Long-term effect of pulmonary valve replacement on QRS duration in patients with corrected tetralogy of Fallot.

Objective: To analyse the long-term course of QRS duration after pulmonary valve replacement in patients with a previous correction for tetralogy of Fallot.
Setting: Tertiary referral centres.
Methods: In a retrospective study, 99 adult patients with tetralogy of Fallot, who had undergone a first pulmonary valve replacement late after initial total correction, were identified from the CONCOR (CONgenital CORvitia) registry. Computer-generated QRS durations were obtained from 12-lead electrocardiogram ECG reports in the medical records. A mixed linear regression model was used to analyse the course of QRS duration over time and to identify risk factors for increase in QRS duration over time. Composite end point was created from sudden cardiac death, ventricular tachycardia or implantable cardioverter-defibrillator discharge.
Results: In total, 99 patients (57% men, mean (SD) age at pulmonary valve replacement 29 (11) years) with a median follow-up of 4.9 (0.1-16) years were analysed. In patients with preoperative QRS <120 ms, surgery caused no significant change in QRS duration (increase 1.3 (7.9) ms; p = 0.65), and after surgery, QRS duration remained stable over time (increase 0.0064 (0.059) ms/year; p = 0.98). By contrast, in patients with a preoperative QRS of 150-180 ms or QRS > or =180 ms, surgery resulted in QRS shortening (mean decrease 9.9 (SE 4.3) ms, p = 0.021, and 12.2 (SE 2) ms; p<0.001, respectively). During follow-up, a QRS widening 1.1(1.3) ms/year (p<0.001) in both groups was observed. In patients with a preoperative QRS > or =180 ms, no significant difference was observed in the number of patients reaching the composite end point compared with patients with a preoperative QRS of 150-180 ms (25% vs 7%; p = 0.08). However, the former more often reached QRS > or =180 ms again after surgery compared with the latter (53% vs 13%; p = 0.02, respectively). None of the patients with a preoperative QRS > or =180 ms died during follow-up.
Conclusion: In our study, we observed a decrease in QRS duration directly after surgery, followed by a steady increase, in patients with a preoperative QRS >150 ms. The beneficial effect of pulmonary valve replacement on QRS duration was transient. The risk of developing ventricular arrhythmias after surgery was substantial when preoperative QRS was > or =180 ms, but mortality remained low.