A minimal or maximal ablation strategy to achieve pulmonary vein isolation for paroxysmal atrial fibrillation: a prospective multi-centre randomized controlled trial (the Minimax study).
OBJECTIVE
Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation of atrial fibrillation (AF). The intervenous ridge (IVR) may be incorporated into ablation strategies to achieve PVI; however, randomized trials are lacking. We performed a randomized multi-centre international study to compare the outcomes of (i) circumferential antral PVI (CPVI) alone (minimal) vs. (ii) CPVI with IVR ablation to achieve individual PVI (maximal).


RESULTS
Two hundred and thirty-four patients with paroxysmal AF underwent CPVI and were randomized to a minimal or maximal ablation strategy. The primary outcome of recurrent atrial arrhythmia was assessed with 7-day Holter monitoring at 6 and 12 months. PVI was achieved in all patients. Radiofrequency ablation time was longer in the maximal group (46.6 ± 14.6 vs. 41.5 ± 13.1 min; P < 0.01), with no significant differences in procedural or fluoroscopy times. At mean follow-up of 17 ± 8 months, there was no difference in freedom from AF after a single procedure between a minimal (70%) and maximal ablation strategy (62%; P = 0.25). In the minimal group, ablation was required on the IVR to achieve electrical isolation in 44%, and was associated with a significant reduction in freedom from AF (57%) compared with the minimal group without IVR ablation (80%; P < 0.01).


CONCLUSIONS
There was no statistically significant difference in freedom from AF between a minimal and maximal ablation strategy. Despite attempts to achieve PVI with antral ablation, IVR ablation is commonly required. Patients in whom antral isolation can be achieved without IVR ablation have higher long-term freedom from AF (the Minimax study; ACTRN12610000863033).
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
Alex J A
AJ
McLellan
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
Liang-Han
LH
Ling
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia.
Sonia
S
Azzopardi
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia.
Geraldine A
GA
Lee
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
Geoffrey
G
Lee
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
Saurabh
S
Kumar
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
Michael C G
MC
Wong
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
Tomos E
TE
Walters
Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
Justin M
JM
Lee
Papworth Hospital, Cambridge, UK.
Khang-Li
KL
Looi
Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia.
Karen
K
Halloran
Waikato Hospital, Hamilton, New Zealand.
Martin K
MK
Stiles
Auckland City Hospital, Auckland, New Zealand.
Nigel A
NA
Lever
Papworth Hospital, Cambridge, UK.
Simon P
SP
Fynn
Papworth Hospital, Cambridge, UK.
Patrick M
PM
Heck
Centre for Heart Rhythm Disorders, University of Adelaide and Royal Adelaide Hospital, Adelaide, SA, Australia.
Prashanthan
P
Sanders
Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia Melbourne Private Hospital, Parkville, VIC, Australia.
Joseph B
JB
Morton
Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia Melbourne Private Hospital, Parkville, VIC, Australia.
Jonathan M
JM
Kalman
Alfred Heart Centre, Alfred Hospital, Melbourne, VIC, Australia Baker IDI Heart and Diabetes Institute, 75 Commercial Road, Melbourne, VIC 3004, Australia Department of Cardiology, Royal Melbourne Hospital, Parkville, VIC, Australia Department of Medicine, University of Melbourne, Parkville, VIC, Australia Melbourne Private Hospital, Parkville, VIC, Australia Avenue Private Hospital, Windsor, VIC, Australia peter.kistler@bakeridi.edu.au.
Peter M
PM
Kistler
D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011667:Pulmonary Veins / Q000601:surgery; D012008:Recurrence; D012086:Reoperation; D016896:Treatment Outcome
D000889:Anti-Arrhythmia Agents
Ablation; Atrial fibrillation; Intervenous ridge; Pulmonary vein isolation; Reconnection