. My EKG resulted in sinus rhythm but possible inferior or anterior infarct - age undetermined. Some paramedics ask patients to hold their breath while they capture a 12-lead ECG. Most of the time it will be obvious that you are dealing with artifact and troubleshooting the problem will be straight forward. However, symptoms may also be present when the body is at rest if bradycardia is severe. Sinus tachycardia occurs when your sinus node sends more rapid electrical pulses, leading to a heart rate thats higher than 100 bpm. Normal QRS complexes within the artifact. 2012;45(1):15-17. doi:10.1016/j.jelectrocard.2010.12.162. In electrocardiography, left axis deviation is a condition where the mean electrical axis of ventricular contraction of the heart lies in a frontal plane direction between 30 and 90. Sinus rhythm with a rate of 90. The amplifier in the ECG machine has to re-find the 'mean'. Thank you, {{form.email}}, for signing up. Sinus rhythm refers to the pace of your heartbeat that's set by the sinus node, your body's natural pacemaker. A physician might treat transient sinus bradycardia by recommending you avoid the kinds of conditions that trigger it. AFib can have potentially serious health effects. If you are having episodes of fainting or . You can read more about the problem of false capture here. Lead (s) Single or multiple Unipolar or bipolar Pacemaker Classification Pacemakers are classified by the nature of their pacing mode. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: executive summary. Learn more about instructions for recovery after this procedure. (2021). What are the Symptoms of Postural Orthostatic Tachycardia Syndrome (POTS)? Using the small block method (1500/13=115) we can determine that the compression rate was about 115/min. First-degree atrioventricular (AV) block, or first-degree heart block, is defined as prolongation of the PR interval on an electrocardiogram (ECG) to more than 200 msec. While these ECG results COULD truly signify an old [previous] myocardial infarction, i.e., heart attack/MI, this result also could be seen in normal hearts. 2. Symptoms of a third-degree heart block include chest pain, fatigue, and shortness of breath. doctor. The fourth beat (purpose circle) is a PVC. Thank you for your really helpful posts! These were the last to items on an EKG and lipid test. Anelectrocardiogram (ECG)will show that the slow heart rate is present. If EKG artifacts are not recognized by physician, anesthesiologist or intensivist unneccasry diagnostic and therapeutic measures could be taken. Ive referenced her excellent work on debunking pseudoscience and quackery frequently. An older person with severe arrhythmia may require a pacemaker. To help minimize 60 cycle interference you can set the diagnostic mode of your 12-lead ECG monitor to 0.05 40 Hz. An ECG is used to measure the electrical signals generated by the heart as it contracts, notes MedicineNet. When to Go to the Hospital for Rapid Heart Rate, Importance of the Atrioventricular (AV) Node, Association of asymptomatic bradycardia with incident cardiovascular disease and mortality:The multi-ethnic study of atherosclerosis (MESA), Vagus nerve as modulator of the braingut axis in psychiatric and inflammatory disorders, Incidence of and risk factors for sick sinus syndrome in the general population, GATA6 is a regulator of sinus node development and heart rhythm, 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines and the Heart Rhythm Society, Anxiety disorders are associated with reduced heart rate variability: A meta-analysis, 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay: executive summary, Brain disorders, especially those associated with, Cardiac trauma due to injury or cardiac surgery. The PR interval of the surface ECG is measured from the onset of atrial depolarization (P wave) to the beginning of ventricular depolarization (QRS complex). People also have lower heart rates when sleeping. . 2011;44(6):810-811. doi:10.1016/j.jelectrocard.2011.04.001. Artifact on the electrocardiogram can result from a variety of internal and external causes from Parkinsonian muscle tremors to dry electrode gel. We guarantee the ACLS Medical Training provider card will be accepted worldwide and offer a 100% money back guarantee. Skipping the doctor dashboard might have an impact on their regulatory compliance requirements Unclear why they dont solve that PVC issue and even add other arrythmia detection, as algorithms exist since decades. It occurs when a short circuit rhythm develops in the upper chamber of the heart. Paroxysmal supraventricular tachycardia (PSVT) is a type of abnormal heart rhythm, or arrhythmia. I also have pronounced respiratory sinus arrhythmia which I think contributes to this misclassification. It is important to differentiate these artifactual changes from genuine changes to prevent misdiagnosis. Last medically reviewed on July 29, 2022. I changed one of my medications, and a few days later Kardia said NSR. However, your heart rate can be either faster or slower than this, depending on the demands placed on your heart as well as other underlying health conditions. I have bigeminy and skipped every beat which I cant seem to find a name for, How are you feeling now ? Evaluating and managing bradycardia. Thomas James, Director of Customer Experience. But yes, previous findings of possible AF were read by my cardio as NSR. 3. When we rushed to the patients room it turned out she was brushing her teeth! 2014;64(6):531. doi:10.1016/j.jacc.2014.03.056, Gharibeh L, Yamak A, Whitcomb J, Lu A, Joyal M, Komati H, et al. For the most common type of sinus arrhythmia, the time between heartbeats can be slightly shorter or longer depending on whether you're breathing in or out. The wavy line after the shock is CPR artifact. It can also happen when youre in a deep sleep or are taking certain types of medications. That is the electrode that is causing this problem. Richard N. Fogoros, MD, is a retired professor of medicine and board-certified internal medicine physician and cardiologist. When one of the limb electrodes is affected by a source of disturbance, it distorts not only the corresponding derivation but also [the others] which are all calculated by mathematical equations, precordial leads [are also affected] because the Wilson central terminal, which constitutes the negative pole of the unipolar leads, is produced by connecting 3 limb electrodes via a simple, resistive network to give an average potential across the body.. You can think of the sinus node as a natural pacemaker. The general causes of bradycardia fall into two categories: sinus node-mediated and heart block. Bradycardia is a heart rate that's slower than normal. When the sinus node produces electrical impulses at a relatively reduced rate, the heart rate becomes slow, resulting in sinus bradycardia. When this occurs without significant disturbances we call it normal sinus rhythm. In adults, normal sinus rhythm usually accompanies a heart rate of 60 to 100 bpm. hYko6+;)I8k#YJ9eK;yZ1L:14 An unstable baseline on the EKG before the event, after the event, or both. Sinus Rhythm: What's Normal and What's Not, The Heart's Electrical System: Anatomy and Function, How to Treat Wide and Narrow Tachycardia in the Field. Curious in this product. Chronic atrial fibrillation can cause, Junctional rhythm is a type of irregular heart rhythm originating from the atrioventricular junction. Chronic or persistent A-fib: What you need to know, Debra Sullivan, Ph.D., MSN, R.N., CNE, COI, certain medications and recreational drugs, tachycardic-bradycardic syndrome, also known as tachy-brady syndrome. At ACLS Medical Training, we pride ourselves on the quality, research, and transparency we put into our content. I find it to be an indispensable tool for many of my patients. Bradycardia is defined as a heart rate of fewer than 60 beats per minute. Yasmine S. Ali, MD, MSCI,is a board-certified preventive cardiologist and lipidologist. 2018;9:44. doi:10.3389/fpsyt.2018.00044, Jensen PN, Gronroos NN, Chen LY, et al. If there remains some question, an echocardiogram can distinguish between an old MI and a normal heart. Interpretive Statements: SINUS RHYTHM BORDERLINE LEFT AXIS DEVIATION CONSIDER ANTEROSEPTAL INFARCT. Muscle tremor (or tension) artifact is a type of motion artifact. Once when I was a cardiac monitoring technician the alarm sounded and it appeared as though ventricular tachycardia was on the monitor. Both new Apple Watch 4 and the Kardia band on the old AW3 indicated irregularities. What Is Considered a Dangerous Heart Rate? A lack of visible P waves preceding QRS complexes suggests a lack of sinus beats; this may occur with sinus dysfunction or in the presence of fibrillation or flutter waves. Learn about the side effects and safety measures, Sinus bradycardia refers to a slower than typical heart rate. Determine Your Heart Rate. Incidence of and risk factors for sick sinus syndrome in the general population. Learn the causes of heart palpitations and when to see a, Healthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. Sinus arrhythmia is an irregularity in the heart rhythm that originates at the sinus node. Verywell Health's content is for informational and educational purposes only. bypeep The question I have is: Did the artifact occur during times that you were experiencing palpitations and if so, might it have masked some events that they needed to look at more closely. Left Ventricular Hypertrophy. Heart block occurs when the heart's electrical impulses are wholly or partially blocked as they travel from the heart's atria to the ventricles. The skeptical cardiologist has many patients who are successfully using their AliveCor/Kardia devices to monitor for episodes of atrial fibrillation (afib). It affects males and females equally. And in addition to that, there is nothing preventing a patient from becoming reasonably competent at reading basic EKG patterns themselves. While most P waves have a subsequent QRS wave, rarely are PACs nonconducted. Tremors and shivering cause motion artifacts. Sinus bradycardia causes can be either transient (meaning that they don't last long) or persistent. The gallery of images below shows a variety of EKG artifacts that are due to tremor, movement, movement disorders and electrical interference. This will give the doctor the clearest sign that the person has sinus arrhythmia. Sometimes, the sinus node sends electric pulses too fast or too slowly. Premature atrial complexes (PACs), Premature junctional complexes (PJCs), and Premature ventricular contractions (PVCs) are present. Sometimes (rarely) it mistakes the premature beats for atrial fibrillation and . doi: 10.1016/j.jemermed.2018.10.003. Sinus bradycardia can be normal for some people, but it may need treatment if it causes symptoms. Ventricles. This is an interesting toy but apparently it has difficulty even recognizing an aberrant sinus rhythm. Children have faster heart rates, but by age 10 the rate of 60 to 100 beats per minute (bpm) is the same as for nearly all adults. This results in a regular but rapid heartbeat that starts and stops abruptly. In most people, there is a slight variation of less than 0.16 seconds. Normal sinus rhythm is a regular rhythm that occurs in generally healthy people. Association of asymptomatic bradycardia with incident cardiovascular disease and mortality:The multi-ethnic study of atherosclerosis (MESA). This is reflected by a QRS complex positive in lead I and negative in leads aVF and II. The risk of dying from bradycardia is relatively low when there are no symptoms. 184 0 obj <>stream Sinus bradycardia is a heart rate between 50 to 60 beats per minute. In AFib, your heart often beats faster than normal. Children who have respiratory sinus arrhythmia will tend to see their symptoms decrease as they get older, without the need for treatment. Third-degree heart block can be fatal if a person does not receive treatment. By using our services, you agree to our use of cookies. Your heart rate increases when you breathe in and slows down when you breathe out. Cases of respiratory sinus arrhythmia in children and young people will often improve without treatment as the people age. Interpretation on ekg says 'sinus rhythm, Low Voltage in precordial leads - RSR (V1)-non diagnostic - Horizontal axis for age. Fourth beat is a premature beat In addition, frequently for this patient AliveCor yields an Unclassified reading for NSR with PACs as in this ECG: I wrote about the first patient I identified in my office who had frequent PVCs which were misdiagnosed by AliveCor as afib here. You will frequently encounter loose lead artifact when dealing with patients who are diaphoretic because the electrodes simply will not stick to the patients body. That being said, the device records a good quality single lead ECG which if read by a physician can easily diagnose PVCs. A typical example is a 100 Hz background distortion from fluorescent lights. J Am Coll Cardiol. 461 c. 422 d. 512 e. 588 e. 588 b. 2023 ACLS Medical Training, All Rights Reserved. In fact, AFib frequently, but not always happens along with sick sinus syndrome. Ventricular ectopics can be diagnosed by accident, if a person has an electrocardiogram (ECG) as part of a general check-up for instance. Such palpitations can mimic the feeling patients get when they go into atrial fibrillation. This article discusses what it means to have sinus tachycardia. If you see artifact that looks like this you should ask your patient if he or she has any implantable medical devices. In reality, sinus tachycardia is a form of SVT, and the rate can easily exceed 150. 1 Sinus bradycardia can be normal for some people, but it may need treatment if it causes symptoms. I have these for 30 years I can feel everyone, thats why it is so hard to live with for me. However, there are occasions when artifact mimics ECG abnormalities that can cause problems for patient care. This sinus arrhythmia can be abolished during exercise and vagolytic therapy. However, if the strips are not sensitive in picking up the pvcs, then itll be much less accurate. Baseline drift. 2021;118(1). Is the ketogenic diet right for autoimmune conditions? Usually its happening because your patient is cold and shivering. In some cases, this is normal, such as sinus tachycardia during exercise or sinus bradycardia in athletes. Persistent reasons are more likely to require treatment. It has made living with pvc, pacs, short runs of afib much easier. While similar, sinus rhythm is a little different from heart rate. Read our, When a Pacemaker Is Needed for a Heart Block. For example, a patient who has a pacemaker with a currently-appropriate native rhythm may have an ECG that looks like the one above. Aslanger E, Yalin K. Electromechanical association: a subtle electrocardiogram artifact. Where should we email your 10% off discount code? The stroke risk is what I am concerned about. Atrial fibrillation and sinus rhythm connection, nhlbi.nih.gov/health-topics/atrial-fibrillation, heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate, nhlbi.nih.gov/health-topics/how-heart-works, ahajournals.org/doi/10.1161/CIRCULATIONAHA.116.018011, sciencedirect.com/topics/medicine-and-dentistry/sinus-rhythm, heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate, heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates, Atrial Fibrillation: How the Maze Procedure Works. A persons heart should beat at regular intervals, much like the second hand on a clock. doi:10.1073/pnas.2007322118. However on the one below the cause of his palpitations can be seen: PVCs.The NSR beats (blue arrows) followed at times by PVCs (red arrows)) I obtained the Normal tracing below from a patient in my office with a biventricular pacemaker and frequent PVCs who had no symptoms.Paced beats (blue arrows) PVCs (red arrows). What is the latest research on the form of cancer Jimmy Carter has? Sinus bradycardia is the opposite of sinus tachycardia and happens when your sinus node sends slower pulses, resulting in a heart rate of fewer than 60 bpm. This is because a childs heart is still growing, and changes to the heart can lead to respiratory sinus arrhythmia. The former is more common of the two. It was cold in the fire station and he was shivering. However, it is not always possible to eliminate artifacts completely. 480 b. Heart block, an abnormal type of bradycardia, may lead to serious symptoms and outcomes. Eschalier R, Ploux S, Ritter P, Hassaguerre M, Ellenbogen KA, Bordachar P Heart Rhythm 2015 May;12(5):1071-9. "*d^M"O9$h[,bpWnb ;E285-GO r:V The example below was obtained from a young, healthy firefighter during routine training. Related article: Left ventricular hypertrophy. Usually it's happening because your patient is cold and shivering. [1] Slower is sinus bradycardia, and faster is sinus tachycardia. Knabben, V., et al. A heart rate below 60 bpm can be normal for some people, particularly younger adults and athletes. Normal sinus rhythm is the gold standard. When your heart rhythm or heart rate is abnormal, its called arrhythmia. There are two main types of bradycardiasinus bradycardia and heart block. In this example loose lead artifact can be seen in leads I and II. Arrhythmias are disorders of arousal formation (e.g. PMID: 25614250. Ischemia, or lack of blood flow, may also cause an abnormal ECG. The muscles in the heart need oxygen to survive, just like any other muscle, according to the American Heart Association. Third-degree atrioventricular block. Sinus bradycardia is a resting heart rate of under 60 beats per minute that arises from the sinus node, which sets heart rhythm. The first ECG shows simple motion artifact in leads I, III, and aVL. Athletes often have lower resting heart rates. Doctoral Degree. Treatment may involve correcting any underlying causes or implanting a pacemaker. It will catch fast heart rhythms and can often help to characterize them. It does not identify the PVCS or PACS. It has several possible implications. However, it can also happen when patients prop themselves up by their arms. It corresponds to the rate at which electrical pulses are sent out from the sinus node. But if thats true why is there also artifact in other leads? 2019 Jan;56(1):e9-e12. What is clear is that premature beats significantly confuse the AliveCor algorithm. Learn about causes and outlook here. Unstable Bradycardia Resolves Following Atropine and Attempted Transcutaneous Pacing (TCP). I was one of the original users of alivecor. Journal of Electrocardiology. It is difficult to determine what the true rhythm in Figure 1 really is. The heart is functioning normally and there is no indication of any cardiac issues. It will detect pauses and their length. Normal Sinus Rhythm Obscured By Artifact J Emerg Med. Select one: a. A healthy body is very good at regulating the heart rate to support the bodys functions. Medical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. 5 years ago. Sinus rhythm refers to the rhythm of your heartbeat, determined by the sinus node of your heart. Slow heart rates without symptoms usually are no cause for concern. Clockwise rotation ECG meaning: Sinus rhythm in an ECG If you see a clockwise rotation on your electrocardiogram (ecg), it can mean a few different things. Pacemaker Components 1. In some cases, yes, but it will depend on the cause. As a result, however, their heart rate can fluctuate between bradycardia andtachycardia(rapid heart rate). By age 70, it's 75 to 128. Sinus arrhythmia is an irregularity in the heart rhythm that originates at the sinus node. This painless procedure provides a picture of the electrical activity of the heart and how the heart is working. Electrical pulses must first be generated by the sinus node (sinus rhythm). There are times when your patient is acutely short of breath and its simply impossible to capture a 12-lead ECG with excellent data quality. When symptoms are present, they can include things like: There are many possible causes of sinus tachycardia, including: Like sinus tachycardia, sinus bradycardia can be dangerous in some cases. ; Cafer Zorkun, M.D., Ph.D. [2]. Im wondering if the false positives/negatives can be ignored if you understand how to read and interpret an EKG? Another time because my heart beat was fast its result unclassified confusing as purpose of recording is to confirm and show these changes. A woman who had undergone an ablation procedure to eliminate her very frequent PVCS began utilizing AliveCor to try to determine if she was having recurrent symptomatic PVCs. 2019;74(7):932-987. doi:10.1016/j.jacc.2018.10.043. (2022). Merck Manual Professional Version. Your 10% OFF discount codehas been sent to your email. Overview. The pace at which a rhythm is conducting can help determine the stability of the rhythm. Until recently only had a few episodes, but recently had one lasting 3 months per Kardia and professional halter monitor that found me constantly in AF. The maze procedure is a surgical intervention used to treat atrial fibrillation when medications can't adequately control frequent arrhythmias. 2013;61:e6-e75. Kardia is going to classify sinus rhythm with premature beats (PVCS or PACs) as normal most of the time. While SSS may be asymptomatic in some cases, it can also cause a person to experience: Treatment often includes the use of a pacemaker. This article looks at what sinus arrhythmia is, how doctors diagnose it, and whether it is a health concern. References Both PVCs and PACs can create a false positive diagnosis of atrial fibrillation when it is not present. Heart failure: Could a low sodium diet sometimes do more harm than good? In many cases, the underlying cause cannot be identified. One of my patients began experiences period palpitations 5 years after an ablation for atrial fibrillation. ; Santosh Patel M.D., FRCA [1]; Associate Editor-In-Chief: Kashish Goel, M.D. Mitchell LB. James Martin/CNET. If bradycardia happens for an extended period of time without treatment, it can lead to complications such as: If you have any symptoms of bradycardia, talk to your healthcare provider to determine the cause. For most people, a resting heart rate of 60 to 100 beats per minute (bpm) is considered normal. un,l>Ud[ftn1|}b9aQ=^& flo|>>uMb;d[mG=s/hD}`"r4`*"yp8-+`BfxCk0`J. Institute for Quality and Efficiency in Health Care (IQWiG). Medications such as digoxin, beta-blockers, and calcium channel blockers can make SSS worse. Nonrespiratory sinus arrhythmia (NRSA) more commonly occurs in adults. Sometimes (rarely) it mistakes the premature beats for atrial fibrillation and sometimes it calls the recording unclassified. An arrhythmia originating from within the atrioventricular node. Sinus bradycardia is a resting heart rate of under 60 beats per minute that arises from the sinus node, which sets heart rhythm. This is when the electrical rhythms of the heart are disrupted or blocked, causing the heart to beat slowly. Confirmed Atrial Fibrillation patient for 2 years. On a normal EKG image, the heart rate will show up as a sudden . By clicking Accept All Cookies, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage, and assist in our marketing efforts. The most common and the reading I got every time I took an ECG is "sinus rhythm.". These devices are working as intended as warning signals to seek further advice. (2021). Aslanger E, Bjerregaard P. Mystery of bizarre electrocardiogram solved. Learn more about it, including its types. Sometimes patients feel these premature beats as a skipping or irregularity of the heart beat. The sinus node creates an electrical pulse that travels through your heart muscle, causing it to contract, or beat. In cases of respiratory sinus arrhythmia, the P-P interval will often be longer than 0.12 seconds when the person breathes out. I should point out that many of my patients get a very reliable assessment from their devices. Keep in mind that in some cases, sinus bradycardia is actually a sign of a well-conditioned heart. 39 cycle interference. For patients who experience either PVCs or PACs the AliveCor device is frequently inaccurate. Sinus tachycardia is a condition, in which a person experiences faster heart rhythm than what it should be in the usual case. Our website services, content, and products are for informational purposes only. Your heart rate is the number of times your heart beats in a minute. While technically outside of the normal range, these values can be entirely normal for some people. We avoid using tertiary references. This often occurs right after lead connection and after electric cardioversion. The hearts of adults at rest normally beat between 60 and 100 times per minute. For this patient,, the AliveCor frequently diagnoses possible atrial fibrillation but all of his episodes turn out not to be afib. Normal sinus rhythm is defined as the rhythm of a healthy heart. Can poor sleep impact your weight loss goals? The inaccuracies worry me but if the ekg strip is accurate, but the findings are not, I dont think I should be too worried. Electrical interference from a nearby electrical appliance. Simply email us through the contact us link displayed on every page of this website any time within 60 days of purchase. When this happens, some potential complications can include: Similar to sinus tachycardia, many people with sinus bradycardia have no symptoms. An algorithm has been described previously[3], which may help in recognizing these artifacts. PC(HL)%Lylk;ehvFVL{K31"TzhyFDiOu,BqJMHDbf&" %zv1sZb:^0hN#Ba^XZ&&1a/4/rX_Eai::XdlLl>yqt,V"EX|&*RIRr$7{S?,UFMi_4Z7ZnQ+'eKQGAB9z+0+M\|xx{DK+.EsV)^_~36 S uPi,- :!%_+r*(5^o`% VqK5GU+QA))zg@A}e8O-&0?g{PI5iYHl6Vw^PA:-GEEwt Heart block, an abnormal type of bradycardia, may lead to serious symptoms and outcomes. Premature beats sometimes are interpreted by AliveCor as normal. To troubleshoot this problem make sure you prep the skin carefully! Non specific ST T wave changes refer to changes in the T waves (such as inversion or flattening) and ST segments (such as ST depression) on the electrocardiogram that due not follow an anatomic distribution and are not diagnostic of any one condition. An arrhythmia is an instance when there is a problem with the hearts rhythm or it beats irregularly. If sinus bradycardia is reversible or produces no symptoms, it can often be managed through regular medical checkups. Sinus bradycardia: ECG, causes & management Definition of sinus bradycardia. An infarct is. The phenomenon was first reported in 2005 by zhan et al. You will find more around Sinus i Continue Reading Consequently, if you have afib and premature beats you cannot be entirely confident that a reading of afib is truly afib. However, S1Q3T3 is also present along with anterior T-wave inversions. doi:10.1016/j.jacc.2012.11.007, Sidhu S, Marine JE. See my post today to see how effective it is in managing afib, however. Ventricular fibrillation is an irregular rhythm caused by rapid, uncoordinated fluttering contractions of the heart's lower chambers. P-waves with constant morphology preceding every QRS complex. It tends to decrease as people age, especially in people living with diabetes or heart failure. https://www.wikidoc.org/index.php?title=EKG_artifacts&oldid=645512, Pages with citations using unsupported parameters, Creative Commons Attribution/Share-Alike License, Atrial or ventricular extrasystoles, pseudowaves (QRS), COBE Prisma System for continuous venovenous hemofiltration, Straight shot microdebrider (nasal endoscopy), Pseudowaves (P), premature atrial contraction, Somatosensory evoked potential monitoring units, Atrial flutter, atrial fibrillation, ventricular tachycardia, Ventricular tachycardia, ventricular fibrillation, non-specific, Transcutaneous electrical nerve stimulator, Spikes, runaway pacemaker, ventricular fibrillation, non-specific, R wave is positive in lead aVR (P wave also positive), Reversal of left arm and right arm electrodes, Very low (<0.1 mV) voltage in an isolated limb lead, Reversal of right leg and left arm or right arm electrodes, Exchanged amplitude of P waves (P wave in lead I > lead II), Reversal of left arm and left leg electrodes, R wave abnormal progression in precordial lead (pre-dominal R in V1 and S in V6), Reversal of precordial electrodes (V1 through V6), Suspect dextrocardia (negative P waves in lead I), Eliminate noise and interference (artifact mimicking tachycardias or ST-T changes. These changes can be misinterpreted as myocardial ischemia or infarction.