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 …show more content…
622 Y. When the AV node receives the signal, it fires and causes the ventricles to depolarize, this is known as the QRS Complex. The atria also repolarizes during this phase. Specifically in the QRS Complex, during the Q wave, the interventricular septum depolarizes, during the R wave, the main mass of the ventricles depolarizes, and during the S wave, the base of the heart, apex, depolarizes. After the QRS Complex, the S-T segment can be identified as a plateau in myocardial action potentials and is when the ventricles actually contract and pump out blood to the pulmonary and systemic circuits. The final phase of the heartbeat is the T wave and this is when the ventricles repolarize before the relax, ventricular diastole, EKG Video Notes and pg. 671 D. These phases represent the cardiac cycle, which is the time and events that occur from the beginning of one heartbeat to the beginning of the next heartbeat. In this lab, the first EKG that I took was my regular heartbeat during rest. In this recording, I was able to see the P wave, followed by the QRS Complex and the T wave as well. Everything looks pretty normal, but the T wave does go a little lower than normal and I believe this is due to the fact that I was diagnosed with sinus bradycardia
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.
Which of the following is NOT part of ECG Changes that is associated with MI?
Two heart sounds are normally heard through a stethoscope on the chest wall, "lab" "dap". The first sound can be described as soft, but resonant, and longer then the second one. This sound is associated with the closure of AV valves (atrioventricular valves) at the beginning of systole. The second sound is louder and sharp. It is associated with closure of the pulmonary and aortic valves (semilunar valves) at the beginning of diastole. There is a pause between the each set of sounds. It is a period of total heat relaxation called quiescent period.
Cardiovascular Activity And How it Influences the body. Introduction: Cardiovascular fitness is a form of aerobic fitness (Neporent and Egan 1997). There are many different ways of evaluating the amount of oxygen used during cardiovascular fitness and one the methods involved is called VO2 Max. VO2 Max is the maximum amount of oxygen that the body can hold.
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.
In Figure 27, there is an increase of 10.3 % while there is an increase of 161.9%. Both demonstrate an anticipated increase in heart rate; however, the expected heart rate is substantially greater. This discrepancy is possible due to the numerous cold experimental treatments prior, the atropine being cold, and the control that the experimental group is being compared. Depending on the accuracy of the control, the experimental group can demonstrate either a positive or negative chronotropic response. It is also possible that dosage was the issue. According to a therapeutic review study conducted on bradycardia patients, a condition where the heart beats abnormally slow, atropine was administered to increase heart rate and improve atrioventricular conduction it was found that in small doses, atropine actually has a paradoxical effect on the heart. Instead of increasing heart rate, it will instead decrease heart rate (Das, 1989). Hence, it is possible that not enough of the atropine was administered uniformly along the surface of the heart or at least along the pacemaker region to produce an effective increase in heart
Each beat of the heart is referred to as the cardiac cycle. When the heart beats, the atria contract simultaneously followed by the ventricles contracting simultaneously, this process is known as systole. The resting phase of the four chambers between beats is referred to as diastole.
The second beat is the semilunar valve opening to allow blood into the aorta or pulmonary trunk. 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.
When you change your posture from sitting to standing or lying down (supine position), some of the things occur in the body in response to this change. It includes change in the number of heart beats per minute (heart rate) and blood pressure (pressure of blood against arterial vessel walls).
The heart has a relatively long refractory period due to the plateau phase. The plateau phase occurs from the maintenance of a high calcium conductance and a delay in the subsequent increase in potassium conductance after a cardiac action potential. The heart membrane remains in a refractory or contracted state until the heart has fully returned to a relaxed state; therefore, tetanus or wave summation does not occur in cardiac muscles (Randall, 2002). When the frog’s heart was stimulated with single stimuli, an extrasystole and an increase in frequency was observed during the relaxation phase, but the amplitude remained constant. These results were analogous to the multiple stimuli treatment, which we expected. Because both single and multiple
AIM: - the aim of this experiment is to find out what the effects of exercise are on the heart rate. And to record these results in various formats. VARIABLES: - * Type of exercise * Duration of exercise * Intensity of exercise * Stage of respiration
The phase of relaxation “diastole” and the phase of contraction “systole”. Since the human heart has four channels there is atrial systole, atrial diastole, ventricular systole, and ventricular diastole. The cardiac cycle is described by the heart rate which is expressed as beats per minute. This cycle consists of four stages: Inflow phase, Isovolumetric contraction, outflow phase, and isovolumetric
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...
In a normal strip, one can clearly identify a P wave before every QRS complex, which is then followed by a T wave; in Atrial Fibrillation, the Sinoatrial node fires irregularly causing there to be no clear P wave and an irregular QRS complex (Ignatavicius & Workman, 2013). Basically, it means that the atria, the upper chambers of the heart, are contracting too quickly and no clear P wave is identified because of this ‘fibrillation’ (Ignatavicius & Workman, 2013). Clinical Manifestations and Pathophysiology A normal heart rhythm begins at the sinoatrial node and follows the heart's conduction pathway without any problems. Typically the sinoatrial node fires between 60-100 times per minute (Ignatavicius & Workman, 2013).
The heart beats when electrical signals move through it. Ventricular fibrillation is a condition in which the heart's electrical activity becomes disordered. When this happens, the heart's lower (pumping) chambers contract in a rapid, unsynchronized way. (The ventricles "flutter" rather than beat.) The heart pumps little or no blood therefore the probability of death is high.