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CHAPTER 3 How to  Make Basic ECG Measurements This chapter continues the discussion of ECG basics introduced in Chapters 1 and 2. Here we focus on recognizing components of the ECG in order to make clinically  important  measurements  from  these time–voltage graphical recordings. STANDARDIZATION   (CALIBRATION) MARK The electrocardiograph is generally calibrated such that a 1-mV signal produces a 10-mm deflection. Modern units are electronically calibrated; older ones may have a manual calibration setting. ECG as a Dynamic Heart Graph The ECG is a real-time graph of the heartbeat. The small ticks on the horizontal axis correspond to intervals of 40  ms. The vertical axis corresponds to the magnitude (voltage) of the waves/deflections (10  mm  =  1  mV) As shown in  Fig. 3.1, the standardization mark produced when the machine is routinely calibrated is a square (or rectangular) wave 10  mm tall, usually displayed at the left side of each row of the electrocardiogram.  If  the  machine 

This guide demonstrates how to read an ECG in a systematic and effective manner. If you want to put your ECG interpretation knowledge to the test, check out our ECG quiz on the new Geeky Medics quiz platform. CHAPTER 2 ECG Basics: Waves, Intervals, and Segments The  first  purpose  of  this  chapter  is  to  present  two fundamental electrical properties of heart muscle cells: (1) depolarization (activation), and (2) repolarization (recovery). Second, in this chapter and the next we define and show how to measure the basic  waveforms,  segments,  and  intervals  essential to ECG interpretation. DEPOLARIZATION AND REPOLARIZATION In Chapter 1, the term  electrical activation (stimulation) was applied to the spread of electrical signals through the atria and ventricles. The more technical term for the cardiac activation process is  depolarization. The return of heart muscle cells to their resting state following depolarization is called  repolarization. These key terms are derived from th

Intrinsic asthma Rackemann described this as asthma caused by substances from “within the body.”  These patients usually have a negative allergy skin test, and therefore do not have allergies and do not benefit from allergy shots or allergy medications. Rackemann believed a common cause of intrinsic asthma was colds, and treating the asthma was as simple as avoiding getting a cold. One suggested remedy here was vaccination.2 Other than colds, he suggested sinus infections, chronic sinusitis, teeth infections, gum infections, and throat infections, as probable causes of asthma. The likely treatment would be treatment of the infection, or avoiding it altogether The  electrocardiogram  (ECG  or  EKG) is a special type of graph that represents cardiac electrical activity from one instant to the next. Specifically, the ECG provides a  time-voltage chart  of the heartbeat. The ECG is a key component of clinical diagnosis and management of inpatients and outpatients because it may provide cri

Tetanus vaccine, also known as tetanus toxoid (TT), is an inactive vaccine used to prevent tetanus.[1] During childhood, five doses are recommended, with a sixth given during adolescence.[1] Additional doses every ten years are recommended.[2] After three doses, almost everyone is initially immune.[1] In those who are not up to date on their tetanus immunization, a booster should be given within 48 hours of an injury.[3] In those with high-risk injuries who are not fully immunized, tetanus antitoxin may also be recommended.[1] Making sure pregnant women are up to date on their tetanus immunization can prevent neonatal tetanus.[1] Tetanus vaccine DPT-IPV-japan Quattro back.jpg Tetanus vaccination is often administered via combination DPT vaccines Vaccine description Target disease Tetanus Type Toxoid Clinical data MedlinePlus a682198 License data US DailyMed: Tetanus ATC code J07AM01 (WHO) Legal status Legal status US: ℞-only Identifiers ChemSpider none  ☒☑ (what is this?)  (verify) The