In restrictive cardiomyopathy the P waves may be wide, but have a particular tendency to be increased in amplitude, reflecting left atrial overload or hypertrophy, as in hypertension
[heart.bmj.com]
Diuretics, Echocardiography, Electrocardiography, Endomyocardial Fibrosis, Heart Failure, Heart Valve Diseases, Hematologic Neoplasms, Hypertension, Pulmonary, Hypertension
[acc.org]
Six of these individuals (III-1, III-3, IV-5, III-6, III-11, III-15) had left ventricular wall hypertrophy of 13–20 mm, including three individuals with a left atrial size
[jci.org]