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Catheter ablation of ventricular tachycardia in structurally abnormal hearts: results of an incremental strategy to produce good long-term outcomes
  1. G Thomas,
  2. V Sawhney,
  3. V Ezzat,
  4. E Duncan,
  5. T Watts,
  6. G Appanna,
  7. N Shah,
  8. M Finlay,
  9. SC Sporton,
  10. RJ Schilling
  1. Barts and the London NHS trust, London, UK

Abstract

Introduction Catheter ablation is an effective method for palliation of ventricular tachycardia (VT) in the setting of structural heart disease, but questions remain about the long-term success. We have applied an incremental strategy for catheter ablation of VT between 2003 and 2008 and examined its long-term outcome.

Methods If patients had stable tolerated VT they underwent map-guided ablation. If an endocardial source could not be identified then an epicardial approach was used. If VT was not tolerated or non-sustained (unmappable) then substrate modification was performed guided by pace mapping if an ECG was available. If substrate was extensive for either mappable or unmappable VT and a suitable coronary vessel was present then ethanol ablation was performed. Patients were followed up in clinic and by telephone interview.

Results 53 patients (male 48) with ischaemic heart disease n  =  38 (72%), idiopathic dilated cardiomyopathy n  =  11 (20%), valvular heart disease n  =  2 (4%) and congenital heart disease n  =  2 (4%), with a mean age of 63 years (range 20–82 years) underwent catheter ablation for VT. Ejection fraction was less than 35% in 29 (55%) patients. 46 (87%) patients had implantable cardioverter defibrillators (ICD). Clinical VT was spontaneous in 23 (43%) patients, inducible in the remaining 30 (57%) patients and haemodynamically unstable in 14 (26%) patients. The mean number of inducible clinical VT was 1.2 (range 1–4) and non-clinical VT was 1.6 (range 1–4). Mapping techniques included conventional n  =  12 (23%), Carto n  =  36 (68%) and non-contact n  =  5 (9%). VT origin was left ventricle in 50 (94%) and right ventricle in three (6%) patients. Ablation energy was delivered via an irrigated 4 mm catheter in 40 (75%), a non-irrigated 4 mm catheter in eight (15%), an 8 mm non-irrigated catheter in one (2%) patient; cryo (epicardial only) in two (4%) and ethanol ablation was performed in two (4%) patients. Epicardial ablation was required in eight (15%) patients. A focal ablation strategy was used in 37 (70%), substrate modification in nine (17%) and linear in seven (13%) patients. Post-ablation, clinical VT was non-inducible in 41 (77%) yet persisted but was modified and amenable to anti-tachycardia pacing (ATP) in 12 (23%) patients. There were no procedural deaths. Complications included a transient ischaemic attack (n  =  1) and pericardial tamponade requiring drainage (n  =  1). Mean follow-up was 27.2 months (range 1.2–65.9 months). Nine (17%) patients died during follow-up. ICD interrogation of the survivors (n  =  39) revealed that 36 (92%) remained shock free and 27(69%) remained free from (appropriate) ATP.

Conclusions An incremental strategy of catheter ablation for VT results in excellent long-term outcomes with low complications.

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