Peripheral edema masks the diagnoses of P pulmonale, P mitrale, and biatrial abnormality: clinical implications for patients with heart failure.

Peripheral edema (PED) impacts the size of the electrocardiogram, attenuating the amplitude and duration of QRS complexes and P waves. Diagnostic configurations of P pulmonale (Pp), P mitrale (Pm), and biatrial abnormality (Pb) are based on measurements of the amplitude and duration of the P waves. To investigate whether PED masks the diagnoses of Pp, Pm, and Pb, 15 patients (nine who suffered PED and six who did not gain weight during hospitalization, who served as controls) were studied. Of nine patients with PED, one had Pp, four had Pm, and four had Pb on admission, but such configurations were abolished after development of PED, except in one patient with Pm. Of six controls, one patient had Pp, three had Pm, and two had Pb, both on admission and at discharge. There was no difference in sex (p=0.61) or age (p=0.27) between the patients with PED and the controls; however, patients with PED were sicker and eventually died, while none of the controls did so. Electrocardiographic atrial abnormalities can be masked by PED, resulting from the attenuation of P waves and mediated by a decrease in the electrical impedance of the body's volume conductor due to water overload. These have clinical implications for patients with heart failure.