The emergence and destiny of automated methods to differentiate wide QRS complex tachycardias.

Accurate differentiation of wide complex tachycardias (WCTs) into ventricular tachycardia (VT) or supraventricular wide complex tachycardia (SWCT) using non-invasive methods such as 12­lead electrocardiogram (ECG) interpretation is crucial in clinical practice. Recent studies have demonstrated the potential for automated approaches utilizing computerized ECG interpretation software to achieve accurate WCT differentiation. In this review, we provide a comprehensive analysis of contemporary automated methods for VT and SWCT differentiation. Our objectives include: (i) presenting a general overview of the emergence of automated WCT differentiation methods, (ii) examining the role of machine learning techniques in automated WCT differentiation, (iii) reviewing the electrophysiology concepts leveraged existing automated algorithms, (iv) discussing recently developed automated WCT differentiation solutions, and (v) considering future directions that will enable the successful integration of automated methods into computerized ECG interpretation platforms.

The Application of a New, Modified Algorithm for the Differentiation of Regular Ventricular and Pre-Excited Tachycardias.

BACKGROUND: The three-step Brugada group algorithm is the only published electrocardiographical (ECG) algorithm for differentiating ventricular tachycardia (VT) from pre-excited tachycardia (PXT) as a cause of regular wide QRS complex tachycardia (WCT). This study aimed to improve the diagnostic accuracy of the Brugada group algorithm. METHODS: This study modified the Brugada group algorithm by adding a new aVR lead criterion (initial positive deflection in lead aVR and the QRS complex area above the baseline is greater than the area below the baseline). The Brugada group algorithm and the new, modified four-step algorithm in 300 WCT ECGs (241 VTs, 59 PXTs) was applied. If any of the criteria were fulfilled, VT was diagnosed; if none were fulfilled, a diagnosis of PXT was established. RESULTS: The test accuracy, VT diagnosis sensitivity, and negative predictive value (NPV) of the new, modified algorithm were significantly greater than that of the Brugada group algorithm: test accuracy 220 of 300 (73%) vs 182 of 300 (61%); sensitivity 73% vs 55% (p<0.001 for both); NPV 40% vs 31% (p=0.0205). The VT diagnosis specificity of the Brugada group algorithm was greater than that of the new, modified algorithm (83% vs 75%; p=0.019). There was no significant difference between the new, modified and Brugada group algorithms in the positive predictive values (92% vs 93%, respectively) for a VT diagnosis, and positive and negative likelihood ratio values (2.87 vs 3.26; 0.36 vs 0.54, respectively). CONCLUSIONS: The new, modified algorithm proved to be more sensitive for the differentiation of VT from PXT than the Brugada group algorithm.

Fibroblast growth factor 21 is associated with widening QRS complex and prolonged corrected QT interval in patients with stable angina.

BACKGROUND: Fibroblast growth factor 21 (FGF21) is produced by cardiac cells, may acts in an autocrine manner, and was suggested to has a cardioprotective role in atherosclerosis. Wide QRS complex and heart rate-corrected QT interval (QTc interval) prolongation are associated to dangerous ventricular arrhythmias and cardiovascular disease mortality. Yet, the role of FGF21 in cardiac arrhythmia has never been studied. The aim of the study was to investigate the relationship between plasma FGF21 and the QRS duration and QTc interval in patients with stable angina. METHODS: Three hundred twenty-one consecutive stable angina patients were investigated. Plasma FGF21 was measured through ELISA, and each subject underwent 12-lead electrocardiography. RESULTS: FGF21 plasma levels were positively associated with the QRS duration (ß = 0.190, P = 0.001) and QTc interval (ß = 0.277, P < 0.0001). With increasing FGF21 tertiles, the patients had higher frequencies of wide QRS complex and prolonged QTc interval. After adjusting for patients' anthropometric parameters, the corresponding odd ratios (ORs) for wide QRS complex of the medium and high of FGF21 versus the low of FGF21 were 1.39 (95% CI 0.51-3.90) and 4.41 (95% CI 1.84-11.59), respectively, and p for trend was 0.001. Furthermore, multiple logistic regression analysis also showed the corresponding odd ratios (ORs) for prolonged QTc interval of the medium and high of FGF21 versus the low of FGF21 were 1.02 (95% CI 0.53-1.78) and 1.93 (95% CI 1.04-3.60) respectively with the p for trend of 0.037. In addition, age- and sex-adjusted FGF21 levels were positively associated with fasting glucose, HbA1c, creatinine, and adiponectin, but negatively associated with albumin, and the estimated glomerular filtration rate. CONCLUSIONS: This study indicates that plasma FGF21 is associated with wide QRS complex and prolonged corrected QT interval in stable angina patients, further study is required to investigate the role of plasma FGF21 for the underlying pathogenesis.

[Predictive value of QRS complex duration in patients with chronic heart failure and atrial fibrillation: retrospective study].

AIM: To study of the features of the clinical course and prognosis in patients with chronic heart failure with low ejection fraction (HFrEF) and atrial fibrillation (AF) depending on the width of the QRS complex. MATERIALS AND METHODS: We studied the case histories of 514 patients (aged 60.213.84 years, 78% men) with HFrEF, hospitalized at the Chazov National Medical Research Center of Cardiology (Moscow) for the period from Jan 1, 2017 to Dec 31, 2018. Patients were divided into 2 groups depending on the duration of the QRS complex. RESULTS: Clinical and statistical retrospective analysis of the medical histories of patients with HFrEF, depending on the QRS duration, showed the predominance of patients with a QRS complex size of less than 130 ms (60.7%). In HFrEF, the expansion of the QRS complex is accompanied by an increase in the rate of readmission in patients with sinus rhythm (p=0.004). In patients with AF, the rehospitalization rate is significantly higher than in sinus rhythm and does not depend on the QRS duration (p=0.001). The incidence of unfavorable outcomes increases in connection with the addition of AF, which is most likely a more significant risk factor than QRS width. CONCLUSION: These results highlight that patients with AF and a narrow QRS complex have the same poor prognosis as those with a wide QRS complex and require the close attention of cardiologists.

Association between wide QRS pulseless electrical activity and hyperkalemia in cardiac arrest patients.

AIM: We evaluated the relationship between hyperkalemia and wide QRS complex in patients with pulseless electrical activity (PEA) cardiac arrest. METHODS: This was a single-center, retrospective observational study of patients over the age of 18 treated for cardiac arrest at a tertiary referral hospital whose initial electrocardiogram rhythm was PEA from February 2010 to December 2019. Wide QRS PEA was defined as a QRS interval of 120 ms or more. Hyperkalemia was defined as serum potassium level > 5.5 mmol/L. The primary outcome was hyperkalemia. Multivariable logistic regression analysis was used to evaluate the relationship between wide QRS and hyperkalemia. RESULTS: Among 617 patients, we analyzed 111 episodes in the wide QRS group and 506 episodes in the narrow QRS group. The potassium level in the wide QRS group was significantly higher than in the narrow QRS group (5.4 mmol/L, IQR 4.4-6.7 vs. 4.6 mmol/L, IQR 4.0-5.6, P < 0.001). Among all patients, 49.6% (n = 55/111) in the wide QRS group had hyperkalemia, which was significantly higher than the 26.7% (n = 135/506) in the narrow QRS group (P < 0.001). In multivariable logistic regression analysis, wide QRS PEA was significantly associated with hyperkalemia (odds ratio = 2.86, 95% confidence interval: 1.80-4.53, P < 0.001). CONCLUSIONS: Wide QRS PEA as an initial cardiac rhythm was significantly associated with hyperkalemia in cardiac arrest patients.

Ventriculoatrial interval variation following atrio-His block during wide-QRS-complex tachycardia with 1:1 ventriculoatrial relationship: What is the diagnosis?

A wide QRS-complex tachycardia with 1:1 ventriculoatrial conduction may present diagnostic difficulties, and multiple pacing maneuvers are often required for an accurate diagnosis. We report a case, in which observation of transient ventriculoatrial interval variation following atrio-His block quickly led to the diagnosis.

Specificity of wide QRS complex tachycardia criteria and algorithms in patients with ventricular preexcitation.

BACKGROUND: Despite substantial progress in the field of differentiation between ventricular tachycardia (VT) and supraventricular tachycardia (SVT) with wide QRS complexes, differentiation between VT and preexcited SVT remains largely unresolved due to significant overlap in QRS morphology. Our aim was to assess the specificities of various single ECG criteria and sets of criteria (Brugada algorithm, aVR algorithm, Steurer algorithm, and the VT score) for diagnosis of VT in a sizable cohort of patients with preexcitation. METHODS: We performed a retrospective study of consecutive accessory pathway ablation procedures to identify preexcited tachycardias. Among 670 accessory pathway ablation procedures, 329 cases with good quality ECG with either bona fide preexcited SVT (n = 30) or a surrogate preexcited SVT (fast paced atrial rhythm with full preexcitation, n = 299) were identified. ECGs were analyzed with the use of wide QRS complex algorithms/criteria to determine specificities of these methods. RESULTS: The Steurer algorithm and VT score (≥3 points), with specificities of 97.6% and 96.1%, respectively, were significantly (p < .01) more specific for the diagnosis of VT than Brugada algorithm, aVR algorithm, and Pava criterion with specificities of 31%, 11.6%, and 57.1%, respectively. The first step of the Brugada algorithm and the first step of the aVR algorithm had also high specificities of 93.3% and 96.0%, respectively. CONCLUSION: There are sufficient electrocardiographical differences between VT and preexcited SVT to allow electrocardiographic differentiation. VT score, Steurer algorithm, and some single criteria do not overdiagnose VT in patients with preexcitation.

A rare form of extremely wide QRS complex due to reversed homologous electrical ventricular separation of acute heart failure.

Electrical ventricular separation, as a special complete intraventricular block, denotes that ventricles be electrically separated into two or more parts caused by severe and wide damage of myocardium and conduction. Electrical ventricular separation can be divided into homologous and heterologous, homologous electrical ventricular separation is a rare phenomenon, literally the excitement of whole ventricle originate from supraventricle, on ECG, there are two different QRS waves which connect with an isoelectric line, one ST segment and T wave. We report a valve heart disease presented with complicated electrophysiological characteristics, which has reversed complex homologous electrical ventricular separation with second degree intraventricular block.

Wide QRS complex supraventricular tachycardia with negative precordial concordance: Electrocardiographic clues for Mahaim pathway with Ebstein anomaly.

Ebstein's anomaly is often accompanied by either Wolff-Parkinson-White syndrome or atriofascicular Mahaim. These bypass tracts give rise to antidromic atrioventricular (AV) re-entrant tachycardias, in which the bypass tract serves as the anterograde limb of the circuit and the AV node as the retrograde limb of the reentrant circuit. Since the antidromic AV reentrant tachycardia over a Mahaim fibre has a typically left bundle braunch block (LBBB) morphology, it is easy to make a misdiagnosis of supraventricular tachycardia with functional LBBB or even of ventricular tachycardia particularly in the presence of negative concordance. Some electrocardiographic clues might prevent misdiagnosis of ventricular tachycardia and inadvertent ICD implantation.

The differential diagnosis of wide QRS complex tachycardia.

Wide complex tachycardia is defined as a cardiac rhythm with a rate greater than 100 beats/min (bpm) and a QRS complex duration greater than 0.10 to 0.12seconds (s) in the adult patient; wide complex tachycardia (WCT) in children is defined according to age-related metrics. The differential diagnosis of the WCT includes ventricular tachycardia and supraventricular tachycardia with aberrant intraventricular conduction, including both relatively benign and life-threatening dysrhythmias. This review focuses on the differential diagnosis of WCT with a discussion of strategies useful in making the appropriate diagnosis, when possible.

Ventricular tachycardia score - A novel method for wide QRS complex tachycardia differentiation - Explained.

Philosophy, merits and limitations of a novel method for wide QRS complex tachycardia differentiation, based on a scoring system and called the ventricular tachycardia (VT) score, were explained. The following criteria were assigned one point: initial dominant R wave in V1; initial r>40 ms in V1 or V2; notched S in V1; initial R wave in aVR; lead II RWPT≥50 ms; and absence of an RS in leads V1-V6. Atrioventricular dissociation (including fusion/capture beats and partial dissociation) was assigned two points. We recommend ≥3 VT score points for a firm diagnosis of VT. A cut-off ≥1 point can be used for diagnosis of VT when highest overall accuracy rather than error-free diagnosis is desired. However, in case of VT score of 0-2 (i.e., not fully diagnostic ECG), we recommend using other options (electrophysiological study, clinical data, previous and following ECGs, etc.) for confirming the diagnosis.

The ventricular tachycardia score: a novel approach to electrocardiographic diagnosis of ventricular tachycardia.

AIMS: Electrocardiographic diagnosis of wide QRS complex tachycardia (WCT) continues to be challenging as none one of the available methods is specific for ventricular tachycardia (VT) diagnosis. We aimed to construct a method for WCT differentiation based on a scoring system, in which ECGs are graded according to the number of VT-specific features. This novel method was validated and compared with Brugada algorithm and other methods. METHODS AND RESULTS: A total of 786 WCTs (512 VTs) from 587 consecutive patients with a proven diagnosis were analysed by two blinded observers. The VT score method was based on seven ECG features: initial R wave in V1, initial r > 40 ms in V1/V2, notched S in V1, initial R in aVR, lead II R wave peak time ≥50 ms, no RS in V1-V6, and atrioventricular dissociation. Atrioventricular dissociation was assigned two points, and each of the other features was assigned one point. The overall accuracy of VT score ≥1 for VT diagnosis (83%) was higher than that of the aVR (72%, P = 0.001) and Brugada (81%) algorithms. Ventricular tachycardia score ≥3 was present in 66% of VTs and was more specific (99.6%) than any other algorithm/criterion for VT diagnosis. Ventricular tachycardia score ≥4 was present in 33% of VTs and was 100% specific for VT. CONCLUSION: The new ECG-based method provides a certain diagnosis of VT in the majority of patients with VT, identifies unequivocal ECGs, and has superior overall diagnostic accuracy to other ECG methods.

R-wave peak time at lead II in Chinese healthy adults.

BACKGROUND: Wide QRS complex tachycardia (WCT) is a common arrhythmia. How to differentiate between WCTs is a challenge in clinical practice. Recently R-wave peak time (RWPT) at lead II was reported to be a helpful and simple tool for differentiating WCTs. However, it has remained unknown about the reference range of RWPT at lead II. In present study, we aimed to investigate the reference range of RWPT at lead II in Chinese healthy adults. METHODS: A retrospective study was conducted in the First Affiliated Hospital of Shantou University Medical College in Southern China. Two thousand four hundred healthy adults aged 21-80 years with no history of structural heart diseases were included. RWPT at lead II was determined. RESULTS: Of 2400 healthy adults, 1200 men and 1200 women were included. The differences of age, mean heart rate and mean QRS duration at lead II between male and female were not significant. RWPT ranged from 16 to 42 ms in male while from 16 to 44 ms in female. The 95 % reference range of RWPT in normal male and female are 19.91 ~ 39.55 ms and 21.75 ~ 37.67 ms, respectively. Compared with the female, the male had a significantly longer RWPT at lead II (29.73 ± 5.01 ms vs 29.71 ± 4.06 ms in female, P = 0.000). CONCLUSION: Our study showed that RWPT at lead II is different between male and female. The male had a significantly longer RWPT at lead II than the female.

A machine learning approach to differentiate wide QRS tachycardia: distinguishing ventricular tachycardia from supraventricular tachycardia.

BACKGROUND: Differential diagnosis of wide QRS tachycardia (WQCT) has been a challenging issue. Published algorithms to distinguish ventricular tachycardia (VT) and supraventricular tachycardia (SVT) have limited diagnostic capabilities. METHODS: A total of 278 patients with WQCT from January 2010 to March 2022 were enrolled. The electrophysiological study confirmed SVT in 154 patients and VT in 65 ones. Two hundred nineteen WQCT 12-lead ECGs were randomly divided into development cohort (n = 165) and testing cohort (n = 54) data sets. The development cohort was split into a training group (n = 115) and an internal validation group (n = 50). Forty ECG features extracted from the 219 WQCT ECGs are fed into 9 iteratively trained ML algorithms. This novel ML algorithm was also compared with four published algorithms. RESULTS: In the development cohort, the Gradient Boosting Machine (GBM) model displayed the maximum area under curve (AUC) (0.91, 95% confidence interval (CI) 0.81-1.00). In the testing cohort, the GBM model had a higher AUC of 0.97 compared to 4 validated ECG algorithms, namely, Brugada (0.68), avR (0.62), RWPTII (0.72), and LLA algorithms (0.70). Accuracy, sensitivity, specificity, negative predictive value, and positive predictive value of the GBM model were 0.94, 0.97, 0.90, 0.94, and 0.95, respectively. CONCLUSIONS: A GBM ML model contributes to distinguishing SVT from VT based on surface ECG features. In addition, we were able to identify important indicators for distinguishing WQCT.

An extremely wide QRS complex tachycardia induced by anamorelin.

Anamorelin, a ghrelin receptor agonist, is used for cancer-related cachexia but can induce life-threatening arrhythmias. A case study illustrates an extremely wide QRS tachycardia, posing diagnostic challenges. Anamorelin cessation led to normalization, highlighting the importance of ECG monitoring, particularly in liver-compromised patients, and hemodynamic support are crucial during suspected toxicity.

Rare electrocardiographic findings in a young woman with acute barium poisoning: A case report.

Background: Barium, as a heavy divalent alkaline earth metal, can be found in various products such as rodenticides, insecticides, depilatories, and fireworks. Barium can be highly toxic upon both acute and chronic exposure. The toxicity of barium compounds is dependent on their solubility. Both suicidal and accidental exposures to soluble barium can cause toxicity. Case summary: We report a case characterized by two different wide QRS complex tachycardia in a patient with acute barium poisoning, one due to barium-induced ventricular tachycardia (VT) under hypokalemia and, subsequently, sino-ventricular conduction with intraventricular conduction delay due to hyperkalemia after aggressive potassium supplementation. The latter may be misdiagnosed as VT for the history of acute barium poisoning and the absence of peaked T wave in hyperkalemia. Of note, another hemodynamically unstable VT and profound hypokalemia occurred during the potassium-lowering therapy, which, in addition to barium poisoning, may also be due to the iatrogenic hypokalemia. We also observed the prominent T-U waves at serum potassium of 4.6 mM 12 hours after admission, which may indicate that barium had not been completely cleared from the plasma at that moment. There are some parallels to the Andersen-Tawil syndrome with prominent T-U waves and risk of ventricular tachycardias. To our knowledge, this is the first case report of conversion from hypokalemia to hyperkalemia, and in a short moment, from hyperkalemia to hypokalemia, in acute barium poisoning. Conclusion: In addition to profound hypokalemia secondary to acute barium poisoning, hyperkalemia may also occur after aggressive potassium supplementation. A more careful rather than too aggressive potassium supplementation may be suitable in these cases of hypokalemia due to an intracellular shift of potassium. And a iatrogenic hypokalemia risk in the treatment of rebound hyperkalemia in barium poisoning must be considered.

Wide QRS tachycardia in a patient with atrial fibrillation: a case report and approach to diagnosis.

Background: Wide QRS complex (QRS) tachycardia in patients with atrial fibrillation (AF) or atrial flutter treated with antiarrhythmic drugs can occur for a variety of reasons and needs careful evaluation for appropriate management of the patient. Case summary: We report a case of wide QRS complex tachycardia in a patient with AF treated with Flecainide who received multiple external cardioversion attempts for a presumed diagnosis of ventricular tachycardia. Intravenous Diltiazem and an oral beta-blocker led to the resolution of wide QRS complex tachycardia. Discussion: Wide QRS tachycardia due to pro-arrhythmic effect or rate-dependency phenomenon of antiarrhythmic agents should be included in the differentials. In this brief report, we discuss the differential diagnosis and outline a practical approach for acute and long-term management of these patients.

Evaluation of Wide Complex Tachycardia.

When a patient develops wide complex tachycardia, it is important to determine the cause quickly and accurately. This article will help the bedside nurse understand different causes, determine the most probable cause, and provide appropriate first-line treatment.

Diagnosis and management of wide complex tachycardia in the emergency department.

INTRODUCTION: While wide complex tachycardia (WCT) is potentially lethal, little is known about its incidence in the ED or about expertise of ED physicians in diagnosing and treating it. We sought to compare WCT ED cases that were primary arrhythmias versus those with rapid heart rate secondary to medical issues, as well as the accuracy of ED diagnosis and appropriateness of treatment. METHODS: We conducted a health records review at a large academic hospital ED staffed by 95 physicians and included consecutive patients over 28 months (2018-2020) with WCT (heart rate ≥ 120 bpm and QRS ≥ 120 ms). Cases were adjudicated for the accuracy of ECG diagnosis versus the cardiology read and for correctness of treatment as per guidelines by two ED physicians and one cardiologist. RESULTS: We identified 306 eligible cases (0.2% of all ED visits): mean age 73.9 years, male 66.0%, admitted 53.3%, died in ED 2.3%. Primary arrhythmias and secondary tachycardias were each 50.0% (95% CI 44.4-55.6%). ED physicians correctly interpreted 81.2% of ECGs. The most common presenting arrythmias and % correct were: atrial fibrillation 42.7% (95.0%), atrial flutter 22.2% (63.5%), sinus tachycardia 12.0% (78.6%), and supraventricular tachycardia (SVT) 11.1% (68.0%). Treatments were judged optimal in 84.3% of primary WCT and 86.9% in secondary WCT. Treatments were suboptimal for: inappropriate drug (3.9% for primary versus 1.3% for secondary), failure to reduce heart rate < 100 prior to discharge home (9.1% for primary versus 34.4% for secondary), and not treating the underlying cause in 5.9% of secondary WCT. CONCLUSIONS: WCT cases were evenly split between primary arrhythmias and secondary cases. ED physicians interpreted the ECG correctly in 81% but over-called atrial flutter and SVT. They implemented appropriate care in most cases but sometimes failed to adequately control heart rate or to treat the underlying condition, suggesting opportunities to improve care of WCT in the ED.

RéSUMé: INTRODUCTION: Bien que la tachycardie à complexe large (wide complex tachycardia WCT) soit potentiellement mortelle, on sait peu de choses sur son incidence aux urgences ou sur l'expertise des médecins des urgences en matière de diagnostic et de traitement. Nous avons cherché à comparer les cas WCT aux urgences qui étaient des arythmies primaires par rapport à ceux avec une fréquence cardiaque rapide secondaire à des problèmes médicaux, ainsi que la précision du diagnostic des urgences et la pertinence du traitement. MéTHODES: Nous avons effectué un examen des dossiers médicaux dans les urgences d'un grand hôpital universitaire où travaillent 95 médecins et avons inclus des patients consécutifs sur 28 mois (2018-2020) présentant un WCT (fréquence cardiaque ≥120 bpm et QRS ≥120 ms). Les cas ont été jugés par deux médecins des urgences et un cardiologue pour l'exactitude du diagnostic ECG par rapport à la lecture cardiologique et pour l'exactitude du traitement conformément aux directives. RéSULTATS: Nous avons identifié 306 cas éligibles (0,2 % de toutes les visites aux urgences) : âge moyen 73,9 ans, hommes 66,0 %, admis 53,3 %, décédés aux urgences 2,3 %. Les arythmies primaires et les tachycardies secondaires étaient chacune de 50,0 % (IC 95 % 44,4-55,6 %). Les médecins des urgences ont interprété correctement 81,2 % des ECG. Les arythmies les plus fréquentes et les pourcentages d'interprétation correcte étaient les suivants : fibrillation auriculaire 42,7 % (95,0 %), flutter auriculaire 22,2 % (63,5 %), tachycardie sinusale 12,0 % (78,6 %) et tachycardie supraventriculaire (TSV) 11,1 % (68,0 %). Les traitements ont été jugés optimaux dans 84,3 % des WCT primaires et 86,9 % des WCT secondaires. Les traitements étaient sous-optimaux pour les raisons suivantes : médicament inapproprié (3,9 % pour le primaire contre 1,3 % pour le secondaire), incapacité à réduire la fréquence <100 avant le retour à domicile (9,1 % pour le primaire contre 34,4 % pour le secondaire) et absence de traitement de la cause sous-jacente dans 5,9 % du WCT secondaire. CONCLUSIONS: Les cas de WCT étaient répartis uniformément entre les arythmies primaires et les cas secondaires. Les médecins du service d'urgence ont correctement interprété l'ECG dans 81 % des cas, mais ont surévalué le flutter auriculaire et la TSV. Ils ont mis en œuvre des soins appropriés dans la plupart des cas, mais n'ont pas toujours réussi à contrôler adéquatement la fréquence cardiaque ou à traiter la maladie sous-jacente, ce qui laisse entrevoir des possibilités d'améliorer les soins de WCT au service d'urgence.