It measures the length of time it takes for the initial impulse to fire at the Sinus Node and then ends in the contracting of the Ventricles. Schematic diagram of normal sinus rhythm for a human heart as seen on ECG. The first upward pulse of the EKG signal, the P wave, is formed when the atria the two upper chambers of the heart contract to pump blood into the ventricles. The next large upward spike segment, the QRS Complex, is formed when the ventricles the two lower chambers of the heart are contracting to pump out blood.
The normal duration interval of the QRS complex is between 0. The next section, the ST segment, measures the end of the contraction of the ventricles to the beginning of the rest period before the ventricles begin to contract for the next beat. These pulses are caused by the movement of positively and negatively charged ions sodium, calcium, potassium, magnesium through proteins called ion channel receptors.
For an excellent discussion and explanation of the science behind the movement of these chemical ions, see Restart Your Heart by Dr. Aseem Desai, p. In the case of Atrial Fibrillation, the consistent P waves are replaced by fibrillatory waves, which vary in amplitude, shape, and timing compare the two illustrations below. The output of an ECG recorder is a graph or sometimes several graphs, representing each of the leads with time represented on the x-axis and voltage represented on the y-axis.
A dedicated ECG machine would usually print onto graph paper which has a background pattern of 1mm squares often in red or green , with bold divisions every 5 mm in both vertical and horizontal directions. Diagram of electrocardiogram paper. Click for Video: Cardiac Conduction System.
Interpreting a ECG strip involves counting the squares of the tracing. For example, by counting the squares of a heart in Normal Sinus Rhythm, you can calculate the heart rate. Potassium , calcium , and magnesium are electrolytes.
If your electrolytes are imbalanced, you may have an abnormal EKG reading. Heart attack or ischemia: During a heart attack, blood flow in the heart is affected and heart tissue can begin to lose oxygen and die.
This tissue will not conduct electricity as well, which can cause an abnormal EKG. Ischemia, or lack of blood flow, may also cause an abnormal EKG.
Heart rate abnormalities: A typical human heart rate is between 60 and beats per minute bpm. An EKG can determine if the heart is beating too fast or too slow. Heart rhythm abnormalities: A heart typically beats in a steady rhythm.
An EKG can reveal if the heart is beating out of rhythm or sequence. Examples of medications that affect heart rhythm include beta-blockers , sodium channel blockers, and calcium channel blockers. Learn more about arrhythmia drugs. Several symptoms can indicate that you may need an EKG to determine if your heart is functioning normally.
Seek emergency medical attention if you experience:. Treatment response to an abnormal EKG typically depends on the underlying cause. This person may require a pacemaker , which helps restore the heart to a more normal rhythm. Someone having a heart attack may require cardiac catheterization or surgery to allow blood flow to return to the heart. People with electrolyte imbalances may require correction with medications or fluids.
For example, a person with dehydration may have imbalanced electrolytes that are causing an abnormal EKG. This person may require fluids, electrolyte-containing beverages, or medications to restore electrolytes.
Sometimes, a doctor may not recommend any treatments for an abnormal EKG. AFib and VFib share similar names, but they're quite different from one another. Learn what sets this pair of conditions apart. Surgery Flashcard Collection. Septic Arthritis. Compartment Syndrome. Anatomical Planes. Anatomy Flashcard Collection. The Inguinal Canal. A man with penile swelling. A man with blood in his urine.
PSA Question Bank. Medical Student Finals Question Bank. ABG Quiz. Share Tweet. Last updated: June 7, Suggest an improvement. You don't need to tell us which article this feedback relates to, as we automatically capture that information for you. This allows us to get in touch for more details if required.
Please write a single word answer in lowercase this is an anti-spam measure. This field is for validation purposes and should be left unchanged. Hint If you are suspicious that there is some atrioventricular block AV block , map out the atrial rate and the ventricular rhythm separately i.
Hint If P waves are absent and there is an irregular rhythm it may suggest a diagnosis of atrial fibrillation. Tips for remembering types of heart block To help remember the various types of AV block, it is useful to know the anatomical location of the block within the conducting system. Third-degree AV block: Occurs at or after the AV node resulting in a complete blockade of distal conduction.
Join the community.
0コメント