|Electrocardiograms from normal dogs and dogs with various cardiovascular diseases were evaluated.
Inclusion criteria were the availability of an electrocardiogram showing a stable isoelectric line, easily recognizable P waves and good quality two-dimensional echocardiographic estimate of left atrial dimensions using the left atrial to aortic root ratio.
Using a metal caliper system, P wave duration was measured to the nearest 10 milliseconds for six consecutive heart beats; data were then averaged for each dog. The accuracy of P wave duration in predicting left atrial enlargement was determined using a receiver operating characteristic analysis.
Results: One hundred and fifty-six dogs were included in the study.
Average P wave durations of 20, 30, 40 and 50 milliseconds yielded sensitivities of 100, 85, 68 and 40% and specificities of 0, 16, 64 and 93%, respectively, for the diagnosis of Left Atrial Enlargement by echocardiography.
The estimated area under curve of the receiver operating characteristic curve was 0Â·70 (95% confidence interval: 0Â·60 to 0Â·80).
Clinical Significance: The diagnostic performance of P wave duration for identification of left atrial enlargement in dogs presents considerable limitations.
Source: Savarino, P., Borgarelli, M., Tarducci, A., Crosara, S., Bello, N. M. and Margiocco, M. L. (2012), Diagnostic performance of P wave duration in the identification of left atrial enlargement in dogs. Journal of Small Animal Practice, 53: 267â272. doi: 10.1111/j.1748-5827.2012.01200.x
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