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Site FeedbackElectrical System of the Heart
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Description | Treatment Options | John Muir Health Capabilities
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Definition
The heart has a unique, built-in electrical system. Every heart has electrical paths, called the conduction system, running throughout its muscle tissue. The sinus node (area of special conduction tissue), often called the heart's natural pacemaker, contains the most active electrical cells. It begins the heartbeat. Additional nodes are responsible for sending signals to different sections of the heart. The atrioventricular node is, found near where the chambers of the heart join together and its job is to send signals from the upper chambers(atria), to the lower chambers (ventricles). The natural pacemaker node and the special conduction paths that run through your heart coordinate contractions in the upper chambers and lower chambers. The coordination makes the heartbeat more powerful so it can do its job effectively.
Description
We normally have our own pacemakers that tell the heart when to beat. The master pacemaker is located in the atrium (upper chamber). It acts like a spark plug and fires in a regular, rhythmic pattern and regulates the heart's rhythm. This "spark plug" is called the sinoatrial (SA), or sinus node. It sends signals to the rest of the heart stimulating the heart muscle to contract. First, the atrium contracts. Like a pebble dropped into a pool of water, the electrical signal from the sinus node spreads through the atria. Next, the electrical signal travels to the area that connects the atria with the ventricles. This electrical connection is critical. Without it, the signal would never reach the ventricles, the major pumping chambers of the heart. The first structure it reaches is another natural pacemaker called the atrioventricular (AV node). A structure called the "bundle of His" emerges from the AV node and divides into thin, wire-like structures called bundle branches that extend into the right and left ventricles. The electrical signal travels down the bundle branches to thin filaments known as Purkinje fibers. These fibers distribute the electrical impulse to the muscles of the ventricles, causing them to contract and pump blood into the arteries.
Without the electrical system, the heart would just sit there and not pump blood. The blood would not circulate and the body would not receive the oxygen and nutrients it needs. When blood flow stops to the brain, the person loses consciousness in seconds and death follows within minutes.
Treatment Options
The EKG provides two kinds of information. The EKG measures time intervals as the heartbeat travels. The doctor can determine how long the electrical wave takes to pass through the heart. This information is important as it helps determine if the electrical activity is normal or slow, fast or irregular. Additional information about the heart muscle can be obtained using the EKG. A new or old heart attack can be identified. The EKG is a valuable tool and is usually the first test performed in a heart examination. Some individuals will need frequent EKG to monitor the stasis of the heart's electrical and conduction system.
John Muir Health Capabilities
John Muir Health is very proud of its Cardiac Rhythm Center. John Muir Health has eight leading cardiac rhythm specialists in the Bay Area on staff at John Muir Medical Center, Walnut Creek Campus and John Muir Medical Center, Concord Campus. These rhythm specialists are cardiologists who completed special training in the care of individuals with heart rhythm problems. Special equipment and well-trained staff at John Muir Health are available to care for those with the complex and life-threatening problems.
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Graphic of the heart's normal electrical system -
example from Heart Rhythm Society