# Impact of Breathing and Anatomical Constraints on Subxiphoid Epicardial Puncture: Insights From a Japanese Cohort

## TL;DR

This study shows that breathing and body size affect the distance from the xiphoid to the pericardium, which is important for safer epicardial procedures.

## Contribution

The study provides new insights into how respiration and anatomy affect subxiphoid epicardial puncture in a Japanese cohort.

## Key findings

- The distance to the pericardium increases significantly during expiration compared to inspiration.
- Probe direction affects measurements during expiration but not during inspiration.
- Body weight, BMI, and chest dimensions correlate positively with the xiphoid-to-pericardium distance.

## Abstract

The subxiphoid approach is increasingly utilized for epicardial interventions. Understanding the effect of respiration on the distance from the xiphoid process to the pericardium is essential for improving procedural safety and efficacy.

A cross‐sectional study was conducted on 51 patients undergoing preprocedural ultrasound imaging. Measurements were taken in the supine position during spontaneous breathing at end‐inspiration and end‐expiration, with the probe directed toward both the midline and the left shoulder. Differences between respiratory phases and probe orientations were analyzed.

The mean xiphoid‐to‐pericardium distance increased significantly from inspiration to expiration for both probe orientations (midline: 42.2 ± 12.2 mm vs. 54.6 ± 14.1 mm, p < 0.001; left shoulder: 40.5 ± 12.3 mm vs. 51.2 ± 14.2 mm, p < 0.001). The expiration‐inspiration difference was greater with the midline direction (mean difference: 12.4 mm) than toward the left shoulder (10.7 mm). Probe direction affected measurements during expiration (p = 0.012) but not during inspiration (p = 0.104). The distance to the pericardium showed a positive correlation with body weight (r = 0.561), body mass index (r = 0.675), and chest dimensions, including anteroposterior (AP) (r = 0.477) and lateral diameters (r = 0.451). In contrast, the chest wall size index (lateral/AP ratio) was negatively correlated (r = −0.365). No significant difference in this distance was found between patients with and without chronic obstructive pulmonary disease.

Respiratory phase and anthropometric parameters significantly influence the distance to the pericardium. These findings may guide safer planning of subxiphoid epicardial procedures.

This study reveals that respiratory phase and anthropometric parameters significantly impact the xiphoid‐to‐pericardium distance, with expiration increasing the depth. These findings support the use of preprocedural ultrasound to optimize subxiphoid epicardial access, enhance safety, and inform needle selection based on individual anatomical characteristics.