Ventricular tachycardia (VT) is a life-threatening heart rhythm disorder and one of the commonest causes of heart-related sudden death. It often affects people who have had a heart attack or other structural heart damage. VT occurs when abnormal electrical circuits develop within and around scar tissue in the heart.
People at risk are usually offered an implantable cardiac defibrillator (ICD), a device that can detect VT and deliver a lifesaving shock. While effective, these shocks can be sudden, painful and distressing. Medications such as amiodarone can also help, but they are often unsuitable for long-term use due to their potential side effects on the liver, lungs and thyroid gland.
An alternative is catheter ablation. Thin tubes (catheters) are threaded from a blood vessel in the groin to the heart, allowing the cardiologist to identify scar tissue and abnormal electrical circuits, which can be destroyed using heat, freezing or electrical energy.
Although ablation can help many patients, VT can return in up to one in three people after the procedure. This is because it can be difficult to precisely identify the scar and surrounding tissue that sustain the abnormal circuits, making it challenging to know exactly where to apply ablation treatment.
Dynamic Voltage Mapping, is a technique which the investigators believe can more accurately identify scar and the critical bordering tissue during ablation. Initial data collected suggests that the approach accurately predicts the VT circuit and helps guide ablation.
In this study, the investigators wish to recruit 40 participants undergoing VT ablation to determine how effective Dynamic Voltage Mapping is in real-world procedures.
Scheduled for clinically indicated VT ablation (due to sustained VT episodes or ICD therapies).
Willing and able to give informed consent for participation in the trial
Male or female aged between 18-85
Ischaemic and non-ischaemic cardiomyopathy
Unable or unwilling to consent
NYHA Class IV (end stage heart failure)
Metastatic cancer
End stage renal disease
Parallel
Dynamic Voltage Mapping
Procedure/SurgeryDynamic Voltage Mapping uses electrical information collected from catheters positioned within the heart to create an individualised map of the heart, which the investigators hypothesise will better identify scar and surrounding tissue responsible for ventricular tachycardia.
Standard of Care Ablation
Procedure/SurgeryStandard catheter ablation of ventricular tachycardia, guided by operator preference
Study Feasibility
1. Proportion of screened patients who were eligible, approached, consented and recruited 2. Attrition rate: calculated as the total number of recruited patients who withdrew from the study or were lost to follow up 3. Adherence: calculated as the proportion of recruited participants who were able to fully follow the study protocol in both DVM and standard of care arms during their VT ablation procedure.
Procedural Time
Measured in minutes
Ablation time/number of lesions
Measured by number of ablation lesions applied
Acute VT non-inducibility
Ability to induce clinical VT at the end of the procedure
VT recurrence Rate
Number of sustained VT episodes/ICD shocks/therapies following procedure, recorded by implanted cardiac device
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