A very unusual wide QRS tachycardia: VT or SVT?

INTRODUCTION: A 13 old girl presented with recurrent wide QRS tachycardia since she was 4. METHODS: An electrophysiologic study was performed. RESULTS: The electrophysiologic study showed that QRS complexes identical to those of the tachycardia could be elicited with premature atrial extrastimuli but with a shorter atrioventricular (AV) delay when the QRS was wide compared with narrow QRS complexes. The tachycardia was ablated at 9 o'clock on the tricuspid annulus demonstrating the presence of an atriofascicular fiber. CONCLUSION: We believe that this atypical behavior can be explained by AV nodal like longitudinal dissociation of a slowly conducting accessory pathway.

Confounding factors leading to misdiagnosing ventricular tachycardia as supraventricular in the emergency room.

Studies conducted during the last 50 years have proposed electrocardiographic criteria and algorithms to determine if a wide QRS tachycardia is ventricular or supraventricular in origin. Sustained ventricular tachycardia is an uncommon reason for consultation in the emergency room. The latter and the complexity of available electrocardiographic diagnostic criteria and algorithms result in frequent misdiagnoses. Good hemodynamic tolerance of tachycardia in the supine position does not exclude its ventricular origin. Although rare, ventricular tachycardia in patients with and without structural heart disease may show a QRS duration <120 ms. Interruption of tachycardia by coughing, carotid sinus massage, Valsalva maneuver, or following the infusion of adenosine or verapamil should not discard the ventricular origin of the arrhythmia. In patients with regular, uniform, sustained broad QRS tachycardia, the presence of structural heart disease or A-V dissociation strongly suggest its ventricular origin. Occasionally, ventricular tachycardia can present with AV dissociation without this being evident on the 12-lead ECG. Cardiac auscultation, examination of the jugular venous pulse, and arterial pulse palpation provide additional clues for identifying A-V dissociation during tachycardia. This paper does not review the electrocardiographic criteria for categorizing tachycardia as ventricular but rather why emergency physicians misdiagnose these patients.

Differential diagnosis of wide QRS tachycardias: comparison of two electrocardiographic algorithms.

AIMS: This study's aim is to compare the ability of two ECG criteria to differentiate ventricular (VT) from supraventricular tachycardia (SVT): Brugada et al. [horizontal plane (HP) leads] and Vereckei et al. [frontal plane (FP), specifically aVR lead], having electrophysiological study (EPS) as gold standard. After comparing, suggestions for better diagnosis of wide QRS-complex tachycardia (WCT) in emergency situations were made. METHODS AND RESULTS: Fifty-one consecutive patients with 12-lead ECG registered during EPS-induced regular WCT were selected. Each ECG was split into two parts: HP (V1-V6) and FP (D1-D3, aVR, aVL, and aVF), randomly distributed to three observers, blinded for EPS diagnosis and complementary ECG plane, resulting in total 306 ECG analyses. Observers followed the four steps of both algorithms, counting time-to-diagnosis. Global sensitivity, specificity, percentage of incorrect diagnoses, and step-by-step positive/negative likelihood ratios (+LR and -LR) were calculated. Kaplan-Meier curve was plotted for final time-to-diagnosis. Inter-observer agreement was assessed with kappa-statistic. Global sensitivity was similarly high in FP and HP algorithms (89.2 vs. 90.1%), and incorrect classifications were 27.4 vs. 24.7%. Forty-eight correct analyses by Vereckei criteria took 9.13 s to diagnose VT in the first step, showing that first step was fast, with high +LR, generating nearly conclusive pre- (72.6%) to post-test (98.0%) changes for VT probability. CONCLUSION: Both algorithms as a whole are similar for diagnosis of WTC; however, the first step of Vereckei (initial R in aVR) is a simple, reproducible, accurate, and fast tool to use. The negativity of this step requires a 'holistic' approach to distinguish VT from SVT.

Late onset of exercise induced focal ventricular tachycardia originating from the ventricular end of an A-V accessory pathway after elimination of conduction.

The authors report the unique case of remote onset of exercise induced focal ventricular tachycardia in a 40-year old male patient that originated from the ventricular end of an accessory atrioventricular pathway 18 months after a successful ablation. There was no residual conduction across the pathway after the first ablation. The ventricular tachycardia (VT) was mapped to and successfully ablated at the same site where the ventricular end of the pathway was previously ablated. The VT morphology was similar to that of the pre-excited QRS beats noted before. Thus far, in all reported cases of accessory pathway related automaticity there was intact conduction over the pathway or acute injury to it. To the best of our knowledge a case similar to our patient is not yet reported.

Flecainide toxicity-Clinical diagnosis and management of an urgent condition.

Clinical suspicion, clinical presentation, and electrocardiogram can help clinicians diagnose flecainide toxicity. Currently, there are no guidelines for the management of patients with flecainide toxicity. Sodium bicarbonate, lipid emulsion therapy, and extracorporeal life support have been used in this setting. Amiodarone and lidocaine can be used for the management of wide QRS complex tachycardias in hemodynamically stable patients with flecainide toxicity.

Lacosamide Intoxication-induced Wide QRS Tachycardia Successfully Treated with Veno-arterial Extracorporeal Membrane Oxygenation.

Lacosamide is an antiepileptic drug that acts on voltage-gated sodium channels and was approved as an antiepileptic by the Food and Drug Administration in 2008. Although the efficacy and safety of lacosamide have been established in many previous trials, some case reports have shown that it may lead to cardiovascular side effects, especially in patients with electrical conduction system disorders. We herein report a case of life-threatening cardiac arrhythmia caused by lacosamide intoxication that was successfully treated with veno-arterial extracorporeal membrane oxygenation.

A Case of Wide QRS Tachycardia After the Local Administration of Epinephrine to Reduce Bleeding During General Anesthesia.

We report a case of wide QRS tachycardia or ventricular tachycardia with a pulse after the administration of epinephrine under general anesthesia. After induction and achieving a sufficiently deep plane of general anesthesia, gauze soaked in a 1:100,000 epinephrine solution was applied to the patient's nasal mucosa and 1% lidocaine with 1:100,000 epinephrine was administered via intraoral infiltration. Several minutes after the start of surgery, the patient's blood pressure and heart rate suddenly increased and a wide QRS tachycardia was observed on the electrocardiogram, which then reverted to a normal sinus rhythm. According to the past reports, similar arrhythmias have occurred after administration of epinephrine in the head and neck. These findings suggest that anesthesia providers must be aware of the risks associated with epinephrine and local anesthetic use, particularly in the head and neck region.

An Incessant Tachycardia with Alternating QRS Complexes: What Is the Mechanism?

We present a patient with ischemic cardiomyopathy who had ventricular tachycardia (VT) with QRS morphology alternans. The electrophysiological findings, in this case, supported the occurrence of antegrade activation of the proximal His-Purkinje system during VT, with the ultimate electrocardiogram morphology dependent on fusion from intramyocardial and His-Purkinje activations.