CLINICAL STUDIES
Detection of concealed left sided accessory atrioventricular pathway by P wave signal averaged electrocardiogram
Teruhisa Yoshida, MDa,
Hisao Ikeda, MDa,
Tatsuro Hiraki, MDa,
Ichiro Kubara, MDa,
Masanobu Ohga, MDa and
Tsutomu Imaizumi, MD, FACCa
a Department of Internal Medicine III and The Cardiovascular Research Institute, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011 Japan
Manuscript received December 23, 1997;
revised manuscript received July 16, 1998,
accepted September 17, 1998.
Address for correspondence: Dr. Tatsuro Hiraki, The Department of Internal Medicine III, Kurume University School of Medicine, 67 Asahi-machi, Kurume, 830-0011 Japan
Objectives. The purpose of this study was to examine whether P wave signal-averaged electrocardiogram (P-SAECG), which detects subtle changes in P wave, detects the concealed accessory atrioventricular pathway (AP).
Background. It is difficult to differentiate atrioventricular reciprocating tachycardia (AVRT) due to the AP from atrioventricular nodal reentrant tachycardia (AVNRT) when the ventricular preexcitation is absent on 12-lead electrocardiograms. By electrophysiological studies, the anterograde conduction in the concealed AP is shown to be blocked near the AP-ventricular interface during sinus rhythm.
Methods. P-SAECG during sinus rhythm was performed in 20 normal volunteers (control), 21 patients with AVRT due to the concealed AP, 19 with AVNRT, 22 with paroxysmal atrial fibrillation (PAF), and 7 with automatic atrial tachycardia (AT). The filtered P wave duration (FPD) and AR20 (power spectrum area ratio of 0–20 to 20–100 Hz) were measured and repeated in AVRT, AVNRT and AT groups at one week after catheter ablation.
Results. The anterograde conduction in the concealed left-sided AP was confirmed in all cases by an electrophysiological study. The FPD in AVRT group was more prolonged than that in controls or AVNRT group. Although the FPD was similar between AVRT and PAF groups, AR20 differentiated between the two groups. Ablation of the concealed AP shortened FPD in AVRT group but that of the slow pathway or the atrial focus did not shorten in the AVNRT or AT groups, respectively. The changes in FPD after ablation were correlated with those in the duration of atrial activity by an electrophysiological study (r = 0.67).
Conclusions. Our findings suggest that P-SAECG detects the concealed left-sided AP, providing a clinical tool in noninvasively assessing atrial activation patterns.
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Abbreviations and Acronyms
| | AP | = accessory atrioventricular pathway | | AVNRT | = atrioventricular nodal reentrant tachycardia | | AVRT | = atrioventricular reciprocating tachycardia | | AT | = atrial tachycardia | | FPD | = filtered P wave duration | | PAF | = paroxysmal atrial fibrillation | | P-SAECG | = P wave signal-averaged electrocardiogram |
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