Time relationship of the P-delta segment in the Wolff-Parkinson-White syndrome

A Single-lead ECG algorithm to differentiate right from left manifest accessory pathways: A reappraisal of the P-Delta interval

INTRODUCTION

Despite numerous ECG algorithms being developed to localize the site of manifest accessory pathways (AP), they often require stepwise multiple-lead analysis with variable accuracy, limitations, and reproducibility. The study aimed to develop a single-lead ECG algorithm incorporating the P-Delta interval (PDI) as an adjunct criterion to discriminate between right and left manifest AP.

METHODS

Consecutive WPW patients undergoing electrophysiological study (EPS) were retrospectively recruited and split into a derivation and validation group (1:1 ratio). Sinus rhythm ECG analysis in lead V1 was performed by three independent investigators blinded to the EPS results. Conventional ECG parameters and PDI were assessed through the global cohort.

RESULTS

A total of 140 WPW patients were included (70 for each group). A score-based, single-lead ECG algorithm was developed through derivation analysis incorporating the PDI, R/S ratio, and QRS onset polarity in lead V1. The validation group analysis confirmed the proposed algorithm's high accuracy (95%), which was superior to the previous ones in predicting the AP side (p < 0.05). A score of ≤+1 was 96.5% accurate in predicting right AP while a score of ≥+2 was 92.5% accurate in predicting left AP. The new algorithm maintained optimal performance in specific subgroups of the global cohort showing an accuracy rate of 90%, 92%, and 96% in minimal pre-excitation, posteroseptal AP, and pediatric patients, respectively.

CONCLUSIONS

A novel single-lead ECG algorithm incorporating the PDI interval with previous conventional criteria showed high accuracy in differentiating right from left manifest AP comprising pediatric and minimal pre-excitation subgroups in the current study.

Body surface potential mapping of a patient with Wolff-Parkinson-White syndrome with two accessory pathways and two atrial pacemaker complexes

As part of an ongoing research protocol, a patient with Wolff-Parkinson-White syndrome underwent body surface potential mapping and electrophysiologic studies before radiofrequency ablation therapy. Careful analysis of the body surface potential mapping data made it possible to distinguish four different map sequences representing four different cardiac complexes. Analysis of these maps is consistent with two accessory pathways, with the additional pathology of two distinct atrial pacemaker sites. A right anterosuperior pathway was found to conduct continuously. The second pathway is consistent with a right inferior pathway conducting intermittently. The analysis demonstrates the type of information that can be extracted from body surface potential maps, even in the presence of complex pathologies.

Body surface isopotential mapping of the entire QRST complex in the Wolff-Parkinson-White syndrome. Correlation with the location of the accessory pathway

Body surface potential maps were recorded during sinus rhythm and during atrial pacing at the time of electrophysiologic studies in 42 patients with Wolff-Parkinson-White syndrome. The locations of the accessory pathways were determined by epicardial mapping during surgery in 34 patients and by multicatheter endocavitary electrophysiologic studies in eight additional patients. During delta wave inscription, the shape and extension of areas of the negative and positive potentials on the thorax correlated better with the preexcitation site (69% of patients) than with the localization of the minimum potential alone (45.2% of patients). Typical potential distributions were present from the beginning of the delta wave and remained stationary during the first half of the QRS complex. During marked preexcitation, the superposition of atrial activity on the delta wave produced a mixed pattern in the earliest maps. However, these alterations of early delta thoracic potential distribution did not persist longer than 30 msec. The spread of the negative potentials during the last half of the QRS complex also characterized each localization: right-sided preexcitation reproduced the depolarization sequence of left bundle branch block, left-sided preexcitation reproduced that of right bundle branch block, and posterior pathways resembled left anterior fascicular block. Anterior left ventricular and more anterior left lateral ventricular preexcitations mimicked a right bundle branch block-left posterior fascicular block pattern. There was good correlation between the body surface potential map obtained during the ST segment and the site of the right-sided preexcitation. However, in left-sided preexcitations, ST patterns concordant with delta wave patterns were found less frequently than in right-sided preexcitations.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial depolarization in Wolf-Parkinson-White and Lown-Ganong-Levine syndrome: vectorcardiographic features

The atrial depolarization pattern was studied in 22 patients with Wolff-Parkinson-White and Lown-Ganong-Levine syndrome. The influence of the accessory pathways on the shape, magnitude and conduction pattern of the PSE loop was analyzed. An accurate evaluation of the beginning of the delta wave and of the P loop distortions was obtained by using high magnification (1 mV = 30 cm) recordings. The Frank lead system was used. The influence of atrial size (documented by echocardiography) on the PSE loop is emphasized. Special attention has been focused on the terminal vectors as compared to a control group. In Wolff-Parkinson-White syndrome the size of the PSE loop was smaller than in Lown-Ganong-Levine syndrome or in the normal group. When atrial conduction disturbances and/or atrial enlargement was present the PSE loop was larger and distorted. The terminal vectors were abnormally oriented in 75 percent of the patients with Wolff-Parkinson-White syndrome, but only in one with Lown-Ganong-Levine syndrome. The beginning of the delta wave in patients with Wolff-Parkinson-White syndrome was located to the left of the E point in all but two. When the "concertina" effect was present, the direction of the terminal vectors remained unchanged. In four patients with the Lown-Ganong-Levine syndrome, the PSE loop closed, and in three patients, a small opening was present. We suggest that the changes in contour, duration and amplitude of the PSE loop are due to an abnormal pattern of atrial depolorization in Wolff-Parkinson-White syndrome.