Changes in left and right ventricular longitudinal function after pulmonary valve replacement in patients with Tetralogy of Fallot

Timing and indication for pulmonary valve replacement (PVR) in patients with repaired Tetralogy of Fallot (rToF) and pulmonary regurgitation (PR) are uncertain. To improve understanding of pumping mechanics, we investigated atrioventricular coupling before and after surgical PVR. Cardiovascular magnetic resonance (CMR) were performed in patients (n=12) with rToF and PR>35% before and after PVR and in healthy controls (n=15). Atrioventricular plane displacement (AVPD), global longitudinal peak systolic strain (GLS), atrial and ventricular volumes and caval blood flows were analysed. Right ventricular (RV) AVPD and RV free wall GLS were lower in patients before PVR compared to controls (p<0.0001; p<0.01) and decreased after PVR (both p<0.0001 for both). Left ventricular (LV) AVPD was lower in patients before PVR compared to controls (p<0.05) and decreased after PVR (p<0.01). Left ventricular GLS did not differ between patients and controls (p>0.05). Right atrial reservoir volume and RV stroke volume (SV) generated by AVPD correlated in controls (r=0.93; p<0.0001) and patients before PVR (r=0.88; p<0.001) but not after PVR. In conclusion, there is a clear atrioventricular coupling in patients before PVR that is lost after PVR, possibly due to loss of pericardial integrity. Impaired atrioventricular coupling complicates assessment of ventricular function after surgery using measurements of longitudinal function. Changes in atrioventricular coupling seen in patients with rToF may be energetically unfavourable and long-term effects of surgery on atrioventricular coupling is therefore of interest. Also, AVPD and GLS cannot be used interchangeably to assess longitudinal function in rToF.