The apical impulse, also known as the point of maximal impulse (PMI), is a localized outward movement of the chest wall caused by the left ventricle during early systole. It represents the point where the cardiac apex comes closest to the chest wall. The apical impulse is typically felt in the 5th intercostal space, medial to the midclavicular line, and is normally less than 2 cm in diameter. Its characteristics can provide valuable information about cardiac size, contractility, and pathological conditions affecting the heart.

Locating the Apical Impulse

• Ask the patient to exhale fully and briefly hold their breath
• For women, consider displacing the left breast upward or laterally
• If not found in supine position, try left lateral decubitus position
• Palpate using palmar surfaces of several fingers (Fig. 16-25)

Note: Apex beat is palpable in 25-40% of adults supine, 50-73% in left lateral decubitus position.

Describing the Location

• Vertical: Intercostal space (usually 5th, sometimes 4th)
• Horizontal: Distance in cm from midclavicular or midsternal line
• Use anterior axillary line if apical impulse is displaced

Assessing the Apical Impulse

• Use fingertips, then one finger for finer assessment (Fig. 16-27)
• Evaluate diameter/area: Normally <2.5 cm (about size of a quarter)
• Assess amplitude and duration: Normally brisk and nonsustained (a tap)

FIGURE 16-27. Palpating the apical impulse with one finger.

Abnormal Findings