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Hallmark ECG features of ventricular tachycardia (VT). AV indicates atrioventricular; LAD, left axis deviation; LBBB, left bundle branch block; NW, northwest; RAD, right axis deviation; RBBB, right bundle branch block; RWPT, R wave peak time; and WCT, wide complex tachycardia. Downloaded from http://ahajournals.org by on May 19, 2020
Source publication
The primary goal of the initial ECG evaluation of every wide complex tachycardia is to determine whether the tachyarrhythmia has a ventricular or supraventricular origin. The answer to this question drives immediate patient care decisions, ensuing clinical workup, and long‐term management strategies. Thus, the importance of arriving at the correct...
Contexts in source publication
Context 1
... definition, atrioventricular dissociation is present when a self-governing ventricular rhythm autonomously subsists the atrial rhythm. Classically, atrioventricular dissociation is characterized by a series of QRS complexes uncoupled from "dissociated" P waves (Figure 1). When interpreting a 12-lead ECG displaying VT, atrioventricular dissociation may be recognized as interspersed P waves nestled between or hidden amidst overlapping QRS complexes and T waves. ...
Context 2
... examination of QRS configurations recorded in particular ECG leads (ie, V1-V2 and V6) may provide essential clues as to whether a WCT has a ventricular or supraventricular origin. The pioneering works put forth by Sandler and Marriott, 13 Wellens et al 1 , and Kindwall et al 14 -collectively known as the "classical morphological criteria"-have added considerable value towards the diagnostic evaluation of WCTs (Figure 1). ...
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... substantial proportion of SWCTs will display QRS durations >160 ms, especially among patients with ongoing antiarrhythmic drug use, electrolyte disturbances, dramatic conduction delays, or severe underlying structural heart disease or cardiomyopathies. On the contrary, many patients demonstrating idiopathic VT variants or VTs that arise from within or rapidly engage the His-Purkinje system demonstrate QRS durations <140 ms ( Figure 1). In rarer cases, VTs may demonstrate substantial impulse propagation within the conduction system and express QRS durations <120 ms (eg, fascicular VT), thereby not fulfilling the technical definition of WCT (ie, heart rate ≥100 beats per minute and QRS duration ≥120 ms). ...
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... the keen observations described originally by Marriott, 16 chest lead concordance has endured as a strong distinguishing feature of VT. According to its strict definition, concordance is present when QRS complexes in all 6 precordial leads (V1-V6) uniformly display a monophasic pattern having the same polarity (ie, "R" for positive concordance and "QS" for negative concordance) (Figure 1). In general, WCTs demonstrating positive concordance most often arise from VT originating from the posterobasal left ventricle. ...
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... 1988, Akhtar and colleagues 15 verified that a rightward superior QRS axis (ie, northwest axis) between −90° and −180° is highly predictive of VT (Figure 1). Subsequently, several manually applied WCT differentiation methods, including Vereckei aVR algorithm, 6 Jastrzebski VT score, 8 and the limb lead algorithm, 10 have knowingly incorporated an ECG criterion (ie, dominant R wave in lead aVR) that essentially employs QRS axis as a key diagnostic determinant. ...
Context 6
... Conversely, a VT wavefront that propagates and spreads from a site of origin remote from specialized conduction tissue, and thereby must utilize slower cardiomyocyte-to-cardiomyocyte conduction, is expected to demonstrate delayed or "slurred" initial components of the QRS complex (eg, R wave peak time [RWPT] in lead II ≥50 ms, or RS interval ≥100 ms in any of the precordial leads [V1-V6]). 2,7 However, once the VT impulse engages the conduction system, and swiftly activates the remainder of the ventricular myocardium, the terminal components of the QRS complex will correspondingly demonstrate more rapid or "sharper" deflections compared with what was observed at the beginning of the QRS complex (eg, ratio of the voltage excursion during the initial [V i ] and terminal [V t ] 40 ms of the QRS complex <1) (Figure 1). 5,6 Comparison to the Baseline ECG ...
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... we introduced novel WCT differentiation methods, 11,12,22 which leverage the magnitude of change between the WCT and baseline ECG as a means to effectively distinguish VT and SWCT (Figure 1). We described how universally available computerized measurements derived from CEI software may be used to precisely quantify specific changes between the WCT and baseline rhythms. ...
Citations
... Electrocardiography (ECG) and Holter monitoring are essential for interpreting these arrhythmias. Despite years of research and the development of numerous criteria and algorithms, their real-world accuracy and efficacy are often inadequate [3,4], as evidenced by numerous publications and case reports highlighting the limitations of these methods [5,6]. ...
... When visualization of atrial waves is poor, reliance on these methods is problematic, necessitating an alternative focus on the morphological characteristics of wide QRS complexes that suggest VT or aberrant conduction. Even as the list of various algorithms grows, their diagnostic precision remains questionable across various patient groups [6]. ...
... The first examines the contours of individual QRS complex deflections, the second measures the durations of the QRS components, and the third assesses the amplitude changes in the initial and terminal parts of the QRS complex and their ratios. However, criteria from the first two groups consistently demonstrate limited diagnostic accuracy when applied to different clinical populations [6]. ...
... Most of these have been validated almost exclusively in patients undergoing electrophysiology study with interpretation by cardiac electrophysiologists outside of the acute clinical setting in which the tachycardia presented. 18 This is important because it gives an indication of why, despite the excellent reported sensitivity and specificity of these algorithms, clinicians in the real world continue to face significant diagnostic uncertainty when interpreting ECGs of WCT. Ultimately, it is likely to be most helpful to apply the principles that the algorithms are derived from rather than to learn the ventricular activation would be slow because of transmission through myocardial tissue, in contrast to specialised CCS tissue. ...
... Other QRS axis features that favour VT include left-axis deviation in RBBB morphology tachycardias and right axis deviation in LBBB tachycardias. 18 The polarity of the lead aVR can also be helpful in differentiating the aetiology of a tachycardia. During conducted rhythms, the initial ventricular activation is septal and subsequent ventricular activation proceeds away from the lead aVR, resulting in a predominantly negative QRS complex in the lead aVR. ...
... As per the image, QRS duration, precordial lead concordance, and QRS axis all suggest VT. Reproduced via a Creative Commons Attribution-NonCommercial License from Kashou et al.18 ...
Ventricular tachycardia (VT) describes rapid heart rhythms originating from the ventricles. Accurate diagnosis of VT is important to allow prompt referral to specialist services for ongoing management. The diagnosis of VT is usually made based on electrocardiographic data, most commonly 12-lead echocardiography (ECG), as well as supportive cardiac telemetric monitoring. Distinguishing between VT and supraventricular arrhythmias on ECG can be difficult. However, the VT diagnosis frequently needs to be made rapidly in the acute setting. In this review, we discuss the definition of VT, review features of wide-complex tachycardia (WCT) on ECG that might be helpful in diagnosing VT, discuss the different substrates in which VT can occur and offer brief comments on management considerations for patients found to have VT.
... A true SVT misdiagnosed as VT might result in the initiation of potentially harmful medications (e. g., antiarrhythmic drugs with noxious side-effects), inappropriate interventions (e.g., implantable cardioverter-defibrillator placement), and increased healthcare expenditures (e.g., cardiac intensive care unit admission). Over the course of five decades numerous manual ECG interpretation criteria and algorithms have been proposed help clinicians differentiate WCTs [13,14]. As a general rule, manual WCT differentiation methods leverage one or more ECG criteria that embody distinctive electrophysiologic properties of VT and SVT. ...
Background:
Artificial intelligence-augmented ECG (AI-ECG) refers to the application of novel AI solutions for complex ECG interpretation tasks. A broad variety of AI-ECG approaches exist, each having differing advantages and limitations relating to their creation and application.
Purpose:
To provide illustrative comparison of two general AI-ECG modeling approaches: machine learning (ML) and deep learning (DL).
Method comparison:
Two AI-ECG algorithms were developed to carry out two separate tasks using ML and DL, respectively. ML modeling techniques were used to create algorithms designed for automatic wide QRS complex tachycardia differentiation into ventricular tachycardia and supraventricular tachycardia. A DL algorithm was formulated for the task of comprehensive 12‑lead ECG interpretation. First, we describe the ML models for WCT differentiation, which rely upon expert domain knowledge to identify and formulate ECG features (e.g., percent monophasic time-voltage area [PMonoTVA]) that enable strong diagnostic performance. Second, we describe the DL method for comprehensive 12‑lead ECG interpretation, which relies upon the independent recognition and analysis of a virtually incalculable number of ECG features from a vast collection of standard 12‑lead ECGs.
Conclusion:
We have showcased two different AI-ECG methods, namely ML and DL respectively. In doing so, we highlighted the strengths and weaknesses of each approach. It is essential for investigators to understand these differences when attempting to create and apply novel AI-ECG solutions.
... Over the last 50-60 years, a plethora of manually applied ECG criteria and algorithms have been proposed (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). While these algorithms can potentially improve discrimination of VT from SWCT, each has relevant diagnostic limitations that pose a challenge for clinical implementation (14)(15)(16)(17)(18)(19)(20). ...
Background
Timely and accurate discrimination of wide complex tachycardias (WCTs) into ventricular tachycardia (VT) or supraventricular WCT (SWCT) is critically important. Previously we developed and validated an automated VT Prediction Model that provides a VT probability estimate using the paired WCT and baseline 12-lead ECGs. Whether this model improves physicians' diagnostic accuracy has not been evaluated.
Objective
We sought to determine whether the VT Prediction Model improves physicians' WCT differentiation accuracy.
Methods
Over four consecutive days, nine physicians independently interpreted fifty WCT ECGs (25 VTs and 25 SWCTs confirmed by electrophysiological study) as either VT or SWCT. Day 1 used the WCT ECG only, Day 2 used the WCT and baseline ECG, Day 3 used the WCT ECG and the VT Prediction Model's estimation of VT probability, and Day 4 used the WCT ECG, baseline ECG, and the VT Prediction Model's estimation of VT probability.
Results
Inclusion of the VT Prediction Model data increased diagnostic accuracy versus the WCT ECG alone (Day 3: 84.2% vs. Day 1: 68.7%, p 0.009) and WCT and baseline ECGs together (Day 3: 84.2% vs. Day 2: 76.4%, p 0.003). There was no further improvement of accuracy with addition of the baseline ECG comparison to the VT Prediction Model (Day 3: 84.2% vs. Day 4: 84.0%, p 0.928). Overall sensitivity (Day 3: 78.2% vs. Day 1: 67.6%, p 0.005) and specificity (Day 3: 90.2% vs. Day 1: 69.8%, p 0.016) for VT were superior after the addition of the VT Prediction Model.
Conclusion
The VT Prediction Model improves physician ECG diagnostic accuracy for discriminating WCTs.
... Linton reports that we are better at diagnosing certain wide-complex tachycardias (Atrial Fibrillation, Ventricular Tachycardia) than others (Supraventricular Tachycardia, Atrial Flutter) but overall have high agreement with cardiologists' ECG interpretation (81.2%) [1]. Specific ECG findings can differentiate aberrant conduction from ventricular tachycardia [2]. Awareness of ECG findings pathognomonic for toxicologic and metabolic causes is also essential [2]. ...
... Specific ECG findings can differentiate aberrant conduction from ventricular tachycardia [2]. Awareness of ECG findings pathognomonic for toxicologic and metabolic causes is also essential [2]. ...
... The vast majority of WCT is caused by ventricular tachycardia which leads some researchers to regard it as the default diagnosis of any WCT, but such way of thinking should be avoided due to the possibility of other forms of tachycardia that can present with a similar ECG appearance. Therefore, numerous researches were conducted aiming to develop algorithms to help differentiate ventricular tachycardia from other mimicking arrhythmias particularly wide complex SVTs (Kashou et al., 2020). ...
... Because WCT will frequently lead to hemodynamic instability. In patients who are deemed to be unstable, prompt use of cardioversion is mandatory to prevent the development of cardiac arrest (Roka et al., 2019;Kashou et al., 2020). ...
... Another possibility is when patients with SVT have a simultaneous metabolic condition causing wide QRS such in the case of hyperkalemia or other electrolyte imbalances. Additionally, the use of some antiarrhythmic drugs for example amiodarone might also lead to widening of the QRS complex in case of drug toxicity (Kashou et al., 2020). Differentiating between VT and other arrhythmias causing wide QRS can be a difficult task, but some ECG clues that generally favor VT diagnosis include the following; the presence of fusion or capture beats, QRS duration exceeding 140ms, extreme axis deviation, and identifying negative QRS complexes in all chest leads. ...
... 2,3 There are various causes of aberrated conduction: (1) pre-existing and/or physiologic/functional bundle branch or interventricular conduction block, (2) metabolic derangements (i.e., hyperkalemia), and (3) druginduced (i.e., propafenone toxicity). 4 The described mechanisms of functional/physiologic block include acceleration-dependent block above the critical heart rate, phase 3 block of the action potential, phase 4 bradycardia-dependent block due to disease in the His-Purkinje system, and transseptal, retrograde, concealed invasion of the bundle branch (BB) rendering it refractory to subsequent depolarizations. 5 Our patient's ECG ( Figure 1B) demonstrates two of these mechanisms: phase 3 block, which caused the first aberrated QRS in the group followed by transseptal, retrograde, concealment into the RB perpetuating the aberrancy. ...
65-year-old man with a history of coronary artery disease s/p percutaneous coronary intervention to the left anterior descending artery and atrial fibrillation s/p recent (<3 months) pulmonary vein isolation presented to the emergency department with symptoms of palpitations for 1 day after admittedly forgetting to take his medications found to be in a wide complex tachycardia. We discuss a stepwise approach using properties of the conduction system to diagnose the patient’s tachycardia.
... pacemakers). (49) The presence of a pre-existing structural cardiac disease (such as ischaemic heart disease or cardiac failure) increases the already high likelihood of the WCT being due to VT. Specific ECG features such as AV dissociation would also confirm a diagnosis of VT. (50) However, if the patient's baseline ECG already demonstrates a wide QRS morphology that is similar to the patient's current WCT, SVT with aberrancy or WPW should be considered. (51) In case of clinical uncertainty, the patient should be managed in the same way as a patient with VT would be ( Fig. 10 shows the algorithm for WCT). ...
Advanced cardiac life support (ACLS) emphasises the use of advanced airway management and ventilation, circulatory support and the appropriate use of drugs in resuscitation, as well as the identification of reversible causes of cardiac arrest. Extracorporeal cardiopulmonary resuscitation and organ donation, as well as special circumstances including drowning, pulmonary embolism and pregnancy are addressed. Resuscitation does not end with ACLS but must continue in post-resuscitation care. ACLS also covers the recognition and management of unstable pre-arrest tachy- and bradydysrhythmias that may deteriorate further.
... None of the criteria for VT were clearly present. Nonetheless, VT could not be excluded with certainty because the presence of certain features used in the differential diagnosis of WCT [18,19] could not be clearly ascertained. Regarding the Brugada algorithm [16], there was no clear concordance, since an rS complex was present in the precordial leads, but the r waves were very small (0.1 mV or less in amplitude). ...
A 69-year-old woman with a history of hypertension and obesity, hospitalized with atypical chest pain, was diagnosed with left ventricular noncompaction. In-hospital monitoring of the cardiac rhythm revealed multiple episodes of atrial tachycardia and one episode of wide complex tachycardia (WCT) with left bundle branch block-like morphology and a right superior QRS axis. The electrocardiographic criteria were suggestive of a supraventricular origin of the WCT. Given the importance of reaching the correct diagnosis when dealing with a WCT, we tried to further define the pattern of ventricular activation using vectorcardiography (VCG). We analyzed the QRS loops during WCT in comparison to a sinus beat, a narrow complex tachycardia beat, and a premature ventricular contraction. The fast initial activation seen in the efferent limb of the QRS loop during the WCT was thought to be reflective of the fast initial activation via the conduction system seen in SVT with aberrancy, which was our final diagnosis for the WCT episode. This case illustrates a novel use of vectorcardiography as an additional diagnostic tool in the differential diagnosis of WCT.
... Different algorithms and criteria have been developed to aid electrocardiographic differentiation of VT and SVT-A. 1 The most commonly used criteria include the Brugada algorithm, 2 the aVR 'Vereckei' algorithm, 3 the lead II R-wave-peak-time criterion 4 and Griffith algorithm. 5 Recently, mathematical logistic regression models (The WCT formula, The WCT formula II, VT prediction Model) [6][7][8] for implementation in computerized ECG interpretation software have also been developed. ...
Background
Electrocardiogram (ECG) differentiation of wide complex tachycardia (WCT) into ventricular tachycardia (VT) and supraventricular tachycardia with aberration (SVT-A) is often challenging.
Objective
To determine if the presence of Q-waveforms (QS, Qr, QRs) in the inferior leads (II, III, aVF) can differentiate VT from SVT-A in a WCT compared to Brugada algorithm. We studied 2 inferior lead criteria namely QWC-A where all the inferior leads had a similar Q wave pattern and QWC-B where only lead aVF had a Q-waveform.
Methods
A total of 181 consecutive cases of WCT were identified, digitally separated into precordial leads and inferior leads and independently reviewed by 2 electrophysiologists. An electrocardiographic diagnosis of VT or SVT-A was assigned based on Brugada and inferior lead algorithms. Results were compared to the final clinical diagnosis.
Results
VT was the final clinical diagnosis in 24.9% of ECG cohort (45/181); 75.1% (136/181) were SVT-A. QWC-A and QWC-B had a high specificity (93.3% and 82.8%) and accuracy (78.2% and 71.0%), but low sensitivity (33.3% and 35.6%) in differentiating VT from SVT-A. The Brugada algorithm yielded a sensitivity of 82.2% and specificity of 68.4%. Area under the curve in ROC analysis was highest with Brugada algorithm (0.75, 95% CI 0.69-0.81) followed by QWC-A (0.63, 95% CI 0.56-0.70) and QWC-B (0.59, 95% CI 0.52-0.67).
Conclusion
QWC-A and QWC-B criteria had poor sensitivity but high specificity in diagnosing VT in patients presenting with WCT. Further research combining this simple criterion with other newer diagnostic algorithms can potentially improve the accuracy of the overall diagnostic algorithm.
