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U wave Overview The U wave is a small (0.5 mm) deflection immediately following the T wave U wave is usually in the same direction as the T wave. U wave is best seen in leads V2 and V3. Source of the U wave The source of the U wave is unknown. Three common theories regarding its origin are: Delayed repolarisation of Purkinje fibres Prolonged repolarisation of mid-myocardial “M-cells” After-potentials resulting from mechanical forces in the ventricular wall Features of Normal U waves The U wave normally goes in the same direction as the T wave U -wave size is inversely proportional to heart rate: the U wave grows bigger as the heart rate slows down U waves generally become visible when the heart rate falls below 65 bpm The voltage of the U wave is normally < 25% of the T-wave voltage: disproportionally large U waves are abnormal Maximum normal amplitude of the U wave is 1-2 mm ...

Regular broad complex tachycardias can be ventricular (VT) or supraventricular (SVT with aberrancy) in origin, and differentiation between the two will significantly influence management of your patients. Unfortunately, the electrocardiographic differentiation of VT from SVT with aberrancy is not always possible. Differential diagnosis of regular broad complex tachycardia Ventricular tachycardia (VT) Supraventricular tachycardia (SVT) with aberrant conduction due to bundle branch block SVT with any metabolic disturbance that slows supraventricular action potential propagation — hyperkalaemia, sodium channel blockade, severe acidosis Antidromic AVRT — re-entrant tachyarrhythmia seen in Wolff-Parkinson-White syndrome Accelerated idioventricular rhythm (AIVR) ECG features increasing the likelihood of VT Electrocardiographic features that increase the likelihood of VT include: ...

The rhythm is best analyzed by looking at a rhythm strip. On a 12 lead ECG this is usually a 10 second recording from Lead II. Confirm or corroborate any findings in this lead by checking the other leads. A longer rhythm strip, recorded perhaps recorded at a slower speed, may be helpful. 7 step approach to ECG rhythm analysis 1. Rate Tachycardia or bradycardia? Normal rate is 60-100/min. 2. Pattern of QRS complexes Regular or irregular? If irregular is it regularly irregular or irregularly irregular? 3. QRS morphology Narrow complex: sinus, atrial or junctional origin. Wide complex: ventricular origin, or supraventricular with aberrant conduction. 4. P waves Absent: sinus arrest, atrial fibrillation Present: morphology and PR interval may suggest sinus, atrial, junctional or even retrograde from the ventricles. 5. Relationship between P waves and QRS complexes AV association (may be difficult to distinguish from isorhythmic dissociation) AV dissociation *complete:*atrial and ventricular activity is always independent. incomplete: intermittent capture. 6. Onset and termination Abrupt: suggests re-entrant process. Gradual: suggests increased automaticity. 7. Response to vagal manoeuvres Sinus tachycardia, ectopic atrial tachydysrhythmia: gradual slowing during the vagal manoeuvre, but resumes on cessation. AVNRT or AVRT: abrupt termination or no response. Atrial fibrillation and atrial flutter: gradual slowing during the manoeuvre. VT: no response. Differential Diagnosis Follow links below for examples of individual rhythms. ...

Misplacement of V1 and V2: Don’t let this mistake mess up your ECG interpretation! The proper location of V1 and V2 have not changed in many decades. They are located in the 4th intercostal space, just right and left, respectively, of the sternum. It is fairly easy to determine this spot using the angle of Louis as a landmark. However, V1 and V2 were being misplaced pretty much right after being invented. This error in lead positioning usually produces trivial changes in the QRS pattern in those leads, and thus no real change in ECG interpretation. But certain erroneous ECG patterns can be generated, and it is important to recognize lead misplacement as a potential cause. ...

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. ...

Description Dressler beat: Specifically a ‘ventricular fusion beat‘ in the presence of paroxysmal ventricular tachycardia. Typically observed in ECG tracings of wide complex tachycardia such as VT with AV dissociation. Supraventricular and a ventricular impulses coincide to produce a hybrid complex which is different to the VT complex and the native complex (capture beat) The term ‘fusion beat‘ was originally used to define any hybrid QRS complex of atria or ventricular origin. Fusion beats (and capture beats) are not ‘diagnostic‘ or ‘pathognomic‘ of VT and can occur in any arrhythmia (including SVT with aberrancy for example) ...

Learning cardiac axis interpretation can be tedious. I have created an open source webapp hosted on CardiacAxis.com. Here you will be able to analyse in English and German the ECG variations with axis deviation. The Axis trainer online is interactive and the arrow can be moved to demonstrate each of the specific QRS complex changes. Bookmark to your phone homepage and try it out for yourself. Below is a quick demonstration through 360 degrees… ...

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 ...

Part five of a 5 part lecture series on ECG/EKG Interpretation with Dr Theo Sklavos and cardiologist A/Prof William Wang. This lecture series is aimed primarily at medical/nursing/paramedicine students and junior trainees, but will hopefully be useful as a refresher course for those with previous experience. Other cardiac conditions Hyperkalemia, hypokalemia Pericarditis, pericardial effusion Pulmonary embolism Long QT syndrome ECG Interpretation lectures The Basics Myocardial ischemia and infarction Conduction disease Tachyarrhythmia Other cardiac conditions References and further reading Hyperkalaemia – Hypokalaemia Pericarditis – Pericardial effusion / tamponade Pulmonary embolism Romano-Ward syndrome (LQTS) Junctional escape rhythm Ventricular escape rhythm ECG LIBRARY ...

Part one of a 5 part lecture series on the basics of ECG/EKG Interpretation with Dr Theo Sklavos and cardiologist A/Prof William Wang. This lecture series is aimed primarily at medical/nursing/paramedicine students and junior trainees, but will hopefully be useful as a refresher course for those with previous experience. The Basics In this first video we walk you through every aspect of the basics of the ECG including: Describe the parts of the ECG Rate, rhythm, axis P wave, PR interval, QRS complex, ST-segment, T wave, QT interval Identify the features of a normal ECG ECG Interpretation lectures The Basics Myocardial ischemia and infarction Conduction disease Tachyarrhythmia Other cardiac conditions References and further reading ECG Rate – Rhythm – Axis Calculation Lead positioning – V1 / V2 misplacement P wave – PR interval – PR Segment Q wave – QRS complex – QT Interval R wave – ST Segment – T wave – U wave ECG Resources/References ECG LIBRARY ...

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. ...