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Catheter Ablation versus Anti-arrhythmic Drugs for Ventricular Tachycardia (CAAD-VT): A Randomised Trial

The number of patients recruited by Canberra Heart Rhythm: not enrolling yet

A randomised trial of patients with structural heart disease and spontaneous or inducible VT who will be randomised in a 1:1 manner to receive either catheter ablation or anti-arrhythmic drugs and followed for a median follow up of 18 months to monitor for recurrence of VT.


Some patients with heart disease due to prior heart attacks (ischemic heart disease), or inflammatory or genetic conditions (non-ischemic heart disease) can develop a life threatening heart rhythm disorder called ventricular tachycardia (VT) which may lead to cardiac arrest/sudden death.

All such patients will receive an internal defibrillator that can terminate VT, but 50% will continue experiencing VT. Treatment options are limited to either medications that may control VT or a keyhole surgical procedure called ablation, that cauterises the electrical short circuits that create VT.

The optimal treatment is unknown. This randomised study will determine if ablation is superior to standard medical therapy for the treatment at VT.

Patients aged ≥18 years with structural heart disease, experienced VT in the past 6 months will be recruited. Participants will be randomised to standard medical therapy or intervention (ablation).

Inclusion Criteria

  1. ≥1 prior episode of sustained VT in the prior 6 months;
  2. Spontaneous VT: ≥1 episode of monomorphic VT treated by anti-tachycardia pacing (ATP) and/or internal shock by an ICD; lasting ≥30 seconds in the absence of intra-cardiac device therapy that could either be self-terminating or require reversion by pharmacological therapy or external cardioversion;
  3. Spontaneous VT: ≥1 episode of sustained spontaneous monomorphic VT lasting ≥30 seconds documented on holter, ECG, Loop recorder or other cardiac monitoring device that could either be self terminating or require reversion by pharmacological therapy or external cardioversion;
  4. Inducible VT: with syncope or palpitations – inducible VT defined as sustained monomorphic VT of CL ≥200ms lasting for ≥10s during a cardiac electrophysiology study (note with 4 extrastimuli with or without provocation with isoprenaline);
  5. Already a recipient of an implanted cardiac device such as a pacemaker, defibrillator or a cardiac resynchronisation therapy device and/or is indicated to receive one given a new diagnosis of structural heart disease, based on current guideline recommendations;(1)
  6. Aged ≥18 years.

Exclusion criteria

  1. Unable or unwilling to provide informed consent or patients physician feels there is not significant equipoise to justify randomisation;
  2. Women who are pregnant, breast feeding;
  3. Medical illness with an anticipated life expectancy <3 months;
  4. Unable to complete study procedures or unwilling to be followed up;
  5. Have a concomitant illness, physical impairment or mental condition which in the opinion of the study team/ primary care physician could interfere with the conduct of the study including outcome assessments;
  6. Known channelopathy such as long QT, short QT, Brugada syndrome, catecholaminergic polymorphic VT;
  7. Known prior diagnosis of no structural heart disease,(2) or idiopathic ventricular arrhythmia.