Impact of the cone operation on left ventricular size, function, and dyssynchrony in Ebstein anomaly: a cardiovascular magnetic resonance study

Abstract

Background: In addition to tricuspid regurgitation (TR) and right ventricular (RV) enlargement, patients with Ebstein anomaly are at risk for left ventricular (LV) dysfunction and dyssynchrony. We studied the impact of the cone tricuspid valve reconstruction operation on LV size, function, and dyssynchrony.

Methods: All Ebstein anomaly patients who had both pre- and postoperative cardiovascular magnetic resonance (CMR) studies were retrospectively identified. From cine images, RV and LV volumes and ejection fractions (EF) were calculated, and LV circumferential and longitudinal strain were measured by feature tracking. To quantify LV dyssynchrony, temporal offsets (TOs) were computed among segmental circumferential strain versus time curves using cross-correlation analysis and patient-specific reference curves. An LV dyssynchrony index was calculated as the standard deviation of the TOs.

Results: Twenty patients (65% female) were included with a median age at cone operation of 16 years, and a median time between pre- and postoperative CMR of 2.8 years. Postoperatively, there was a decline in the TR fraction (56 ± 19% vs. 5 ± 4%, p < 0.001), RV end-diastolic volume (EDV) (242 ± 110 ml/m² vs. 137 ± 82 ml/m², p < 0.001), and RV stroke volume (SV) (101 ± 35 vs. 51 ± 7 ml/m², p < 0.001). RV EF was unchanged. Conversely, there was an increase in both LV EDV (68 ± 13 vs. 85 ± 13 ml/m², p < 0.001) and LV stroke volume (37 ± 8 vs. 48 ± 6 ml/m², p < 0.001). There was no change in LV EF, or global circumferential and longitudinal strain but basal septal circumferential strain improved (16 ± 7% vs. 22 ± 5%, p = 0.04). LV contraction become more synchronous (dyssynchrony index: 32 ± 17 vs. 21 ± 9 msec, p = 0.02), and the extent correlated with the reduction in RV EDV and TR.

Conclusions: In patients with the Ebstein anomaly, the cone operation led to reduced TR and RV stroke volume, increased LV stroke volume, improved LV basal septal strain, and improved LV synchrony. Our data demonstrates that the detrimental effect of the RV on LV function can be mitigated by the cone operation.

Keywords: Cardiovascular magnetic resonance; Cone operation; Dyssynchrony; Ebstein anomaly; Strain.

Fig. 1

Circumferential polar plots demonstrating left ventricular pre- and postoperative regional circumferential strain (%, mean ± standard deviation). There was no significant change in strain for any segment except for the basal septum (16±7% vs. 22±5%, p = 0.03)

Fig. 2

Representative patient demonstrating a change in the dyssynchrony index between pre- and postoperative CMR examinations. The images show segmental strain versus time curves at the mid-ventricular level. In this patient, the dyssynchrony index decreased from 57 to 13 msec

Fig. 3

Pre- and postoperative LV dyssynchrony index for each of the 20 patients

Fig. 4

Circumferential polar plot of the mean temporal offset (msec) for each left ventricular segment at the preoperative and postoperative CMR examinations. Negative numbers represent early contraction (red) and positive numbers represent late contraction (blue)