Wide-complex tachycardia: continued evaluation of diagnostic criteria

Diagnostic accuracy of different ECG-based algorithms in wide QRS complex tachycardia: a systematic review and meta-analysis

OBJECTIVE

Several ECG-based algorithms have been proposed to enhance the effectiveness of distinguishing Wide QRS complex tachycardia (WCT), but a comprehensive comparison of their accuracy is still lacking. This meta-analysis aimed to assess the diagnostic precision of various non-artificial intelligence ECG-based algorithms for WCT.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

Electronic databases (PubMed, MEDLINE, the Cochrane Library, and Web of Science) are searched up to May 2022.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

All studies reporting the diagnostic accuracy of different ECG-based algorithms for WCT are included. The risk of bias in included studies is assessed using the Cochrane Collaboration's risk of bias tools.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed risk of bias. Data were pooled using random-effects model and expressed as mean differences with 95% CIs. Heterogeneity was calculated by the I² method. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool was applied to assess the internal validity of the diagnostic studies.

RESULTS

In total, 467 studies were identified, and 14 studies comprising 3966 patients were included, involving four assessable ECG-based algorithms: the Brugada algorithm, Vereckei-pre algorithm, Vereckei-aVR algorithm and R wave peak time of lead II (RWPT-II) algorithm. The overall sensitivity was 88.89% (95% CI: 85.03 to 91.86), with a specificity of 70.55% (95% CI: 62.10 to 77.79) and a diagnostic OR (DOR) of 19.17 (95% CI: 11.45 to 32.10). Heterogeneity of the DOR was 89.1%. The summary sensitivity of each algorithm was Brugada 90.25%, Vereckei-pre 94.80%, Vereckei-aVR 90.35% and RWPT-II 78.15%; the summary specificity was Brugada 64.02%, Vereckei-pre 75.40%, Vereckei-aVR 60.88% and RWPT-II 88.30% and the summary DOR was Brugada 16.48, Vereckei-pre 60.70, Vereckei-aVR 14.57 and RWPT-II 27.00.

CONCLUSIONS

ECG-based algorithms exhibit high sensitivity and moderate specificity in diagnosing WCT. A combination of Brugada or Vereckei-aVR algorithm with RWPT-II could be considered to diagnose WCT.

PROSPERO REGISTRATION NUMBER

CRD42022344996.

Computerized electrocardiogram data transformation enables effective algorithmic differentiation of wide QRS complex tachycardias

BACKGROUND

Accurate automated wide QRS complex tachycardia (WCT) differentiation into ventricular tachycardia (VT) and supraventricular wide complex tachycardia (SWCT) can be accomplished using calculations derived from computerized electrocardiogram (ECG) data of paired WCT and baseline ECGs.

OBJECTIVE

Develop and trial novel WCT differentiation approaches for patients with and without a corresponding baseline ECG.

METHODS

We developed and trialed WCT differentiation models comprised of novel and previously described parameters derived from WCT and baseline ECG data. In Part 1, a derivation cohort was used to evaluate five different classification models: logistic regression (LR), artificial neural network (ANN), Random Forests [RF], support vector machine (SVM), and ensemble learning (EL). In Part 2, a separate validation cohort was used to prospectively evaluate the performance of two LR models using parameters generated from the WCT ECG alone (Solo Model) and paired WCT and baseline ECGs (Paired Model).

RESULTS

Of the 421 patients of the derivation cohort (Part 1), a favorable area under the receiver operating characteristic curve (AUC) by all modeling subtypes: LR (0.96), ANN (0.96), RF (0.96), SVM (0.96), and EL (0.97). Of the 235 patients of the validation cohort (Part 2), the Solo Model and Paired Model achieved a favorable AUC for 103 patients with (Solo Model 0.87; Paired Model 0.95) and 132 patients without (Solo Model 0.84; Paired Model 0.95) a corroborating electrophysiology procedure or intracardiac device recording.

CONCLUSION

Accurate WCT differentiation may be accomplished using computerized data of (i) the WCT ECG alone and (ii) paired WCT and baseline ECGs.

Wide complex tachycardia discrimination tool improves physicians' diagnostic accuracy

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.

Validation of a Simple Electrocardiographic Algorithm for Detection of Ventricular Tachycardia

Fundamento

O diagnóstico diferencial de taquicardia de QRS largo, entre taquicardia ventricular (TV) ou taquicardia supraventricular com condução aberrante (TSV-A) é algumas vezes difícil de ser feito na sala de emergência.

Objetivo

Avaliar a acurácia de um algoritmo novo e simples para a detecção de TV no eletrocardiograma (ECG) em pacientes com taquicardia de QRS largo.

Métodos

ECGs de 12 derivações para detecção de taquicardia de QRS largo foram obtidos prospectivamente de 120 pacientes durante estudo eletrofisiológico. Seis médicos com diferentes experiências analisaram os ECGs, e fizeram o diagnóstico com base no algoritmo D12V16, que envolve a análise da polaridade predominante do complexo QRS nas derivações I, II, V1 e V6. O diagnóstico foi comparado com os obtidos pelo algoritmo tradicional de Brugada e pelo estudo eletrofisiológico, o qual é considerado padrão ouro. Adotou-se um nível de significância de 5% (p<0,05) nas análises estatísticas.

Resultados

De acordo com o estudo eletrofisiológico, 82 ECGs eram de TV e 38 de TSV-A. Doenças cardíacas estruturais estavam presentes em 71 (86,6%) dos pacientes com TV e em oito (21,1%) com TSV-A. O algoritmo de Brugada teve uma maior sensibilidade global (87,2%), enquanto o algoritmo D12V16 apresentou maior especificidade global (85,1%) para TV. Tanto o algoritmo D12V16 como o de Brugada apresentou um alto valor preditivo positivo (90,9% vs. 85,8%, respectivamente) e acurácia similar (73,8% vs. 81,4%, respectivamente) para o diagnóstico de TV. Nos avaliadores experientes, a acurácia foi maior utilizando o algoritmo de Brugada que o algoritmo D12V16, mas a acurácia dos dois algoritmos foi similar segundo os avaliadores menos experientes.

Conclusão

O algoritmo simplificado pode ser um método útil para reconhecer TV no ECG, principalmente para médicos menos experientes. (Arq Bras Cardiol. 2021; [online].ahead print, PP.0-0)

Conceptual and literature basis for wide complex tachycardia and baseline ECG comparison

Accurate wide QRS complex tachycardia (WCT) differentiation into either ventricular tachycardia or supraventricular wide complex tachycardia using 12‑lead electrocardiogram (ECG) interpretation is essential for diagnostic, therapeutic, and prognostic reasons. There is an ever-expanding variety of WCT differentiation methods and criteria available to clinicians. However, only a few make use of the diagnostic value of comparing the ECG during WCT to that of the patient's baseline ECG. Therefore, we highlight the conceptual rationale and scientific literature supporting the diagnostic value of WCT and baseline ECG comparison.

Wide QRS tachycardias: the rationale behind electrocardiographic diagnostic criteria

Wide QRS tachycardias represent one of the most challenging scenarios in the interpretation of the electrocardiogram, even among experienced professionals or specialists. The various existing diagnostic criteria are essential tools for the correct identification of the origin of tachycardia, however, the knowledge of the electrophysiological principles of cardiac depolarization is fundamental to understand them, thus allowing greater accuracy in the interpretation of the exam.

Differentiating wide complex tachycardias: A historical perspective

One of the most critical and challenging skills is the distinction of wide complex tachycardias into ventricular tachycardia or supraventricular wide complex tachycardia. Prompt and accurate differentiation of wide complex tachycardias naturally influences short- and long-term management decisions and may directly affect patient outcomes. Currently, there are many useful electrocardiographic criteria and algorithms designed to distinguish ventricular tachycardia and supraventricular wide complex tachycardia accurately; however, no single approach guarantees diagnostic certainty. In this review, we offer an in-depth analysis of available methods to differentiate wide complex tachycardias by retrospectively examining its rich literature base - one that spans several decades.

Utility of Inferior Lead Q-waveforms in diagnosing Ventricular Tachycardia

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.

Wide Complex Tachycardia Differentiation: A Reappraisal of the State-of-the-Art

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 diagnosis cannot be understated and has naturally spurred rigorous research, which has brought forth an ever‐expanding abundance of manually applied and automated methods to differentiate wide complex tachycardias. In this review, we provide an in‐depth analysis of traditional and more contemporary methods to differentiate ventricular tachycardia and supraventricular wide complex tachycardia. In doing so, we: (1) review hallmark wide complex tachycardia differentiation criteria, (2) examine the conceptual and structural design of standard wide complex tachycardia differentiation methods, (3) discuss practical limitations of manually applied ECG interpretation approaches, and (4) highlight recently formulated methods designed to differentiate ventricular tachycardia and supraventricular wide complex tachycardia automatically.

Electrical storm: A focused review for the emergency physician

BACKGROUND

Electrical storm is a dangerous condition presenting to the Emergency Department that requires rapid diagnosis and management.

OBJECTIVE

This article provides a review of the diagnosis and management of electrical storm for the emergency clinician.

DISCUSSION

Electrical storm is defined as ≥3 episodes of sustained ventricular tachycardia, ventricular fibrillation, or shocks from an implantable cardioverter defibrillator within 24 h. Patients may present with a wide array of symptoms. Initial evaluation should include an electrocardiogram with a rhythm strip and continuous cardiac monitoring, a medication history, assessment of hemodynamic stability, and identification of potential triggers. Management includes an antiarrhythmic and a beta blocker. Refractory patients may benefit from double-sequential defibrillation or more invasive procedures such as intra-aortic balloon pumps, catheter ablation and extracorporeal membrane oxygenation for critically ill patients. These patients will typically require admission to an intensive care unit.

CONCLUSION

Electrical storm is a condition associated with significant morbidity and mortality. It is important for clinicians to be aware of the current evidence regarding the evaluation and management of these patients.

Initial evaluation and management of wide-complex tachycardia: A simplified and practical approach

The evaluation and treatment of wide QRS-complex tachycardia remains a challenge, and mismanagement is quite common. Diagnostic aids such as wide-complex tachycardia algorithms perform poorly in the real-life setting. The purpose of this review is to offer a simple clinical-electrocardiographic approach for the initial evaluation and management of the adult patient with stable wide-complex tachycardia that does not require recollection of complex guidelines or algorithms.

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.

Wide Complex Tachycardia - Ventricular Tachycardia or Not Ventricular Tachycardia, That Remains the Question

Arriving at the correct diagnosis in cases of wide complex tachycardia remains problematic for many clinicians. In this paper, we review the historical development of criteria used to differentiate among the major diagnostic possibilities and compare the strengths and weaknesses of various differentiating algorithms.

The Lewis Lead for Detection of Ventriculoatrial Conduction Type

BACKGROUND

Identification of a possible ventriculoatrial (VA) dissociation in wide QRS complex tachycardias is one of the most reliable criteria for differentiation of tachycardia origin. The Lewis lead has been proposed for detection of atrial activity during ventricular tachycardias.

HYPOTHESIS

A modified Lewis-lead-ECG will be superior to the standard-lead ECG for detection of ventriculoatrial conduction during ventricular tachycardia.

METHODS

Forty-seven patients underwent electrophysiological study, stimulated with a fixed cycle length of 400 ms in the ventricle. During stimulation, a standard-lead ECG and a modified Lewis-lead ECG were recorded. Simultaneously, VA conduction was documented by intracardiac electrograms. Surface ECGs were presented to 6 blinded examiners for VA conduction assessment.

RESULTS

Type of VA conduction was correctly diagnosed in significantly more ECGs in the Lewis-lead ECG group (mean, 35.0 [75%]) than in the standard-lead ECG group (mean, 29.2 [62%]; P = 0.045). Ventriculoatrial dissociation also was significantly more often correctly diagnosed in the Lewis-lead ECG group (mean, 17.7 [71%]) than in the standard-lead ECG group (mean, 12.7 [49%]; P = 0.014). Interobserver agreement was moderate in both groups (κ = 0.45 and κ = 0.49, respectively).

CONCLUSIONS

Compared with standard-lead ECG, modified Lewis-lead ECG is associated with significantly improved detection of VA conduction type during fast ventricular pacing and thus may help improve ECG diagnosis.

Current algorithms for the diagnosis of wide QRS complex tachycardias

The differential diagnosis of a regular, monomorphic wide QRS complex tachycardia (WCT) mechanism represents a great diagnostic dilemma commonly encountered by the practicing physician, which has important implications for acute arrhythmia management, further work-up, prognosis and chronic management as well. This comprehensive review discusses the causes and differential diagnosis of WCT, and since the ECG remains the cornerstone of WCT differential diagnosis, focuses on the application and diagnostic value of different ECG criteria and algorithms in this setting and also provides a practical clinical approach to patients with WCTs.

Comparison of the "real-life" diagnostic value of two recently published electrocardiogram methods for the differential diagnosis of wide QRS complex tachycardias

OBJECTIVES

The diagnostic values of the aVR lead or "Vereckei algorithm," and the lead II R-wave peak time (RWPT) criterion, recently devised for the differential diagnosis of wide QRS complex tachycardias (WCTs), were compared.

METHODS

A total of 212 WCTs (142 ventricular tachycardias [VTs], 62 supraventricular tachycardias [SVT], and eight preexcitation SVTs) from 145 patients with proven electrophysiologic diagnoses were retrospectively analyzed by seven examiners blinded to the electrophysiologic diagnoses.

RESULTS

The overall test accuracy of the Vereckei algorithm was superior to that of the RWPT criterion (84.3% vs. 79.6%; p = 0.0003). The sensitivity of the Vereckei algorithm for VT diagnosis was greater than that of RWPT criterion (92.4% vs. 79.1%; p < 0.0001). The negative predictive value (NPV) for the Vereckei algorithm was also greater (77.8%; 95% confidence interval [CI] = 73.6% to 82.1%) than that of the RWPT criterion (61.6%; 95% CI = 57.6% to 65.6%). The specificity of the Vereckei algorithm was lower than that of the RWPT criterion (64.7% vs. 80.9%; p < 0.0001). The positive predictive value (PPV) was also lower for the Vereckei algorithm (86.4%; 95% CI = 84.4% to 88.4%) than for the RWPT criterion (90.9%; 95% CI = 89.1% to 92.8%). Incorrect diagnoses made by the Vereckei algorithm were mainly due to misdiagnosis of SVT as VT (65.7% of cases), and those made by the RWPT criterion were due to the more dangerous misdiagnosis of VT as SVT (72.5% of cases).

CONCLUSIONS

The Vereckei algorithm was superior in overall test accuracy, sensitivity, and NPV for VT diagnosis and inferior in specificity and PPV to the RWPT criterion. All of these parameters were lower in "real life" than those reported by the original authors for each of the particular electrocardiographic methods.

Vereckei criteria used as a diagnostic tool by emergency medicine residents to distinguish between ventricular tachycardia and supra-ventricular tachycardia with aberrancy

BACKGROUND

Accurate electrocardiographic (ECG) differentiation of ventricular tachycardia (VT) from supraventricular tachycardia with aberrancy (SVT-A) on ECG is key to therapeutic decision-making in the emergency department (ED) setting.

OBJECTIVE

The goal of this study was to test the accuracy and agreement of emergency medicine residents to differentiate VT from SVT-A using the Vereckei criteria.

METHODS

Six emergency medicine residents volunteered to participate in the review of 114 ECGs from 86 patients with a diagnosis of either VT or SVT-A based on an electrophysiology study. The resident reviewers initially read 12-lead ECGs blinded to clinical information, and then one week later reviewed a subset of the same 12-lead ECGs unblinded to clinical information.

RESULTS

One reviewer was excluded for failing to follow study protocol and one reviewer was excluded for reviewing less than 50 blinded ECGs. The remaining four reviewers each read 114 common ECGs blinded to clinical data and their diagnostic accuracy for VT was 74% (sensitivity 70%, specificity 80%), 75% (sensitivity 76%, specificity 73%), 61% (sensitivity 81%, specificity 25%), and 68% (sensitivity 84%, specificity 40%). The intraclass correlation coefficient (ICC) was 0.31 (95% CI 0.22-0.42). Eliminating two of the four reviewers who left a disproportionately high number of ECGs unclassified resulted in an increase in overall mean diagnostic accuracy (70-74%) and agreement (0.31-0.50) in the two remaining reviewers. Three reviewers read 45 common ECGs unblinded to clinical information and had accuracies for VT 93%, 93% and 78%.

CONCLUSION

The new single lead Vereckei criteria, when applied by emergency medicine residents achieved only fair-to-good individual accuracy and moderate agreement. The addition of clinical information resulted in substantial improvement in test characteristics. Further improvements (accuracy and simplification) of algorithms for differentiating VT from SVT-A would be helpful prior to clinical implementation.

[Regular tachycardia with broad QRS complex: differential diagnosis on 12-lead ECG]

Differential diagnosis of regular tachycardia with broad QRS complex can be challenging in daily practice. There are four different arrhythmias that have to be taken into account when being confronted with a broad QRS complex tachycardia: (1) ventricular tachycardia (VT); (2) supraventricular tachycardia (SVT) with bundle branch block (BBB); (3) SVT with AV conduction over an accessory AV pathway; (4) paced ventricular rhythm. Due to potentially fatal consequences, the correct diagnosis is important in view of both the acute treatment and the long-term therapy. Since SVT with accessory conduction is rare and a paced ventricular rhythm can be identified easily by stimulation artifacts, in most cases, a VT has to be differentiated from an SVT with BBB. Several ECG criteria can be helpful: (1) QRS complex duration > 140 ms in right BBB tachycardia or > 160 ms in left BBB tachycardia; (2) ventricular fusion beats; (3)"Northwest" QRS axis; (4) ventriculoatrial dissociation; (5) absence of an RS complex or RS interval > 100 ms in leads V(1)-V(6); (6) a positive or negative concordant R wave progression pattern in leads V(1)-V(6); (7) absence of an initial R wave or an S wave in lead V(1) in right BBB tachycardia; (8) absence of an R wave or an R/S ratio < 1 in lead V(6) in right BBB tachycardia; (9) absence or delay of the initial negative forces in lead V(1) in left BBB pattern (R wave duration > 30 ms in V(1); interval between onset of R wave and Nadir of S wave > 60 ms in V(1)); (10) presence of Q wave. Any of these variables favor VT. However, none of the criteria has both a sufficient sensitivity and specificity when utilized on its own. Therefore, various diagnostic algorithms have been proposed using a number of the above criteria consecutively. By doing so, the specificity and sensitivity of correctly identifying a VT or an SVT with BBB can be raised to > 95%.

Performance of emergency medicine residents on a novel practice examination using visual stimuli

OBJECTIVES

In 2004, the format of the Royal College of Physicians and Surgeons of Canada certification exam in Emergency Medicine was modified to include an audiovisual session. Residents' performance on such stimuli is unknown. This study aims to determine the performance of Emergency Medicine postgraduate year 5 (PGY-5) on a novel practice examination using visual stimuli, in an effort to guide residents' preparatory study, and to help educators focus the teaching related to visual stimuli.

METHODS

In this prospective observational study, 30 PGY-5 residents from 12 Emergency Medicine programs across Canada participated in a practice examination in which they had to answer 133 questions related to 80 visual stimuli. The stimuli included electrocardiograms, medical imaging and clinical photographs. Three experienced faculty provided "reference standard" answers for the visual stimuli. For analysis purpose, stimuli were classified into 9 clinical domains, outlined in The Model of the Clinical Practice of Emergency Medicine.

RESULTS

Insufficient question numbers in 3 domains prevented reliable inferences. Correct answers were given for 65% of remaining questions, with the following domain distribution: 69% respiratory, 64% trauma, 73% cardiovascular, 62% head-eyes-ears-nose-throat (HEENT), 63% musculoskeletal and 69% cutaneous. Seventy-four percent of ECGs, 64% of imaging, and 62% of photograph-related questions were answered correctly. Incorrect answers were related to a lack of knowledge as well as imprecise or incomplete responses.

CONCLUSIONS

PGY-5 subjects scored lowest in the HEENT and musculoskeletal domains. Medical educators should emphasize these domains in their teaching, and insist on precision and completeness of answers.

Value of the 12-Lead ECG in Wide QRS Tachycardia

A wealth of useful diagnostic criteria is available to assist the health care worker in arriving at the correct diagnosis in cases of a wide QRS tachycardia (WQRST). Despite the abundance of good criteria for determining the diagnosis in cases of WQRST, they are of no use if they cannot be readily applied in an urgent clinical situation because they cannot be easily recalled or are too complex and cumbersome to use. It may be that refresher courses in the differential diagnosis of WQRST, especially for emergency physicians who are often the "first responders" to patients with WQRST, can improve physicians' diagnostic accuracy in this important disorder.

Cardiovascular Emergencies in the Elderly

Already the major cause of mortality in the United States, cardio-vascular emergencies will become increasingly prevalent in the future as the geriatric population doubles. This article discusses five cardiovascular emergencies: acute coronary syndrome, congestive heart failure, dysrythmias, aortic dissection, and ruptured abdominal aortic aneurysm. The discussion focuses on the differences in presentation, management, and outcomes that characterize each disease amongst the elderly. As a rule, the elderly have significantly worse outcomes than younger patients.