[Echocardiographic features of small heart].

To clarify the clinical significance of a small heart; i.e., a small cardiac silhouette on chest radiography, an echocardiographic study was performed. Sixty persons with small heart according to cardiothoracic ratios less than or equal to 40%, and 23 age- and sex-matched normal controls (42% less than cardiothoracic ratio less than or equal to 50%) received two-dimensional and M-mode echocardiography. The body weights and body surface areas (BSA) in the small heart group were significantly less than those in the control group. On the lateral chest radiographs, numerous cases with small heart had straight spines and chests with decreased anteroposterior diameters. More than half of the small heart group had a variety of cardiovascular complaints, including chest pain, palpitation, dyspnea, and dizziness. Echocardiographic measurements were performed and hemodynamic indices were calculated. The results were as follows: Left ventricular dimension at end-diastole (LVDd), left ventricular dimension at end-systole (LVDs), left atrial dimension (LAD), and left ventricular mass (LV mass) of the small heart group were significantly less than those of the control group. There were, however, no differences in the values corrected by BSA (LVDd/BSA, LVDs/BSA, LAD/BSA and LV mass/BSA) between the two groups. We found no differences in hemodynamic indices (heart rate, stroke volume, ejection fraction, and cardiac output) at rest between the small heart and control groups. Nineteen cases (32%) had mitral valve prolapse (MVP) on echocardiography in the small heart group. Characteristic phonocardiographic findings were found in 11 cases with MVP (systolic click in four, mitral regurgitant murmur in three, and both in four).(ABSTRACT TRUNCATED AT 250 WORDS)