Abstract 13730: Electrical Axes of P and T but Not QRS Waves on ECG Are New Indicators of Successfulness of the Nuss Operation for Pectus Excavatum Considering Anatomical Severity as Indicated by the Haller Index Acquired by CT

Abstract

Introduction: Pectus excavatum (PEX) is a depression of the sternum which can physically constrict the heart and cause abnormal ECGs. The Nuss operation is a minimally invasive technique for PEX repair. Hypothesis: As right (RA) and left atria (LA) are compressed in PEX, axes of P, QRS, and T waves are abnormal and the Nuss operation normalizes them. We also took the Haller index (HI) into to account. Methods: 17 PEX patients (14 male, 12±6 years) underwent CT and ECG before and after the Nuss operation. Results: All Nuss operations were successful, and HI was significantly improved from 5.62±2.29 to 3.29±0.65 (P=0.0002). There were no significant differences before and after surgery for electrical axes of P waves (46±20 vs 65±55, P=0.20), and QRS waves (75±33 vs 76±23, P=0.72), but T waves were greater thereafter (22±27 vs 40±19, P=0.001). Correlation coefficients (CC) between the degree of axes of P, QRS and T waves, and HI before operation were -0.23, -0.06, and 0.11, respectively. These values after operation were -0.25, -0.06, and 0.19, respectively. As HI is an indirect indicator of heart compression, we evaluated the degree of RA and LA compression qualitatively as none, mild, and moderate/more. Of 17 patients, 5 had moderate/more compression of RA and/or LA by PEX (group 1); the remaining 12 did not show compression (group 2). Only P wave values were significantly smaller in group 1 than 2 before surgery, but these differences disappeared after surgery. In both groups, degree of axes of T waves was significantly greater after the operation. Conclusion: In patients with PEX, axes of T waves after the Nuss operation became significant greater than before the operation in patients with moderate or more compression of RA and/or LA by PEX. For P waves, this was smaller before the operation in those with compression but this was improved by the Nuss operation. P and T wave axes but not QRS could be therefore non-invasive indicators of Nuss operation success in addition to gross PEX appearance.