2 CONGENITAL HEART DEFECTS What’s here This section provides some information about the cardiovascular system—the heart, valves, and blood vessels, before and after birth. It also provides general information about congenital heart defects (CHDs) and related health concerns. WRITE & ASK The topics include: ■ What is a Congenital Heart Defect? ■ How the Heart A TIP FROM THE and Blood Vessels Work ■ Before Birth—Mother Provides What Baby Needs HEALTH CARE TEAM ■ After Birth ■ How To Find Out If Your Baby Has a CHD ■ Congestive Heart Failure ■ Cyanosis ■ Infection Called Bacterial Endocarditis WRITE DOWN YOUR QUESTIONS AS YOU THINK OF THEM AND Diagram of a Normal Heart DON’T BE AFRAID TO ASK QUESTIONS blood from upper body aorta to body superior to lungs vena cava main pulmonary pulmonary veins from artery lungs LEFT pulmonary ATRIUM veins septum from lungs pulmonary mitral valve valve RIGHT ATRIUM aortic valve LEFT tricuspid valve VENTRICLE RIGHT VENTRICLE inferior vena cava septum aorta to blood from lower body lower body HEART & SOUL - YOUR GUIDE TO CONGENITAL HEART DEFECTS 2-1 CONGENITAL HEART DEFECTS WHAT IS A CONGENITAL Sometimes a CHD is associated with other HEART DEFECT? health problems. For example, babies with Down Syndrome often have a particular “Congenital defect” comes from the words heart defect. congenital, meaning “existing at birth” and “defect”,meaning a problem. The heart is HOW THE HEART AND COMMON completely formed by the 8th week of BLOOD VESSELS WORK DENOMINATOR pregnancy. If a problem occurs in the way the CHDS HAPPEN TO heart or the blood vessels close to the heart Every cell in the body needs oxygen and ABOUT ONE IN EVERY are formed the baby is born with what is nutrients to work properly.The cardio- ONE HUNDRED BABIES called a congenital heart defect, CHD for vascular system (from “cardio”,meaning short. Congenital heart defects are some- heart, and “vascular”, meaning blood vessels) times called congenital heart disease. refers to the heart and blood vessels by THEY ARE MORE which blood carrying oxygen and nutrients COMMON THAN ANY About one of every one hundred babies born is pumped throughout the body. O THER TYPE OF has some form of heart defect (i.e., 1%).This CONGENITAL DEFECT ranges from a tiny hole that will never require treatment to a life threatening heart defect. THEY ARE MORE COMMON IN CHILDREN WITH OTHER Diagram of Heart, Lungs, Alveoli and Capillaries CONDITIONS SUCH AS DOWN SYNDROME superior left vena cava lung right lung RIGHT ATRIUM inferior vena cava pulmonary vein to left heart pulmonary artery from right heart capillary alveoli plexus (air sac) 2-2 HEART & SOUL - YOUR GUIDE TO CONGENITAL HEART DEFECTS CONGENITAL HEART DEFECTS The heart is a two-sided pump ■ blood rich in oxygen returns to the heart through the pulmonary veins to the left Your child’s heart is a hollow, muscular organ atrium, about the size of a child’s fist. It is located ■ between the lungs, slightly to the left of the the left atrium squeezes, which forces middle of the chest. the blood through the mitral valve into the left ventricle, Here are the main parts or the heart: ■ the left ventricle squeezes, which pushes ■ a wall made up of membranous and the aortic valve open, muscular areas called the septum, divides the right and left sides of the heart, ■ with each beat of the heart, blood rushes through the aortic valve into the aorta, ■ two chambers on each side of the heart—the upper ones called atria, which branches into smaller arteries that collect blood, and the lower ones called supply the body with oxygen-rich blood, ventricles, pump blood out, ■ blood rushing through the arteries creates ■ small doors called valves open and close a pulse you can feel with your fingertips when the heart beats, (pulse rate depends on how fast the heart must beat to send blood to all parts of ■ the great vessels—the aorta, which takes the body). blood to the body, and the pulmonary artery, which takes blood to the lungs. The electrical system How does the heart work? (Please refer to the diagram on page 2-4) ELECTROCARDIOGRAM The heart’s own electrical system makes Clench your fist, relax it, and clench it again. it beat through a series of actions: This squeezing and relaxing is similar to how ■ the sinoatrial node (SA node), the the heart beats or contracts. heart’s natural pacemaker located in the The heart collects oxygen-poor blood, pumps right atrium, causes the atria to contract it to the lungs to get oxygen and then pumps and pump out blood, it out to the body through arteries. ■ the signals travel to the atrioventricular Here is the series of actions: node (AV node), ■ the right atrium, a collecting chamber, ■ the AV node delays the signal slightly, which receives oxygen-poor blood (blood that allows the blood to pass from the atria to looks bluish), the ventricles, ■ the right atrium contracts (squeezes), which ■ the AV node sends the signal to the pushes open the tricuspid valve (the door ventricles, causing them to contract.When to the right ventricle) and the blood moves the nodes are working well together, the through the valve to the right ventricle, heart pumps blood into the lungs and to ■ the right ventricle, a pumping chamber, con- the rest of the body. If the electrical system tracts, which pushes open the pulmonary is interrupted, this may cause an irregular valve (the door to the pulmonary artery), heart rhythm. ■ the pulmonary artery carries blood low in oxygen to the lungs, where carbon dioxide is removed and oxygen is added, HEART & SOUL - YOUR GUIDE TO CONGENITAL HEART DEFECTS 2-3 CONGENITAL HEART DEFECTS CHDs, the blood leaving the heart does not electrical impulses become filled with oxygen and the child SA node appears blue (see Cyanosis—Blueness of the AV node Skin, page 2-11). bundle DYSRHYTHMIAS of HIS Blood delivery through the blood vessels Electrical problems affecting the heart Blood is delivered by a network of rate or rhythm are called dysrhythmias, blood vessels, including arteries, veins, and include: and capillaries: ■ the arteries carry blood away from BRADYCARDIA the heart, (A SLOWER THAN NORMAL HEART RATE) ■ the veins carry blood back to the heart, purkinje ■ the capillaries (tiny blood vessels connecting fibers TACHYCARDIA the arteries and veins) allow oxygen and (A FASTER THAN nutrients to be delivered to the cells and NORMAL HEART RATE) Healthy blood waste products to be picked up. The blood has many different parts. The main parts are: Blood pressure FIBRILLATION (A DISORGANIZED ■ red blood cells, which carry oxygen Blood pressure is a measure of the pressure OR IRREGULAR to the body, HEARTBEAT) against the walls of the arteries.The first ■ white blood cells, which help fight infection, number is called the systolic pressure, and the ■ platelets, which help the blood to clot, second number is called the diastolic pressure. For example, a blood pressure of 120/80 ■ plasma, which contains protein such means 120 systolic, 80 diastolic. as albumin. Here’s an explanation.The heart muscle Oxygen is needed by every part of the body. contracts and relaxes in a rhythm: The red blood cells carry oxygen around ■ contraction (or squeezing), when blood is the body. squeezed out of the heart, is called systole (pronounced “SISS-tow-lee”), The oxygen attaches itself to haemoglobin, a part of a red blood cell.When the haemo- ■ relaxation, when the heart refills with globin is full of oxygen, the blood looks bright blood, is called diastole (pronounced red.When the oxygen level is low, the blood “die-AS-tow-lee”), looks purple or blue. ■ when the heart contracts, a wave of blood The cells use the oxygen, and the waste is pushed out of the heart, putting pressure product is carbon dioxide. on the walls of the artery, When blood rich in oxygen leaves the lungs ■ when the heart relaxes, pressure in the to be pumped around the body, it normally arteries lessens. looks red. Blood returning to the heart is low in oxygen and high in carbon dioxide and normally looks blue.With some types of 2-4 HEART & SOUL - YOUR GUIDE TO CONGENITAL HEART DEFECTS CONGENITAL HEART DEFECTS Blood pressure can be too high (hypertension) As the baby doesn’t use its lungs to or too low (hypotension). Possible causes of breathe until after birth, most of the hypertension include: a) a structural defect blood bypasses the lungs through of the aorta, b) a change in blood flow to the two connectors: kidneys or kidney disease or c) a change in ■ the foramen ovale allows most of the the flow of blood through the small blood blood to pass from the right atrium to BLOOD vessels. Possible causes of hypotension the left atrium, PRESSURE include: a) the heart not pumping blood ■ a blood vessel called the ductus effectively, b) a side effect of certain medica- BLOOD PRESSURE arteriosus carries the blood from CAN BE T OO HIGH tions, or c) if there is not enough blood the pulmonary artery into the aorta. IF SOMETHING IS going through the body. BLOCKING THE Before birth, most babies with CHD do BLOOD FLOW BEFORE BIRTH—MOTHER not have any problems because the placenta PROVIDES WHATBABY NEEDS provides oxygen-rich blood to the baby and because oxygen needs in the womb are lower BLOOD PRESSURE CAN BE TOO LOW IF than after birth. Once the baby is born and Before a baby is born, the placenta in the THE HEART IS NOT the umbilical cord is cut, the mother’s and mother’s womb does the work of the lungs BEATING WELL adding oxygen and removing carbon dioxide.