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
Throughout the heart, Cardiac Muscle cells are connected together to form a large network from one end to the other. These cells form a shape such that each individual cell always remains in-contact with 3 others cells at all times.
The blood circulates through coronary arteries and then to smaller vessels into cardiac muscle (myocardium). The blood flow is influenced by aortic pressure, which increases in systole, and the pumping activity of the ventricles. When the ventricle contracts, in systole, the coronary vessels are compressed by the contracted myocardium and partly blocked by the open aortic valve therefore the blood flow through the myocardium stops.
An electrocardiogram (ECG) is one of the primary assessments concluded on patients who are believed to be suffering from cardiac complications. It involves a series of leads attached to the patient which measure the electrical activity of the heart and can be used to detect abnormalities in the heart function. The ECG is virtually always permanently abnormal after an acute myocardial infarction (Julian, Cowan & Mclenachan, 2005). Julies ECG showed an ST segment elevation which is the earliest indication that a myocardial infarction had in fact taken place. The Resuscitation Council (2006) recommends that clinical staff use a systematic approach when assessing and treating an acutely ill patient. Therefore the ABCDE framework would be used to assess Julie. This stands for airways, breathing, circulation, disability and elimination. On admission to A&E staff introduced themselves to Julie and asked her a series of questions about what had happened to which she responded. As she was able to communicate effectively this indicates that her airways are patent. Julie looked extremely pale and short of breath and frequently complained about a feeling of heaviness which radiated from her chest to her left arm. The nurses sat Julie in an upright in order to assess her breathing. The rate of respiration will vary with age and gender. For a healthy adult, respiratory rate of 12-18 breaths per minute is considered to be normal (Blows, 2001). High rates, and especially increasing rates, are markers of illness and a warning that the patient may suddenly deteriorate. Julie’s respiratory rates were recorded to be 21 breaths per minute and regular which can be described as tachypnoea. Julies chest wall appeared to expand equally and symmetrical on each side with each breath taken. Julies SP02 levels which are an estimation of oxygen
The study of cardio physiology was broken up into five distinct parts all centering on the cardiovascular system. The first lab was utilization of the electrocardiogram (ECG). This studied the electrical activities of the heart by placing electrodes on different parts of the skin. This results in a graph on calibrated paper of these activities. These graphs are useful in the diagnosis of heart disease and heart abnormalities. Alongside natural heart abnormalities are those induced by chemical substances. The electrocardiogram is useful in showing how these chemicals adjust the electrical impulses that it induces.
The heart serves as a powerful function in the human body through two main jobs. It pumps oxygen-rich blood throughout the body and “blood vessels called coronary arteries that carry oxygenated blood straight into the heart muscle” (Katzenstein and Pinã, 2). There are four chambers and valves inside the heart that “help regulate the flow of blood as it travels through the heart’s chambers and out to the lungs and body” (Katzenstein Pinã, 2). Within the heart there is the upper chamber known as the atrium (atria) and the lower chamber known as the ventricles. “The atrium receive blood from the lu...
Firstly we lay them on the back to get the resting heart rate and we
...ts, electrocardiogram, sonogram and cardiac rehabilitation. As a clinical observer, I found an opportunity to create a solid foundation on patient diagnosis and treatment, and not to mention, long hours with charting and recording patients’ information.
The heart is two sided and has four chambers and is mostly made up of muscle. The heart’s muscles are different from other muscles in the body because the heart’s muscles cannot become tired, so the muscle is always expanding and contacting. The heart usually beats between 60 and 100 beats per minute. In the right side of the heart, there is low pressure and its job is to send red blood cells. Blood enters the right heart through a chamber which is called right atrium. The right atrium is another word for entry room. Since the atrium is located above the right ventricle, a mixture of gravity and a squeeze pushes tricuspid valve into the right ventricle. The tricuspid is made up of three things that allow blood to travel from top to bottom in the heart but closes to prevent the blood from backing up in the right atrium.
The heart is a pump with four chambers made of their own special muscle called cardiac muscle. Its interwoven muscle fibers enable the heart to contract or squeeze together automatically (Colombo 7). It’s about the same size of a fist and weighs some where around two hundred fifty to three hundred fifty grams (Marieb 432). The size of the heart depends on a person’s height and size. The heart wall is enclosed in three layers: superficial epicardium, middle epicardium, and deep epicardium. It is then enclosed in a double-walled sac called the Pericardium. The terms Systole and Diastole refer respectively and literally to the contraction and relaxation periods of heart activity (Marieb 432). While the doctor is taking a patient’s blood pressure, he listens for the contractions and relaxations of the heart. He also listens for them to make sure that they are going in a single rhythm, to make sure that there are no arrhythmias or complications. The heart muscle does not depend on the nervous system. If the nervous s...
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...
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.
A microprocessor inside the defibrillator interprets (analyzes) the victim's heart rhythm through adhesive electrodes (some AED models require you to press an ANALYZE button). The computer analyzes the heart rhythm and advises the operator whether a shock is needed. AEDs advise a shock only to ventricular fibrillation and fast ventricular tachycardia. The electric current is delivered through the victim's chest wall through adhesive electrode pads.
“Transesophageal scans done in the operating room provide real-time feedback to the surgeon about the health and functioning of the heart and its valves, so that appropriate choice of surgery required may be made at the time of cardiac surgery (hopkinsmedicine.org n.pag.). TEE is most commonly used in open heart surgeries if the patient will allow. It can also be very common in cardiac procedures such as mitral valve repair. During these type of operations, the transesophageal echocardiogram acts as a monitoring tool for the surgeons. It can be used immediately after procedures to make sure everything went as