Thorac Cardiovasc Surg 2016; 64 - OPIT1
DOI: 10.1055/s-0036-1571900

Role of Right Ventricular Three-Dimensional Electroanatomic Voltage Mapping for the Arrhythmic Risk Stratification of Patients with Corrected Tetralogy of Fallot or Other Congenital Heart Disease Involving the Right Ventricle Outflow Tract

V. Pazzano 1, C. Di Mambro 1, M. S. Russo 1, M. S. Silvetti 1, R. Palmieri 1, Gimigliano F. Fabrizio 1, S. Giannico 2, B. Leonardi 2, A. Amodeo 3, V. M. Di Ciommo 4, F. Drago 1
  • 1Cardiac Arrhythmia Unit and Syncope Unit, Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children's Hospital and Research Institute, Fiumicino (Rome) Italy
  • 2Cardiac Arrhythmia Unit and Syncope Unit, Department of Pediatric Cardiology and Cardiac Surgery, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy
  • 3ECMO Functional Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy
  • 4Department of Health, Unit of Epidemiology, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy

Introduction: Among adult patients with previous surgical correction for Tetralogy of Fallot (ToF) or other repaired Congenital Heart Disease (rCHD) involving the Righ Ventricular (RV) outflow, ventricular arrhythmias (VA) and sudden cardiac death (SCD) represent a late complication. The impaired hemodynamics that lead to RV dilatation and overload could also modify its electrical properties. 3D Electroanatomic Voltage Mapping (EVM) of the RV could confirm the presence of myocardial electrical abnormalities, allowing to better identify patients at risk of life-threatening arrhythmias.

Methods: From the cohort of patients with rCHD involving the RV followed up in our center, we selected the 146 (age 19.2 ± 7.0, time from repair 18.0 ± 6.2years) with arrhythmic risk factors represented by nonsustained ventricular arrhythmias and hemodynamic impairment. These patients underwent 3D EVM of the RV. We analyzed the features of the maps and tested the correlation between size of scars (areas with voltage < 0.5 mV) and several parameters associated with the risk of VA in this particular patient population.

Results: In 141 (96.6%) patients, EVM demonstrated areas of low voltage in the anterolateral RVOT. In 129 (88.4%) cases there was an anterolateral scar, 65 of which (44.5% of the total) extending to the posteroseptal area, while 14 (9.6%) presented exclusive involvement of the posteroseptal RVOT. 86 patients (58.9%) had a peritricuspid scar, and in 28 (19.2%) other areas of the RV were interested. Total low voltage area, expressed as % of total endocardial area, was significantly higher in patients with history of PVCs (3.2% [± 2.6] vs. 2.2% [± 1.8], p< 0.05), complex PVCs at 24-hour Holter ECG (Lown class ≥4) (3.4% [± 2.5] vs. 2.6% [± 2.3], p< 0.05), exercise inducible PVCs (3.8% [± 2.4] vs. 2.6% [ ± 2.2], p = 0.01), history of previous shunt (4.0% [± 2.7] vs. 2.6% [± 2.2], p = 0.01), necessity of reintervention (4.2% [± 3.2] vs. 2.6% [± 2.0], p = 0.008) and QRS duration ≥ 180ms on ECG (4.5% [± 2.5] vs. 2.8% [± 2.4], p = 0.014). Scar size was also positively correlated with age (ρ  = 0.01), age at correction (ρ  = 0.01) and QRS duration (ρ  < 0.05).

Conclusion: In patients with rCHD involving the RV it is common to observe endocardial low-voltage areas with variable distribution, not always corresponding to the sites of surgical lesion. Moreover, the size of the scar tissue area correlates with some of the parameters which have been already identified as risk factors for life-threatening arrhythmias and SCD in adult patients with CHD. We suggest that EVM should become part of the routine tests for the stratification of arrhythmic risk in this population.