EKG Refresher: Atrial and Junctional Rhythms | RN.com Nursing News Contributed by the CardioNetwork (CC BY-SA 3.0 https://creativecommons.org/licenses/by-sa/3.0/deed.en), EKG showing accelerated idioventricular rhythm in a patient who was treated with primary PCI. (n.d.). When this area controls the pace of the heart, it is known as junctional rhythm. Ventricular escape beat [Online image]. Junctional rhythm can be without p wave or with inverted p wave, while p wave is absent in idioventricular rhythm. Isorhythmic dissociation, fusion or capture beats can occur when sinus and ectopic foci discharge at the same rate.[2]. Junctional and ventricular rhythms are two such rhythms. Junctional Escape Rhythm: Rate: Usually 40-60 bpm Rhythm: Regular P waves: Usually inverted P-waves before the QRS or after the QRS. StatPearls Publishing, Treasure Island (FL). Last reviewed by a Cleveland Clinic medical professional on 05/20/2022. But it does not occur in the normal fashion. 6. New comments cannot be posted and votes cannot be cast. Hohnloser SH, Zabel M, Olschewski M, Kasper W, Just H. Arrhythmias during the acute phase of reperfusion therapy for acute myocardial infarction: effects of beta-adrenergic blockade. Atrioventricular Dissociation: Background, Pathophysiology, Etiology I understand interpreting EKGs/ECGs are not the easiest and it takes a lot of practice. In such scenarios, cells in the bundle of His (which possess automaticity) will not be reached by the atrial impulse and hence start discharging action potentials and an escape rhythm. Review the clinical context leading to idioventricular rhythm and differentiate from ventricular tachycardia and other similar etiologies. Dont stop taking them unless your provider tells you to do so. Figure 2: Ventricular Escape Rhythm ECG Strip [1] A ventricular escape beat occurs after a pause caused by a supraventricular pacemaker failing to fire and appears late after the next expected sinus beat. Junctional and ventricular escape rhythms arise when the rate of supraventricular impulses arriving at the AV node or ventricle is less than the intrinsic rate of the ectopic pacemaker. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. However, an underlying condition causing it could present a problem if not treated. The default pacemaker area is the SA node. Symptomatic hypervagotonia in a highly conditioned athlete. Policy. } Junctional Escape Rhythm-A junctional escape rhythm, also called a junctional rhythm, is a dysrhythmia that occurs when the SA node ceases functioning, and the AV junction takes over as the pacemaker of the heart at a rate of 40-60 BPM.-Rhythm is typically regular, with littler variation between R-R intervals. Saeed, M. (n.d.). Junctional rhythm may arise in the following situations: Figure 1 (below) displays two ECGs with junctional escape rhythm. padding-bottom: 0px; Ventricular fibrillation is an irregular rhythm caused by rapid, uncoordinated fluttering contractions of the heart's lower chambers. In: StatPearls [Internet]. Near-death experiences exposed: Surge of brain activity, Light at the end of the tunnel for scientists studying near-death experienc, POSSIBLE HINTS OF CONSCIOUSNESS AFTER DEATH FOUND IN RATS, In Dying Brains, Signs of Heightened Consciousness, Hyperactive Brain May Create "Near Death" Visions, A Last-Second Surge of Brain Activity Could Explain Near-Death Experiences, The brains swan song: hyperactivity near death, Near-death experiences: The brains last hurrah, Could a final surge in brain activity after death explain near-death experi, Jimo Borjigin's study has been blown out of proportion, Near Death Experiences and Deus Ex: Tell It To Me in Videogames. What isIdioventricular Rhythm The effect of thrombolytic therapy on QT dispersion in acute myocardial infarction and its role in the prediction of reperfusion arrhythmias. [11], However, in reperfusion post-myocardial ischemia and cardiomyopathy, the use of beta-blockers has not shown to decrease the risk of occurrence of idioventricular rhythm.[12]. This encounter shows a complete dissociation between the atria and ventricles, indicating a third degree heart block. This topic reviews the evaluation and management of idioventricular rhythm. Atrioventricular Block - StatPearls - NCBI Bookshelf The heart is a complex structure containing many different parts that work together to produce a heartbeat. in Molecular and Applied Microbiology, and PhD in Applied Microbiology. In junctional tachycardia, it is higher than 100 beats per minute, while in junctional bradycardia, it is lower than 40 beats per minute. It can occur for a variety of reasons, and junctional rhythm itself is not typically a problem. When the sinoatrial node is blocked or depressed, latent pacemakers become active to conduct rhythm secondary to enhanced activity and generate escape beats that can be atrial itself, junctional or ventricular. Ventricular Premature Complexes Differential Diagnoses - Medscape For all courses in basic or introductory cardiography Focused coverage and realistic hands-on practice help students master basic arrhythmias Basic Arrhythmias , 8th Edition , gives beginning students a strong basic understanding of the common, uncomplicated rhythms that are a foundation for further learning and success in electrocardiography. With regular medical care, many people live full, healthy lives with a junctional rhythm. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. There is a complete dissociation between the atria and ventricles. If you have a junctional rhythm, you may not have any signs or symptoms. 1 The patient's presenting ECG shows regular flutter waves and regular QRS complexes but with varying intervals from flutter wave to QRS complex. National Heart, Lung, and Blood Institute. Doses and alternatives are similar to management of bradycardia in general. Junctional and ventricular rhythms. PR interval: Normal or short if the P-wave is present. These cookies do not store any personal information. Idioventricular Rhythm Article - StatPearls Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. I know escape rhythm is when one of the latent pacemakers depolarizes the ventricles instead of the SA node. Cleveland Clinic is a non-profit academic medical center. If there are cells (with automaticity) distal to the block, an escape rhythm may arise in those cells. (Interview), Near-death experiences are 'electrical surge in dying brain', The Stuff of Those Visions in Clinical Death, Why Near-Death Experiences Might Be Scientifically Legit, Near-death experiences may be triggered by surging brain activity, Surge of brain activity may explain near-death experience, study says, Shining light on 'near-death' experiences, Near death experiences could be surge in electrical activity. Slow ventricular tachycardia. This is asymptomatic and benign. The types and associated heart rates include: Symptoms can vary and may not be present in people with a junctional rhythm. Its not their normal job, but they can fill in for your sleeping conductor and keep your heart going. Functionally, SA node is responsible for the rhythmic electrical activity of the heart. What are the three types of junctional rhythms? - Sage-Answers Dying brains: will our last hurrah be an explosion of conscious experience? The following must be noted: In both cases listed above the impulse will originate in the junction between the atria and the ventricles, which is why ectopic beats and ectopic rhythms originating there are referred to as junctional beats and junctional rhythms. Both originate due to secondary pacemakers. The atria and ventricles conduct independent of each other. Required fields are marked *. If you have a junctional rhythm, a small wave called a P wave is either inverted (upside down) or missing on your EKG. During complete heart block (third-degree AV-block) the block may be located anywhere between the atrioventricular node and the bifurcation of the bundle of His. The heart has several built-in pacemakers that help control its rhythm. These include: Diagnosis will likely start with a review of the persons personal and family medical history. With this issue, its common to get junctional rhythm. How Viagra became a new 'tool' for young men, Ankylosing Spondylitis Pain: Fact or Fiction, https://borjigin.lab.medicine.umich.edu/research/ecm/ecm-arrhythmia-library/junctional-arrhythmias/accelerated-junctional-rhythm, https://onlinelibrary.wiley.com/doi/full/10.1002/joa3.12410, https://www.ncbi.nlm.nih.gov/books/NBK554520/, https://www.ncbi.nlm.nih.gov/books/NBK507715/, https://www.ncbi.nlm.nih.gov/books/NBK557664/, https://www.ncbi.nlm.nih.gov/books/NBK544253/, https://www.kaweahhealth.org/documents/float-pool/Arrhythmia-Study-Guide-3-Junctional-and-Ventricular.pdf, https://borjigin.lab.medicine.umich.edu/research/ecm/ecm-arrhythmia-library/junctional-arrhythmias/junctional-escape-rhythm, https://my.methodistcollege.edu/ICS/icsfs/mm/junctional_rhythm-resource.pdf?target=5a205551-09a5-4fef-a7ef-e9d1418db53a, https://www.ncbi.nlm.nih.gov/books/NBK459238/, https://bmcneurol.biomedcentral.com/articles/10.1186/s12883-016-0645-9, https://www.ncbi.nlm.nih.gov/books/NBK531498/, https://www.texasheart.org/heart-health/heart-information-center/frequently-asked-patient-questions/can-you-explain-if-when-junctional-rhythm-is-a-serious-issue/, https://www.ncbi.nlm.nih.gov/books/NBK546663/. But in more severe cases, you may have symptoms like shortness of breath or fatigue. 5. Third Degree Heart Block with Junctional Escape Rhythm During ventricular tachycardia, ECG generally shows a rate greater than 120 bpm. Retrieved July 27, 2016, from, Ventricular escape beat. These cells are capable of spontaneous depolarization (i.e they displayautomaticity) and can therefore act as latent pacemakers (which become active when atrial impulses do not reach the atrioventricular node). To prevent a junctional rhythm from getting worse, see your provider regularly. 4. clear: left; Also note, the QRS complexes are narrow as the AV node is above the ventricles. Some possible causes include the following conditions and health factors: Certain medications and therapies may also cause junctional rhythm. This category only includes cookies that ensures basic functionalities and security features of the website. It can also present in athletes.[7]. It regularly causes a heart rate of less than 50, though other types can cause increased heart rate, as with different types of junctional rhythm. Idioventricular rhythm is a slow regular ventricular rhythm, typically with a rate of less than 50, absence of P waves, and a prolonged QRS interval. Your hearts backup pacemakers keep your heart beating, but they might make your heartbeat slower or faster than normal. The LBBB morphology (dominant S wave in V1) suggests a ventricular escape rhythm arising from the. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. When both the SA node and AV node fail to conduct rhythms, ventricles act as their own pacemaker and conduct idioventricular rhythm. There are cells with pure automaticity around the atrioventricular node. Pages 7 Course Hero uses AI to attempt to automatically extract content from documents to surface to you and others so you can study better, e.g., in search results, to enrich docs, and more. PR interval: Normal or short if the P-wave is present. AV node acts as the pacemaker and creates junctional rhythm. Riera AR, Barros RB, de Sousa FD, Baranchuk A. Monophasic R-wave with smooth upstroke and notching on the downstroke (i.e., the so-called taller left peak or "rabbit-ear".). It is very rare among adults and elderly, but isrelatively commonin children. If you have a junctional rhythm, you may not have any symptoms. A healthcare professional typically classifies them based on the number of beats per minute. PEA encompasses a number of organized cardiac rhythms, including supraventricular rhythms (sinus versus nonsinus) and ventricular rhythms (accelerated idioventricular or escape). Undefined cookies are those that are being analyzed and have not been classified into a category as yet. Well-trained athletes may have very high Vagaltone which lowers the automaticity in the sinoatrial node to the point where cells in the AV-junction establishes an escape rhythm. With treatment, the outlook is good. Management is clinical monitoring. Coming to a Cleveland Clinic location?Hillcrest Cancer Center check-in changesCole Eye entrance closingVisitation, mask requirements and COVID-19 information, Notice of Intelligent Business Solutions data eventLearn more. So, this is the key difference between junctional and idioventricular rhythm. Ventricular escape rhythm's low rate can lead to a drop in blood pressure and syncope. As discussed in Chapter 1 the atrioventricular node does not exhibit automaticity, meaning that it does not dischargespontaneous action potentials, at least not under normal circumstances. Junctional rhythm can cause your heartbeat to be slower than normal (bradycardia), or faster than normal (tachycardia). Sometimes it happens without an obvious cause. A junctional rhythm doesnt have to stop you from doing things you love. Cardiovascular health: Insomnia linked to greater risk of heart attack. Junctional rhythm c. Complete (third-degree) AV block with ventricular escape pacemakerd. What is the Difference Between Junctional and Idioventricular Rhythm Many medical conditions (See Causes and Symptoms section) can cause junctional escape rhythm. Idioventricular Rhythm. StatPearls [Internet]., U.S. National Library of Medicine, 7 Apr. It is often found in children or adults who have: During a normal heartbeat, your SA node sends a signal to the AV node, which travels to your bundle of His. The rate usually is less than 45 beats per minute, which helps to differentiate it from other arrhythmias. The mechanism involves a decrease in the sympatheticbut an increase in vagal tone. Retrograde P-wave before or after the QRS, or no visible P-wave. Cleveland Clinic is a non-profit academic medical center. The signs and symptoms for the idioventricular or accelerated idioventricular rhythm are variable and are dependent on the underlying etiology or causative mechanism leading to the rhythm. (adsbygoogle = window.adsbygoogle || []).push({}); Copyright 2010-2018 Difference Between. Necessary cookies are absolutely essential for the website to function properly. [2] Ventricular escape beats become ventricular escape rhythm when three or more escape beats occur in a row at a rate of 20-40 bpm. If your healthcare provider finds a junctional escape rhythm and you dont have symptoms, you probably wont need treatment. Access free multiple choice questions on this topic. #mc-embedded-subscribe-form .mc_fieldset { People who are healthy and dont have symptoms dont need treatment. A persons outlook is generally positive when a healthcare professional identifies and treats the condition causing the junctional rhythm. 2. Sinus pause / arrest (there is a single P wave visible on the 6-second rhythm strip). . It usually self-limits and resolves when the sinus frequency exceeds that of ventricular foci and arrhythmia requires no treatment. Gildea TH, Levis JT. Managing any symptoms and getting treatment can help you feel your best. If you have not done so already, I suggest you read my articles on the Hearts Electrical System, Sinus Rhythms and Sinus arrest: ECG Interpretation, and Atrial Rhythms: ECG Interpretation. Hafeez, Yamama. Subsequently, the ventricle may assume the role of a dominant pacemaker. In mild cases of junctional rhythm, you may not feel any different. This is called normal sinus rhythm. Premature ventricular contractions (PVCs) are present. One of the causes of idioventricular rhythm is heart defect at birth. So let us continue to Junctional Rhythms which occurs when the primary pacemaker of the heart is the AV node. Common complications of junctional rhythm can include: The following section provides answers to commonly asked questions about junctional rhythm. What is the latest research on the form of cancer Jimmy Carter has? Types include bradyarrhythmia or supraventricular arrhythmia. Medical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. Your symptoms are getting worse or they prevent you from doing daily activities. An interprofessional team that provides a holistic and integrated approach is essential when noticing an idioventricular rhythm. The primary objective is to treat the underlying cause and/or eliminate provocativemedications. Best food forward: Are algae the future of sustainable nutrition? This site uses cookies from Google to deliver its services and to analyze traffic. Join our newsletter and get our free ECG Pocket Guide! Your heart has three pacemakers that send electrical impulses through your heart. Castellanos A, Azan L, Bierfield J, Myerburg RJ. Junctional bradycardia: Less than 40 BPM. [1] Figure 1: Ventricular Escape Beat ECG Strip[1], Figure 2: Ventricular Escape Rhythm ECG Strip[1], A ventricular escape beat occurs after a pause caused by a supraventricular pacemaker failing to fire and appears late after the next expected sinus beat. This refresher series will explore the basics of rhythm strip analysis; sinus, atrial, junctional, and ventricular rhythms; blocks, pacemakers, and 12-lead EKGs. Ornek E, Duran M, Ornek D, Demirelik BM, Murat S, Kurtul A, iekiolu H, etin M, Kahveci K, Doger C, etin Z. Accelerated idioventricular rhythm: history and chronology of the main discoveries. Her research interests include Bio-fertilizers, Plant-Microbe Interactions, Molecular Microbiology, Soil Fungi, and Fungal Ecology. ), which permits others to distribute the work, provided that the article is not altered or used commercially. Monophasic R-wave with smooth upstroke and (more), Rhythm idioventricular. font: 14px Helvetica, Arial, sans-serif; Sinus rhythm is the rhythm of our heartbeat. This noninvasive test measures and records your hearts rhythm. Tell your provider if you have new symptoms or if your symptoms get worse. Indeed, the surface ECG frequency cannotdifferentiate escape rhythms originating near the atrioventricular node from those originating in the bundle of His. The more current data correlates the presence of AIVR with reperfusion with myocardial infarction during the acute phase with the suggestion of vessel opening however does not suggest it to be a marker for reperfusion during the acute phase of myocardial infarction.[6]. The trigger activity is the main arrhythmogenic mechanism involved in patients with digitalis toxicity.[6]. But if you need treatment, medications or a pacemaker can often relieve your symptoms. A junctional escape beat is a delayed heartbeat that occurs when "the rate of an AV junctional pacemaker exceeds that of the sinus node." [2] Junctional Rhythms are classified according to their rate: junctional escape rhythm has a rate of 40-60 bpm, accelerated junctional rhythm has a rate of 60-100 bpm, and junctional tachycardia has a rate greater than 100 bpm. Ventricular escape beat - Wikipedia The absence of peripheral pulses should not be equated with PEA, as it may be due to severe peripheral vascular disease. 1. They often occur during sinus arrest or after premature atrial complexes. Conditions leading to the emergence of a junctional or ventricular escape rhythm include: Sinus arrest with a ventricular escape rhythm, Complete heart block with a ventricular escape rhythm, Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. In junctional the PR will be .12 or less, inverted, buried in the QRS or retrograde (post-QRS), but the QRS should still be narrow as the beats are rising from the junction. If the normal sinus impulse disappears (e.g. When occurring in adults and elderly it is referred to asnonparoxysmal junctional tachycardia (NPJT) whereas it is referred to asjunctional ectopic tachycardia (JET) in children. a. Atrial flutter b. Atrial fibrillation c. Wandering atrial pacemaker d. Premature atrial complexes. The command to beat normally starts in your sinoatrial node (SA node) and works its way down through your heart. He has a passion for ECG interpretation and medical education | ECG Library |, MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. But there are different ways your heartbeat may change when this happens. Twitter: @rob_buttner. Dr.Samanthi Udayangani holds a B.Sc. You should contact your provider if you think your pacemaker isnt working or you have an infection. Response to ECG Challenge. [2], Idioventricular rhythm is mostly benign, and treatment has limited symptomatic or prognostic value. Your heart responds by using one of your backup pacemakers instead. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. You can learn more about how we ensure our content is accurate and current by reading our. My next article regarding ECG interpretation will breakdown ventricular rhythms, ventricular ectopic beats, and asystole. Broad complex escape rhythm at around 27 bpm. Can anyone tell me what the difference between the two is? If symptoms interfere with your daily life, your provider may recommend treatment to regulate your heartbeat. Junctional Bradycardia. Other people may need treatment for an underlying condition, such as Lyme disease or heart failure. In some cases, a doctor may need to switch a persons medications or discontinue certain medications that may be responsible. Nasir JM, Durning SJ, Johnson RL, Haigney MC. P-waves: Usually inverted P-waves before the QRS or after the QRS. The most common rhythm arising in the AV node is junctional rhythm, which may also be referred to as junctional escape rhythm. [6], Accelerated Idioventricular rhythm is also be rarely seen in patients without any evidence of cardiac disease. Last medically reviewed on December 5, 2022. If you have a junctional rhythm, your hearts natural pacemaker, known as your sinoatrial (SA) node, isnt working as it should. Idioventricular rhythm is very similar to ventricular tachycardia, except the rate is less than 60 bpm and is alternatively called a "slow ventricular tachycardia." Advertising on our site helps support our mission. Identify the characteristic features of an idioventricular rhythm. The QRS complex is generally normal, unless there is concomitant intraventricular conduction disturbance. Ventricular Escape Rhythm: A ventricular rhythm with a rate of 20-40 bpm. This essentially concludes the breakdown of Junctional Rhythms! The RBBB (dominant R wave in V1) + left posterior fascicular block (right axis deviation) morphology suggests a ventricular escape rhythm arising from the. Therefore, close coordination between teams is mandatory. Clinical electrocardiography and ECG interpretation, Cardiac electrophysiology: action potential, automaticity and vectors, The ECG leads: electrodes, limb leads, chest (precordial) leads, 12-Lead ECG (EKG), The Cabrera format of the 12-lead ECG & lead aVR instead of aVR, ECG interpretation: Characteristics of the normal ECG (P-wave, QRS complex, ST segment, T-wave), How to interpret the ECG / EKG: A systematic approach, Mechanisms of cardiac arrhythmias: from automaticity to re-entry (reentry), Aberrant ventricular conduction (aberrancy, aberration), Premature ventricular contractions (premature ventricular complex, premature ventricular beats), Premature atrial contraction(premature atrial beat / complex): ECG & clinical implications, Sinus rhythm: physiology, ECG criteria & clinical implications, Sinus arrhythmia (respiratory sinus arrhythmia), Sinus bradycardia: definitions, ECG, causes and management, Chronotropic incompetence (inability to increase heart rate), Sinoatrial arrest & sinoatrial pause (sinus pause / arrest), Sinoatrial block (SA block): ECG criteria, causes and clinical features, Sinus node dysfunction (SND) and sick sinus syndrome (SSS), Sinus tachycardia & Inappropriate sinus tachycardia, Atrial fibrillation: ECG, classification, causes, risk factors & management, Atrial flutter: classification, causes, ECG diagnosis & management, Ectopic atrial rhythm (EAT), atrial tachycardia (AT) & multifocal atrial tachycardia (MAT), Atrioventricular nodal reentry tachycardia (AVNRT): ECG features & management, Pre-excitation, Atrioventricular Reentrant (Reentry) Tachycardia (AVRT), Wolff-Parkinson-White (WPW) syndrome, Junctional rhythm (escape rhythm) and junctional tachycardia, Ventricular rhythm and accelerated ventricular rhythm (idioventricular rhythm), Ventricular tachycardia (VT): ECG criteria, causes, classification, treatment, Long QT (QTc) interval, long QT syndrome (LQTS) & torsades de pointes, Ventricular fibrillation, pulseless electrical activity and sudden cardiac arrest, Pacemaker mediated tachycardia (PMT): ECG and management, Diagnosis and management of narrow and wide complex tachycardia, Introduction to Coronary Artery Disease (Ischemic Heart Disease) & Use of ECG, Classification of Acute Coronary Syndromes (ACS) & Acute Myocardial Infarction (AMI), Clinical application of ECG in chest pain & acute myocardial infarction, Diagnostic Criteria for Acute Myocardial Infarction: Cardiac troponins, ECG & Symptoms, Myocardial Ischemia & infarction: Reactions, ECG Changes & Symptoms, The left ventricle in myocardial ischemia and infarction, Factors that modify the natural course in acute myocardial infarction (AMI), ECG in myocardial ischemia: ischemic changes in the ST segment & T-wave, ST segment depression in myocardial ischemia and differential diagnoses, ST segment elevation in acute myocardial ischemia and differential diagnoses, ST elevation myocardial infarction (STEMI) without ST elevations on 12-lead ECG, T-waves in ischemia: hyperacute, inverted (negative), Wellen's sign & de Winter's sign, ECG signs of myocardial infarction: pathological Q-waves & pathological R-waves, Other ECG changes in ischemia and infarction, Supraventricular and intraventricular conduction defects in myocardial ischemia and infarction, ECG localization of myocardial infarction / ischemia and coronary artery occlusion (culprit), The ECG in assessment of myocardial reperfusion, Approach to patients with chest pain: differential diagnoses, management & ECG, Stable Coronary Artery Disease (Angina Pectoris): Diagnosis, Evaluation, Management, NSTEMI (Non ST Elevation Myocardial Infarction) & Unstable Angina: Diagnosis, Criteria, ECG, Management, STEMI (ST Elevation Myocardial Infarction): diagnosis, criteria, ECG & management, First-degree AV block (AV block I, AV block 1), Second-degree AV block: Mobitz type 1 (Wenckebach) & Mobitz type 2 block, Third-degree AV block (3rd degree AV block, AV block 3, AV block III), Management and treatment of AV block (atrioventricular blocks), Intraventricular conduction delay: bundle branch blocks & fascicular blocks, Right bundle branch block (RBBB): ECG, criteria, definitions, causes & treatment, Left bundle branch block (LBBB): ECG criteria, causes, management, Left bundle branch block (LBBB) in acute myocardial infarction: the Sgarbossa criteria, Fascicular block (hemiblock): left anterior & left posterior fascicular block on ECG, Nonspecific intraventricular conduction delay (defect), Atrial and ventricular enlargement: hypertrophy and dilatation on ECG, ECG in left ventricular hypertrophy (LVH): criteria and implications, Right ventricular hypertrophy (RVH): ECG criteria & clinical characteristics, Biventricular hypertrophy ECG and clinical characteristics, Left atrial enlargement (P mitrale) & right atrial enlargement (P pulmonale) on ECG, Digoxin - ECG changes, arrhythmias, conduction defects & treatment, ECG changes caused by antiarrhythmic drugs, beta blockers & calcium channel blockers, ECG changes due to electrolyte imbalance (disorder), ECG J wave syndromes: hypothermia, early repolarization, hypercalcemia & Brugada syndrome, Brugada syndrome: ECG, clinical features and management, Early repolarization pattern on ECG (early repolarization syndrome), Takotsubo cardiomyopathy (broken heart syndrome, stress induced cardiomyopathy), Pericarditis, myocarditis & perimyocarditis: ECG, criteria & treatment, Eletrical alternans: the ECG in pericardial effusion & cardiac tamponade, Exercise stress test (treadmill test, exercise ECG): Introduction, Indications, Contraindications, and Preparations for Exercise Stress Testing (exercise ECG), Exercise stress test (exercise ECG): protocols, evaluation & termination, Exercise stress testing in special patient populations, Exercise physiology: from normal response to myocardial ischemia & chest pain, Evaluation of exercise stress test: ECG, symptoms, blood pressure, heart rate, performance.