Objectives. Lead Placement. Hexaxial System. ECG Paper. Systematic Approach to Reading an ECG. Page 3. Lead Placement. Page 4. Hexaxial System. Part I ECG fundamentals. 1. Cardiac anatomy and physiology. 3. 2. Obtaining a rhythm strip. 3. Interpreting a rhythm strip. Part II Recognizing arrhythmias. P wave = atrial depolarisation. PR Interval = impulse from atria to ventricles to ventricles. QRS complex = ventricular depolarisation. ST segment = isoelectric -.
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Introduction. This guide demonstrates how to read an ECG in a systematic and effective manner. Confirm the name and date of birth of the patient matches the. General Introduction to ECG. Reading Assignment (p in PDF 'Outline'). Objectives. 1. Practice the 5-step 'Method'. 2. Differential Diagnosis: R & L axis. Introduction. This is the second in a series of articles that aim to help readers to understand and interpret recordings of the surface ECG. The first article.
Heart rate, like other vital signs like blood pressure and respiratory rate, change with age. In adults, a normal heart rate is between 60 and bpm normocardic where in children it is higher. A complication of this is when the atria and ventricles are not in synchrony and the "heart rate" must be specified as atrial or ventricular e. In normal resting hearts, the physiologic rhythm of the heart is normal sinus rhythm NSR.
Generally, deviation from normal sinus rhythm is considered a cardiac arrhythmia. Thus, the first question in interpreting an ECG is whether or not there is a sinus rhythm. Once sinus rhythm is established, or not, the second question is the rate. For a sinus rhythm this is either the rate of P waves or QRS complexes since they are 1-to If the rate is too fast then it is sinus tachycardia and if it is too slow then it is sinus bradycardia.
If it is not a sinus rhythm, then determining the rhythm is necessary before proceeding with further interpretation. Some arrhythmias with characteristic findings: Absent P waves with "irregularly irregular" QRS complexes is the hallmark of atrial fibrillation A "saw tooth" pattern with QRS complexes is the hallmark of atrial flutter Sine wave pattern is the hallmark of ventricular flutter Absent P waves with wide QRS complexes and a fast heart rate is ventricular tachycardia Determination of rate and rhythm is necessary in order to make sense of further interpretation.
Axis[ edit ] The heart has several axes, but the most common by far is the axis of the QRS complex references to "the axis" imply the QRS axis.
Each axis can be computationally determined to result in a number representing degrees of deviation from zero, or it can be categorized into a few types. The QRS axis is the general direction of the ventricular depolarization wavefront or mean electrical vector in the frontal plane.
It is often sufficient to classify the axis as one of three types: normal, left deviated, or right deviated.
In a healthy individual it should be an isoelectric line neither elevated or depressed. T waves are normally inverted in V1 and inversion in lead III is a normal variant.
Inverted T waves in other leads are a nonspecific sign of a wide variety of conditions: You must take this ECG finding and apply it in the context of your patient. Biphasic T waves have two peaks and can be indicative of ischaemia and hypokalaemia.
Another non-specific sign, this may represent ischaemia or electrolyte imbalance. These become larger the slower the bradycardia — classically U waves are seen in various electrolyte imbalances or hypothermia , or antiarrhythmic therapy such as digoxin, procainamide or amiodarone. This site uses functional cookies and external scripts to improve your experience. Which cookies and scripts are used and how they impact your visit is specified on the left.
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The revenue we generate from these adverts allows us to keep the website free. Table of Contents. Introduction This guide demonstrates how to read an ECG in a systematic and effective manner. Confirm the date and time the ECG was performed.
Count the number of large squares present within one R-R interval Divide by this number to calculate the heart rate e. Step 2 — Heart rhythm The heart rhythm can be regular or irregular. Irregular rhythms can be either: Inferior infarction. Probably misplaced electrodes.
If the rhythm is wide QRS complex tachycardia, then the cause is probably ventricular tachycardia. Up to baseline. ST-segment depression is particularly suspicious in the chest leads. Prinzmetal's angina coronary vasospasm. Early repolarization.
Nonspecific intraventricular conduction disturbance. Brugada syndrome.
Takotsubo cardiomyopathy. Post cardioversion. Pulmonary embolism.
Aortic dissection engaging the coronary arteries. Left ventricular aneurysm. Physiological ST-segment depression. High sympathethic tone.
Heart failure. Should be positive accepted in lead V1 and lead III. In some instances the T-wave in most leads. Rarely, all T-waves normal in chest leads. One type of post-ischemic T-wave inversion is especially acute, namely Wellen's syndrome characterized by deep T-wave inversions in V1—V6 in patient with recent episodes of chest pain.
Cerebrovascular insult bleeding. Perimyocarditis after normalization of the ST-segment elevation, T-waves become inverted in perimyocarditis. Occasionally perimyocarditis.