In order to evaluate if pre-P activity can be detected by surface electrocardiogram, at least 200 consecutive sinus beats were collected by each of 3 bipolar orthogonal leads (horizontal, vertical, and sagittal position) in 17 patients. During recording, each lead signal (0.5-300 Hz) was independently averaged using P wave as a trigger by means of an algorithm based on the template comparing method. In this way, it is possible to eliminate atrial ectopic beats or grossly noisy signals and to obtain a better alignement of recording period. For purposes of external recording of pre-P activity, the period between T wave of the preceding beat and P wave of the subsequent beat was visualized. Each lead signal was then filtered (0.5-25 Hz) and amplified. Amplification revealed the presence in each of these patients of a progressive upstroke slope beginning during the isoelectric line and ending at the onset of P wave. This onset was delimited as the first observed in the non-amplified and non-filtered 3 leads. The upstroke slope could be present in only one lead or in more than one lead; in the latter case, the longest duration was utilized. The slope of the pre-P could be linear (13 cases) or with a plateau (4 cases). The length of this pre-P signal was compared in each patient with that furnished by direct intraatrial recording of sinus node electrogram (0.05-35 Hz, mean of at least 20 measurements). Mean values (± 1SD) of non-invasive and invasive pre-P signal lengths were respectively: 77 ± 35 msec and 77 ± 36 msec. The correlation coefficient utilizing linear regression analysis was 0.9932 (p <0.001). In conclusion, our data indicate that the length of pre-P potential obtained from surface ECG is strictly correlated with that obtained by direct intraatrial recording of sinus node electrogram. Thus, pre-P activity can be easily and reliably determined non-invasively amplifying P wave-triggered signal-averaged ECG.
|Number of pages||7|
|Journal||New Trends in Arrhythmias|
|Publication status||Published - 1992|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine