixing is only possible if there is an atrial septal defect and/or a patent ductus arteriosus. In the absence of successful mixing, transposition of the great arteries is usually fatal.
AV Node Disorders
The AV node is a cluster of specialized electrical cells positioned right near the middle of the heart. It is responsible for conducting electrical impulses from the top 2 chambers of the heart, the right and left atria, to the bottom 2 chambers of the heart, the right and left ventricles (see normal electrical conduction). Typically the AV node is the only pathway electricity can travel to get from the top to the bottom of the heart.
Cyanotic Heart Defects
Cyanotic heart defects are typically congenital heart defects, or birth defects of the heart. The normal heart has four chambers. Blue or deoxygenated blood returning from the body is pumped by the right ventricle through the pulmonary artery to the lungs. Red or oxygenated returning from the lungs is pumped by the left ventricle back out to the body (see normal heart anatomy and normal blood flow).
AV Node
The AV node is a group of specialized conducting cells found in the middle of the heart. The AV node is responsible for transmitting electrical impulses originating in the sinus node and the top part of the heart through to the bottom part of the heart. First degree AV block in children refers to a condition where the transmission of impulses through the AV node is slower than expected.