Electrocardiographic Evidence of Left Atrial Hypertension in Acute Myocardial Infarction

Abstract

The relationship between mean left atrial pressure (LA m ) and P-wave abnormalities in lead V 1 of standard 12-lead electrocardiograms was evaluated in 30 patients with acute myocardial infarction. In each patient pulmonary artery diastolic pressure or pulmonary wedge pressure was measured, and these values were used as an estimate of LA m . Electrocardiograms recorded at the time of the pressure measurements were used for P-wave analysis. Patients with a history of hypertension were excluded from analysis. There was a significant correlation between the magnitude of the P terminal force in lead V 1 (PTF-V 1 ) and the estimated LA m (r = –0.78, P < 0.001). Sixteen patients had a normal PTF-V 1 on admission; 11 of them had a normal LA m . All 14 patients with an abnormal PTF-V 1 (more negative than –0.03 mm-sec) on admission had an elevated LA m (>12 mm Hg). Thus, in 25 of the 30 patients, the PTF-V 1 correctly identified whether the LA m was normal or abnormal on admission. On subsequent days, simultaneous measurements of PTF-V 1 and estimated LA m were made in 27 of the patients. Significant changes occurred in both PTF-V 1 and LA m ; discordant changes were observed on only seven of 56 occasions. Measurement of PTF-V 1 appears to be a useful and reliable estimate of left ventricular filling pressure in patients with acute myocardial infarction.