[1] Beth Israel Deaconess Med Ctr, Harvard Thorndike Electrophysiol Inst, Clin Cardiac Electrophysiol Labs, Boston, MA 02215 USA
[2] Beth Israel Deaconess Med Ctr, Arrhythmia Serv, Boston, MA 02215 USA
[3] Montreal Gen Hosp, Montreal, PQ H3G 1A4, Canada
[4] Natl Heart Inst, Cairo, Egypt