Improved Tricuspid Valve Function, Preload Recruitment and Ventricular Efficiency During Submaximal Exercise in...

Adolescents and adults with native Ebstein's anomaly (EA) are at the benign part of the Ebstein spectrum, having survived infancy without surgery. In this population, surgical indication and timing remain objects of controversy and depend, among other factors, on exercise capacity.

To better understand the pathophysiology of exercise adaptation in native EA.

Retrospective.

Ten patients with unoperated EA (age range 18-61 years) and 13 healthy subjects as controls.

Balanced steady-state free precession cine and phase contrast flow sequences at 1.5 T.

We measured volumes and flows at rest and during submaximal exercise. Hemodynamic parameters including stroke volume (SV), cardiac index (CI), ejection fraction (EF), and tricuspid regurgitation (TR) were calculated.

We used nonparametric Mann-Whitney U-test and Wilcoxon signed-rank test. A P-value of <0.05 was considered statistically significant.

Rest CI and SV were significantly higher in controls; rest heart rate (HR) was similar in the two groups (median 71 bpm by patients and 65 bpm by controls, P = 0.448). During exercise, CI increased significantly in both groups: from 2.40 to 3.35 L/min/m² in the patient group and from 3.60 to 4.20 L/min/m² in controls; HR increased significantly in both groups. SV increased significantly in the patient group, whereas it remained stable in controls (P = 0.5284). Patients' median TR decreased significantly: median 42% at rest and 30% during exercise; concomitantly, left ventricular (LV) preload increased significantly (+3% indexed LV end-diastolic volume) as did LVEF (median 59% at rest vs. 65% during exercise).

During submaximal exercise, patients with mild to moderate EA improved their cardiovascular system's total efficiency by increasing CI; this was obtained by an increase in HR and by the recruitment of volume, as shown by an increased LV end-diastolic volume and SV, with simultaneous decrease in TR. This was different from healthy subjects in which CI increased only due to HR increase.

3 TECHNICAL EFFICACY STAGE: 3.