Sex-specific reference values for automated three-dimensional echocardiography across healthy and physically active individuals with different fitness levels
Authors: Hofbauer T , Heber S , Schoeny H , Ritter H , Wessner B , Neidenbach R , Scharhag J 
Published: June 2024

Abstract

Three-dimensional (3D) echocardiography is a valuable tool to assess the athlete’s heart. However, specific reference values for automated 3D methods are scarce for young, healthy individuals, especially in the field of recreational sports. Furthermore, different company-specific 3D methods are used.

Purpose
To quantify automated 3D heart volumes and masses, in young, healthy individuals with varying fitness levels. Moreover, to analyze their association with exercise capacity determined by V̇O2max.

Methods
291 recreationally active individuals to non-professional competitive athletes (mean age 27 ± 4 years; 162 males) were evaluated. Echocardiography was conducted using Philips EPIQ CVx to quantify 3D left and right ventricular and left atrial volumes, as well as left ventricular mass indexed to body surface area (LV EDVI, RV EDVI, LAVI, LV MI). Furthermore, the LV remodeling index (LVRI) was assessed. Offline analyses were performed by Philips QLAB using Dynamic HeartModelA.I for LV and LA, and 3D Auto RV for the RV. Cardio-pulmonary exercise testing was performed to determine V̇O2max. Quantile regression analysis was conducted to estimate conditional volumes and masses dependent on V̇O2max. Results are presented as the median and 10th to 90th percentiles.

Results
Females and males with mild exercise capacity, defined as V̇O2max ≤45 and ≤50 ml/min/kg, presented with the following parameters: LV EDVI 73 (61-84) and 85 (70-102) ml/m2, RV EDVI 64 (56-82) and 79 (58-94) ml/m2, LAVI 25 (18-32) and 29 (20-37) ml/m2, LVMI 64 (56-75) and 76 (64-88) g/m2 and LVRI 0.90 (0.82-0.97) and 0.92 (0.80-0.99) g/ml, respectively.
Females and males with moderate exercise capacity (V̇O2max 46-55 and 51-60 ml/min/kg) presented with the following parameters: LV EDVI 79 (72-91) and 90 (75-102) ml/m2, RV EDVI 71 (59-85) and 85 (65-98) ml/m2, LAVI 30 (23-38) and 32 (23-38) ml/m2, LVMI 68 (61-79) and 79 (68-92) g/m2 and LVRI 0.86 (0.76-0.96) and 0.89 (0.79-0.97) g/ml, respectively.
Females and males with high exercise capacity (V̇O2max &gt;55 and &gt;60 ml/min/kg) presented with the following parameters: LV EDVI 88 (74-104) and 98 (88-114) ml/m2, RV EDVI 75 (63-89) and 87 (74-110) ml/m2, LAVI 33 (24-46) and 34 (24-46) ml/m2, LVMI 77 (65-87) and 84 (70-96) g/m2 and LVRI 0.85 (0.78-0.93) and 0.86 (0.75-0.93) g/ml, respectively.
Ratios of RV and LV EDV were about 1.1 (0.9-1.3) and remained constant in all groups (p&lt;0,05).

Conclusion
This study characterizes automated three-dimensional echocardiographic parameters in physically active young adults, across different fitness levels in both sexes. LV, RV, and LA volumes, along with LV mass, significantly increased with endurance capacity. LV remodeling indices and LV/RV ratios exhibited no significant changes, suggesting a balanced, harmonious hypertrophy of both ventricles across fitness levels. These reference values may aid in distinguishing between physiological and pathological cardiac changes in recreational athletes.