P wave analysis in 2464 orthogonal electrocardiograms from normal subjects and patients with atrial overload.

SUMMARY The purpose of this study was to establish limits of normal for P wave measurements, and to propose criteria for routine electrocardiographic readings and for multivariate analysis to recognize left atrial overload (LAO) and right atrial overload (RAO) in the orthogonal electrocar-diogram (ECG). Frank ECG's were obtained from 2464 subjects, including 580 normals, 164 patients with mitral valve disease (MVD) forming the LAO group, and 623 with chronic lung disease (CLD) as the RAO sample. Each group was divided into training and test sets. Using a digital computer, 120 different P wave measurements were computed for each ECG to find optimal discriminators between normal (N), LAO, and RAO. In the training set of MVD, using three scalar measurements, LAO was recognized in 57% with 3% false positives. These criteria diagnosed LAO in 70% of the test cases of MVD. Four discriminators identified RAO in 30% and 37% of training and test cases of CLD with 11% false positives. A set of 15 measurements obtained by multivariate analysis was used in a classification in which the three groups, N, LAO, and RAO were considered simultaneously. Ninety-four percent N, 74% LAO, and 45% RAO in the training sets, and 95%, 71%, and 24% in N, LAO, and RAO test sets were correctly identified. An attempt was made to correlate the rate of recognition of LAO with the degree of LAO estimated by cardiac catheterization. Data reported in the present study can serve as standard for P wave analysis in the Frank ECG. Computer analysis Left atrial overload Multivariate analysis Right atrial overload RELIABLE ELECTROCARDIOGRAPHIC evidence of atrial abnormality and the precise differentiation of right and left atrial overloading can be extremely useful in the differential diagnosis of cardiac lesions. In more recent years, several criteria have been proposed for the conventional 12-lead electrocardiogram (ECG).' 7 The terminal P forces in the right precordial leads4 have been widely accepted as indicative of left atrial overload (LAO). New criteria have been proposed for the recognition of right atrial overloading (RAO) in children,8 and some previously proposed criteria for RAO such as "P pulmonale" or the Macruz in-dex' have been found to be lacking in sensitivity or specificity or both.9' 10 In the orthogonal ECG, however, no comprehensive analysis of P wave abnormalities has so far been performed, although several investigations of the normal P wave have been reported."1 5 The widespread use of …