Heidi A. P. Peeters

Body-Surface QRST Integral Mapping Arrhythmogenic Right 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. METHODS AND RESULTS Body-surface QRST integral maps were obtained during sinus rhythm in 8 patients with ARVD, 8 patients with IRVT, and 27 healthy control subjects. QRST integral maps were analyzed both visually and mathematically. All control subjects had a normal dipolar QRST integral map. In all patients with ARVD, a specific dipolar QRST integral map with an abnormally large negative area covering the entire inferior and right anterior thorax was recorded. In 6 of 8 patients with IRVT, a normal map pattern was found, whereas the remaining 2 patients showed an abnormally large negative area on the right anterior thorax. CONCLUSIONS Patients with ARVD display a specific abnormal QRST integral map that may be related to delayed repolarization in the structurally abnormal right ventricle. The majority of patients with IRVT demonstrate a normal QRST integral map. A slightly abnormal QRST integral map was noted in 2 of 8 patients with IRVT, which may be related to minor structural abnormalities, undetectable by the present routine diagnostic techniques. These preliminary results indicate that body-surface QRST integral mapping may become an important diagnostic tool to differentiate patients with ARVD from those with IRVT.

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. METHODS In 17 patients with a first episode of idiopathic VF, 62-lead body surface QRST integral maps, QT dispersion on the 12-lead ECG and XYZ-lead signal-averaged ECGs were computed. RESULTS All subjects of a healthy control group had a normal dipolar QRST integral map. In patients with idiopathic VF, either a normal dipolar map (29%,), a dipolar map with an abnormally large negative area on the right side of the thorax (24%) or a nondipolar map (47%) were recorded. Only four patients (24%) had increased QT dispersion on the 12-lead ECG and late potentials could be recorded in 6 (38%) of 16 patients. During a median follow-up duration of 56 months (range 9 to 136), a recurrent arrhythmic event occurred in 7 patients (41%), all of whom had an abnormal QRST integral map. Five of these patients had late potentials, and three showed increased QT dispersion on the 12-lead ECG. CONCLUSIONS In patients with idiopathic VF, ventricular areas of slow conduction, regionally delayed repolarization or dispersion in repolarization can be identified. Therefore, various electrophysiologic conditions, alone or in combination, may be responsible for the occurrence of idiopathic VF. Body surface QRST integral mapping may be a promising method to identify those patients who do not show a recurrent episode of VF.

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 (EGG) 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. Important advantages of the new method are the objectivity and reproducibility of the localization results.

Body surface mapping of atrial arrhythmias: Atlas of paced p wave integral maps to localize the focal origin of right atrial tachycardia☆

Abstract 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. This technique has been previously applied to develop a reference data base of 17 different paced P wave integral map patterns. The data base was designed by performing right atrial pace mapping in patients without structural heart disease. Each P wave integral map pattern in the data base is unique to ectopic activation onset in a circumscribed right atrial endocardial segment. Localization of the segment of AT origin is accomplished by matching the P wave integral map of a single AT beat with the data base of paced P wave integral maps. The use of body surface mapping as an integral part of the mapping protocol during radiofrequency catheter ablation of right AT offers the possibility to: (1) noninvasively determine the arrhythmogenic target area for ablation using a single beat analysis approach; (2) confine detailed catheter activation mapping to a limited area; and (3) accelerate the overall procedure and limit fluoroscopic exposure by reducing the time required for mapping.

Quantitative algorithm for the localization of the origin of ectopic ventricular beats using catheter pace mapping

In the treatment of a ventricular tachycardia by radiofrequency ablation, it is essential to position the tip of the catheter at the origin of the arrhythmia. A quantitative algorithm has been developed to estimate the site of origin of the arrhythmia on the basis of paced QRS integral maps and the corresponding spatial coordinates of the catheter tip positions. The algorithm has been validated by simulation, using catheter pace maps and spatial coordinates obtained in WPW-patients undergoing RF ablation. When assuming a coupled linear relation between coordinates of the catheter tip positions and the pace map, 71% of the required positions were estimated with an accuracy within the resolution of the position measurements.