2009;29:2923. eCollection 2022. Characterization of fetal arrhythmias by means of fetal magnetocardiography in three cases of difficult ultrasonographic imaging. With the evolution of autocorrelation in many of the newer monitors, great advances have been made in both signal quality and continuity. vol. 1993;12:66971. 2018;122:A20644. Br Heart J. Lethal arrhythmias are high priority and will kill a pt in 8 minutes or less. This research shows a way of developing a unique non-invasive and low-cost fetal arrhythmia diagnosis method and evaluated the learning model for evaluating the leave one out (LOO) cross-validation. Capuruo et al. Bigeminy is a type of heart arrhythmia in which the heart beats once normally and once abnormally in quick succession, followed by a pause. Please enable it to take advantage of the complete set of features! Both, artifacts and cardiac arrhythmias represent outliers of the FHR signals, so they affect both time domain and time frequency signal analysis. For fetuses with hydrops, the placental transfer of the digoxin is limited. PubMed Central J Arrhythm. The National Library of Medicine (NLM), on the NIH campus in Bethesda, Maryland, is the world's largest biomedical library and the developer of electronic information services that delivers data to millions of scientists, health professionals and members of the public around the globe, every day. First-line antiarrhythmic transplacental treatment for fetal tachyarrhythmia: a systematic review and meta-analysis. Strizek B, Berg C, Gottschalk I, Herberg U, Geipel A, Gembruch U. High-dose flecainide is the most effective treatment of fetal supraventricular tachycardia. Cite this article. 1997;18:3616. Ueda K, Maeno Y, Miyoshi T, Inamura N, Kawataki M, Taketazu M, on behalf of Japan Fetal Arrhythmia Group, et al. Cardiac arrhythmias and artifacts in fetal heart rate signals: detection and correction. B. Maternal hypotension. & Gynecol. Circ Arrhythm Electrophysiol. The outcomes of intrauterine therapy of fetal tachyarrhythmias depend on the types or etiology of fetal arrhythmias and fetal conditions. [13] reported that they used a two-dimensional scan head with M-mode recordings for the diagnosis of fetal arrhythmias. We sought to determine to what extent fMCG contributed to the precision and accuracy of fetal arrhythmia diagnosis and risk assessment, and in turn, how this altered pregnancy management. Ethics, Husbandry, and Fetal Treatment Following institutional and external review and approval of the protocol (IACUC-UTHSCSA #20110096AP; USDA protocol #74-R-003; OLAW-NIH #D16-00048), we utilized the 125-day gestational (postmenstrual) age, 14 days ventilated baboon model of extreme prematurity described by Seidner et al. Fetal tachycardia is a faster heart rate than expected. Flecainide versus digoxin for fetal supraventricular tachycardia: comparison of two drug treatment protocols. Br J Obstet Gynaecol. Arrhythmia vs. Dysrhythmia: Is There a Difference? - Healthline Heart Rhythm. Both authors read and approved the final manuscript. 1985;8:110. Echocardiography is typically used to determine if the fetal heart arrhythmia is benign or if there is a pathological abnormality. These can include tachycardia-an increased heart rate-or bradycardia, which is a slowed heartbeat. Stirnemann J, Maltret A, Haydar A, Stos B, Bonnet D, Ville Y. 2010;81:84450. The European scaling factors accentuate apparent FHR variability and tend to make periodic changes appear more abrupt than American scaling factors. The overall mortality was 8%, only 4% of which was arrhythmia-related. Miyoshi T, Maeno Y, Sago H, Inamura N, Yasukouchi S, Kawataki M, et al. 2013;42:28593. Rev Port Cardiol. The modes of administration, intraumbilical, intraamniotic, intraperitoneal, intramuscular and intracardiac, have been selected as routes of administration. Pacing Clin Electrophysiol. Yaksh A, van der Does LJME, Lanters EAH, de Groot NMS. Front Pediatr. ; ; . TMJ. In fetuses with short VA tachycardia, it may display a distinctive Doppler flow velocity pattern with a 1:1 AV conduction and a tall A wave superimposed on the aortic ejection wave. [53] reported, for fetuses with complete AV block with poor responses to transplacental therapies, fetal transthoracic ventricular pacing ensures temporary fetal ventricular rate acceleration. EFM certification Flashcards | Quizlet Donofrio MT, Gullquist SD, Mehta ID, Moskowitz WB. Alvarez A, Vial Y, Mivelaz Y, Di Bernardo S, Sekarski N, Meijboom EJ. Moreover, heart function and congenital heart defects exaggerate the severity of congestive heart failure [15]. HHS Vulnerability Disclosure, Help 2018;257:1607. The occurrence of paroxysmal AF can be a result of TBX5 gain-of-function mutations and overexpressions of Nppa, Cx40, Kcnj2 and Tbx3 genes [7]. Arrhythmia vs Dysrhythmia. Correspondence to 8,12,16 The use of fetal echocardiography, M-mode and pulse-wave Doppler has lead to improved diagnosis of fetal arrhythmias, and remains the cornerstone of diagnosis. To remove noise and artifacts, the . Yellow Raft unfolds with a distinctive rhythm as the reader moves backwards and forwards in time, encountering first the story of Rayona, then the story of her mother Christine, and finally the story of Aunt Ida, whose real relationship to the first two becomes one of the novels more powerful revelations. It can be helpful in making prenatal diagnoses of a variety of fetal arrhythmias, such as complete AV block, premature contractions, paroxysmal SVT and Wolff-Parkinson-White syndrome and long QT syndrome [19]. In Europe, standard factors are 20 BPM/cm (vertical) and 1 or 2 cm/minute (horizontal). Friday, June 10, 2022posted by 6:53 AM . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. In nonhydropic fetuses, the successful rate of flecainide was higher than digoxin (96% vs. 79%, P=0.10). Antiarrhythmia agents; arrhythmias; diagnosis; fetus. 2021 Oct;10(10):2432-2438. doi: 10.21037/tp-21-233. Objective: To assess whether noninvasive fetal electrocardiography (NI-FECG) enables the diagnosis of fetal arrhythmias. PubMed PubMed To understand the significance of the FHR display, it is important to understand what the monitor can and cannot count. [9] reported that PACs were the most common fetal arrhythmias representing 55.5% (100/180), followed by bi- or trigemy (12/180, 0.7%), sinus tachycardia (18.3%, 33/180), SVT (15.6%, 28/180), and AF 0.4% (7/180). In fetal cases of atrioventricular blocks, an etiological treatment for the maternal antibody exposure by steroids could be an alternative remedy. Karmegeraj B, Namdeo S, Sudhakar A, Krishnan V, Kunjukutty R, Vaidyanathan B. 2022 Jul 15;12(7):1722. doi: 10.3390/diagnostics12071722. While new wide-beam ultrasound transducers decrease signal loss due to fetal movement, they increase the chance of recording MHR (see section on signal ambiguity). Fetal Arrhythmia Doppler | Children's Hospital Colorado The phonocardiographic signal is clearer than the Doppler signal, resulting in less artifactual jitter. For this reason, phonocardiography historically was widely used for antepartum FHR monitoring. It showed an immediate conversion to sinus rhythm. Fetal Arrhythmia Diagnosis and Pharmacologic Management It connects to the Corometrics 259cx Series . Part of This mechanical energy may be sensed by a microphone and amplified, producing an electrical signal that may then be reconverted to sound or used to produce a phonocardiogram, an oscillographic tracing of the heart sounds. It is indicated for fetal long QT syndrome type 2 and complete AV block [45]. Fetal arrhythmias: prenatal evaluation and intrauterine therapeutics. Fetal arrhythmia: Prenatal diagnosis and perinatal management Respondek et al. This management usually takes place during the second or third trimester. Autonomous Nervous System Disturbances of cardiac rhythm or arrhythmias are common in people, often benign, and often intermittent. HUM 100 Cultures and Artifacts Worksheet; Newest. The time to conversion to sinus rhythm for sotalol varied from 1 to 5days (median 1day) for Shah et al. For the obstetrician or obstetric nurse to interpret fetal monitor tracings correctly, it is necessary to have some understanding of the processes involved in the acquisition and processing of data relating to fetal heart rate (FHR) and uterine activity. Fetal Arrhythmia - American Pregnancy Association Phonocardiography was the first method used to record FHR electronically. 2023 Feb 18;13(4):779. doi: 10.3390/diagnostics13040779. Hamela-Olkowska A, Szymkiewicz-Dangel J. Fetal tachyarrhythmia--current state of knowledge. A transducer innovation employed by second-generation monitors is pulsed Doppler. Fetal echocardiography has been the mainstay of fetal arrhythmia diagnosis; however, fetal magnetocardiography (fMCG) has recently become clinically available. PACscommon and not dangerous. The treatment of choices for fetal tachyarrhythmias was listed in Table2. 2017;19:2325. M.G. Rev Med Suisse. Google Scholar. It was worthwhile mentioning that the initial ventricular pacing threshold was very low in the hydropic fetus. Fetal heart rate and rhythm were measured by detecting semilunar and AV valve opening and closing points, A waves, plus ventricular wall motion. by | Jun 10, 2022 | north river road, ottawa | texas roadhouse fundraiser rolls directions | Jun 10, 2022 | north river road, ottawa | texas roadhouse fundraiser rolls directions The frequency increases if the reflecting interface is moving toward the signal source and decreases if the reflecting interface is moving away from the signal source. Ventricular tachycardia in a fetus: benign course of a malignant arrhythmia. Cardiotocography is the most commonly used noninvasive diagnostic technique that provides physicians information about fetal development (in particular about development of autonomous nervous system - ANS) and wellbeing. 2012 Jun 1;109(11):1614-8. doi: 10.1016/j.amjcard.2012.01.388. Front Pharmacol. 2023 BioMed Central Ltd unless otherwise stated. In comparison to flecainide or digoxin, sotalol was less effective to convert SVT to sinus rhythm. The main drawback to phonocardiographically derived FHR systems is that they are extremely sensitive to ambient noise such as maternal bowel sounds, voices in the room, certain air-conditioning systems, and, especially, noise produced by any motion of the microphone or of the bed clothing against the microphone. Therefore, the fetal electrocardiogram (ECG) signal provides the clinician with a measure of the electrical activity of the fetal heart. Meanwhile, "dys" is . Sustained fetal arrhythmias associated with major structural heart disorders, hydrops fetalis, and fetal heart failure warrant intrauterine pharmaceutical conversion of heart rhythm or early pacemaker implant in order to avoid fetal demise. Fetal cardiac pacings are effective methods to restore sinus rhythm in drug-resistant or hemodynamically compromised cases. The proposed framework uses only a single abdomen ECG. Sotalol and flecainide have good placental transfer ability, and they should be used as first-line treatment for hydropic fetal tachyrrhythmias. Fetal bradyarrhythmia associated with congenital heart defects - nationwide survey in Japan. Capuruo CA, Mota CC, Rezende GD, Santos R. P06.03: fetal tachyarrhythmia: diagnosis, treatment and outcome. Jaeggi ET, Carvalho JS, De Groot E, Api O, Clur SA, Manlhiot C, et al. Ginekol Pol. fetal arrhythmia vs artifact. J Perinat Med. The primary goal of fetal therapy is the prevention or resolution of hydrops. A. Stimulation of fetal chemoreceptors. The ability to distinguish one from the other requires knowledge of FHR and MHR characteristics and monitoring technology. If maternal transplacental treatment fails, intraumbilical, intraperitoneal, or direct fetal intramuscular injection of antiarrhythmic agents can be attempted. Aggarwal S, Czaplicki S, Chintala K. Hemodynamic effect of fetal supraventricular tachycardia on the unaffected twin. This section will deal with the methodology involved in the clinical application of these techniques. Arrhythmia Electrophysiol Rev. Ishikawa T, Tsuji Y, Makita N. Inherited bradyarrhythmia: a diverse genetic background. 2018;31:40712. [40] and a median of 12days for Jaeggi et al. [23] reported that PACs required antiarrhythmic treatments with digoxin, verapamil, or both in 14% of the cases. Fetal rhythm abnormalities, which include irregular fetal heart rates, occur in up to 2% of pregnancies and account for 10 to 20% of referrals to fetal cardiologists. This article reviews heart rate monitoring . The intrauterine or neonatal mortality rate in hydropic fetuses treated with flecainide was much lower than that treated with digoxin (0% vs. 43%, P=0.06). Stirnemann et al. Sotalol is usually well-tolerated and has little or no negative inotropic effect on the fetal heart. Ann Pediatr Cardiol. Watch this videoFor any support, please contact Mindray India on the below . Europ. A Machine Learning Framework for Fetal Arrhythmia - SpringerLink Yuan, SM., Xu, ZY. Jaeggi ET, Carvalho JS, De Groot E, Api O, Clur SA, Rammeloo L, et al. Fetal PVCs warrant close monitoring as they may develop into proxysmal ventricular tachycardias (VTs). Uterine contraction intensities. In addition, the actual signal created by the fetal cardiac motion is greatly affected by the position and movement of the transducer with respect to the fetus. ; Disney Surprise Drinks The clinical outcome and prognosis of patients are usually determined by the type and extent of cardiac malformation [55]. van der Heijden LB, Oudijk MA, Manten GT, ter Heide H, Pistorius L, Freund MW. 2009;29:68290. The institutional Review Board approves this study. Mller cells in eyes of 39 human fetuses (11-38 weeks of gestation, WOG) and 6 infants (5 died of abusive head trauma, AHT, aged 1-9 months) were immunohistochemically stained and investigated for spatial and temporal immunoreaction of nestin, CD44, collagen IX and GFAP, which are . Fouron J. Fetal complete AV block with structural heart disease often shows a worse prognosis, such as fetal demise or pacemaker implant requirement. 8600 Rockville Pike The transplacental administration of antiarrhythmic agents, including digoxin, flecainide, sotalol, and amiodarone, is applied for fetal tachycardia in many centers [25]. Benefit vs. Risk of Internal Monitoring Benefits Provides continuous monitoring Helpful for maternal positioning in bed, fetal movement, maternal body habitus Twins/Multiples More accurate/less artifact Helpful in detecting arrhythmias/ dysrhythmias Risks Invasive Creates portal for infection Potential injury . The literature reporting on prenatal diagnosis and treatment of fetal arrhythmias published in the recent two decades were retrieved, collected and analyzed. Alsaied T, Baskar S, Fares M, Alahdab F, Czosek RJ, Murad MH, et al. Machado MV, Tynan MJ, Curry PV, Allan LD. 1,2 To improve the outcome in such cases, various studies of prenatal diagnosis and perinatal management have been published. Myoinositol reduction in medial prefrontal cortex of obsessive The heart [] XZY: Substantial contribution to the conception and design of the work; and the acquisition, analysis, and interpretation of data for the work; drafting the work and revising it critically for important intellectual content; final approval of the version to be published; agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy and integrity of any part of the work are appropriately investigated and resolved. J Pract Obstet Gynecol. Contribution of Fetal Magnetocardiography to Diagnosis, Risk Assessment 2003;29:S85. Immediate postnatal pacemaker implantation is warranted in refractory cases. Individualized treatment and clinical treatment should be determined according to specific types. (2007). Clinically, uterine contractions can be monitored by two techniques: external tocodynamometry or intrauterine pressure measurement. Fetal Arrhythmias | GLOWM Article Fetal Arrhythmia and Dysrhythmia Facts and Treatments - Lifespan For this reason, a manual gain control offers a great advantage when using abdominal fetal phonocardiography for recording heart rate. Apply intervention and collect data o Process Portfolio - demonstrates steps on how IV. Can digoxin and sotalol therapy for fetal supraventricular tachycardia and hydrops be successful? The normal heart rate for a fetus is anywhere between 120 and 160 beats per minute.This is a rare condition, occurring in only 1-2% of pregnancies, and is normally a temporary, benign occurrence. (eds) 11th Mediterranean Conference on Medical and Biomedical Engineering and Computing 2007. All those with complete AV block by maternal autoantibodies positivity survived, but 42.8% needed a pacemaker. Abb. IFMBE Proceedings, vol 16. Besides, sustained fetal arrhythmias predispose to the occurrence of hydrops fetalis, cardiac dysfunction, or even fetal demise [10]. Some cases of fetal arrhythmia are benign, but others can lead to fetal heart failure and/or pose a risk both to the fetus and to . 25 with slight . Up-to-date . Heart Rhythm. statement and Refaat M, El Dick J, Sabra M, Bitar F, Tayeh C, Abutaqa M, Arabi M. J Neonatal Perinatal Med. Kang SL, Howe D, Coleman M, Roman K, Gnanapragasam J. Foetal supraventricular tachycardia with hydrops fetalis: a role for direct intraperitoneal amiodarone. fetal arrhythmia vs artifact 2015;79:85461. This occurs only with fetal supraventricular tachyarrhythmias (paroxysmal atrial tachycardia, atrial fibrillation, or atrial flutter), intermittent premature atrial contractions (PACs), or premature ventricular contractions (PVCs) (, An additional instance that may cause confusion is the patient with a cardiac pacemaker. In this article, the clinical diagnosis and treatment of fetal arrhythmias are presented, and advantages and disadvantages of antiarrhythmic agents for fetal arrhythmias are compared. 2013;42:28593. Immediate postnatal pacemaker implantation is warranted in refractory cases. Uterine tachsystole. Supraventricular Tachycardia (SVT) Complete Heart Block. J Ultrasound Med. Am J Cardiol. and transmitted securely. EKG Interpretation & Heart Arrhythmias Cheat Sheet - Nurseslabs All of the following are likely causes of prolonged decelerations except: A. Fetal bradycardias may be due to sinus bradycardia, blocked PACs, or high degree AV block [46]. J Am Coll Cardiol. Sotalol as an effective adjunct therapy in the management of supraventricular tachycardia induced fetal hydrops fetalis. The proposed study will allow the investigators to evaluate . The raw fetal ECG signal is amplified and fed into a beatto-beat cardiotachometer (, Most fetal ECG systems will not record R-R intervals less than 250 milliseconds, which corresponds to a rate of 240 BPM. 5 things you should know about fetal arrhythmia | Texas Children's Would you like email updates of new search results? van der Heijden LB, Oudijk MA, Manten G, ter Heide H, Pistorius H, Freund MW. Respondek M, Wloch A, Kaczmarek P, Borowski D, Wilczynski J, Helwich E. Diagnostic and perinatal management of fetal extrasystole. . With all of the firstgeneration fetal monitors and many second-generation monitors, the signal is transmitted and the reflected signals received continuously by multiple crystals contained in the transducer. 2004;27:164755. Saileela R, Sachdeva S, Saggu DK, Koneti NR. C. Umbilical vein compression. fetal arrhythmia vs artifact. The purpose of this study was to investigate Mller cells during the fetal development of the human eye. Nav1.5 gain-of-function mutation is proved to be associated with an increased risk of multifocal atrial and ventricular ectopies and dilated cardiomyopathy [8]. PubMed Central Digoxin is more suitable for rhythm conversion of fetal AF and SVT in fetuses free of hydrops fetalis, while sotalol shows better effects for those with hydrops fetalis. Tutschek B, Schmidt KG. This process is experimental and the keywords may be updated as the learning algorithm improves. M-mode ultrasound can detect the AV and ventriculoatrial (VA) intervals, fetal heart rate, AV conduction, and even ejection fraction [11], but detection qualities may be compromised by early detection in first trimester, unfavorable fetal position, hydrops fetalis, fetuses with cardiac contractile dysfunction and obese pregnant women [12]. Fetal congenital arrhythmia is an irregular beating of the heart of a fetus, caused by a congenital disability or an inherited genetic condition. Merriman JB, Gonzalez JM, Rychik J, Ural SH. As the fetal heart beats, closure of the valves may be detected by listening with a suitable stethoscope through the mothers abdominal wall. Amiodarone is a second-line treatment, especially in hydropic fetuses with SVT [27]. After the pacing wire was advanced into the right atrium and subsequently the right ventricle, the pacing rate was set up at 140bpm. By detecting flow imaging frequency spectrum of the pulmonary arteries and pulmonary veins, the pulse Doppler echocardiography can determine the rhythm changes between the spectra and the arrhythmic patterns. Ultrasound Obstet Gynecol. One of the most successful achievements of fetal intervention is the pharmacologic management of fetal arrhythmias. Unable to display preview. One of the most useful and commonly used diagnostic tools is electrocardiography (EKG) which measures the heart's electrical activity as waveforms. fetal arrhythmia vs artifact - tutanc.org While most arrhythmias in the fetus are benign, both tachy and bradyarrhythmias can lead to fetal hydrops or cardiac dysfunction and require treatment . By using this website, you agree to our In general, digoxin is widely accepted as a first-line antiarrhythmic drug. Multifocal atrial and ventricular premature contractions with an increased risk of dilated cardiomyopathy caused by a Nav1.5 gain-of-function mutation (G213D). Abstract. Doctors have been using ECG signals to detect heart diseases such as arrhythmia and myocardial infarctions for over 70 years. Doppler waveforms detected from the inferior vena cava and the descending aorta helps in obtaining information of atrial and ventricular systoles simultaneously. Flecanide and sotalol cross the placental barrier easier, especially in hydropic fetuses, and a higher drug concentration can be achieved in the amniotic fluid. The impact of intrauterine treatment on fetal tachycardia: a nationwide survey in Japan. J Matern Fetal Neonatal Med. Med Ultrason. Regular screening by fetal echocardiography and transplacental treatment could prevent this risk factor [9]. Moreover, fetal cardiac arrhythmias can have an effect on FHR signals. 2003;53:2869. This safe, noninvasive test shows the structure of the heart and helps determine the type of arrhythmia. A burden for the pediatric cardiologist and a review of the literature. Assessment of fetal arrhythmia by simultaneous Doppler recording of flow patterns in the ascending aorta and superior vena cava. Digoxin, flecainide and sotalol can be the first-line treatments. Both fetal magnetocardiogram and electrocardiogram provide information of . These arrhythmias do not represent an expression of the physiological behavior of the ANS. Miyoshi et al. Article The conversion rate to sinus rhythm of flecainide for short VA SVT was higher than digoxin (96% vs. 69%, P=0.01). 1988;16:3944. Cardiol Young. 1,7. DeVore GR, Horenstein J. Flecainide as first-line treatment for fetal supraventricular tachycardia. PubMedGoogle Scholar, Faculty of Electrical Engineering, University of Ljubljana, Trzaska 25, 1000, Ljubljana, Slovenia, Tomaz Jarm,Peter Kramar&Anze Zupanic,&, Cesarelli, M., Romano, M., Bifulco, P., Fratini, A. Fetal demise occurred in 5 (26.3%), and neonatal death in 10 (41.7%). Fetal Mediastinal Mass Associated with Arrhythmia: Artifact and Casual Comparison of transplacental treatment of fetal supraventricular tachyarrhythmias with digoxin, flecainide, and sotalol: results of a nonrandomized multicenter study. Almost all arrhythmias fall into one of three categories: irregular, tachycardic, or bradycardic. 2004;24:1127. In PACs, extra heartbeats can come from the top of the heart, separate from the sinus node. 2018;31:260510. When the transmitted ultrasonic beam encounters an interface of increased density, a portion of the signal is reflected. Long QT syndrome can cause 2:1 AV block or sinus bradycardia. This biphasic signal is immersed in noise created by fetal movements, arterial blood flow, maternal movements, and random muscle contractions. A healthy fetus has a heartbeat of 120 to 160 beats per minute, beating at a regular rhythm. fetal arrhythmia vs artifactdiscretionary housing payment hackney. Most isolated fetal PVCs usually resolve spontaneously. An arrhythmia is an irregular heart rate too fast, too slow, or otherwise outside the norm. J Am Heart Assoc. Oudijk MA, Visser GH, Meijboom EJ. The literature reporting on prenatal diagnosis and treatment of fetal arrhythmias published in the recent two decades were retrieved, collected and analyzed. Ann Pediatr Cardiol. Both methods have advantages and disadvantages, and one or the other is more applicable in certain clinical situations. As the train approaches, the whistle gets both louder and higher in frequency. PubMed Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips. This form of short-term memory is supported by the prefrontal cortex (PFC) and is believed to rely on the ability of selectively tuned pyramidal neuron networks to persist in firing even after a to-be-remembered stimulus is removed from the environment. In long VA tachycardia, an A wave of normal amplitude with normal AV time interval could be detected in front of the aortic ejection wave [16]. Among other causes, the fetal arrhythmia is accountable for a significant portion of such . Sotalol, flecainide and amiodarone are used as second-line drugs when digoxin fails to achieve conversion to sinus rhythm. The neonatal and overall survival rates for fetal bradyarrhythmia with structural heart disease were much higher, which were 66 and 48%, respectively. Although US clinicians find 1 cm/minute tracings are harder to read than the same tracings at 3 cm/minute, the slower rate of tracing is commonly used in Europe, South America, and certain centers in this country.