The heart is a pump that is made up cardiac muscle tissue. The way the heart pumps is controlled by a conduction system that causes the heart muscles to contract when electrical impulse passes through it. The sinoatrial node (SAN) is where impulse is generated. It is the pacemaker of the heart. The impulse generated frequently is about 60-100 beats per minute (Gandelman G, 2013). The SAN is located in the right atrium and as impulse leaves, the left atrium conducts it by way of Bachmann’s bundle. Impulse travel to the AV node and are briefly delayed so contracting atria can empty all the blood into the ventricles. The impulse travels to the bundle of His, to the bundle branches and Purkinje fibers (Gandelman G, 2013).
An ECG is a test that records the rhythm and activity of the heart through the use of electrodes on the skin and it is graphically displayed. 10 electrical cables are placed on the body; one to each limb (4cables) and the other six across the chest (Ashley EA, 2004).
Lead- The word lead has two meaning in the ECG terms:
- a cable that helps the ECG recorder to be attached to an electrode.
-from anyone arrangement of the electrodes the electrical view of the heart.
When an ECG is carried out: the patient undresses to the waist and lay down, excess hair is removed if required, the limb leads are fixed anywhere on the limb and the chest leads are attached as follows:
V1 and V2 – 4th intercostals space to the right and left of the sternum respectively
V3 – midway between V2 and V4
V4 – on the heart apex
V5 and V6 – anterior axillary and mid axillary at the same line as V4
Ask patient to stay calm and push record button (Rautaharju PM, 1987).
The 10 electrical cables have 12 electrical views and this is how a standard ECG reading is taken. The angles the electrodes “look” at the heart are reflected by these different views and the heart’s electrical depolarization direction (Ashley EA, 2004). (Dr Kavanagh Sean, 2013)
The pacemaker of the heart is the sino atrial node (SAN).
There are several different heart problems that show up as an abnormal EKG reading. For example, a heart block can occur when there is a delay in the signals coming from the SA node, AV node, or the Purkinje fibers. However, clinically the term heart block is used to refer to an AV block. This delays or completely stops communication between the atria and the ventricles. AV block is shown on the EKG as a delayed or prolonged PR interval. The P wave represents the activity in the atria, and the QRS complex represents ventricular activity. This is why the PR interval shows the signal delay from the AV node. There are three degrees of severity, and if the delay is greater than .2 seconds it is classified as first degree. Second degree is classified by several regularly spaced P waves before each QRS complex. Third degree can be shown by P waves that have no spacing relationship to the QRS complex. Another type of blockage is bundle branch block. This is caused by a blockage in the bundle of His, creating a delay in the electrical signals traveling down the bundle branches to reach the ventricles. This results in a slowed heart beat, or brachycardia. On an EKG reading this is shown as a prolonged QRS complex. A normal QRS is about .8-.12 seconds, and anything longer is considered bundle branch block. Another type of abnormal EKG reading is atrial fibrillation, when the atria contracts very quickly. On the EKG this is shown by no clear P waves, only many small fibrillating waves, and no PR interval to measure. This results in a rapid and irregular heartbeat. On the other hand, ventricular fibrillation is much more serious and can cause sudden death if not treated by electrical defibrillation.
In this lab, I took two recordings of my heart using an electrocardiogram. An electrocardiogram, EKG pg. 628 Y and pg. 688 D, is a recording of the heart's electrical impulses, action potentials, going through the heart. The different phases of the EKG are referred to as waves; the P wave, QRS Complex, and the T wave. These waves each signify the different things that are occurring in the heart. For example, the P wave occurs when the sinoatrial (SA) node, aka the pacemaker, fires an action potential. This causes the atria, which is currently full of blood, to depolarize and to contract, aka atrial systole. The signal travels from the SA node to the atrioventricular (AV) node during the P-Q segment of the EKG. The AV node purposefully delays
Which of the following is NOT part of ECG Changes that is associated with MI?
Supraventricular tachycardia (SVT) is a heart condition where the heart beats irregularly due to electrical abnormalities. It is fairly common, especially in children and women, yet unfamiliar to most people who are not diagnosed with it. There are three types of SVT: atrioventricular nodal re-entry tachycardia, atrial tachycardia, and Wolff-Parkinson-White syndrome. All three types have the same symptoms during episodes, which can last from seconds to hours and include palpitations, fatigue, dizziness, etc. However, the three types have different causes, all of which are unknown. To detect this condition an electrocardiograph is typically used. It compares the waves of the patient’s heart to a normal heart’s waves. Vagal maneuvers are
In this article, it tells how an EKG scan is on grid paper and each small block, which is one millimeter (mm) long, represents 0.04 seconds and each larger box, which is five millimeters long, represents 0.2 seconds. On a EKG scan, the voltage of the heart is measured in millivolts (mV) along the y-axis. On the scan grid, ten millimeters is equal to one millivolt. According to this source, in order to calculate the beats per minute (BPM), one divides the number of number of large boxes between each heart beat (QRS wave) in 300 small boxes. However, that used for a more consistent and steady heart rate. For a more varied and irregular rhythm, one has to count the number of QRS waves in six seconds and then multiply that number by ten. For an example, if there are eight QRS waves, then the estimated heart rate would be 80
A normal heart rhythm begins at the sinoatrial node and follows the hearts conduction pathway without any problems. Typically the sinoatrial node fires between 60-100 times per minute (Ignatavicius & Workman, 2013). When a person has Atrial Fibrillation, the sinoatrial node releases multiple quick impulses at a rate of 350 -600 times per minute. When this happens, the ventricles respond by beating around 120- 200 beats per minute, making it tough to identify an accurate heart rate. This arrhythmia can be the result of various things. During a normal heart beat, the electrical impulse begins at the sinoatrial node and travels down the conduction pathway until the ventricles contract. Once that happe...
Most people with symptoms related to the function of the heart will have an electrocardiogram (ECG), chest x-ray and echocardiogram (Echo), which allows the structure and function of the heart to be examined.
To understand the complications that occur in the heart when dealing with AF, one must first understand how the heart functions and how it sends the electrical signals that cause the heart to beat. In the upper right chamber of the heart, known as the right atrium, electrical signals are sent from the sinoatrial (SA) node through the electrical impulses known as autorhythmic cells. These autorhythmic cells essentially make the heart beat because they begin the electrical impulses that cause the heart to pulse in a rhythmic pattern. The right atrium fills with blood and then uses the electrical impulse created by the SA node to push the blood to the lower right chamber of the heart known as the right ventricle. The autorhythmic cells are sent through the atriums of the heart, which causes it to contract. That electrical impulse arrives at the atrioventricular (AV) bundle in a lower part of the right atrium. The (AV) bundle uses these electrical impulses to separate the tricuspid valves to allow blood from t...
In a normal ECG reading, the components are P, Q, R, S, and T. P correspond to atrial depolarization, QRS corresponds to the ventricle depolarization and atrial repolarization, and T corresponds to ventricular repolarization. The whole process is a complete beat of the heart. There are a few variants of AVNRT, but the most typical presentation is when the atrium has another depolarization at or near the onset of the ventricular depolarization. This commonly leads to the P wave in the ECG to be masked by the QRS complex (Figure
If there are no blood clots, then electrical mapping will be performed to see where the false signals are coming from. Small wires are then stuck in blood vessels and thread to the heart. Once to the heart, the wires will target the area where the false signals are being sent and diminish it. (Treatment 3) If the AV node is the area sending out false signals, a pacemaker must be put in the AV node’s place (3). A pacemaker is an electrical device that sends out electrical signals telling the heart to beat (5). A more serious procedure done to treat atrial fibrillation is called the maze procedure.
Due to the fact that we thrive in a prevalent world of technological advances significantly more convenient machines have been granted. Furthermore, the diagnostic tests that can be done to evaluate heart function are:
I had the opportunity to observe two cardiac catheterization during clinical this week. A cardiac catheterization is a procedure to examine how well a patient heart is working. A thin tube called a catheter is inserted into a large blood vessel that leads to the patient heart. This procedure is done through angiography, a contrast dye visible X-rays is injected through the catheter. These X-ray images show the dye as it flows through the heart arteries, and shows where arteries are blocked (A H A, 2016).
I will first identify myself as well as the patient, and make sure the patient has the right information on ID wrist band as I do on the requisition. The butterfly ETS system is what I will be using on the patient, needle size for butterfly ETS will be 23g. The tubes in order of draw will be; Red (plain) or GOLD/brick top, Blue top(buffered sodium citrate), Lavender (EDTA).
Electrocution occurs when a small, specific amount of electrical current flows through the heart for 1 to 3 seconds. 0.006-0.2 Amps (i.e. 6-200 milliamps) of current flowing through the heart disrupts the normal coordination of heart muscles. These muscles lose their vital rhythm and begin a process known as ventricular fibrillation. Death soon follows.
The cardiac cycle is composed of five stages. These stages are atrial systole, early ventricular systole, late ventricular systole, early ventricular diastole, and late ventricular diastole. In order for atrial systole to occur, the blood that has been flowing between the atrium and ventricle via the opened atrioventricular valves must be deposited into the ventricles. The SA node is responsible for the contraction of the atrial myocardium. Once the atrium contracts, blood cannot flow back into or enter the atria because the openings of the great veins has been narrowed by pressure. The ventricles are now filled with blood accomplishing end-diastolic volume which is another term for how much blood your ventricles can contain while your body is at rest. The next phase is early ventricular systole. Now that all the blood is in your ventricles, it must continue onward to the