Potential role of body surface ECG mapping for localization of atrial fibrillation trigger sites.

Catheter ablation has revolutionized the clinical management of atrial fibrillation (AF) by offering a curative treatment option for this highly prevalent arrhythmia. Ablation therapy is aimed at electrical isolation of the pulmonary veins (PVs) as a means to prevent rapidly firing focal activation within the PVs from penetrating into the left atrium (LA) and initiate reentrant wavelet propagation. However, non-PV AF trigger sites may be present and lead to unsuccessful ablation or post-ablation AF recurrences.

Clinical and electrophysiologic characteristics of left septal atrial tachycardia.

Objectives: It was the purpose of this study to define the electrophysiologic (EP) identity of left septal atrial tachycardia (AT).

Background: The clinical and EP characteristics of this particular type of arrhythmia have not been fully described.

Methods: A total of 120 patients with AT underwent invasive EP evaluation.

Conversion of left ventricular endocardial positions from patient-independent co-ordinates into biplane fluoroscopic projections.

Electrocardiographic body surface mapping is used clinically to guide catheter ablation of cardiac arrhythmias by providing an estimate of the site of origin of an arrhythmia. The localisation methods used in our group produce results in left-ventricular cylinder co-ordinates (LVCCs), which are patient-independent but hard to interpret during catheterisation in the electrophysiology laboratory. It is preferable to provide these results as three-dimensional (3D) co-ordinates which can be presented as projections in the biplane fluoroscopic views that are used routinely to monitor the catheter position.

Relation between body surface mapping and endocardial spread of ventricular activation in postinfarction heart.

Introduction: Body surface mapping (BSM) can be used to identify the site of earliest endocardial activation of ventricular tachycardias (VTs). The multielectrode QRS morphology during VT is determined by both the site of earliest activation and the subsequent spread of electrical activation through the ventricles. This study investigated the relationship between the site of earliest endocardial activation, endocardial spread of activation, and the morphology of the multielectrode surface map in patients with remote myocardial infarction.

Electrocardiographic analysis of ectopic atrial activity obscured by ventricular repolarization: P wave isolation using an automatic 62-lead QRST subtraction algorithm.

Introduction: Atrial activity on the surface ECG during premature beats and supraventricular arrhythmias frequently is obscured by the superimposed QRST complex of the previous cardiac cycle. This study examines the performance of a newly developed automatic QRST subtraction algorithm to isolate ectopic P waves from the preceding T-U wave.

Methods And Results: The 62-lead ECG recordings were obtained during (1) sinus rhythm and programmed right atrial stimulation in 12 patients (group A); and (2) sinus rhythm and atrial premature beats, atrial tachycardia, or paroxysmal atrial fibrillation in 5 patients (group B).

Derivation of an optimal lead set for measuring ectopic atrial activation from the pulmonary veins by using body surface mapping.

Atrial fibrillation is often initiated by atrial premature beats originating in the pulmonary veins. Non-invasive localization of these ectopic beats would be of significant value in guiding therapy. Body surface potential mapping was performed in nine patients undergoing invasive electrophysiologic study.

The role of the crista terminalis in atrial flutter and fibrillation: a computer modeling study.

Although atrial fibrillation is a common arrhythmia, the underlying mechanisms are incompletely understood. Recent studies have determined the role of the crista terminalis in the mechanisms of a simpler arrhythmia, atrial flutter. We hypothesize that as transverse coupling across the crista terminalis increases, the activation pattern that results is less like typical atrial flutter and more like atrial fibrillation.

Continuous localization of cardiac activation sites using a database of multichannel ECG recordings.

Monomorphic ventricular tachycardia and ventricular extrasystoles have a specific exit site that can be localized using the multichannel surface electrocardiogram (ECG) and a database of paced ECG recordings. An algorithm is presented that improves on previous methods by providing a continuous estimate of the coordinates of the exit site instead of selecting one out of 25 predetermined segments. The accuracy improvement is greatest, and most useful, when adjacent pacing sites in individual patients are localized relative to each other.

Body surface mapping of counterclockwise and clockwise typical atrial flutter: a comparative analysis with endocardial activation sequence mapping.

Objectives: This study was directed at developing spatial 62-lead electrocardiogram (ECG) criteria for classification of counterclockwise (CCW) and clockwise (CW) typical atrial flutter (Fl) in patients with and without structural heart disease.

Background: Electrocardiographic classification of CCW and CW typical atrial Fl is frequently hampered by inaccurate and inconclusive scalar waveform analysis of the 12-lead ECG.

Methods: Electrocardiogram signals from 62 torso sites and multisite endocardial recordings were obtained during CCW typical atrial Fl (12 patients), CW typical Fl (3 patients), both forms of typical Fl (4 patients) and CCW typical and atypical atrial Fl (1 patient).

Use of electroanatomic mapping to delineate transseptal atrial conduction in humans.

Background: Interaction between wave fronts in the right and left atrium may be important for maintenance of atrial fibrillation, but little is known about electrophysiological properties and preferential routes of transseptal conduction.

Methods And Results: Eighteen patients (age 44+/-12 years) without structural heart disease underwent right atrial electroanatomic mapping during pacing from the distal coronary sinus (CS) or the posterior left atrium. During distal CS pacing, 9 patients demonstrated a single transseptal breakthrough near the CS os, 1 patient in the high right atrium near the presumed insertion of Bachmann's bundle and 1 patient near the fossa ovalis.

The spatial dispersion of atrial refractoriness and atrial fibrillation vulnerability.

The local dispersion of conduction and refractoriness has been considered essential for induction of atrial arrhythmias. This study sought to determine whether a difference of refractoriness and vulnerability for induction of atrial fibrillation between trabeculated and smooth as well as high and low right atrium may contribute to initiation of atrial fibrillation in dogs. In 14 healthy mongrel dogs weighing 22.

Low-power radiofrequency application and intracardiac echocardiography for creation of continuous left atrial linear lesions.

Introduction: Continuity of radiofrequency (RF) lesions for a catheter-based cure of atrial fibrillation is essential in order to avoid reentrant tachycardias. In the present study, we assessed the value of intracardiac echocardiography and preablation electrode-tissue interface parameters for creation of left atrial linear lesions.

Methods And Results: In six healthy dogs, two left atrial linear lesions (lesion 1, along the inferior posterior left atrium; lesion 2, from the appendage to the left atrial roof) were attempted via a transseptal approach using a deflectable catheter with six 7-mm coil electrodes.

Clinical application of an integrated 3-phase mapping technique for localization of the site of origin of idiopathic ventricular tachycardia.

Background: Radiofrequency (RF) catheter ablation provides curative treatment for idiopathic ventricular tachycardia (VT).

Methods And Results: Nineteen consecutive patients with an idiopathic VT underwent RF catheter ablation. An integrated 3-phase mapping approach was used, consisting of the successive application of online 62-lead body surface QRS integral mapping, directed regional paced body surface QRS integral mapping, and local activation sequence mapping.

Body surface mapping of atrial arrhythmias: atlas of paced P wave integral maps to localize the focal origin of right atrial tachycardia.

Successful curative treatment of right atrial tachycardia (AT) can be obtained provided detailed catheter activation mapping of the target site for radiofrequency energy application has been accomplished. However, right AT mapping may be difficult with a single roving catheter due to infrequent presence or noninducibility of the arrhythmia. The present report describes the preliminary clinical use of body surface mapping as an adjunctive noninvasive method to identify the region of AT origin prior to catheter ablation.

Organized activation during atrial fibrillation in man: endocardial and electrocardiographic manifestations.

Introduction: Atrial fibrillation is not entirely random, but little is known about the spatiotemporal endocardial organization and its surface ECG manifestations.

Methods And Results: In 16 patients with atrial fibrillation (chronic, n = 14), endocardial mapping of the trabeculated, the posteroseptal smooth right atrium, and the coronary sinus was performed using multipolar catheters. The surface ECG was analyzed by determining "fibrillation wave" (F wave) amplitude, rate, and polarity.

Electrocardiographic identification of abnormal ventricular depolarization and repolarization in patients with idiopathic ventricular fibrillation.

Objectives: We sought to gain more insight into the arrhythmogenic etiology of idiopathic ventricular fibrillation (VF) by assessing ventricular depolarization and repolarization properties by means of various electrocardiographic (ECG) techniques.

Background: Idiopathic VF occurs in the absence of demonstrable structural heart disease. Abnormalities in ventricular depolarization or repolarization have been related to increased vulnerability to VF in various cardiac disorders and are possibly also present in patients with idiopathic VF.

Body surface mapping during pacing at multiple sites in the human atrium: P-wave morphology of ectopic right atrial activation.

Background: The morphology and polarity of the P wave on 12-lead ECG are of limited clinical value in localizing ectopic atrial rhythms. It was the aim of this study to assess the spatial resolution of body surface P-wave integral mapping in identifying the site of origin of ectopic right atrial (RA) impulse formation in patients without structural atrial disease.

Methods And Results: Sixty-two-lead ECG recordings were obtained during RA pacing at 86 distinct endocardial sites in nine patients with normal biatrial anatomy.

Relationship between atrial fibrillation and typical atrial flutter in humans: activation sequence changes during spontaneous conversion.

Background: A transitional rhythm precedes the spontaneous onset of atrial flutter in an animal model, but few data are available in man.

Methods And Results: In 10 patients, 16 episodes of atrial fibrillation (166+/-236 seconds) converting into atrial flutter during electrophysiological evaluation were analyzed. A 20-pole catheter was used for mapping the right atrial free wall.

Body-surface QRST integral mapping. Arrhythmogenic righ ventricular dysplasia versus idiopathic right ventricular tachycardia.

Background: Ventricular tachycardia originating in the right ventricle may arise in the presence or absence of structural heart disease. The two main causes of right ventricular tachycardia are arrhythmogenic right ventricular dysplasia (ARVD) and idiopathic right ventricular tachycardia (IRVT) originating from the outflow tract. This study was carried out to determine whether body-surface QRST integral mapping can differentiate patients with ARVD from patients with IRVT.

Association of left ventricular remodeling and nonuniform electrical recovery expressed by nondipolar QRST integral map patterns in survivors of a first anterior myocardial infarction. Captopril and Thrombolysis Study Investigators.

Background: Progressive left ventricular dilatation after myocardial infarction is associated with a high mortality rate, the majority of which is arrhythmogenic in origin. The underlying mechanism of this relation remains unknown. It has been suggested, however, that left ventricular dilatation is accompanied by changes in repolarization characteristics that may facilitate the occurrence of life-threatening ventricular arrhythmias.

Value of body surface mapping in localizing the site of origin of ventricular tachycardia in patients with previous myocardial infarction.

Objectives: This study examined the performance of the 62-lead body surface electrocardiogram (ECG) in identifying the site of origin of ventricular tachycardia in patients with a previous myocardial infarction.

Background: Because the accuracy of ECG localization of ventricular tachycardia using standard 12-lead recordings is restricted to the identification of rather large ventricular areas, application of multiple torso lead recordings may augment the resolving power of the surface ECG and result in more discrete localization of arrhythmogenic foci.

Methods: Thirty-two patients were selected for electrophysiologically guided ablative therapy for drug-resistant postinfarction ventricular tachycardia.

Automatic QRS onset and offset detection for body surface QRS integral mapping of ventricular tachycardia.

A QRS onset and offset detection algorithm has been developed for use in body surface QRS integral mapping of ventricular tachycardia. To determine QRS intervals, the algorithm uses two computed signals: the sum of the absolute values of the first derivatives of all leads and the sum of the absolute values of all leads. The second order derivative of the latter parameter is used to detect the time instants of QRS onset and offset.

Atlas of paced body surface QRS integral maps for localization of the site of origin of postinfarction ventricular tachycardia.

Current mapping during radiofrequency (RF) catheter ablation of postinfarction ventricular tachycardia (VT) is based primarily on the use of single-site mapping techniques. Although such techniques are highly suitable for distinguishing the ultimate site where RF energy is delivered by enabling detailed localization of the exit site or critical component of the VT reentrant circuit, they are time-consuming and inefficient for initial rapid identification of the arrhythmogenic target area. This study features the design and preliminary clinical application of a new noninvasive method that is aimed at speeding up the initial phase of the VT mapping procedure.

Localization of the site of origin of postinfarction ventricular tachycardia by endocardial pace mapping. Body surface mapping compared with the 12-lead electrocardiogram.

Background: The purpose of this study was to assess the value of body surface mapping and the standard 12-lead ECG in localizing the site of origin of postinfarction ventricular tachycardia (VT) during endocardial pace mapping of the left ventricle.

Methods And Results: Simultaneous recordings of 62-lead body surface QRS integral maps and scalar 12-lead ECG tracings were obtained in 16 patients with prior myocardial infarction during a total of 26 distinct VT configurations and during subsequent left ventricular catheter pace mapping at 9 to 24 different endocardial sites. Anatomic pacing site locations were computed by means of a biplane cineradiographic method and plotted on a polar projection of the left ventricle.

Body surface mapping of ectopic left ventricular activation. QRS spectrum in patients with prior myocardial infarction.

To improve electrocardiographic localization of the site of origin of ectopic left ventricular (LV) impulse formation in the heart with prior myocardial infarction, 62-lead body surface QRS integral maps were studied during LV pacing at a total of 221 endocardial sites in 14 patients with previous anterior (AMI), inferior (IMI), lateral (LMI), or anterior and inferior (AMI/IMI) myocardial infarction. The anatomic location of each pacing site was computed using digitized biplane fluoroscopic images and plotted on standardized LV endocardial polar projections. A data base of characteristic AMI and IMI mean QRS integral maps was developed after visually selecting subgroups with nearly identical QRS integral morphology from the ectopic activation sequences produced at 110 sites in eight patients with AMI and at 66 sites in four patients with IMI.