Wide QRS in hyperkalemia merges with the tall T waves, producing a sine wave pattern, which is also absent here. Recognition of intermittent “cannon” A waves on the jugular venous waveform (JVP) during ongoing WCT is an important physical examination finding because it implies VA dissociation, and can clinch the diagnosis of VT. The rhythm strip shows sinus tachycardia at the beginning and at the end; each sinus P wave is marked. Aberrancy implies the patient has an EKG with baseline wide QRS (from a bundle branch block (BBB)). Wide QRS complex, as defined by QRS duration >120mil - liseconds measured on a standard 12-lead ECG, has been associated with an increased risk of ventricular arrhythmia. At first observation, there appears to be clear evidence for VA dissociation, with the atrial rate being slower than the ventricular rate. Wide complex tachycardia in the setting of metabolic disorders. It must be acknowledged that there are many clinical scenarios where different criteria will provide conflicting indications as to the etiology of a WCT. Cardiorenal syndrome in heart failure patients. Figure 1. Causes of a widened QRS complex include right or left BBB, pacemaker, hyperkalemia, ventricular preexcitation as is seen in Wolf-Parkinson-White pattern, and a ventricular rhythm. She has missed her last two hemodialysis appointments. The timing of engagement of the His-Purkinje network: at some point during propagation of the VT wave front, the His-Purkinje network is engaged, resulting in faster propagation; the earlier this occurs, the narrower the QRS complex. 2008 May; [PubMed PMID: 19561715] Vereckei A, Current algorithms for the diagnosis of wide QRS complex tachycardias. The following observations can be made from the second ECG, obtained after amiodarone: The heart rate is 111 bpm, with a right inferior axis of about +140° and a narrow QRS. Causes of a widened QRS complex include right or left BBB, pacemaker, hyperkalemia, ventricular preexcitation as is seen in Wolf-Parkinson-White pattern, and a ventricular rhythm. Measurement of the two flutter cycle lengths (↔) exactly equals the rate of the WCT in Figure 8. The QRS morphology suggests an old inferior wall myocardial infarction, favoring VT. ECG findings to help distinguish causes of WCT when the QRS complex in V1 is terminally upright – RBBB-like morphology. Wide complex tachycardia related to rapid ventricular pacing. It is atrial flutter with grouped beating. Furthermore, there will often be evidence of VA dissociation, with the ventricular rate being faster than the atrial rate, pointing to the correct diagnosis of VT. If the patient is conscious and cardioversion is decided upon, it is strongly recommended that sedation or anesthesia be given whenever possible prior to shock delivery. Capturing the onset or termination of WCT on telemetry strips can be especially helpful. European Heart J. vol. The normal R wave can be up to 0.8 mV tall in cats, 2.5 mV in small dogs, and 3.0 mV in large dogs. The Bayesian approach improves the electrocardiographic diagnosis of broad complex tachycardia. 2012 Aug. pp. If an old EKG is available, the baseline wide QRS will be present. He has a recent diagnosis of IgA myeloma. A wide QRS complex with rightward shift of the QRS complex, particularly the terminal forces (manifested partially by a positive R-wave in lead aVR), is an important feature of TCA poisoning. The newer methods were not more accurate than the classic … By the fourth wide complex beat, there is 1:1 VA conduction, and now there is VA association with a retrograde P wave (P’). The wider the QRS complex, the more likely it is to be VT. The R-wave peak time in lead II is >50 ms, which is diagnostic of VT. 3, blz. Past medical history was significant for type II diabetes, hypertension, hyperlipidemia, and chronic kidney disease (CKD). WIDE COMPLEX TACHYCARDIA:ECG AV dissociation, QRS morphology QRS axis in frontal plane QRS width Capture beats Fusion beats Baerman JM et al. When VT occurs in patients with prior myocardial infarction, the QRS complex during VT shows “pathologic Q waves” in the same leads that showed pathologic Q waves in sinus rhythm. In between, there is a WCT with a relatively narrow QRS complex with an RBBB-like pattern. 1 In the remaining 20% of cases, supraventricular tachycardia with bundle branch block, preexcitation, aberrant ventricular conduction, severe cardiomyopathy, hypothermia, electrolyte abnormalities, and toxic effects of drugs should be considered. 15. Known history of pacemaker implantation and comparison to prior ECGs usually provide the correct diagnosis. The ECG in Figure 2 was obtained upon presentation. It is important to go over some basic definitions describing what WCTs are, what causes them, how to diagnose them, and how to manage/treat them. Wide QRS tachycardias present a diagnostic and therapeutic challenge for the clinician, as they may be a manifestation of benign arrhythmias, such as aberrantly or potentially fatal supraventricular tachycardias, such as ventricular tachycardias or preexcited arrhyth mias. The wide QRS complexes follow some of the pacing spikes, and show varying degrees of QRS widening due to intramyocardial aberrancy. 2008. pp. 1165-71. Because ventricular activation occurs over the RBB, the QRS complex during this VT exactly resembles the QRS complex during SVT with LBBB aberrancy. Depending on which pathway the electrical stimulus takes, it will affect how the QRS complex will be visualized on the EKG. Miguel A. Arias, MD, PhD, Alberto Puchol, MD, Eduardo Castellanos, MD, PhD, Luis Rodríguez-Padial, MD, PhD From the Cardiac Arrhythmia and Electrophysiology Unit, Department of Cardiology, Hospital Virgen de la Salud, Figure 5: An 88-year-old female with a dual-chamber pacemaker presented after three syncopal episodes within 24 hours. This is one VT where the QRS complex morphology exactly mimics that of SVT with aberrancy. 2016 Apr. P waves are not seen, even though the ECG machine gives a P wave axis and PR interval measurement. Furthermore, the P waves are inverted in leads II, III, and aVF, which is not consistent with sinus origin. When a WCT abruptly becomes a narrow complex tachycardia with acceleration of the heart rate, SVT (orthodromic atrioventricular reciprocating tachycardia using an accessory pathway on the same side as the blocked bundle branch) is confirmed (Coumel’s law). For example, VTs that arise within scar tissue located in the crest of the interventricular septum may “break into” (engage) the His bundle or proximal bundle branches early, and subsequent spread of electrical activation occurs via the His-Purkinje network, resulting in relatively narrower QRS complexes. This is also indicative of VT (ventricular oscillations precede and predict atrial oscillations). Roughly 80% of all wide complex tachycardias are caused by ventricular tachycardia, and this figure rise to 90% among patients with ischemic heart disease (coronary artery disease). Atrial tachycardia is a rare supraventricular tachycardia. Cardiovascular events are the leading cause of fatal outcomes of TCA overdose, with dysrhythmia and hypotension being the clinical manifestations of cardiotoxic effects. Am J of Cardiol. He had a history of paroxysmal atrial fibrillation. The major clinical problem that arises when dealing with someone exhibiting a wide complex tachycardia is that it is not always immediately clear if the rhythm represents supraventricular tachycardia or ventricular tachycardia. Correct interpretation is crucial for appropriate decision making. However, a VT arising in the septum may result in a tachycardia with a shorter QRS duration. During narrow QRS complex tachycardias, the premature ventricular complex conducts transseptally to enter the tachycardia circuit in a patient with a left-sided AP, and the PI is much longer. Huemer, M, Meloh, H, Attanasio, P, Wutzler, A. 1649-59. Wide QRS complexes, or those lasting longer than the normal rate, indicate ventricle impairment such as bundle branch blocks. The PR interval is .32 seconds, or 320 ms. However, it should be noted that the “dissociated” P waves occur at repeating locations. ', Netherlands Heart Journal, vol. An experienced electrocardiogapher looking at a wide complex may immediately sort it into the most common categories that have earned instant recognition status: LBBB morphology, RBBB morphology (+/- LAFB or LPFB), ventricular paced rhythm (based on pacer spikes and appropriately wide QRS immediately following), or something that doesn't easily fit into any of those categories. The following observations can be made from the first ECG: The WCT shows a QRS complex duration of 180 ms; the rate is 222 bpm. Several arrhythmias can manifest as WCTs (Table 21-1); the most common is ventricular tachycardia (VT), which accounts for 80% of all cases of WCT. The ECG in Figure 4 is representative. In other words, the default diagnosis is VT, unless there is no doubt that the WCT is SVT with aberrancy. VA “dissociation” is best seen in rhythm leads II and V1. Although initial perusal may suggest runs of nonsustained VT, careful observation reveals that there is a clear pacing spike prior to each wide QR complex (best seen in lead V4), making the diagnosis of a paced rhythm. Such a re-orientation of lead I electrodes so that they “straddle” the right atrium, often allows more accurate recognition of atrial activity, and if dissociated P waves are seen, the diagnosis of VT is established. There is left axis deviation in the frontal plane and poor R wave progression in the horizontal plane. No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. It is important to note that all the analyses that help the clinician distinguish SVT with aberrancy from VT also help to distinguish single wide complex beats (i.e., APD with aberrant conduction vs. VPD). The exact same pattern of LBBB aberrancy was reproduced during rapid atrial pacing at the time of the electrophysiology study. This work by ECG Guru is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.Permissions beyond the scope of this license may be available. The frontal axis superiorly directed, but otherwise difficult to pin down. However, such patients are usually young, do not have associated structural heart disease, and most importantly, show manifest preexcitation (WPW pattern) during sinus rhythm. We would welcome comments below from all our members! The QRS complexes are wide, measuring about 200 ms; the rate is 125 bpm. However, such patients have severe, dilated cardiomyopathy, and preexisting BBB or intraventricular conduction delays (wide QRS in sinus rhythm). Figure 8: WCT tachycardia recorded in a male patient on postoperative day 3 following mitral valve repair. INTRODUCTION: Prolonged paced QRS duration is a predictor of development of heart failure during chronic right ventricular pacing. Wide complex tachycardiaDiagnostic approach/algorithms Comparison of five electrocardiographic methods for differentiation of wide QRS-complex tachycardias Brugada, Bayesian, Griffith, and aVR algorithms, and the lead II R- wave-peak-time (RWPT) criterion All five algorithms/criteria had equal moderate diagnostic accuracy. QRS duration. In Torsades de pointes, it can sometimes appear that the QRS waves twist around from top to bottom and back again. Pacing results in a wide QRS complex since the wave front of depolarization starts in the myocardium at the ventricular lead location, and then propagates by muscle-to-muscle spread. 101. Electrolyte disorders (such as severe hyperkalemia) and drug toxicity (such as poisoning with antiarrhythmic drugs) can widen the QRS complex. This constitutes first-degree AV block. 14, nr. Related TopicsAberrancy, ventricular tachycardia, supraventricular tachycardia, right-bundle branch block (RBBB), left-bundle branch block (LBBB), intraventricular conduction delay (IVCD), pre-excited tachycardia.DefinitionsThe normal QRS complex during sinus rhythm is “ This constitutes first-degree AV block. Because of this reason, many patients have only ECG telemetry (rhythm) strips available for analysis; however, there is often sufficient information within telemetry strips to make an accurate conclusion about the nature of WCT. The hallmark of VT is ventriculoatrial (VA) dissociation (the ventricular rate being faster than the atrial rate), the following examination findings (Table II), when clearly present, “clinch” the diagnosis of VT. The Q wave in aVR is >40 ms, favoring VT. When confronted with a wide-QRS-complex tachycardia it can be difficult to differentiate between a supraventricular tachycardia with aberrancy or ventricular tachycardia.A separate chapter deals with this dilemma: Approach to the Wide Complex Tachycardia. The clinical situation that is commonly encountered is when the clinician is faced with an electrocardiogram (ECG) that shows a wide QRS complex tachycardia (WCT, QRS duration ≥120 ms, rate ≥100 bpm), and must decide whether the rhythm is of supraventricular origin with aberrant conduction (i.e., with bundle branch block), or whether it is of ventricular origin (i.e., VT). There is a suggestion of a P wave prior to every QRS complex, best seen in lead V1, favoring SVT. The QRS complex duration is wide (>0.12 seconds or 3 small boxes) in every lead. - Drug Monographs A 70-year-old woman with prior inferior wall MI presented with an episode of syncope resulting in lead laceration, followed by spontaneous recovery by persistent light-headedness. One such special lead is called the “modified Lewis lead”; the right arm electrode is intentionally placed on the second right intercostal space, and the left arm electrode on the fourth right intercostal space. The QRS complex is wide at .12 seconds, or 120 ms., representing interventricular conduction delay (IVCD). The ECG shows atrial fibrillation with both narrow and wide QR complexes. Aberrancy, ventricular tachycardia, supraventricular tachycardia, right-bundle branch block (RBBB), left-bundle branch block (LBBB), intraventricular conduction delay (IVCD), pre-excited tachycardia. The WCT is at a rate of about 100 bpm, has a normal frontal axis, and shows a typical LBBB morphology; the S wave down stroke in V1-V3 is swift (<70 ms). QRS duration. Ventricular arrhythmias are almost allways wide-QRS-complex arrhythmias. Sign in - Conference Coverage When approaching an electrocardiogram (ECG) with wide complex tachycardia, one must differentiate between ventricular tachycardia and supraventricular tachycardia conducted with aberrancy. Wide complex tachycardia is a cardiac rhythm with more than 100 ventricular beats per minute and a QRS complex of 120 ms or greater. In summary, a diagnosis of AV reentry was reasonable from Fig. This group also includes antidromic AVRT and regular tachycardias with aberrancy. When the direction is reversed (down the LBB, across the septum, and up the RBB), the QRS complex exactly resembles the QRS complex during SVT with RBBB aberrancy. All these findings suggest that the wide QRS complex tachycardia is VT. 1 On applying the aVR algorithm, the 12-lead ECG has an initial Q wave that lasts >40 ms. Leads V2 and V3, however, show swift down strokes (onset to nadir <70 ms), favoring SVT with LBBB aberrancy. The PR interval is.32 seconds, or 320 ms. The QRS complex is wide, measuring about 130 ms; the frontal axis is rightward and inferior, suggestive of left posterior fascicular block (LPFB). 5 Additionally, wide QRS complex was also found to be more prominent in symptomatic BrS patients. Atrial Tachycardia. Bundle branch reentry (BBR) is a special type of VT wherein the VT circuit is comprised of the right and left bundles and the myocardium of the interventricular septum. Conclusion: The “nonsustained VT” was actually a paced rhythm due to inappropriate and intermittent tracking of atrial fibrillation by the dual-chamber pacemaker. The tracing of Figure 1 (leads II, III, and V1 taken simultaneously) has been recorded from a 58-year-old man during the recovery phase of exercise stress testing. Whenever possible, a 12-lead ECG should be obtained during WCT; obviously, this is not applicable to the hemodynamically unstable patient (such as presyncope, syncope, pulmonary edema, angina). Therefore, this tracing represents VT with 3:2 VA conduction (VA Wenckebach); this still counts as VA dissociation. This observation clinches the diagnosis of orthodromic atrioventricular tachycardia using a left-sided accessory pathway (Coumel’s law). In ECG #1 — the rhythm is regular — extremely fast — the QRS complex is extremely wide (ie, ~0.15 second) — and sinus P waves are absent. A special consideration is WCT due to anterograde conduction over an accessory pathway. The frontal axis is pointing to the right shoulder, and favors VT. Wide-complex tachycardia. I. All QRS complexes are irregularly irregular. Lau EW, Pathamanathan RK, Ng GA, Cooper J, Skehan JD, Griffith MJ. As is true of all situations in medicine, the clinical context in which the wide complex tachycardia (WCT) occurs often provides important clues as to whether one is dealing with VT or SVT with aberrancy. The width of the QRS complex, both with aberrancy and during VT, can vary from patient to patient. conduction of a supraventricular impulse from atrium to ventricle over an accessory pathway (bypass tract) – so called “pre-excited” tachycardia. It should be noted that hemodynamic stability is not always helpful in deciding about the probable etiology of WCT. A train of 3 beats is delivered with a cycle length of 410 ms during tachy- cardia; cycle length ¼ 437 ms. No one was available to provide information about past medical history or the onset of this event. Electrocardiographic criteria for ventricular tachycardia in wide complex left bundle branch block morphology tachycardias. 89-98. At first glance (as was the incorrect interpretation by the emergency room physicians), the ECG may be thought to show narrow QRS complexes interspersed with wide QRS complexes. A normal QRS should be less than 0.12 seconds (120 milliseconds), therefore a wide QRS will be greater than or equal to 0.12 seconds. The first 2 beats are sinus, whereas the third QRS complex starts a tachycardia with an average rate of about 160 beats/min. The presence of antiarrhythmic drugs (especially class Ic or class III antiarrhythmic drugs) or electrolyte abnormalities (such as hyperkalemia) can slow intra-myocardial conduction velocity and widen the QRS complex. Ventricular arrhythmias are almost allways wide-QRS-complex arrhythmias. The QRS duration is very broad, approaching 200 ms; the rate is 125 bpm. For complete dissociation, this would require that the VT rate would fortuitously have to be at an exact multiple of the sinus rate. Flecainide, a class Ic drug, is an example that is notorious for widening the QRS complex at faster heart rates, often resulting in bizarre-looking ECGs that tend to cause diagnostic confusion. Of course, such careful evaluation of the patient is only possible when the patient is hemodynamically stable during VT; any hemodynamic instability (such as presyncope, syncope, pulmonary edema, angina) should prompt urgent or emergent cardioversion. Vereckei, A, Duray, G, Szenasi, G. “Application of a new algorithm in the differential diagnosis of wide QRS complex tachycardia”. Looks like you’re enjoying our content... You’ve viewed {{metering-count}} of {{metering-total}} articles this month. Such confusion is most often related to the occasional patient where aberrancy results in a particularly bizarre QRS complex morphology, raising the likelihood that the WCT might be VT. 28. He presented with a complaint of nausea and vomiting and was found to have a worsening of acute kidney infection. - Full-Length Features The QRS complex is wide at .12 seconds, or 120 ms., representing interventricular conduction delay (IVCD). All rights reserved. When confronted with a wide-QRS-complex tachycardia it can be difficult to differentiate between a supraventricular tachycardia with aberrancy or ventricular tachycardia.A separate chapter deals with this dilemma: Approach to the Wide Complex Tachycardia. Note that as the WCT rate oscillates, the retrograde P waves follow the R-R intervals. 589-600. This page includes the following topics and synonyms: QRS Complex, QRS Duration, Wide QRS, QRS Widening. 5–11A , but the location of the AP could not be determined from just this figure. In an effort to aid the clinician, scoring systems have been recently proposed, but their clinical performance is only marginally superior to older criteria (see references). In other words, the VT morphology shows the infarct location because VT most often arises from the infarct scar location. On a practical matter, telemetry recordings are often erased once the patient leaves that location, and it is important to print out as many examples of the WCT as possible for future review by the cardiology or electrophysiology consultant. Subtle changes in QRS amplitude for some QRS complexes are observed (asterisk). The ECG signs of RVOT are: wide QRS complex, left bundle branch block pattern (QRS negative in V1 and positive in Leads I and V6), heart rate over 100 bpm, rightward or inferior axis (LBBB usually has a normal to leftward axis), AV dissociation. PMID: 17254598 “The Lewis Lead for Detection of Ventriculoatrial Conduction Type”. Current cardiology reviews. • The most common noncardiac causes of VT are hypoxemia, electrolyte imbalances (hypokalemia), acid-base disorders, and drugs.