High-quality chest compressions are central to effective CPR and are traditionally performed over the lower third of the sternum [1]. Emerging evidence suggests that targeting the left ventricle (LV) directly may enhance hemodynamics and outcomes [2]. The LV may not lie directly beneath the sternum, and limited data exist to define this positional relationship. The study aimed to quantify the distance from the sternum-to-LV using transthoracic ultrasound (TTE) and to evaluate clinical and demographic factors associated with increased distance.

This retrospective observational study was conducted in the emergency department of a suburban academic tertiary center. Adult patients who underwent TTE for non-arrest indications were included. The primary outcome was the distance from the lower third of the sternum to the center of the LV.

From March–May 2025, 110 patients were included. The mean sternum-to-LV distance was 4.85 cm (SD ± 1.44). Multivariate linear regression showed male sex (β = 0.56, p  = 0.004), obesity (β = 0.71, p  = 0.047), and having five or more comorbidities (β = 1.20, p  = 0.007) were independently associated with greater distance.

This study identified a substantial distance between standard CPR hand placement and LV location, especially in males, obese patients, and those with multiple comorbidities. These findings suggest that anatomical variation may affect CPR efficacy and call into question the universality of current guidelines.

Transthoracic echocardiography (TTE) may help identify optimal compression sites, and further research is needed to validate this approach and evaluate its clinical impact.