Author + information
Background: Current iterations of the Fontan circulation (FC) have no antegrade atrial or ventricular contribution to pulmonary blood flow. Systemic cardiac output (CO) is maintained by systemic atrial and ventricular function. The contribution of systemic atrial (SA) systole to systemic ventricular (SV) mechanics is well defined. Atrial diastolic mechanics have more recently been evaluated, with careful attention to echo doppler analysis of pulmonary venous (PV) S and D flow patterns. We observed in our patients with FC presence of PV S waves in the absence of a pulmonary ventricle. This suggested atrial diastolic “suction” could be a significant contributor to CO and decreasing pulmonary arterial, pulmonary venous (PV), and systemic venous pressure.
Methods: For four FC patients: Dynamic changes in relative F atrial volume were measured by frame by frame planimetry (apical 4 chamber view) converting derived radius to volume. Dynamic delta AV was temporally correlated (ECG as baseline) with PV velocities. PV D velocity/flow profile (VFP) was temporally matched with mitral valve (MV) VFP and delta LAV during early diastole: trans-mitral atrial VFP during atrial systole were correlated with delta LAV during atrial systole. Trans-mitral E VFP was assumed to be “conduit” flow; MV A flow VFP was correlated with atrial delta V during atrial systole PV S flow and simultaneous delta LAV are presumed to be secondary to atrial “suction.” Atrial emptying or filling fraction was calculated as maximal atrial volume – minimal atrial volume/maximum atrial volume. Mean atrial filling fraction was 49% and is ascribed to atrial “suction.” Delta atrial volume during MV A wave was 48% of atrial emptying fraction, and “conduit” flow accounted for 52%. PV S wave flow was equal to PV D wave flow.
Results: Mean atrial filling fraction was 49% and is ascribed to atrial suction. Delta atrial volume during MV A wave was 48% of atrial emptying fraction, and conduit flow accounted for 52%. PV S wave flow was equal to PV D wave flow.
Conclusions: In “clearing” pulmonary circulation in FC, atrial “suction” appears to be a very important contributor to systemic CO, dependent of course on the presence of preceding atrial contraction.
Poster Hall, Hall C
Sunday, March 19, 2017, 9:45 a.m.-10:30 a.m.
Session Title: Redefining the “F” Word
Abstract Category: 9. Congenital Heart Disease: Adult
Presentation Number: 1270-010
- 2017 American College of Cardiology Foundation