conduction system of the heart pdf basics

Although several genes involved in mature conduction system function have been identified, their association with development of specific subcomponents of the cardiac conduction system remains challenging. Development of the cardiac conduction system is a complex biological process that can be wrought with problems. If the electrical rhythm is abnormal, you may need medicine or a procedure.Diseases of the cardiovascular system that cause sudden cardiac deaths are often caused by lethal arrhythmias that originate from defects in the cardiac conduction system. This painless test involves recording the electrical activity of your heart with several small stickers attached to your chest. Your doctor may do an ECG (electrocardiogram) to assess the rhythm of the heart.

Symptoms of an arrhythmia can include a feeling that your heart is fluttering (heart palpitations), shortness of breath, dizziness, or fainting. This causes a faster or slower heartbeat. The normal conduction pathway is interruptedĪnother part of the heart takes over as pacemaker. The heart's natural pacemaker (the sinus node) becomes diseased and slows down An abnormal heartbeat (arrhythmia) may occur when: Under some abnormal conditions, certain heart tissue is capable of starting a heartbeat, or becoming the 'pacemaker,' just like the sinus node. What can go wrong with the heart's electrical system? In general, your heart rate slows as you age. Normally at rest, the heart contracts about 60 to 100 times a minute depending on your age. The bundle of His divides into right and left pathways (bundle branches) to give electrical stimulation to the right and left ventricles. After passing through the AV node, the electrical current then continues down the conduction pathway, through a pathway called the bundle of His, and into the ventricles. The blood from the atria empties into the ventricles before the ventricles contract. This allows the atria to contract a fraction of a second before the ventricles. In the AV node, the impulses are slowed down for a very short period. This node is located between the atria and the ventricles. The signal travels to the AV node (atrioventricular node). The original electrical impulse travels from the sinus node across the cells of your heart's right and left atria. The ventricles then contract to push blood out into the blood vessels of the body.

The right and left atria are stimulated first and contract to push blood from the atria into the ventricles. This electrical pulse travels down through the conduction pathways and causes the heart's lower chambers (ventricles) to contract and pump out blood. In an adult, the sinus node sends out a regular electrical pulse 60 to 100 times per minute. The sinus node is a small mass of special tissue in the right upper chamber of the heart (right atrium). It's also called the sinoatrial node (SA node). Click Image to Enlarge How does the heart beat?Īn electrical stimulus is generated in a special part of the heart muscle called the sinus node.

Conduction system of the heart pdf basics