Left Ventricular Size after Acute Myocardial Infarction

The distance from the midline to the left heart border measured in a standardized manner on calibrated chest roentgenograms was determined serially in 125 patients after acute myocardial infarction. This external left heart dimension (LHD) was compared to the normal value, and its prognostic value was assessed during early and late follow-up periods (average 10½, range 2-31 months). Within 96 hours after acute myocardial infarction the initial LHD was enlarged (>52 mm/m 2 BSA body surface area) in 42% of the patients. The LHD became normal, or remained persistently normal in 60% of the 115 patients without shock, and it became enlarged or remained persistently enlarged in 40%. If the 10 patients with cardiogenic shock are excluded, early death (<4 weeks) occurred in three of 68 patients (4%) with initially normal LHD, and in 12 of 47 patients (26%) with initially enlarged LHD ( P < 0.001). The LHD remained normal or became normal in 62 of 96 patients followed who survived more than 1 month. During the follow-up period, 8% of patients with a normal LHD have died and the remainder (with one exception) are in New York Heart Association (NYHA) class I or II. Only 5% of this group died of acute cardiac causes. In 34 patients the LHD became or remained persistently enlarged; of these patients 24% have expired ( P < 0.05) and 42% are in NYHA class III ( P < 0.001). This study validates a method for the early detection and serial assessment of left ventricular enlargement and indicates that the LHD is a useful predictor of survival and morbidity after acute myocardial infarction.