Ecg Library

QRS Complex Morphology Main features to consider: Width of the complexes: Narrow versus broad. Voltage (height) of the complexes. Spot diagnoses: Specific morphology patterns that are important to recognise. QRS Complex Naming Convention Courtesy of ECGwaves.com QRS Width Normal QRS width is 70-100 ms (a duration of 110 ms is sometimes observed in healthy subjects). The QRS width is useful in determining the origin of each QRS complex (e.g. sinus, atrial, junctional or ventricular). ...

First reported by Dutch Professor of Cardiology, Robbert J. de Winter in 2008, the de Winter ECG pattern is an anterior STEMI equivalent that presents without obvious ST segment elevation. These patients are suffering occlusion myocardial infarction (OMI) and require immediate reperfusion therapy. ECG Diagnostic Criteria Tall, prominent, symmetrical T waves in the precordial leads Upsloping ST segment depression > 1mm at the J point in the precordial leads Absence of ST elevation in the precordial leads Reciprocal ST segment elevation (0.5mm – 1mm) in aVR Typical STEMI morphology may precede or follow the De Winter pattern ...

VT or not VT…that is the question Most of us know this question all to well. We are also probably familiar with the long list of ECG features “suggestive” of ventricular tachycardia (VT). Unfortunately, this list is not always intuitive, and can be difficult to recall and apply under pressure on the floor. How can we simplify things? I’ve spent the last few days coming up with a more easily applicable approach to this common dilemma. ...

The J point The J point is the the junction between the termination of the QRS complex and the beginning of the ST segment. The J (junction) point in the ECG is the point where the QRS complex joins the ST segment. It represents the approximate end of depolarization and the beginning of repolarization as determined by the surface ECG. There is an overlap of around 10ms. The J point marks the end of the QRS complex, and is often situated above the baseline, particularly in healthy young males. The J point may deviate from the baseline in early repolarization, epicardial or endocardial ischaemia or injury, pericarditis, RBBB, LBBB, RVH, LVH or digitalis effect. ...

The following headings and prompts can be used as template for ECG-based exam questions. Amjid Rehman (@amjidrehman) has made an easy interactive online template ‘ECG made easier‘ based on the template structure outlined ECG type and recording 12 lead vs rhythm strip, rate (normal 25 mm/s) Calibration (5mm wide, 10mm high = 1mV) Unusual leads – right, posterior, lead grouping format Rate normal 60 – 100/min tachy/bradycardia (SA node) vs –arrhythmia (not SA node) method: 300/RR interval (large squares) or number of QRS complexes x 6 (if 25mm/s) ...

I have had a few people ask me about the following statement from ECG Case 121: “The reciprocal ST depression seen in leads III and aVF (in high lateral infarction) is often mistaken for inferior ischaemia. One must recall that ST depression does not localise, and such ST depression should be assumed to be a reflection of ST elevation in mirror image leads.” Buttner, Aslanger: ECG Case 121 “ST depression does not localise” – what does this mean? The term “localise” has two relevant interpretations here. ...

Delta Wave Overview The Delta wave is a slurred upstroke in the QRS complex. It relates to pre-excitation of the ventricles, and therefore often causes an associated shortening of the PR interval. It is most commonly associated with pre-excitation syndromes such as WPW. The characteristic ECG findings in Wolff-Parkinson-White syndrome are: Short PR interval (< 120ms) Broad QRS (> 100ms) A slurred upstroke to the QRS complex (the delta wave) ...

The ECG is one of the most useful investigations in medicine. Electrodes attached to the chest and/or limbs record small voltage changes as potential difference, which is transposed into a visual tracing Basic landmarks 3-electrode system Uses 3 electrodes (RA, LA and LL) Monitor displays the bipolar leads (I, II and III) To get best results – Place electrodes on the chest wall equidistant from the heart (rather than the specific limbs) ...

P Wave Overview The P wave is the first positive deflection on the ECG and represents atrial depolarisation. The P wave is the first positive deflection on the ECG It represents atrial depolarisation Normal duration: < 0.12 s (< 120ms or 3 small squares) Characteristics of the Normal Sinus P Wave Morphology Smooth contour Monophasic in lead II Biphasic in V1 Axis ...

ECG Library Homepage Related Topics Anterior STEMI Lateral STEMI High Lateral STEMI Inferior STEMI Posterior AMI ST Elevation in aVR Advanced Reading Online Wiesbauer F, Kühn P. ECG Mastery: Yellow Belt online course. Understand ECG basics. Medmastery Wiesbauer F, Kühn P. ECG Mastery: Blue Belt online course: Become an ECG expert. Medmastery Kühn P, Houghton A. ECG Mastery: Black Belt Workshop. Advanced ECG interpretation. Medmastery Rawshani A. Clinical ECG Interpretation ECG Waves Smith SW. Dr Smith’s ECG blog. Wiesbauer F. Little Black Book of ECG Secrets. Medmastery PDF Textbooks ...

Evaluating the Differences in Approach to the ECG Between Experts and Novices We know that emergency medicine attendings are generally faster and more accurate at ECG interpretation than residents and medical students. But how are they able to process this information so much quicker while maintaining accuracy? And can we use these strategies to help learners progress to their own ‘expert-like’ level? Our study combined eye-tracking and interview data to come up with a few ways in which EM attendings look and think about ECGs differently than more novice learners.1 ...

↪ ECG Basics Homepage PR Interval The PR interval is the time from the onset of the P wave to the start of the QRS complex. It reflects conduction through the AV node. The normal PR interval is between 120 – 200 ms (0.12-0.20s) in duration (three to five small squares). If the PR interval is > 200 ms, first degree heart block is said to be present. PR interval < 120 ms suggests pre-excitation (the presence of an accessory pathway between the atria and ventricles) or AV nodal (junctional) rhythm. ...

↪ ECG Basics Homepage The PR segment is the flat, usually isoelectric segment between the end of the P wave and the start of the QRS complex. PR segment abnormalities These occur in two main conditions: Pericarditis Atrial ischaemia Pericarditis The characteristic changes of acute pericarditis are: PR segment depression. Widespread concave (‘saddle-shaped’) ST elevation. Reciprocal ST depression and PR elevation in aVR and V1 Absence of reciprocal ST depression elsewhere. NB. PR segment changes are relative to the baseline formed by the T-P segment. ...

↪ ECG Basics Homepage R wave Overview The R wave is the first upward deflection after the P wave. The R wave represents early ventricular depolarisation Abnormalities of the R wave There are three key R wave abnormalities: Dominant R wave in V1 Dominant R wave in aVR Poor R wave progression 1. Dominant R wave in V1 Causes of Dominant R wave in V1 Normal in children and young adults Right Ventricular Hypertrophy (RVH) Pulmonary Embolus Persistence of infantile pattern Left to right shunt Right Bundle Branch Block (RBBB) Posterior Myocardial Infarction (ST elevation in Leads V7, V8, V9) Wolff-Parkinson-White (WPW) Type A Incorrect lead placement (e.g. V1 and V3 reversed) Dextrocardia Hypertrophic cardiomyopathy Dystrophy Myotonic dystrophy Duchenne Muscular dystrophy Examples of Dominant R wave in V1 Normal paediatric ECG (2 yr old) ...

↪ ECG Basics Homepage Who is SAM? As a routine part of ECG analysis, we need to determine the ECG AXIS. It isn’t really enough to just whimper… “Is it normal?” So, to help understand axis a tiny bit…I need to introduce you to SAM – the Super Axis Man Building SAM – the Super Axis Man (1) Draw a circle and put SAMs head on the top. Note: SAM is smiling today because he is learning something… ...