Author + information
- Received March 14, 2001
- Revision received August 13, 2001
- Accepted August 29, 2001
- Published online December 1, 2001.
- Luciano Daliento, MD, FESC, FACC*,* (, )
- Antonio Franco Folino, MD, PhD*,
- Liana Menti, MD*,
- Pierluigi Zanco, MD†,
- Maria Cristina Baratella, MD* and
- Sergio Dalla Volta, MD*
- ↵*Reprint requests and correspondence: Dr. Luciano Daliento, Department of Cardiology, University of Padua, Via Giustiniani, 2, 35128 Padova, Italy
The study was done to define the role of the autonomic nervous system in postoperative tetralogy of Fallot.
Subsequent to surgical correction of tetralogy of Fallot, patients are at long-term risk of sudden death owing to ventricular electrical instability. The status of the sympathetic nervous system in these patients, known to play an important role in other patients at risk, remains unknown.
We used 123I metaiodobenzylguanidine (MIBG) with tomographic imaging, combined with assessment of heart rate variability (HRV), to evaluate the activity of the sympathetic nervous system. We analyzed 22 patients who had undergone total correction of tetralogy of Fallot: 13 with either no or minor ventricular arrhythmias, and 9 with sustained ventricular tachycardia or ventricular fibrillation.
Analysis of HRV revealed a reduction in vagal control and sympathetic dominance in all patients compared with a healthy control group of 20 subjects. A significant difference was found in the standard deviation of all the adjacent intervals between normal beats (SDNN) in patients with or without severe ventricular arrhythmias. A significant reduction in uptake of 123I MIBG was demonstrated 30 min after IV injection, and a trend toward reduction after 5 h, associated with reduced washout indices. These data reflect a decrease in the number of nerve endings in the right and left ventricular walls, and an inhomogeneous distribution of the adrenergic nervous system. The uptake of MIBG was significantly reduced in the patients at risk of ventricular tachycardia or fibrillation.
Subsequent to surgical correction of tetralogy of Fallot, the positive correlation between myocardial uptake of MIBG, SDNN and the QRS dispersion confirmed the usefulness of analysis of the adrenergic nervous system to stratify patients at risk of life-threatening arrhythmias.
☆ This study was supported by the Veneto Region Target Project, Venice “Follow-up postoperatorio delle cardiopatie congenite.”
- Received March 14, 2001.
- Revision received August 13, 2001.
- Accepted August 29, 2001.
- American College of Cardiology