Narrow Complex Tachycardia

A 69-year-old woman had three syncopal events while flying on an airplane. She was found to be profoundly bradycardic. Two 12‑lead electrocardiograms (ECGs) showed ventricular rates in the thirties. In one, the QRS complexes were narrow. In the second ECG, there were wide negative deflections following the QRS complexes. Analysis of telemetry recordings revealed the underlying mechanism and helped establish appropriate programing of an implanted pacemaker.

Introduction: We report a case of accelerated idioventricular rhythm (AIVR) identified by Emergency Medical Services (EMS) monitoring of an infant presenting with lethargy and respiratory distress. Accelerated idioventricular rhythms are rare ventricular rhythms originating from the His-Purkinje system or ventricular myocytes, consisting of >3 monomorphic beats with gradual onset and termination. 1 An AIVR is usually well-tolerated and does not require treatment, though sustained arrythmia may induce syncope, and the rhythm has been seen in newborn infants with congenital heart diseases...

A 51-year-old female with congenitally corrected transposition of great arteries (CCTGA), situs solitus, dextrocardia, atrial septal defect and persistent left superior vena cava underwent electrophysiology study for recurrent palpitations with documented narrow complex, short RP tachycardia. With a catheter in the region of the anterior mitral annulus, a His signal was recorded and HV interval was 35 msec. Tachycardia was induced with a ventricular extrastimulus. During the tachycardia there was 1:1 ventriculo-atrial conduction and central atrial activation with a VA interval of 20 msec...

We present a case of a 67-year-old male with heart failure with reduced ejection fraction due to a previous myocardial infarction, slow-conducting atrial fibrillation with an indication of pacemaker implantation, and sustained ventricular tachycardia, requiring defibrillation support in prevention of sudden cardiac death. Current guidelines recommend biventricular over conventional right ventricular pacing for patients with ejection fraction <40 % and atrioventricular conduction disorders in either sinus rhythm or atrial fibrillation, but in patients with a narrow baseline QRS complex, biventricular pacing still induces a form of electrical dyssynchrony...

QUESTION: Recently, a 3-year-old patient in my practice urgently needed to go to the emergency department. The patient was found to have supraventricular tachycardia (SVT) and needed immediate treatment with adenosine. What evidence is currently available for management of SVT in children? ANSWER: Supraventricular tachycardia is a common cardiac condition in the pediatric population that manifests as a narrow QRS complex tachycardia on electrocardiography. Symptoms may range from palpitations, poor feeding, and irritability to more substantial hemodynamic instability...

No abstract text is available yet for this article.

BACKGROUND: The aim of this study was to assess long-term efficacy and safety of empirical slow pathway (ESP) ablation in pediatric and adult patients with a special interest in patients without dual AV nodal physiology (DAVNP). METHODS: A retrospective single-center review of patients who underwent ESP ablation between December 2014 and September 2022 was performed. Follow-up included telephone communication, letter questionnaire and outpatient presentation. Recurrence was based on typical symptoms...

BACKGROUND: We describe a child with a broad and narrow complex tachycardia causing haemodynamic collapse. CASE SUMMARY: A 9-year-old girl (weight 26 kg, height 114 cm) with a 5-year history of refractory 'epilepsy' presented with cardiorespiratory arrest and tonic-clonic seizure, witnessed by her mother. Electrocardiogram documented recurrent episodes of simultaneous broad and narrow tachycardias associated with haemodynamic compromise. Diagnostic electrophysiologic study (EPS) confirmed a dual tachycardia mechanism...

INTRODUCTION: This study describes a rare case of concealed epicardial accessory pathway (AP) successfully ablated using ethanol infusion (EI) through a variant vessel connecting the right atrium (RA) and the right ventricle (RV) surface. METHODS AND RESULTS: A 58-year-old male referred to our hospital for prior failed AP ablation. Cardiac-enhanced computerized tomography scan showed there was a variant vessel at the tip of right atrial appendage and a pulmonary artery (PA)-RA fistula at the roof of RA...

A Junctional ectopic tachycardia diagnosis was performed using two electrophysiological maneuvers in an adult female with a narrow-complex supraventricular tachycardia with a bystander AV-node slow pathway conduction, who previously underwent catheter ablation attempts for an atrio-ventricular nodal re-entrant tachycardia misdiagnosis. The first maneuver was atrial entrainment with an atrial-His-His-atrial response. The second was based on the response to a premature atrial complex delivered at different phases of the tachycardia cycle confirming that anterograde slow pathway conduction and retrograde fast pathway were not involved...

Exercise-induced tachycardia-dependent atrioventricular block with a normal electrocardiogram at rest is rare. Herein, we present a case of a 65-year-old woman with exercise-related chest suppression and treadmill exercise test-induced second- and third-degree atrioventricular blocks with narrow QRS wave and normal resting electrocardiogram. High atrioventricular block leads to tissue and organ insufficiency, resulting in exercise intolerance, dyspnea, dizziness, and syncope. Ths diagnosis was exercise-induced high-degree atrioventricular block...

We present the case of a 77-year-old man with ischemic heart disease and baseline right bundle branch block having a well-tolerated and regular wide complex tachycardia with right bundle branch block morphology. A wide complex tachycardia (WCT) could be of supraventricular or ventricular origin. In this setting, we discuss the differential diagnosis of WCT, the usefulness and limitations of the diagnostic criteria for ventricular tachycardia.

No abstract text is available yet for this article.

BACKGROUND: The most frequent atrioventricular tachycardia in the emergency room is atrioventricular nodal reentrant tachycardia (AVNRT). The first treatment option for ending stable narrow QRS complex SVTs is vagal maneuvers and adenosine. When adenosine or vagal maneuvers fail to change a patient's rhythm to normal sinus rhythm, long-acting AV nodal-blocking medications, including nondihydropyridine calcium channel blockers (verapamil and diltiazem), flecainide, or beta-blockers, are employed...

Flecainide is a class IC antiarrhythmic utilized in prophylaxis of refractory paroxysmal supraventricular tachycardias in pediatric populations. Despite being a highly effective agent, its narrow therapeutic index increases the risk of toxicity and proarrhythmic events, including wide-complex tachycardia. In the absence of direct plasma sampling in the fetus to quantitate flecainide systemic concentrations, clinicians typically make drug dosing decisions from maternal plasma concentrations and QRS duration on maternal ECGs...

INTRODUCTION: Late atrial arrhythmias after catheter ablation for atrial fibrillation occur in up to 30% of post-ablation patients and are increasingly encountered by emergency physicians. However, diagnosing the exact mechanism of the arrhythmia on the surface electrocardiogram (ECG) remains challenging due to atrial scarring leading to heterogeneous P-wave morphology. CASE REPORT: A 74-year-old male with a history of prior catheter ablation for atrial fibrillation presented with palpitations and subacute symptoms of heart failure...

A patient presented with symptoms of palpitations. Her standard 12-lead electrocardiogram captured 3 potential causes of her symptoms (premature atrial contractions, junctional rhythm, and narrow complex tachycardia). Further workup uncovered dual atrioventricular node physiology with 1:2 sinus conduction and resultant alternating QRS from a slow and fast conduction pathway. ( Level of Difficulty: Intermediate. ).

A 70-year-old female presented with incessant supraventricular tachycardia that was refractory to metoprolol and sotalol. ECG revealed a narrow complex tachycardia with a rate of 163 beats per minute with a short RP relationship. She had salvos of atrial tachycardia which led to a severe reduction in ejection fraction as noted on echocardiography and hemodynamic instability. An electrophysiological study was performed, and findings suggested this to be an atrial tachycardia with earliest activation in the perinodal area...

Calcium is an essential electrolyte in impulse generation and contraction of cardiac muscle. Hypocalcemia can occur in cases of parathyroid hormone deficiency, primarily due to inadvertent removal of the parathyroid gland during thyroidectomy, however most cases are idiopathic. We present a case of an adult male who developed sustained narrow complex tachycardia due to hypocalcemia in the setting of untreated idiopathic hypoparathyroidism.

OBJECTIVES: Atrioventricular accessory pathways are abnormal electrical connections between the atria and ventricles that predispose to ventricular pre-excitation (VPE) and tachycardias. ANIMALS: Seventeen cats with VPE and 15 healthy matched-control cats. MATERIAL AND METHODS: Multicenter case-control retrospective study. Clinical records were searched for cats with VPE, defined as preserved atrioventricular synchrony, reduced PQ interval, and increased QRS complex duration with a delta wave...