Changes in the P-wave terminal segment correlated with left ventricular end-diastolic pressure

A statistically highly significant correlation exists between the values of left ventricular end-diastolic pressure and the dimensions of the terminal segment of the P wave in the electrocardiographic V 1 lead. Values lower than -0.03 mmsec were found only in patients with pathologically elevated left ventricular end-diastolic pressure. In a group of 94 patients with acute transmural myocardial infarction, pathologically low values were found in 43% of the patients on the first day of the disease; on the fifth day of disease the frequency of pathological values of PTF---V 1 sank statistically significantly. A gradual decrease in the values of PTF---V 1 is a sign of bad prognosis in patients with acute myocardial infarction. Changes in the terminal segment of the P wave, at preserved sinus rhythm, can be read off any electrocardiographic curve. Their evaluation offers valuable information about changes in left ventricular end-diastolic pressure, when facilities for catheterization of the patient are not available. This possibility constitutes the main practical value of the method described.