Abstract 12279: Heterogeneity of Ventricular Sympathetic Nervous Activity Predicts Clinically Relevant Ventricular Arrhythmias in Postoperative Patients With Tetralogy of Fallot
Objectives: Our study was conducted to clarify an impact of cardiac sympathetic nervous system (CSNS) on severity of ventricular arrhythmia (VA) using myocardial scintigraphy with 123I metaiodobenzylguanidine (MIBG) in postoperative patients of tetralogy of Fallot (TOF).
Backgrounds: VA in repaired TOF is life-threatening complication and electrophysiological and hemodynamic abnormalities have been considered as substrates responsible for the VA in these patients. On the other hand, abnormal sympathetic activity plays an important pathophysiological role on VA in adult cardiac patients. Myocardial scintigraphy with MIBG provides unique information on CSNS. However, an impact of CSNS on VA in TOF remains unclear.
Methods: We analyzed 25 postoperative TOF patients. Of those, 11 had a clinically relevant VA (VA group), and the other 14 had no/minor VA (non-VA group). Heart-to-mediastinum ratio at delayed phase (HMR) and washout ratio (WR) from planar images of MIBG myocardial scintigraphy were calculated as indices of global CSNS assessment. We made tomographic images and generated polar maps with 20 segments then calculated the standard deviation of %uptake of 20 segments (SD-uptake) as an index of heterogeneous MIBG uptake to myocardium, representing heterogeneity of global CSNS activity. We also evaluated the severity of pulmonary valve regurgitation, QRS duration, indexed right ventricular volume and brain natriuretic peptide.
Results: There were no significant differences in HMR ( 2.1±0.2 vs 2.2±0.4 ) nor WR ( 42.6±10.5 vs 42.0±10.4 ) between groups of the VA and non-VA. The SD-uptake of VA group was significantly higher than that of the non-VA group (15.5±4.5 vs 11.8±2.7, p=0.017 ). We could not found any significant difference in other indices between the two groups. In multivariate logistic model, the SD-uptake was the only independent predictor of the VA group (p=0.013).
Conclusions: Heterogeneity, rather than global impairment, of CSNS activity is closely associated with clinically relevant VA in postoperative TOF patients.
- © 2013 by American Heart Association, Inc.