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.

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.

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.

Two cases of wide QRS complex tachycardia caused by anamorelin.

Anamorelin is prescribed for cancer cachexia treatment. Anamorelin is a ghrelin receptor antagonist and exerts a sodium channel blockade effect, possibly inducing disorders of the cardiac conduction system. We herein report two cases of wide QRS complex tachycardia caused by anamorelin. In both cases, the patients had liver dysfunction. Anamorelin is mainly metabolized in the liver; hence, sodium channel blockade by anamorelin during liver dysfunction can cause serious side effects, including wide QRS complex tachycardia, similar to flecainide toxicity. The differential diagnosis of wide QRS tachycardia caused by anamorelin can be challenging because conventional electrocardiogram criteria cannot be applicable in patients with drug intoxication. It can worsen the situation for the use of antiarrhythmic drugs for wide QRS tachycardia. The appropriate treatment is supportive care until anamorelin is metabolized. To our best knowledge, this is the first study to report the life-threatening adverse effects of anamorelin. Learning objective: Anamorelin is prescribed for cancer cachexia treatment. Anamorelin can cause wide QRS complex tachycardia. Our findings in the two cases we encountered indicate that we should be aware of wide QRS complex tachycardia in patients taking anamorelin, especially if they have liver dysfunction. We should suspect the condition to be the adverse effect of anamorelin and monitor the electrocardiogram and blood test findings regularly to prevent this fatal side effect.

Simplified Integrated Clinical and Electrocardiographic Algorithm for Differentiation of Wide QRS Complex Tachycardia: The Basel Algorithm.

BACKGROUND: Prompt differential diagnosis of wide QRS complex tachycardia (WCT) is crucial to patient management. However, distinguishing ventricular tachycardia (VT) from supraventricular tachycardia (SVT) with wide QRS complexes remains problematic, especially for nonelectrophysiologists. OBJECTIVES: This study aimed to develop a simple-to-use algorithm with integration of clinical and electrocardiographic (ECG) parameters for the differential diagnosis of WCT. METHODS: The 12-lead ECGs of 206 monomorphic WCTs (153 VT, 53 SVT) with electrophysiology-confirmed diagnoses were analyzed. In the novel Basel algorithm, VT was diagnosed in the presence of at least 2 of the following criteria: 1) clinical high risk features; 2) lead II time to first peak >40 ms; and 3) lead aVR time to first peak >40 ms. The algorithm was externally validated in 203 consecutive WCT cases (151 VT, 52 SVT). Its' diagnostic performance and clinical applicability were compared with those of the Brugada and Vereckei algorithms. RESULTS: The Basel algorithm showed a sensitivity, specificity, and accuracy of 92%, 89%, and 91%, respectively, in the derivation cohort and 93%, 90%, and 93%, respectively, in the validation cohort. There were no significant differences in the performance characteristics between the 3 algorithms. The evaluation of the clinical applicability of the Basel algorithm showed similar diagnostic accuracy compared with the Brugada algorithm (80% vs 81%; P = 1.00), but superiority compared with the Vereckei algorithm (72%; P = 0.03). The Basel algorithm, however, enabled a faster diagnosis (median 36 seconds vs 105 seconds for the Brugada algorithm [P = 0.002] and 50 seconds for the Vereckei algorithm [P = 0.02]). CONCLUSIONS: The novel Basel algorithm based on simple clinical and ECG criteria allows for a rapid and accurate differential diagnosis of WCT.

Management of hemodynamically stable wide QRS complex tachycardia in patients with implantable cardioverter defibrillators.

Management of hemodynamically stable, incessant wide QRS complex tachycardia (WCT) in patients who already have an implantable cardioverter defibrillator (ICD) is challenging. First-line treatment is performed by medical staff who have no knowledge on programmed ICD therapy settings and there is always some concern for unexpected ICD shock. In these patients, a structured approach is necessary from presentation to therapy. The present review provides a systematic approach in four distinct phases to guide any physician involved in the management of these patients: PHASE I: assessment of hemodynamic status and use of the magnet to temporarily suspend ICD therapies, especially shocks; identification of possible arrhythmia triggers; risk stratification in case of electrical storm (ES). PHASE II: The preparation phase includes reversal of potential arrhythmia "triggers", mild patient sedation, and patient monitoring for therapy delivery. Based on resource availability and competences, the most adequate therapeutic approach is chosen. This choice depends on whether a device specialist is readily available or not. In the case of ES in a "high-risk" patient an accelerated patient management protocol is advocated, which considers urgent ventricular tachycardia transcatheter ablation with or without mechanical cardiocirculatory support. PHASE III: Therapeutic phase is based on the use of intravenous anti-arrhythmic drugs mostly indicated in this clinical context are presented. Device interrogation is very important in this phase when sustained monomorphic VT diagnosis is confirmed, then ICD ATP algorithms, based on underlying VT cycle length, are proposed. In high-risk patients with intractable ES, intensive patient management considers MCS and transcatheter ablation. PHASE IV: The patient is hospitalized for further diagnostics and management aimed at preventing arrhythmia recurrences.

Wide QRS complex tachycardia after surgical repair of an isolated atrial septal defect: What is the mechanism?

Macroreentrant atrial tachycardia within the right atrium is the dominant mechanism in patients with prior surgical repair of atrial septal defects, with dual-loop circuits much more common than single-loop circuits. This case highlights the importance of clinical history for predicting arrhythmia mechanisms. Considering prior cardiac surgery may assist in preprocedural preparations and discussions regarding potential risks and benefits of catheter ablation.

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.

Fibrilación auricular por vía accesoria con patrón de preexcitación ventricular: Informe de un caso / Atrial fibrillation by accessory pathway with pattern of ventricular pre-excitation: A case report

RESUMEN La fibrilación auricular por vía accesoria es una peligrosa enfermedad que puede provocar muerte súbita; es poco frecuente y necesita una conducta exacta, mucho más si aparece un patrón de preexcitación ventricular. Se presenta el caso de un adolescente masculino de 17 años de edad y piel blanca, con antecedentes de palpitaciones cortas a esfuerzos moderados y pérdida ocasional del conocimiento de breve duración, sin otra sintomatología asociada. Al momento del ingreso presenta un cuadro de palpitaciones, fatiga, palidez e hipotensión arterial, y en el electrocardiograma se observa una taquicardia con QRS ancho, irregular, con onda delta y frecuencia ventricular rápida, que fue interpretada como fibrilación auricular preexcitada. Se realizó cardioversión eléctrica sincronizada al QRS con 100 julios y se logró restaurar el ritmo sinusal con patrón electrocardiográfico de preexitación ventricular (síndrome de Wolff-Parkinson-White).

ABSTRACT Atrial fibrillation by accessory pathway is a dangerous disease that can cause sudden death, it is rare and it needs a careful management, even more, if a pattern of ventricular pre-excitation appears. The case of a white skin 17-year-old teenager with a history of short palpitations at moderate effort, and occasional loss of consciousness of short duration, without other associated symptoms, is presented. At the moment of admission, he presents palpitations, fatigue, pallor and low blood pressure; in the electrocardiogram a tachycardia with wide, irregular QRS, with delta wave and rapid ventricular rate is observed, which was interpreted as pre-excited atrial fibrillation. Synchronized electrical cardioversion to QRS with 100 joules was performed, and sinus rhythm was restored with electrocardiographic pattern of ventricular pre-excitation (Wolff-Parkinson-White syndrome).

Diagnóstico diferencial de las taquicardias de complejo ancho: un desafío permanente / Wide QRS tachycardia: a diagnostic challenge

El diagnóstico electrocardiográfico correcto de la causa de una taquicardia de complejo QRS ancho (TCA) es fundamental, ya que tanto el manejo, como el pronóstico del paciente, es diferente según su etiología, y define el estudio que debemos realizar. Numerosos criterios y algoritmos han sido descritos para diferenciar el origen de estas taquicardias. Sin embargo, muchos de estos son complejos y difíciles de aplicar para el médico menos experimentado. Esto es particularmente importante en los servicios de emergencia, donde se necesita una definición rápida que permita un manejo agudo apropiado. En la presente revisión analizamos los diferentes mecanismos de las TCA y los principales criterios diagnósticos en el ECG, reforzando, especialmente, aquellos de aplicación rápida y de alto rendimiento diagnóstico.

The correct electrocardiographic diagnosis of the cause of a wide QRS complex tachycardia (WCT) is essential since both management and prognosis of the patient. The correct electrocardiographic diagnosis of the cause of a wide QRS complex tachycardia (WCT) is essential since both management and prognosis is different according to its etiology and defines the study that we should perform. Numerous criteria and algorithms have been described to differentiate the origin of these tachycardias. However, many of these are complex and difficult to apply to the less experienced doctor. This is particularly important in emergency rooms, where a rapid definition is needed to allow proper therapy. In this review we analyze the different mechanisms of WCT and the main EKG diagnostic criteria, emphasizing those which can be applied rapidly and have high diagnostic value.

Simple electrocardiographic criteria for rapid identification of wide QRS complex tachycardia: The new limb lead algorithm.

BACKGROUND: The electrocardiogram (ECG) is essential for the differential diagnosis of wide QRS complex tachycardia (WCT). OBJECTIVE: The purpose of this study was to evaluate the diagnostic value of a novel ECG algorithm on the basis of the morphological characteristics of the QRS on the limb leads. METHODS: The limb lead algorithm (LLA) was evaluated by analyzing 528 monomorphic WCTs with electrophysiology-confirmed diagnoses. In the LLA, ventricular tachycardia (VT) is diagnosed in the presence of at least 1 of the following: (1) monophasic R wave in lead aVR; (2) predominantly negative QRS in leads I, II, and III; and (3) opposing QRS complex in the limb leads: concordant monophasic QRS in all 3 inferior leads and concordant monophasic QRS in 2 or 3 of the remaining limb leads with a polarity opposite to that of the inferior leads. The diagnostic performance of the LLA was compared with that of the Brugada, Vereckei, and R-wave peak time (RWPT) algorithms. RESULTS: Of 528 WCT cases, 397 were VT and 131 supraventricular tachycardia. The interobserver agreement for the LLA was excellent (κ = 0.98), better than that for the other algorithms. The overall accuracy of the LLA (88.1%) was similar to that of Brugada (85.4%) and Vereckei (88.1%) algorithms but was higher than that of the RWPT algorithm (70.8%). The LLA had a lower sensitivity (87.2%) than did Brugada (94.0%) and Vereckei (92.4%) algorithms, but not the RWPT algorithm (67.8%). Furthermore, the LLA showed a higher specificity (90.8%) than did Brugada (59.5%), Vereckei (76.3%), and RWPT (80.2%) algorithms. CONCLUSION: The LLA is a simple yet accurate method to diagnose VT when approaching WCTs on the ECG.

Paroxysmal Atrial Fibrillation of Vagal Mechanism with Episodes of Wide QRS Complex Tachycardia Due to Gouaux-Ashman's Phenomenon.

A 38-year-old male patient consulted for nocturnal palpitations described as fast chest pounding that woke him up from sleep. A physical examination yielded no remarkable findings. A 24-hour Holter ECG monitoring demonstrated nocturnal episodes of paroxysmal atrial fibrillation (PAF) with the coexistence of wide QRS complex tachycardia. To the best of our knowledge, this is the first reported case of nocturnal episodes of wide QRS complex tachycardia during vagally mediated PAF resulting from Gouaux-Ashman's phenomenon. It is paramount for general physicians to recognize this phenomenon because it should be differentiated from ventricular tachycardia, since prognosis and treatment of both entities are entirely different. General and emergency physicians should be aware in order to improve adequate diagnostic and therapeutic management of the arrhythmic episodes.

Arritmias provocadas por ondansetrón: Presentación de un caso / Arrhythmias caused by ondansetron: Case report

RESUMEN El ondansetrón se usa para prevenir las náuseas y los vómitos causados por la quimioterapia, radioterapia y cirugías, pertenece a los antagonistas de receptores de serotonina 5-HT3, una sustancia natural que puede causar náuseas y vómitos, y bloquea su acción. El ondansetrón viene envasado en forma de tabletas de desintegración rápida, como una solución para tomar por vía oral y en ámpulas, para su uso parenteral. Se presenta el caso de una paciente de 67 años de edad con diagnóstico de carcinoma de mama, a la cual se realizó mastectomía radical con vaciamiento axilar, y recibió quimioterapia con adriamicina, ciclofosfamida y paclitaxel; así como ondansetrón para tratar las náuseas y vómitos. La paciente presentó una taquicardia con QRS ancho después de utilizar el fármaco.

ABSTRACT The ondansetron is used to prevent nausea and vomiting caused by chemotherapy, radiotherapy and surgery, belonging to the serotonin 5-HT3 receptor antagonists, a natural substance that can cause nausea and vomiting, and it blocks its action. The ondansetron is packaged in the form of rapid disintegration tablets, as a solution to be taken orally and in ampules, for parenteral use. The case of a 67-year-old female patient is presented, with a diagnosis of breast carcinoma, who underwent radical mastectomy with axillary dissection was performed, and who received chemotherapy with adriamycin, cyclophosphamide and paclitaxel; as well as ondansetron to treat nausea and vomiting. The patient presented a wide QRS complex tachycardia after taking the drug.

Advanced Cardiac Signal Recording.

Implantable loop recorders allow prolonged and continuous single-lead electrocardiogram recording, with the pivotal addition of remote monitoring. They have significantly shortened time to electrocardiographic diagnosis and appropriate therapy of many bradyarrhythmias/tachyarrhythmias and proved helpful in arrhythmia burden definition, offering invaluable information in the diagnostic workup for syncope and atrial fibrillation. Advanced cardiac signal recording is also possible by transesophageal catheters. They have been used to orient diagnosis during wide and narrow QRS complex tachycardias and also to perform minimally invasive pacing. Intracardiac electrophysiologic study remains, however, essential for diagnosis of several arrhythmias in the perspective of curative catheter ablation.

Challenging Cases of Wide Complex Tachycardias: Use and Limits of Algorithms.

Electrocardiographic algorithms are particularly useful to differentiate, in the presence of a wide complex tachycardia, between supraventricular aberrancy and ventricular tachycardias (VT). There are numerous limitations to the sensitivity and specificity of these algorithms including the presence of accessory pathways, use of antiarrhythmic drugs, congenital heart diseases, electrolytes impairments, and artificial pacing. Once the diagnosis of VT has been reached, other algorithms can help in localizing the origin of the ventricular arrhythmia. These approaches are also limited by the anatomic structure of where the arrhythmia originates. This article illustrates the difficulties in applying common algorithms in many clinical circumstances.

Peculiar Electrocardiographic Aspects of Wide QRS Complex Tachycardia: When Differential Diagnosis Is Difficult.

Wide complex tachycardia may represent a challenge for correct interpretation of standard electrocardiogram, which is crucial for proper patient management. For this reason, algorithms based on electrocardiographic criteria have been developed to guide interpretation in a step-by-step approach. Despite their greater accuracy, some cases of wide QRS complex tachycardia are a challenge. Some peculiar forms of ventricular tachycardia, and complex supraventricular substrate or particular clinical condition, may originate a challenging electrocardiographic pattern. In this article, a series of peculiar cases of wide QRS complex tachycardia is presented as paradigm of how important a comprehensive clinical approach is in these patients.