Multimodality Assessment of Ventricular Scar Arrhythmogenicity.
Multimodality Assessment of Ventricular Scar Arrhythmogenicity.
We aim to improve our understanding of a life-threatening heart rhythm disorder known as
 ventricular tachycardia (VT). This is a disorder which originates from the lower chamber of
 the heart and frequently is associated with heart disease. We will use an MRI scan to
 generate a computer based model of the heart which can predict areas of the heart which are
 important in generating this rhythm disorder. We intend to assess how accurate this computer
 model is compared to traditional invasive assessment of the heart muscle. We also aim to
 assess the electrical characteristics of those areas which were predicted by the computer
 model in order to see why they were thought to be so important.

 All patients seen at St George's Hospital with VT will be eligible. As is routine for these
 patients, they will have an MRI scan of the heart. We will then use this scan to create a
 virtual reconstruction of the heart from which predictions of the critical areas of the heart
 which are generating the rhythm problem will be made. Then we will perform a VT ablation
 (studying the electrical properties and if necessary making a burn to treat the rhythm
 problem) - as per standard of care, however during the ablation we will spend extra time
 collecting information comparing the accuracy of the computer-generated model to the
 traditional invasive signals which guide ablation. We will study the electrical properties of
 those predicted areas to see what is special about them. The study will last up to three
 years.
Patients will be eligible for this trial both from referrals as an outpatient, where VT has
 been detected on a heart rhythm monitor or ECG (electrical heart tracing), or as an inpatient
 where they have been admitted to hospital with symptoms of VT. Our study investigators will
 discuss the research with the patient and give them the relevant information in an
 understandable format as part of a Patient Information Sheet so that they can make an
 informed decision about whether or not to participate in the research.

 An MRI scan of the heart is a standard investigation for patients presenting with VT, however
 if the patient is included in the study, the MRI scan images will be anonymised and sent
 confidentially to the Institute of Computational Modelling at Johns Hopkins University in USA
 where the images will be reconstructed into a 3D representation of the patients heart, where
 the electrical pathways and source of the VT can be seen. This information will be sent back
 (again confidentially and anonymously) to St George's Hospital in time for their routine VT
 ablation procedure.

 During the VT ablation The MRI scan model will be combined with the invasively-obtained
 information and we will assess the various areas of the heart which are responsible for the
 VT, particularly relating to areas of scar within the heart, which are frequently seen in
 these patients. We will assess the electrical properties of the areas highlighted as the
 cause of the VT from the MRI scan.

 We will assess the accuracy of the computer model compared to the traditional invasive
 measurements that we take. We will first ablate those areas of the heart which the model
 predicted as being important (as long as the invasive characteristics support ablation there)
 and then see what effect this had on the electrical properties of other areas of the heart.
 However, we will not ablate any area of the heart based solely on the MRI model; it will only
 influence the order of ablation and not tell us whether to ablate or not.

 The procedure can take 4-6 hours in total. The extra information gathered as part of the
 research protocol may extend this by a maximum of 10%. No extra pieces of equipment,
 procedures or medications are involved in the research, just the time taken to generate a
 computer model of the heart as well as a extra time to assess the heart in more detail during
 the ablation.

 Following the ablation, the patients will be followed at 3, 6 and 12 months with a heart
 rhythm monitor and a clinical review as an outpatient as per routine standard of care. From
 this, we will collect data on frequency of recurrence of rhythm disturbance, therapy from
 their implantable cardioverter-defibrillators, symptoms and complications following the
 ablation procedure.

 The information gathered during the procedure will be analysed and research papers generated
 from the results.
Inclusion Criteria:

 Adult inpatients admitted to St George's Hospital London with sustained ventricular
 tachycardia or outpatients identified from the arrhythmia clinic with significant
 monomorphic ventricular tachycardia noted on cardiac monitoring who:

 -  Have sustained, monomorphic scar-dependent ventricular tachycardia

 -  Are symptomatic

 -  Failed, unable or unwilling to tolerate anti-arrhythmic medications

 -  Able to have a cardiac MRI

 -  Have a life expectancy > 1 year

 -  At least 40 days following a myocardial infarction

 Exclusion Criteria:

 -  Patients under the age of 18

 -  Patients who are unable to give informed consent

 -  Pregnant patients

 -  Unable to have cardiac MRI

 -  Prohibitive procedural risk

 -  Unable to tolerate the ablation procedure due to haemodynamic instability