Left atrial compression and right ventricular outflow tract diameter on echocardiography are independently associated...

Large hiatal hernia (HH) is often associated with left atrial (LA) compression, anteroposterior cardiac compression (manifesting as reduced right ventricular outflow tract (RVOT) diameter), and left ventricular (LV) compression (manifesting as systolic paradoxical outward motion (LV-PM) of the posterobasal LV segment). Exercise impairment, also common in this population, improves following HH surgery. We aimed to identify echocardiographic parameters independently associated with exercise impairment due to HH-mediated cardiogenic compression.

Patients with a large HH (>30% intra-thoracic stomach, n = 163) referred for cardiac evaluation were included. Echocardiographic parameters were retrospectively analyzed in relation to HH-related LA compression severity and the presence of LV-PM. Echocardiographic parameters independently associated with exercise capacity were identified by multivariable analysis.

Mean baseline metabolic equivalents were reduced (70 ± 28% predicted). Moderate-severe LA compression and LV-PM were present in 91 of 163 (56%) and 65 of 162 (40%) patients, respectively. Patients with moderate-severe LA compression and LV-PM had decreased LA and LV dimensions. Moderate-severe LA compression was also associated with reduced RVOT diameter while LV-PM predicted a greater reduction in LV volumes. LA compression and RVOT diameter were independently associated with baseline exercise capacity and increased following HH surgery performed in a subgroup (n = 72, LA diameter: 14 ± 5 vs 20 ± 4 mm/m² ; RVOT diameter: 17 ± 3 vs 19 ± 3 mm/m² , P < .001 for both). Conversely, LV-PM was not independently associated with exercise capacity.

Hiatal hernia-related cardiac compression reduces LA and RVOT dimensions. These parameters are independently associated with baseline exercise capacity and improve following HH surgery. LV-PM is associated with decreased LV volumes but not exercise capacity in this population.