Causes of Exercise Intolerance in Pectus Excavatum: a Study of 111 Cases and 20 Controls

pp 519-523

Abstract

Background: Despite several studies have reported lower exercise capacity in patients with pectus excavatum, none of them could demonstrate a clear pathophysiology.
Objective: The aim of this study was to evaluate cardiac hemodynamics and systolic and diastolic function at rest and during exercise in patients with pectus excavatum and compare it with healthy controls.
Methods: Stress echocardiography was performed in 111 subjects with pectus excavatum and 20 healthy controls.
Results: Patients with pectus excavatum had lower right ventricular inflow minimum diameter: 1.29±0.26 cm/m2 versus 1.89±0.25 cm/m2 (p <0.01). Peak exercise capacity was lower in patients with pectus excavatum: 8.3±1.4 METs versus 15±4.5 METs (p <0.0001).
Left ventricular diastolic dysfunction was observed in 34.6% of the patients with pectus excavatum and in 5% of the healthy controls(p=0.007), while 40% of the subjects with pectus excavatum and 15% of the healthy controls presented right ventricular diastolic dysfunction (p=0.04). Medium tricuspid pressure gradient during exercise was higher in patients with pectus excavatum: 6.21±2.29 mm Hg versus 4.8±1.17 mm Hg in healthy controls (p=0.01). The tricuspid valve area remained fixed during exercise in patients with pectus excavatum: 1.48±0.57 cm2/m2 versus 2.11±0.88 cm2/m2 in healthy controls (p=0.0001).
Conclusions: Patients with pectus excavatum present functional abnormalities, probably due to external compression of the heart, which are evident by a small tricuspid annulus, a higher diastolic tricuspid pressure gradient during exercise, tricuspid area that remains fixed at exercise and rest, and signs suggestive of diastolic dysfunction of both ventricles. Such abnormalities contribute to explain the lower exercise performance.