Detection of patients with sick sinus syndrome by use of low amplitude potentials early in filtered P wave

Division of Cardiology, Osaka Prefectural Hospital, Japan.

OBJECTIVES: This study sought to determine whether patients with sick sinus syndrome could be detected by analyzing the initial portion of the signal-averaged P wave corresponding to the electrical activity of the perinodal atrial myocardial cells. BACKGROUND: In sick sinus syndrome, pathophysiologic abnormalities have been shown not only in the sinus node, but also in the atrial muscle, especially the perinodal portion. METHODS: The study included 41 patients with sick sinus syndrome and 140 age-matched control subjects. Eighteen of 41 patients with sick sinus syndrome had paroxysmal atrial fibrillation. Signal-averaged P wave electrocardiograms (ECGs) were recorded through a bandpass filter of 40 to 300 Hz with a P wave-triggering technique. Signals of the orthogonal bipolar leads were combined into a spatial magnitude. The root mean square voltage for the initial 30 ms (EP30) and the duration of initial low amplitude signals < 4 microV (ED4) of the filtered P wave were measured. The root mean square voltage for the last 20 ms (LP20) and the duration of the filtered P wave were also measured. RESULTS: EP30 was significantly lower and ED4 was significantly longer in patients with sick sinus syndrome than in the control subjects (EP30 [mean +/- SD]: 2.18 +/- 0.90 vs. 3.94 +/- 1.45 microV, p < 0.0001; ED4: 31.7 +/- 14.5 vs. 14.0 +/- 7.4 ms, p < 0.0001), although there was no significant difference in LP20 between patients with sick sinus syndrome without paroxysmal atrial fibrillation and the control subjects. The duration of the filtered P wave was significantly but minimally longer in patients with sick sinus syndrome than in the control subjects (139.8 +/- 18.8 vs. 127.3 +/- 13.6 ms, p < 0.0001). The criteria of EP30 < 3.0 microV and ED4 > 22 ms as atrial early potential gave a sensitivity of 76%, a specificity of 91%, a positive predictive value of 74% and a negative predictive value of 93% for identification of patients with sick sinus syndrome. CONCLUSIONS: These results suggest that the long, low amplitude signals early in the filtered P wave on the signal-averaged ECGs are characteristic of sick sinus syndrome. Thus, the atrial early potential could be a useful marker to identify patients with sick sinus syndrome.

This article has been cited by other articles:

				V. Tuzcu, B. Ozkan, N. Sullivan, P. Karpawich, and M. L. Epstein P wave signal-averaged electrocardiogram as a new marker for atrial tachyarrhythmias in postoperative Fontan patients J. Am. Coll. Cardiol., August 1, 2000; 36(2): 602 - 607. [Abstract] [Full Text] [PDF]