The initial electrocardiographic evaluation of every tachyarrhythmia should begin by addressing the question of whether the QRS complex is wide or narrow. The most important cause of wide complex tachycardia (WCT) is ventricular tachycardia. However, supraventricular tachycardia can also manifest with a wide QRS complex. The ability to differentiate between ...

Postural tachycardia syndrome (POTS) is characterized by the presence of orthostatic tachycardia in the absence of orthostatic hypotension with a heart rate increase of >or=30 bpm. Patients often relate complaints of palpitations, exercise intolerance, fatigue and near-syncope or syncope, other non-specific symptoms such as headache and nausea may be present ...

Bundle branch reentrant ventricular tachycardia (BBR-VT) is a form of macroreentrant tachycardia involving the bundle of His, both bundle branches, and the ventricular myocardium in the circuit. It generally occurs in the background of dilated cardiomyopathy, prior valve surgery, or other cardiac disease with an underlying His-Purkinje system (HPS) disease. ...

A 42-year-old male had history of recurrent palpitation and was documented to have wide QRS tachycardia. Magnetic resonance imaging angiogram showed evidence of arrhythmogenic right ventricular dysplasia and severe right ventricular dysfunction. Electrophysiology study showed evidence of bundle branch reentry ventricular tachycardia. It was successfully treated by radiofrequency ablation of ...

Fetal cardiac dysrhythmias are potentially life-threatening conditions. However, intermittent extrasystoles, which are frequently encountered in clinical practice, do not require treatment. Sustained forms of brady- and tachyarrhythmias might require fetal intervention. Fetal echocardiography is essential not only to establish the diagnosis but also to monitor fetal response to therapy. In ...

OBJECTIVE: The present study aimed to evaluate the management of fetal cardiac dysrhythmias based on prior identification of the underlying electrophysiological mechanism. METHODS: We studied 36 consecutive fetuses with cardiac dysrhythmia. Rhythm diagnosis was based on M-mode, pulsed wave Doppler and tissue Doppler imaging (TDI). Only fetuses with: (i) incessant ...

Congenital ventricular diverticulum is a rare congenital cardiac defect. Most patients with this abnormality will remain asymptomatic and without complications during long-term follow-up. However a subgroup of these patients may experience life threatening complications such as ventricular arrhythmias, systemic embolism, sudden death, spontaneous rupture, and valvular regurgitation. We present a ...

The term tachycardia-induced cardiomyopathy or tachycardiomyopathy refers to impairment in left ventricular function secondary to chronic tachycardia, which is partially or completely reversible once the tachyarrhythmia is controlled. Tachycardia- induced cardiomyopathy has been shown to occur both in experimental models and in patients with incessant tachyarrhythmia. Data from several studies ...

BACKGROUND: Tachycardia is a physiological mechanism for adapting cardiac output to modifications in energy consumption in the organism. The repercussions that short-duration tachycardia has on myocardial contractility have not been sufficiently studied.<br /> To study the effects of short-duration tachycardia on regional myocardial function in the anterior face of the ...

Supraventricular tachycardia (SVT) is the most common symptomatic arrhythmias in children. Re-entry tachycardias are the most common form, on the contrary automatic tachycardias are relatively rare. There are four types or re-entry: along anomalous pathway with bi-directional (Wolff-Parkinson-White) or unidirectional conduction, intranodal re-entry, intra-atrial re-entry that is common after surgical ...

The purpose of our work was to define the complex electrophysiological characteristics seen in second- (2 degrees) and third-degree (3 degrees) atrioventricular block (AVB) and to longitudinally follow the development of atrial and ventricular heart rate and rhythm patterns with a goal of identifying heart rate and rhythm patterns associated ...

A fetus who was diagnosed at 25 weeks of gestation with isoimmune AV block presented at 34 weeks with a precipitous fall in ventricular rate and periods of tachycardia. Magnetocardiography revealed the tachycardia to be ventricular. After delivery, nonsustained ventricular tachycardia continued. The baby then successfully paced, and at higher ...

Ventricular tachycardia originating from the right ventricular outflow tract (RVOT) is considered benign, but sometimes it causes polymorphic ventricular tachycardia and ventricular fibrillation, resulting in sudden cardiac death. A 58-year-old woman without structural heart disease was admitted for evaluation of recurrent episodes of syncope. Surface ECG showed frequent repetitive premature ...

A young girl with complex congenital heart disease and a Fontan procedure presented with frequent episodes of atrial tachycardias with 1:1 atrioventricular conduction. The patient underwent placement of a dual-chamber AT500 pacemaker with epicardial leads but because of the detection algorithm requiring > or = 2:1 AV relation, she received ...

AIMS: Significant brady- and tachyarrhythmias may occur in active endurance athletes. It is controversial whether these arrhythmias do persist after cessation of competitive endurance training. METHODS AND RESULTS: Among all 134 former Swiss professional cyclists [hereafter, former athletes (FAs)] participating at least once in the professional bicycle race Tour de ...

The patient was a 50-year-old male in 2002, who was first suspected of having a Brugada-type electrocardiogram (ECG). A drug challenge test using pilsicainide was performed and unmasked a typical coved type ST elevation followed by ventricular arrhythmias (VAs) manifesting a QRS pattern with a right bundle branch block and ...

We describe the case of a 16-year-old woman with a surgically corrected tetralogy of Fallot presenting with recurrent wide-QRS-complex tachycardia. The tachycardia could be induced and terminated with ventricular stimulation only. QRS morphology during sinus rhythm and tachycardia was identical and variable VA-conduction was observed. Mapping of the tachycardia showed ...

We describe the case of a 59-year-old-man with acute myocardial infarction and severely impaired left ventricular systolic function who was intubated because of recurrent ventricular fibrillation in the setting of coronary angioplasty. Repeated ventilator weaning attempts and extubation initially failed, as severe tachycardia and hypertension occurred each time the patient ...

Ventricular tachycardia arising from a healed myocardial infarction scar continues to be a significant cause of morbidity and mortality. Drug therapy has been inadequate to meet this challenge, and implantable devices are limited by expense and technical problems. We have proposed the use of gene therapy for cardiac arrhythmias. In ...

There are great differences in the type of fibrosis that composes an infarcted area. The type of fibrosis will affect the characteristics of recorded extracellular electrograms. Patchy fibrosis, which is often present in the infarcted zone, gives rise to fractionated electrograms. The amount of fractionation has been shown to increase ...

Accelerated ventricular rhythm is similar in rate to the original sinus rhythm. Although 19 cases have been reported in healthy neonates without congenital disease, it is seen with some regularity at tertiary care paediatric cardiac centres. Accelerated ventricular rhythm carries good prognosis, but it is frequently misdiagnosed as ventricular tachycardia ...

Ablation therapy is the widely accepted definitive therapy for atrioventricular reentry tachycardia. Noninducibility of the tachycardia is the targeted end point of the procedure. We report on 21 patients with documented narrow QRS tachycardia, in whom the clinical tachycardia could not be induced during the electrophysiologic study. After exclusion of ...

INTRODUCTION: Rhythm disturbances in children with structurally normal hearts are usually associated with abnormalities in cardiac ion channels. The phenotypic expression of these abnormalities ("channelopathies") includes: long and short QT syndromes, Brugada syndrome, congenital sick sinus syndrome, catecholaminergic polymorphic ventricular tachycardia, Lènegre-Lev disease, and/or different degrees of cardiac conduction disease. ...

Three mechanisms underlie the initiation and maintenance of ventricular tachycardia: automaticity, triggered activity, and reentry. As straightforward as these mechanisms are, assessing which mechanism is operative in a particular patient's ventricular tachycardia can be difficult. The optimal treatment strategy for ventricular tachycardia in a given patient can be influenced by ...

We recently documented that paraplegia (T(5) spinal cord transection) alters cardiac electrophysiology and increases the susceptibility to ventricular tachyarrhythmias induced by programmed electrical stimulation. However, coronary artery occlusion is the leading cause of death in industrially developed countries and will be the major cause of death in the world by ...

Ventricular tachycardia most often arises from the ventricular outflow tracts in patients with apparently structurally normal hearts, and is often termed idiopathic ventricular tachycardia. These tachycardias are characterized by a left bundle branch block, inferior axis QRS morphology, and a unique electropharmacologic profile. The choice of treatment is dictated by ...

Homeopathic Digitalis 6c was evaluated in two clinical cases of atrial paroxysmal tachycardia in dogs. Tachycardias are common cardiac problems in dogs, and atrial paroxysmal tachycardia is a serious cardiac arrhythmia that may lead to syncope. Both adult dogs (Labrador and German Shepherd) were treated with Digitalis 6c, 4 drops ...

Electroconvulsive therapy (ECT) is an effective and safe treatment for a variety of neuropsychiatric disorders. Premedication with atropine has been recommended in order to avoid bradycardia and transient asystole induced by ECT. In contrast, some other arrhythmias can happen such as atrial flutter and fibrillation. But ventricular tachycardia is rare. ...

Cardiac tumors in children are rare. Although most are histologically benign, they can be associated with life-threatening arrhythmias and sudden death. We report a 7-year-old boy, with a first episode of symptomatic tachycardia, who was found to have a left ventricular (LV) fibroma. He had a normal echocardiogram prior to ...

This article presents a review on the efficacy of surgical ventricular restoration and direct surgery for ventricular tachycardia in patients with left ventricular aneurysm or dilated ischemic cardiomyopathy. The procedure includes a non-electrophysiologically guided subtotal endocardiectomy and cryoablation in addition to endoventricular patch plasty of the left ventricle. Coronary artery ...

We present the case of a 45-year-old female with a normal heart, who exhibited an episode of a broad QRS tachycardia that was initially suggested to be sustained ventricular tachycardia. Coronary angiography showed the left main stem originating from the right aortic sinus with an interarterial course between aorta and ...

OBJECTIVE: Electrocardiographic (ECG) rhythm analysis algorithms for cardiac rhythm analysis in automated external defibrillators (AEDs) have been tested against pediatric patient rhythms (patients < or = 8 years old) using adult ECG algorithm criteria. However these adult algorithms may fail to detect non-shockable pediatric tachycardias because they do not account ...

INTRODUCTION: Despite recent advances in clinical electrophysiology, diagnosis of atrial tachycardia (AT) originating near Koch's triangle remains challenging. We sought a novel technique for rapid and accurate diagnosis of AT in the electrophysiologic laboratory. METHODS: Sixty-two supraventricular tachycardias including 18 ATs (10 ATs arising from near Koch's triangle), 32 atrioventricular ...

Junctional ectopic tachycardia is usually a limited but potentially life-threatening postoperative arrhythmia. We describe a case of malignant postoperative junctional ectopic tachycardia in a 13-month-old child who had undergone transatrial and transpulmonary repair of tetralogy of Fallot resistant to all conventional therapeutic measures and complicated by recurrent ventricular tachycardia. The ...

OBJECTIVE: Extracorporeal life support (ECLS) has been applied successfully to patients with cardiopulmonary failure in extreme situations. Refractory ventricular tachycardia has high mortality and morbidity rates if not terminated in time. This study describes our preliminary experiences in using ECLS to treat patients with refractory ventricular tachycardia. DESIGN: Retrospective chart ...

OBJECTIVE: We present the improved method of recognition of sustained ventricular tachycardia (SVT) based on new filtering technique (FIR), extended signal-averaged electrocardiography (SAECG) description by 9 parameters and the application of support vector machine (SVM) classifier. METHODS: The dataset consisted of 376 patients (100 patients with sustained ventricular tachycardia after ...

A 47-year-old man with palpitations underwent electrophysiologic testing (EPS). Burst atrial pacing while infusing isoproterenol induced non-reproducible wide QRS tachycardias with an unusual pattern of an H-A-V activation with the same tachycardia cycle length and two different initiation patterns. The tachycardia had the earliest atrial activation at the His bundle ...

INTRODUCTION: No prior studies have systematically investigated the diagnostic value of cycle length (CL) variability in differentiating the mechanism of paroxysmal supraventricular tachycardia (PSVT). METHODS AND RESULTS: We studied 173 consecutive patients with PSVT; 86 typical atrioventricular nodal reentrant tachycardia (AVNRT), 11 atypical AVNRT, 47 orthodromic reciprocating tachycardia (ORT), and ...

BACKGROUND: Infarct border zone (IBZ) geometry likely affects inducibility and characteristics of postinfarction reentrant ventricular tachycardia, but the connection has not been established. OBJECTIVE: The purpose of this study was to determine characteristics of postinfarction ventricular tachycardia in the IBZ. METHODS: A geometric model describing the relationship between IBZ geometry ...

A 77-year-old female was admitted in our hospital for uterine prolapse surgery. She developed ventricular tachycardia during induction of general anaesthesia and after initial symptomatic measures, she was transferred to the coronary care unit. Heart failure persisted and electrocardiographic changes mimicking acute myocardial infarction appeared. Coronary angiography was normal and ...

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a highly lethal form of inherited arrhythmogenic disease characterized by adrenergically mediated polymorphic ventricular tachycardia. The mutations in cardiac ryanodine receptor and calsequestrin genes are responsible for the autosomal dominant and recessive variants of CPVT, respectively. The clinical presentation encompasses exercise- or emotion-induced syncopal ...

Idiopathic ventricular tachycardia is a defined set of tachycardias when structural or pathological cause has been ruled out for the same. This paper tries to define and classify these arrhythmias to organize a logical therapeutic approach to deal with them. 60-80% of the idiopathic tachycardias originate from the right ventricular ...

We report on the case of an 18-year-old girl with asymptomatic incessant ventricular tachycardia. Initial attempts at endocardial ablation failed and she was monitored until her cardiac function deteriorated. A percutaneous epicardial approach with electroanatomical mapping was then used which successfully terminated the tachycardia. Left ventricular size and function subsequently ...

A previously asymptomatic 15-year-old boy was treated at our institution after an episode of chest pain, palpitation, and syncope while playing in a high school soccer game. The patient's resting electrocardiogram was normal. A transthoracic echocardiogram showed an anomalous left main coronary artery originating from the right sinus of Valsalva. ...

The effects of dronedarone, a non-iodinated derivative of amiodarone, on ventricular tachycardia and ventricular fibrillation post-myocardial infarction are not well established. Fifty-five Wistar rats were randomly allocated to a 2-week oral treatment with either vehicle (n=18), amiodarone (30 mg/kg, n=20), or dronedarone (30 mg/kg, n=17). After acute coronary artery ligation, ...

BACKGROUND: The Precordial Thump (PT) is commonly used for cardiopulmonary resuscitations both in and out of hospitals. However, the support for its efficiency relies mainly on sporadic cases. In this current prospective large study, we tested the effectiveness and safety of PT in a wide range of malignant ventricular tachyarrhythmias. ...

The evaluation of a nonsustained wide QRS tachycardia in a life insurance applicant's exercise test presents a special challenge to the medical director because of the unpredictable and potentially lethal nature of these arrhythmias. Ventricular tachycardia accounts for up to 80% of wide QRS tachycardias in unselected populations and more ...

Isolated left ventricular noncompaction is a rare cardiomyopathy that is often not recognised. So far, it is not well established how best to manage this abnormality. We describe a patient in whom the diagnosis of isolated left ventricular noncompaction was made after presentation with a subacute myocardial infarction. Because of ...

Symptomatic arrhythmias are frequently observed in the intensive care unit and often lead to significant hemodynamic compromise because of the presence of multisystem disease. In particular, prompt evaluation of patients with tachycardia is critical because treatment depends on the accurate diagnosis of the arrhythmia mechanism. The electrocardiogram remains the most ...

We report a patient with re-entrant atrial tachycardia that originated at the inferolateral tricuspid annulus. Single atrial extra-stimulation reproducibly induced the atrial tachycardia with an inverse relationship between the coupling interval of extra-stimulation and the return cycle of the first tachycardia beat. A real-time three-dimensional electroanatomical mapping showed focal atrial ...