Table 1. FIRM – Real progress over conventional techniques.

	Conventional	FIRM
Single procedure success, 1 year	≈50%	≈80%
Proof of success	Some implanted ECG Intermittent Holter recording	Many (majority) implanted ECG
Multicenter	✔	14 centers, ~200 reported cases
Ability to predict who will do well/recur?	✖	✔
Ability to explain why patients do well/recur?	✖	✔
Defined patient specific mechanism	Triggers – Sometimes defined Sustainers – rarely defined	Defined consistently. Validated by mapping pre/post ablation.
Basic science supports mechanisms	✔/✖	✔
Future work	1.PV reconnection 2.Other triggers, whether PVs isolated or not? 3.Other sustainers?	1.Fibrillatory conduction from rotors (i.e. why do patients do well even if AF does not terminate procedurally?) 2.Why do rotors form where they do?