R. Calvanese

Electrophysiological changes following balloon valvuloplasty and angioplasty for aortic stenosis and coartaction of aorta: clinical evidence for mechano-electrical feedback in humans

BACKGROUND Basic research and animal experiments have shown electrophysiological changes during or after changes in mechanical loading. Electrical instability following mechanical stretch has been observed as development of after-depolarisation and dispersion of refractoriness and repolarisation. The aim of the present study was to evaluate the presence of the mechano-electrical feedback in humans, assessing the ventricular repolarisation changes following acute changes in left ventricular pressure. MATERIAL AND METHODS The study group comprised 30 consecutive patients (22 M and 8 F, aged 2 days-24 years) affected by severe congenital aortic stenosis and 30 patients (20 M and 10 F, aged 6 months-16 years) affected by severe coartaction of aorta. Ventricular repolarisation was evaluated before and after percutaneous balloon valvuloplasty and angioplasty in terms of absolute measures (JT, JTc, QT, QTc) and in terms of dispersion across the myocardium: QT and QTc dispersion (QTD, QTcD), JT and JTc dispersion (JTD and JTcD) and T-peak to T-end interval (Tp-Te). RESULTS Patients with severe aortic stenosis and patients with aortic coartaction showed a significant decrease in dispersion of ventricular repolarisation time indexes (QTD, QTcD, JTD, JTcD and Tp-Te) following valvuloplasty and angioplasty. CONCLUSIONS Changes in hemodynamic loading can also produce electrophysiological effects in humans. Acute reduction in left ventricular pressure overload following balloon valvuloplasty and angioplasty, decreases electrical instability, as expressed by the reduction across the myocardium of the dispersion of ventricular repolarisation.

5. Atrial Tachycardia, Atrial Flutter & WPW Syndrome

Purpose Radiofrequency catheter ablation (RFCA) of the postero-septal accessory pathways (AP) has been reported to be more difficult than for AP located in other areas. Aim of the study was to evaluate the efficacy and risks of RFCA of postero-septal AP in a single centre paediatric population. Methods Between January 2002 and March 2005, 20 patients (9M/11F, aged 11-17 years, mean age 15±2.6) with a postero-septal AP underwent attempt to RFCA. Results In the 20 pts with a postero-septal AP (12 with overt ventricular pre-excitation and 8 with concealed by-pass tract) RF was delivered in the earliest site of activation on the mitral or tricuspidal annulus. Only a patient showed an AP with decremental conduction properties. Time of procedure, was 145±56min and time of radiation exposure was 58±22 min. Successful RF pulses were delivered on right postero-septal area in 8 pts, on left postero-septal area in 3 pts, in the proximal coronary sinus in 6 pts. True epicardial postero-septal AP was found in 3 pts, and the RFCA was considered to be not feasible. Four weeks and 12 weeks after RFCA all patients underwent a non-invasive evaluation. Only a patient underwent a second procedure for recurrence of arrhythmias. Conclusion RFCA of postero-septal AP in paediatric age is technically challenging. More RF pulses, longer procedure time and longer radiation exposure are needed to achieve successful results, and recurrences of AP conduction are not unusual.

Radiofrequency Catheter Ablation of Postero-Septal Accessory Pathways in Paediatric Patients: A Challenging Procedure

Purpose Radiofrequency catheter ablation (RFCA) of the postero-septal accessory pathways (AP) has been reported to be more difficult than for AP located in other areas. Aim of the study was to evaluate the efficacy and risks of RFCA of postero-septal AP in a single centre paediatric population. Methods Between January 2002 and March 2005, 20 patients (9M/11F, aged 11-17 years, mean age 15±2.6) with a postero-septal AP underwent attempt to RFCA. Results In the 20 pts with a postero-septal AP (12 with overt ventricular pre-excitation and 8 with concealed by-pass tract) RF was delivered in the earliest site of activation on the mitral or tricuspidal annulus. Only a patient showed an AP with decremental conduction properties. Time of procedure, was 145±56min and time of radiation exposure was 58±22 min. Successful RF pulses were delivered on right postero-septal area in 8 pts, on left postero-septal area in 3 pts, in the proximal coronary sinus in 6 pts. True epicardial postero-septal AP was found in 3 pts, and the RFCA was considered to be not feasible. Four weeks and 12 weeks after RFCA all patients underwent a non-invasive evaluation. Only a patient underwent a second procedure for recurrence of arrhythmias. Conclusion RFCA of postero-septal AP in paediatric age is technically challenging. More RF pulses, longer procedure time and longer radiation exposure are needed to achieve successful results, and recurrences of AP conduction are not unusual.

5. Atrial Tachycardia, Atrial Flutter & WPW Syndrome5.7 Radiofrequency Catheter Ablation of Postero-Septal Accessory Pathways in Paediatric Patients: A Challenging Procedure

Purpose Radiofrequency catheter ablation (RFCA) of the postero-septal accessory pathways (AP) has been reported to be more difficult than for AP located in other areas. Aim of the study was to evaluate the efficacy and risks of RFCA of postero-septal AP in a single centre paediatric population. Methods Between January 2002 and March 2005, 20 patients (9M/11F, aged 11-17 years, mean age 15±2.6) with a postero-septal AP underwent attempt to RFCA. Results In the 20 pts with a postero-septal AP (12 with overt ventricular pre-excitation and 8 with concealed by-pass tract) RF was delivered in the earliest site of activation on the mitral or tricuspidal annulus. Only a patient showed an AP with decremental conduction properties. Time of procedure, was 145±56min and time of radiation exposure was 58±22 min. Successful RF pulses were delivered on right postero-septal area in 8 pts, on left postero-septal area in 3 pts, in the proximal coronary sinus in 6 pts. True epicardial postero-septal AP was found in 3 pts, and the RFCA was considered to be not feasible. Four weeks and 12 weeks after RFCA all patients underwent a non-invasive evaluation. Only a patient underwent a second procedure for recurrence of arrhythmias. Conclusion RFCA of postero-septal AP in paediatric age is technically challenging. More RF pulses, longer procedure time and longer radiation exposure are needed to achieve successful results, and recurrences of AP conduction are not unusual.