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enseignants",{"title":54,"url":55},{"title":57,"url":58},{"title":186,"group":48,"menu":187},"Produit",[188,189,190,191,192,193,194],{"title":38,"url":7},{"title":65,"url":66},{"title":68,"url":69},{"title":71,"url":72},{"title":74,"url":75},{"title":15,"url":77},{"title":195,"url":10},"Tarification",{"title":197,"group":48,"menu":198},"Mentions légales",[199,200,201,202,203],{"title":197,"url":84},{"title":86,"url":87},{"title":89,"url":90},{"title":92,"url":93},{"title":95,"url":96},{"title":205,"group":48,"menu":206},"Service client",[207,208,209],{"title":101,"url":102},{"title":104,"url":105},{"title":107,"url":108},{"content":211,"related":268,"meta":334,"internal":344},{"title":212,"leadIn":213,"category":214,"elements":217,"becomeAnExpert":250,"author":252,"readDuration":266,"readDurationFormatted":267},"Interpreting ECG duration","Find out how to determine whether the duration of a certain part of the ECG is inaccurate.",{"id":215,"name":216},1,"Course previews",[218,228,233,238,245],{"type":219,"data":220},"video",{"readDurationInSeconds":221,"video":222},411,{"platform":223,"name":212,"url":224,"size":225},"YouTube","https:\u002F\u002Fwww.youtube.com\u002Fwatch?v=4NPbBvCsnuc",{"width":226,"height":227},200,150,{"type":229,"data":230},"free_text",{"readDurationInSeconds":231,"text":232},11.733333333333333,"\u003Cp>Sometimes the duration of certain parts of an ECG can be off the mark. In this video from our ECG Mastery: Yellow Belt course, you'll find out how to dig deeper into your patient's ECG and interpret the duration of the P wave, PR interval, and QRS complex in order to determine whether there is a discrepancy.\u003C\u002Fp>",{"type":229,"data":234},{"readDurationInSeconds":235,"title":236,"text":237},19.2,"Join our ECG Mastery: Yellow Belt course today!","\u003Cp>Want to master ECG interpretation? Start with our \u003Ca href=\"https:\u002F\u002Fwww.medmastery.com\u002Fcourse\u002Fecg-mastery-yellow-belt\">\u003Cstrong>ECG Mastery: Yellow Belt\u003C\u002Fstrong>\u003C\u002Fa>\u003Cstrong> \u003C\u002Fstrong>course! This easy-to-understand and no-nonsense course teaches all of the ECG basics you'll need to follow a case discussion and learn about ECG on the job. Plus, you'll learn how to diagnose important structural heart problems like myocardial infarction, hypertrophy, and volume overload. This course is highly recommended for anyone who wants to improve or refresh their ECG analysis skills.\u003C\u002Fp>",{"type":239,"data":240},"cta",{"readDurationInSeconds":241,"text":242,"buttonText":243,"buttonUrl":244},3.466666666666667,"Become a great clinician with our video courses and workshops","Start learning for free","https:\u002F\u002Fwww.medmastery.com\u002Fuser\u002Fregister",{"type":229,"data":246},{"readDurationInSeconds":247,"title":248,"text":249},185.6,"Video Transcript","\u003Cp dir=\"ltr\">\u003Cstrong>[00:00:00] \u003C\u002Fstrong>As we've learned in the previous sessions, several diagnoses can already be made, just by performing simple measurements on the time or x-axis. In order to understand if the duration of certain parts of the ECG are off, we need to look at the normal values first. In this session, we're going to talk about the duration of the P wave, the duration of the\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:00:30] \u003C\u002Fstrong>PR interval, and the duration of the QRS complex. Let's first look at the P wave duration. Do you remember from the last chapter, P wave duration starts when the P wave leaves the isoelectric line and it ends when it reaches the isoelectric line again. The normal duration of the P wave is below 0.12 seconds. If the atria are enlarged, especially when the left atrium is enlarged, depolarization takes a little longer\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:01:00] \u003C\u002Fstrong>and the P wave will, therefore, also be wider than normal. In these instances, we also have a second peak of the P wave, usually seen in lead 2, and this entity is called P mitrale. Please note that an enlargement of the right atrium will not cause a prolongation of the P wave. The take-home message here is that when the P wave is 0.12 seconds long or above, that usually means that the\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:01:30] \u003C\u002Fstrong>left atrium is enlarged. We also call this type of P, P mitrale. Next, let's talk about the duration of the PR interval. The PR interval starts at the beginning of the P wave and ends at the beginning of the QRS complex. It represents the time the atrial depolarization takes to travel through the AV node, in order to reach the ventricles. So, the PR interval represents AV conduction time. The normal value for\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:02:00]\u003C\u002Fstrong> the PR interval is 0.12 to 0.2 seconds. Let's look at some situations when the PR interval is considered abnormal. First, let's look at the situation when the PR interval is longer than 0.2 seconds. As in this example. As you can see here, the PR interval is 1, 2, 3, 4, 5, 6, 7, almost 8 mm long. We know that 1 mm stands for\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:02:30]\u003C\u002Fstrong> 0.04 seconds and 0.04 times 8 is 0.32 seconds, so that's way over 0.2 seconds. And in this special case, there is a constant prolongation of the PR interval. We see prolongation here, we see a prolongation here, and also here, and this is an example of a first degree AV block. You're going to learn much more about this entity in later\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:03:00]\u003C\u002Fstrong> chapters. Now, let's turn to situations when the PR interval is shorter than 0.12 seconds. When the PR interval is shorter than 0.12 seconds, that means that ventricular depolarization starts earlier than normal. Since the AV node has a certain maximum conduction velocity, that usually indicates that there is an additional, faster pathway, through which the impulse can travel from the atria to the ventricles. So, this time is\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:03:30] \u003C\u002Fstrong>shortened. These special circumstances are called preexcitation syndromes. There are two important forms of preexcitation syndromes that you should remember. First, there's the so-called Lown-Ganong-Levine Syndrome. In this syndrome, the QRS immediately follows the P wave and the PR interval is below 0.12 seconds. Let's look at an example.\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:04:00]\u003C\u002Fstrong> As you can see here, the QRS, this entity here immediately follows the P wave at a distance of somewhat between 0.08 and 0.1 seconds, so that's definitely too short. The impulse is traveling through an accessory pathway from the atria to the ventricles. This accessory pathway conducts the impulse faster than the AV node and that's why the PR interval is shortened. The second entity that\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:04:30]\u003C\u002Fstrong> causes a shortening of the PR interval is the so-called Wolff-Parkinson-White syndrome or WPW syndrome. Here, the QRS or delta wave, immediately follow the P wave and the PR interval, is below 0.12 seconds. Let's look at an example again. Here, we have a strange looking entity. We have the P wave and then immediately the QRS complex starts but we have this strange thing here, and that's what's called a\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:05:00] \u003C\u002Fstrong>delta wave. Delta because it resembles the Greek letter Delta. The regular components of the QRS complex follow after the delta wave. And finally, let's talk about the duration of the QRS complex. Here you can see a normal QRS complex. It starts here and ends here. So, this is the QRS duration. As you can see here, the duration of the QRS complex is about 1, 2,\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:05:30]\u003C\u002Fstrong> 2.5 mm long. So, 2.5 times 0.04 is 0.1 seconds. And the normal duration of the QRS complex is 0.1 seconds or below so we have a normal QRS duration in this case. Now, let's look at another example. You can already see that something must be wrong here. Let's look at the QRS duration. The QRS stars here and ends here. The duration is over 0.12 seconds. Let's count, 1,\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:06:00] \u003C\u002Fstrong>2, 3, 3.5—3.5 times 0.04 that's 0.14 seconds and that's longer than 0.12 seconds. So, what we have here is a complete bundle branch block. As you probably know, the depolarization is taken down from the AV node to the ventricles through the bundle branches. There's a right bundle branch and the left bundle branch. And when one of these branches is blocked, depolarization of the ventricle\u003C\u002Fp>\u003Cp dir=\"ltr\">\u003Cstrong>[00:06:30]\u003C\u002Fstrong> takes longer than normal, and that's why the QRS complex is broadened in this instance. The following examples may seem familiar to you. But at this time, not only the measurement but also the correct diagnosis is required. Note that there may be more than only one abnormality in a single example.\u003C\u002Fp>",{"courses":251,"showAwardsBelow":48},[],{"id":253,"name":254,"image":255,"profession":256,"relativeUrl":259,"specializations":260},1563,"Franz Wiesbauer, MD MPH","https:\u002F\u002Fmedmastery-backend-prod-kjbeds.s3.eu-west-1.amazonaws.com\u002Fmedia\u002Fimages\u002F9c43cef0-41ee-4005-9e4a-d8711c816401",{"name":257,"description":258},"Internist","Franz is the founder and CEO of Medmastery. He is an internist with a specialization in cardiology and a master’s in public health from Johns Hopkins University.","\u002Fteachers\u002Ffranz-wiesbauer-md-mph",[261,262,263,264,265],"Nephrology","Professional development","Cardiology","Ultrasound","Emergency medicine and critical care",224,"4m",[269,291,310],{"id":270,"title":271,"text":272,"image":273,"author":281,"path":284,"readDuration":285,"readDurationFormatted":286,"internal":287},1350,"How to Recognize INOCA (ANOCA) on an Exercise Stress Test ","Angina, abnormal stress test, clean coronaries—that's INOCA (or ANOCA), and it carries real risk. Learn to recognize and report it with exercise stress ECG.",{"alt":274,"title":275,"size":276,"location":278},"Illustration of the heart's coronary vasculature showing large coronary arteries and the extensive network of smaller vessels affected in INOCA (ischemia with nonobstructive coronary arteries).","",{"width":277,"height":277},1200,{"bucket":279,"key":280},"public-drupal-medmastery-assets-production","\u002F2026-05\u002FC17(1)_magazine image_0.png",{"id":253,"title":254,"relativeURL":259,"image":255,"professionLong":258,"profession":282,"weight":283},{"name":257},4,"\u002Fmagazine\u002Fexercise-stress-ecg-inoca",141,"3m",{"created":288,"updated":289,"published":290},1778115738,1778118425,1778118255,{"id":292,"title":293,"text":294,"image":295,"author":301,"path":303,"readDuration":304,"readDurationFormatted":305,"internal":306},1348,"Hyperlipidemia screening: who, when, & what to measure","Testing for hyperlipidemia can help you mitigate your patients' cardiovascular risk. Learn who to screen and when, which measures to request, and how to stratify risk.",{"alt":296,"title":275,"size":297,"location":299},"Lipid panel blood sample tubes used to test for hyperlipidemia in a laboratory setting",{"width":298,"height":298},600,{"bucket":279,"key":300},"\u002F2026-04\u002FC121_magazine image.png",{"id":253,"title":254,"relativeURL":259,"image":255,"professionLong":258,"profession":302,"weight":283},{"name":257},"\u002Fmagazine\u002Ftest-for-hyperlipidemia",246,"5m",{"created":307,"updated":308,"published":309},1777403036,1777572381,1777412421,{"id":311,"title":312,"text":313,"image":314,"author":319,"path":328,"readDuration":329,"readDurationFormatted":267,"internal":330},1347,"Outpatient care for COPD exacerbations","Most acute COPD exacerbations can be managed with outpatient treatment. Learn how to treat mild and moderate COPD exacerbations—and when to escalate care.",{"alt":315,"title":275,"size":316,"location":317},"Older patient using a handheld nebulizer to inhale bronchodilator medication during an acute COPD exacerbation",{"width":298,"height":298},{"bucket":279,"key":318},"\u002F2026-04\u002FC133(4)_ exacerbations_magazine image.png",{"id":320,"title":321,"relativeURL":322,"image":323,"professionLong":324,"profession":325,"weight":327},5365,"Siamak Moayedi, MD","\u002Fteachers\u002Fsiamak-moayedi-md","https:\u002F\u002Fmedmastery-backend-prod-kjbeds.s3.eu-west-1.amazonaws.com\u002Fmedia\u002Fimages\u002F9c43cf02-1064-4074-817b-0eb5de6ded74","Professor and Director of Medical Student Education, University of Maryland and Course Director, Essential and Critical Procedures, Emergency Medicine.",{"name":326},"Emergency medicine physician",1533,"\u002Fmagazine\u002Facute-copd-exacerbation-treatment",191,{"created":331,"updated":332,"published":333},1776705362,1776710540,1776710541,{"seo":335,"og":337},{"title":336,"description":213},"Interpreting ECG duration | Medmastery",{"title":336,"description":213,"image":338},{"alt":275,"title":275,"size":339,"location":342},{"width":340,"height":341},1750,1296,{"bucket":279,"key":343},"\u002Fmigrated-images\u002FScreen Shot 2018-04-13 at 3.21.10 pm.png",{"id":345,"created":346,"updated":347,"published":346},208,1523629650,1693921781]