Electrocardiographic Patterns of Ventricular Arrhythmias in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

Ventricular arrhythmias in patients with ARVD/C are common. Differentiation between idiopathic ventricular tachycardia and arrhythmogenic right ventricular dysplasia is of utmost importance. Baseline sinus rhythm electrocardiography as well as electrocardiographic differences during ventricular arrhythmias (VT or PVCs) can be helpful in differentiating the two disease states. The pathological fibrofatty myocyte replacement in ARVD/C as well as ventricular arrhythmia origin are likely responsible for these differences

Wolff-Parkinson-White syndrome: where is the pathway?

A 31-year old male presented with atrial fibrillation and ventricular preexcitation that was positive in leads V1-V4, negative in lead II, and positive in lead AVR. The patient was cardioverted and invasive electrophysiologic study was performed. Based on the ECG findings, the coronary sinus and its branches were interrogated during orthodromic atrioventricular reentrant tachycardia. The earliest local activation was seen in the true coronary sinus lumen at the bifurcation of the posterolateral branch. Radiofrequency energy application at this area led to loss of preexcitation. When localizing left septal and posterior accessory pathways, ventricular preexcitation that is both negative in II and positive in AVR has been shown in previous studies to be highly sensitive and specific for a subepicardial location. Therefore, investigation of the coronary sinus and its branches may allow for effective ablation without the need for left ventricular access

Bidirectional ventricular tachycardia in cardiac sarcoidosis.

A 73-year-old man with history of pulmonary sarcoidosis was found to have runs of non-sustained bidirectional ventricular tachycardia (BVT) with two different QRS morphologies on a Holter monitor. Cardiac magnetic resonance delayed gadolinium imaging revealed a region of patchy mid-myocardial enhancement within the left ventricular basal inferolateral myocardium. An 18-fluorodeoxyglucose positron emission tomography (FDG-PET) showed increased uptake in the same area, consistent with active sarcoid, with no septal involvement. Follow-up FDG-PET one year later showed disease progression with new septal involvement. Cardiac sarcoidosis, characterized by myocardial inflammation and interstitial fibrosis that can lead to conduction system disturbance and macro re-entrant arrhythmias, should be considered in differential diagnosis of BVT. BVT may indicate septal involvement with sarcoidosis before the lesions are large enough to be detected radiologically

Clinical and electrophysiologic characteristics of left septal atrial tachycardia

AbstractObjectivesIt was the purpose of this study to define the electrophysiologic (EP) identity of left septal atrial tachycardia (AT).BackgroundThe clinical and EP characteristics of this particular type of arrhythmia have not been fully described.MethodsA total of 120 patients with AT underwent invasive EP evaluation. Five patients (two men and three women; mean age 49 ± 15 years) with left septal AT were identified. Mapping of the right and left atrium was performed using conventional electrode catheters (five patients) and a three-dimensional electroanatomic mapping system (three patients) followed by radiofrequency (RF) ablation at the earliest site of local endocardial activation.ResultsFive tachycardias with a mean cycle length of 320 ± 94 ms were mapped, and the earliest endocardial electrogram occurred 22 ± 10 ms before the onset of the surface P-wave. Three left septal ATs were found to be originating from the left inferoposterior atrial septum and two from the left midseptum. During tachycardia, positive (three patients), biphasic negative-positive deflection (one patient), or isoelectric (one patient) P waves were recorded in lead V1. The inferior leads demonstrated a positive or biphasic P-wave morphology in four of five patients (80%). Four patients were given both adenosine and verapamil during AT. In three of four patients, verapamil successfully terminated AT after adenosine had failed. Adenosine successfully terminated AT in one of four patients. Successful RF ablation was performed in all patients (mean 2.2 ± 1.7 RF applications) without affecting atrioventricular conduction properties. No recurrence of AT was observed after a mean follow-up of 14 ± 8 months.ConclusionsLeft septal AT ablation is safe and effective. There was no consistent P-wave morphology associated with this particular type of AT. This arrhythmia appears to be resistant to adenosine and moderately responsive to calcium antagonists

Results of Catheter Ablation of Ventricular Tachycardia Using Direct Current Shocks

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74779/1/j.1540-8159.1989.tb02654.x.pd

Diagnosis and Management of Complex Reentrant Arrhythmias Involving the His-Purkinje System

The His-Purkinje system is a network of bundles and fibres comprised of specialised cells that allow for coordinated, synchronous activation of the ventricles. Although the histology and physiology of the His-Purkinje system have been studied for more than a century, its role in ventricular arrhythmias has recently been discovered with the ongoing elucidation of the mechanisms leading to both benign and life-threatening arrhythmias. Studies of Purkinje-cell electrophysiology show multiple mechanisms responsible for ventricular arrhythmias, including enhanced automaticity, triggered activity and reentry. The variation in functional properties of Purkinje cells in different areas of the His-Purkinje system underlie the propensity for reentry within Purkinje fibres in structurally normal and abnormal hearts. Catheter ablation is an effective therapy in nearly all forms of reentrant arrhythmias involving Purkinje tissue. However, identifying those at risk of developing fascicular arrhythmias is not yet possible. Future research is needed to understand the precise molecular and functional changes resulting in these arrhythmias

Use of P wave configuration during atrial tachycardia to predict site of origin

Objectives.This study sought to construct an algorithm to differentiate left atrial from right atrial tachycardia foci on the basis of surface electrocardiograms (ECGs).Background.Atrial tachycardia is an uncommon form of supraventricular tachycardia, often resistant to drug therapy.Methods.A total of 31 consecutive patients with atrial tachycardia due to either abnormal automaticity or triggered rhythm underwent detailed atrial endocardial mapping and successful radiofrequency catheter ablation of a single atrial focus. P wave configuration was analyzed from 12-lead ECGs during tachycardia during either spontaneous or pharmacologically induced atrioventricular block. P waves inscribed above the isoelectric line (TP interval) were classified as positive, below as negative, above and below (or conversely, below and above) as biphasic and flat P waves as isoelectric (0). In 17 patients the tachycardia was located in the right atrium: crista terminalis (n = 4); right atrial appendage (n = 4); lateral wall (n = 4); posteroinferior right atrium (n = 3); tricuspid annulus (n = 1); and near the coronary sinus (n = 1). In 14 patients, atrial tachycardia was located in the left atrium: at the entrance of the right (n = 6) or left (n = 4) superior pulmonary veins; left inferior pulmonary vein (n = 1); inferior left atrium (n = 1); base of left atrial appendage (n = 1); and high lateral left atrium (n = 1).Results.There were no differences in P wave vectors between sites at the right atrial lateral wall versus the right atrial appendage or between sites at the entrance of right versus left superior pulmonary veins. However, analysis of P wave configuration showed that leads aVL and V1were most helpful in distinguishing right atrial from left atrial foci. The sensitivity and specificity of using a positive or biphasic P wave in lead aVL to predict a right atrial focus was 88% and 79%, respectively. The sensitivity and specificity of a positive P wave in lead V1in predicting a left atrial focus was 93% and 88%, respectively.Conclusions.1) Analyses of surface P wave configuration proved to be reasonably good in differentiating right atrial from left atrial tachycardia foci. 2) Leads II, III and aVF were helpful in providing clues for differentiating superior from inferior foci