Can MRI-based Computational Modelling of the Heart be Used to Predict Critical Substrate in Scar-dependent Ventricular Tachycardia Ablation?

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.