The importance of recognizing symptomatic heart failure with preserved left ventricular (LV) systolic function has only recently been appreciated. To determine its frequency and identify clinical features that make the bedside diagnosis likely, 82 patients admitted for decompensated heart failure were classified into 2 groups based on their LV systolic performance, as defined by fractional shortening (FS): group I (n = 59), with impaired systolic function (fractional shortening less than 24%), and group II (n = 23) with preserved systolic function (fractional shortening greater than or equal to 24%). Mean fractional shortening was 15 +/- 5% and 39 +/- 1% for groups I and II, respectively. Female gender (p less than 0.05), obesity (p less than 0.01) and diastolic blood pressure greater than or equal to 105 mm Hg (p less than 0.05) predominated in group II. Jugular venous distention was identified more frequently in group I (p less than 0.05). No statistically significant difference between the 2 groups was noted among various demographic variables (age, duration of symptoms, history of hypertension, ischemic heart disease and heavy alcohol drinking) or physical findings (S3 gallop, edema, cardiomegaly, pulmonary congestion and pulmonary edema). Echocardiographic mean left ventricular dimension measured 6.6 +/- 1 versus 5.0 +/- 1 cm (p less than 0.01) and mean posterior wall thickness 1.1 +/- 0.3 versus 1.4 +/- 0.4 cm (p less than 0.01) in group I and II, respectively. The combination of diastolic blood pressure greater than or equal to 105 mm Hg and an absence of jugular venous distention had a high specificity and positive predictive value (100%) for identifying group II patients.(ABSTRACT TRUNCATED AT 250 WORDS)