Choon Hiang Koay
Westmead Hospital
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Publication
Featured researches published by Choon Hiang Koay.
Circulation-arrhythmia and Electrophysiology | 2008
Toon Wei Lim; Choon Hiang Koay; Rebecca McCall; Valerie A. See; David L. Ross; Stuart P. Thomas
Background—Single-ring isolation of the posterior left atrium is feasible, but the incidence and mechanisms of postprocedural arrhythmias have not been described in detail. Methods and Results—The first 100 consecutive patients (58.8±11.2 years old, 80 male) who underwent single-ring isolation for atrial fibrillation (66 intermittent, 18 persistent, 16 long-standing persistent) were followed up for 9.1±4.5 months. Recurrences were diagnosed by clinical symptoms and Holter monitoring. Patients with recurrences of sustained atrial arrhythmia >3 months after the procedure were offered a repeat procedure and were studied to determine the mechanisms of recurrence. Forty-six patients (46%) experienced sustained postprocedural atrial arrhythmias (35 had atrial fibrillation, and 34 had atrial flutter). Of these, 34 required a second procedure 7.0±3.1 months after their initial procedure. Reconnection of the posterior left atrium was seen in all patients with atrial fibrillation. Atrial flutter was most commonly due to mitral isthmus-dependent macroreentry (n=8, cycle length 368±116 ms) or macroreentry through 2 gaps in the ring of lesions (n=6, cycle length 328±115 ms). Posterior left atrium reisolation was achieved at the second procedure in all patients. Atrial flutter was successfully ablated and rendered noninducible in all patients. Six months after their last procedure, the Kaplan-Meier estimate of freedom from recurrence for all 100 patients was 81±5%. Conclusions—Atrial fibrillation and atrial flutter recurrence is common after single-ring isolation. Reconnection of the posterior left atrium and macroreentry are the common mechanisms. Repeat ablation results in satisfactory short-term outcomes.
Circulation-arrhythmia and Electrophysiology | 2012
Toon Wei Lim; Choon Hiang Koay; Valerie A. See; Rebecca McCall; W. Chik; R. Zecchin; Karen Byth; Swee-Chong Seow; Liza Thomas; David L. Ross; Stuart P. Thomas
Background—Electric isolation of the pulmonary veins and posterior left atrium with a single ring of radiofrequency lesions (single-ring isolation [SRI]) may result in fewer atrial fibrillation (AF) recurrences than wide antral pulmonary vein isolation (wide antral isolation [WAI]) by abolishing extravenous AF triggers. The effect of mitral isthmus line (MIL) ablation on outcomes after SRI has not previously been assessed. Methods and Results—We randomly assigned 220 consecutive patients (58±10 years old; 82% men) with highly symptomatic AF (61% paroxysmal, 39% persistent/longstanding persistent) to undergo either SRI or WAI. Half of each cohort was also randomly allocated to have left lateral MIL ablation (2×2 factorial study design). Patients were followed clinically and with 7-day Holter studies for arrhythmia recurrences. The primary end points were recurrence of AF and organized atrial tachyarrhythmias. AF-free survival at 2 years was better after SRI (74% [95% CI, 65%–82%]) than WAI (61% [51%–70%]; P=0.031). Organized atrial tachyarrhythmia–free survival was similar after SRI and WAI (67% [57%–75%] ersus 64% [54%–72%], respectively, at 2 years; P=0.988). MIL ablation resulted in better 2-year organized atrial tachyarrhythmia–free survival (71% [62%–79%] versus 60% [50%–69%]; P=0.07), which approached statistical significance. Survival free of any atrial arrhythmia after one procedure was not significantly affected by isolation technique or MIL ablation. Conclusions—SRI resulted in fewer AF recurrences compared with WAI on long-term follow-up but did not reduce the recurrence of all atrial arrhythmias. MIL ablation may reduce organized atrial tachyarrhythmia recurrences. Clinical Trial Registration—http://www.anzctr.org.au; ACTRN12606000467538.
Circulation-arrhythmia and Electrophysiology | 2008
Toon Wei Lim; Choon Hiang Koay; Rebecca McCall; Valerie A. See; David L. Ross; Stuart P. Thomas
Background—Single-ring isolation of the posterior left atrium is feasible, but the incidence and mechanisms of postprocedural arrhythmias have not been described in detail. Methods and Results—The first 100 consecutive patients (58.8±11.2 years old, 80 male) who underwent single-ring isolation for atrial fibrillation (66 intermittent, 18 persistent, 16 long-standing persistent) were followed up for 9.1±4.5 months. Recurrences were diagnosed by clinical symptoms and Holter monitoring. Patients with recurrences of sustained atrial arrhythmia >3 months after the procedure were offered a repeat procedure and were studied to determine the mechanisms of recurrence. Forty-six patients (46%) experienced sustained postprocedural atrial arrhythmias (35 had atrial fibrillation, and 34 had atrial flutter). Of these, 34 required a second procedure 7.0±3.1 months after their initial procedure. Reconnection of the posterior left atrium was seen in all patients with atrial fibrillation. Atrial flutter was most commonly due to mitral isthmus-dependent macroreentry (n=8, cycle length 368±116 ms) or macroreentry through 2 gaps in the ring of lesions (n=6, cycle length 328±115 ms). Posterior left atrium reisolation was achieved at the second procedure in all patients. Atrial flutter was successfully ablated and rendered noninducible in all patients. Six months after their last procedure, the Kaplan-Meier estimate of freedom from recurrence for all 100 patients was 81±5%. Conclusions—Atrial fibrillation and atrial flutter recurrence is common after single-ring isolation. Reconnection of the posterior left atrium and macroreentry are the common mechanisms. Repeat ablation results in satisfactory short-term outcomes.
Circulation-arrhythmia and Electrophysiology | 2008
Toon Wei Lim; Choon Hiang Koay; Rebecca McCall; Valerie A. See; David L. Ross; Stuart P. Thomas
Background—Single-ring isolation of the posterior left atrium is feasible, but the incidence and mechanisms of postprocedural arrhythmias have not been described in detail. Methods and Results—The first 100 consecutive patients (58.8±11.2 years old, 80 male) who underwent single-ring isolation for atrial fibrillation (66 intermittent, 18 persistent, 16 long-standing persistent) were followed up for 9.1±4.5 months. Recurrences were diagnosed by clinical symptoms and Holter monitoring. Patients with recurrences of sustained atrial arrhythmia >3 months after the procedure were offered a repeat procedure and were studied to determine the mechanisms of recurrence. Forty-six patients (46%) experienced sustained postprocedural atrial arrhythmias (35 had atrial fibrillation, and 34 had atrial flutter). Of these, 34 required a second procedure 7.0±3.1 months after their initial procedure. Reconnection of the posterior left atrium was seen in all patients with atrial fibrillation. Atrial flutter was most commonly due to mitral isthmus-dependent macroreentry (n=8, cycle length 368±116 ms) or macroreentry through 2 gaps in the ring of lesions (n=6, cycle length 328±115 ms). Posterior left atrium reisolation was achieved at the second procedure in all patients. Atrial flutter was successfully ablated and rendered noninducible in all patients. Six months after their last procedure, the Kaplan-Meier estimate of freedom from recurrence for all 100 patients was 81±5%. Conclusions—Atrial fibrillation and atrial flutter recurrence is common after single-ring isolation. Reconnection of the posterior left atrium and macroreentry are the common mechanisms. Repeat ablation results in satisfactory short-term outcomes.
Circulation-arrhythmia and Electrophysiology | 2008
Toon Wei Lim; Choon Hiang Koay; Rebecca McCall; Valerie A. See; David L. Ross; Stuart P. Thomas
Archive | 2017
Toon Wei; Choon Hiang Koay; David L Ross; Stuart P Thomas BMed; Stuart Phillip Thomas
Global heart | 2014
C. Nalliah; Choon Hiang Koay; Stuart P. Thomas
Global heart | 2014
Adam Lee; See Valerie; Toon Wei Lim; Choon Hiang Koay; W. Chik; Joseph Descellar; David L. Ross; Stuart P. Thomas; Liza Thomas
Global heart | 2014
C. Nalliah; Choon Hiang Koay; Stuart P. Thomas
Heart Lung and Circulation | 2013
C. Nalliah; T. Lim; Choon Hiang Koay; W. Chik; J. Thelander; R. Zecchin; David L. Ross; Stuart P. Thomas