Integrated analysis of atrioventricular interactions in tetralogy of Fallot

Abstract

The atria play an important role in cardiac performance. We evaluated their function and the atrioventricular interaction in operated patients with tetralogy of Fallot (TOF). Twenty patients who had undergone surgical repair of TOF and seven controls were investigated. Patients had residual pulmonary but no major tricuspid valve insufficiency. Atrial and ventricular strain rates were obtained by echocardiographic speckle tracking. Cine MRI-derived volumetric analysis provided atrial and ventricular time volume and time volume change curves yielding emptying and filling parameters. In addition, at the atrial level, reservoir, conduit and pump function, and cyclic volume change were calculated. At the atrioventricular valve level, tricuspid and mitral annular plane systolic excursion (TAPSE and MAPSE, respectively) were measured by two-dimensional echocardiography. In the patients compared with controls, right ventricular end-diastolic volumes were increased and biventricular ejection fraction was decreased (all P < 0.05). Biventricular measures of early diastolic ventricular filling were at control levels, but in late diastole, right ventricular filling parameters and strain rates were decreased (P < 0.001). The maximal right atrial size was slightly but not significantly diminished, but cyclic volume change was significantly reduced (P < 0.0001). Pump and reservoir function were decreased (P < 0.05), and conduit function was elevated (P < 0.001). The left atrium showed reduced reservoir function and cyclic volume change (P < 0.05). TAPSE and MAPSE were also decreased (P < 0.05). There were statistically significant interdependencies between RV ejection fraction, TAPSE, and right atrial filling and emptying parameters (all P < 0.05). In TOF patients, moderate systolic and diastolic right ventricular dysfunction is associated with clearly impaired right atrial function. The left atrium is affected to a lesser extent.

Figures

Fig. 1.

Atrial function. Shown is an exemplary atrial time volume curve of a control subject with assessment of atrial performance and function. Whereas reservoir volume, pump volume, and cyclic volume change are calculated from atrial volumes at special time points (see methods), the conduit volume, which is passing the atrium without causing atrial volume change, is calculated by the subtraction of the sum of reservoir and pump volume from the effective stroke volume of the left ventricle (LV).

Fig. 2.

Right atrial (RA) and right ventricular (RV) time volume (A and C) and time volume change curves (B and D) of the patient and control groups. Mean values are shown.

Fig. 3.

Left atrial (LA) and LV time volume (A and C) and time volume change curves (B and D) of the patient and control groups. Mean values are shown.

Fig. 4.

Conduit flow for one typical patient and one typical control subject. In the patient, the conduit flow is delayed but higher in its magnitude.