The apical impulse palpation is a key component of cardiac physical examination, which offers insights into ventricular size and function. Its diagnostic accuracy in detecting cardiac enlargement in infants is unknown.

This cross-sectional observational study was done in infants 1 month to 1 year of age visiting a tertiary care hospital. The apical impulse was palpated and marked in supine position and its location in terms of the intercostal space and distance from mid-sternal line was noted. Echocardiography was performed to assess cardiac chamber enlargement. Z score of echo parameters was calculated. z score > 2 was considered to be an enlarged cardiac chamber. The diagnostic accuracy of a displaced apical impulse in detecting ventricular enlargement was evaluated using echocardiography as the reference standard.

309 infants were enrolled in the study. 22 % of the study subjects had a structurally normal heart. A displaced apical impulse had a diagnostic accuracy of 71.5%. Using another definition to define a displaced apical impulse, namely, horizontal displacement of > 4 cm from the mid-sternal line (regardless of the level of intercostal space), increased the diagnostic accuracy to 79.0 % with sensitivity and specificity of 76.4% and 81.1 %, respectively.

Horizontal displacement of the apical impulse 4 cm or more from the mid-sternal line (regardless of the level of intercostal space) is a simple and fairly accurate method to identify left ventricular enlargement in infants.