Abstract 13986: De Novo Occurrence Of Fragmented QRS Waves In V5 And 6 Leads After Successful Nuss Surgery For Pectus Excavatum Considering QRS Wave Axis And Width And Heart Compression On Computed Tomography

Introduction: On ECG, fragmented QRS waves (fQRS), otherwise known as a notch in the QRS complex, may indicate conduction abnormalities. Pectus excavatum (PEX) physically depresses the heart (mainly the right and left aria (RA, LA)). The Nuss operation is a minimal invasive technique for PEX repair. Hypothesis: We hypothesize that fQRS may occur in PEX even in patients without right bundle branch block (RBBB), and that the Nuss operation would reduce these, depending on the Haller index (HI) of anatomical severity as calculated from CT imaging (CLINICS 2007; 62:599). Methods: 17 patients (14 male, 12±6 years) underwent the Nuss operation for PEX, all of which were successful. HI was significantly improved from 5.62±2.29 to 3.29±0.65 (P=0.0002). Before the Nuss operation, 6 patients had incomplete RBBB; of the 11 without RBBB, 6 (55%) had fQRS waves. We evaluated the degree of RA and LA compression in these PEX patients by CT. Results: We compared 6 patients with fQRS waves but no RBBB before surgery with 5 patients without fQRS waves but no RBBB before surgery, and only LA diameter on CT before surgery was significantly greater in the former than the latter (P=0.004) (Table). Of 6 patients with fQRS waves but no RBBB before surgery, 3 patients (50%) had de novo fQRS waves in V5 and 6 after surgery. There were no significant differences of QRS axis and width before and after surgery in these3 patients who had de novo fQRS waves in V5 and 6 after surgery. Of 5 patients without any fQRS waves but no RBBB before surgery, 4 patients (80%) had de novo fQRS waves in V5 and 6 after surgery. There were no significant differences of QRS axis and width before and after surgery in these 4 patients who had de novo fQRS waves in V5 and 6 after surgery. Conclusions: In patients with PEX, de novo fQRS waves can occur after a successful Nuss operation, especially in the V5 and V6 leads, even in patients without RBBB and without changes of QRS axis and width. This may be caused by heart rotation or some effects of the Nuss procedure.