Loss of Septal Q Waves Is Associated With QRS Widening After Transcatheter Aortic Valve Implantation

BACKGROUND: Conduction disturbances remain a common complication following transcatheter aortic valve implantation (TAVI). While baseline conduction abnormalities are well-established predictors of post-procedural conduction disease or permanent pacemaker implantation, risk stratification in patients without baseline PR or QRS prolongation remains limited. Loss of septal Q waves (LSQ) may reflect underlying conduction system vulnerability but has not been systematically evaluated in this setting. METHODS: We conducted a retrospective observational study of consecutive patients undergoing TAVI at a single tertiary center between 2018 and 2024. Patients without baseline PR or QRS prolongation were included. LSQ was defined as the absence of Q waves in leads I, V5, and V6. The primary outcome was an increase in QRS duration ≥ 20 ms. RESULTS: Among 87 patients without baseline PR or QRS prolongation, 86 were evaluable for the primary outcome and QRS widening ≥20 ms occurred in 31 patients (36.0%). LSQ was present in 40.2% of patients. LSQ was associated with increased odds of QRS widening in unadjusted analysis (OR 2.71, 95% CI 1.09-6.74; p = 0.031). The association remained significant after adjustment for AF (adjusted OR 2.76, 95% CI 1.07-7.11; p = 0.035) (Table 2). AF was also independently associated with QRS widening (adjusted OR 3.79, 95% CI 1.10-13.08; p = 0.035). CONCLUSION: LSQ on pre-procedural ECG was independently associated with post-procedural QRS widening in patients undergoing TAVI without baseline PR or QRS prolongation. LSQ may serve as a simple, non-invasive marker of conduction system vulnerability with potential utility in risk stratification and post-procedural monitoring. These findings are hypothesis generating and warrant validation in larger prospective cohorts.