Abstract 10124: The Sano Modification: Friend or Foe?
Introduction: The Sano modification of the Norwood procedure involves a right ventriculotomy which has a potential to lead to ventricular arrhythmias and decreased ventricular function. This study aimed to assess the impact of the ventriculotomy on the electrical activity of the ventricle in patients who have undergone the Sano modification, using 3D electroanatomical mapping.
Methods: 10 normal subjects (ages 6-18 years) and 5 Hypoplastic Left Heart Syndrome (HLHS) subjects (ages 3-6 years) with normal right ventricular function (RV) and no ventricular arrhythmias were studied a mean duration of 4.1 ± 1.4 years after their Sano modification. Voltage maps were generated for each ventricle.
Results: HLHS subjects demonstrated a discrete area of low-amplitude (<0.5 mV) bipolar electrograms on the mid-anterior free wall of the right ventricle compared to the rest of the right ventricle in the same patients (average amplitude 0.3 ± 0.01 vs 2.5 ± 0.08 mV, p<0.001) and compared to normal control subjects (3.7 ± 1.4 mV, p = 0.02). This low-amplitude area indicates an area of scar tissue. The area of low amplitude electrograms is surrounded by a border zone (0.5 to 1.5 mV) that transitioned into normal myocardium (>1.5 mV). In contrast, the normal subjects did not demonstrate any areas of low-amplitude electrograms.
Conclusions: Children with HLHS who have undergone the Sano modification of the Norwood procedure have right ventricular scar tissue, presumably related to the ventriculotomy. The presence of this discrete scar tissue combined with systemic pressure over time may potentially lead to ventricular arrhythmias and ventricular dysfunction as seen with other forms of congenital heart disease and will need to be evaluated with future studies.
- © 2011 by American Heart Association, Inc.