Clinical Trial Summary
Each year in the UK, approximately 150,000 people have a heart attack when the blood supply
to their heart is compromised. As a result, affected regions of the heart can become diseased
and scarred. In a healthy person, electrical waves propagate across the heart in a regulated
pattern which triggers contraction to pump blood around the body. The scar tissue that forms
as a result of a heart attack can disrupt the propagation of the electrical waves. If
significant disruptions occur, blood cannot be pumped out of the body effectively, leading to
sudden death.
Ablation therapy aims to eliminate areas of diseased tissue that cause disruption to the
heart rhythm, by applying radiofrequency using catheters inserted into the heart. The most
accurate techniques used to locate the region to ablate require the induction of dangerous
heart rhythms, which are only inducible in about 65% of people.
Pace mapping is a technique used to locate regions to ablate, which can be performed during
normal heart rhythm. ECG data, which records electrical signals from the heart, is collected
when the patient has an abnormal heart rhythm. From this template ECG, a clinician can tell
the approximate location of the diseased tissue. A catheter is directed to that location, the
heart stimulated, and another ECG, called the paced ECG is recorded. If the paced ECG matches
the template ECG, it is assumed that the heart was paced in the location that requires
ablation.
Current ablation techniques are difficult, time consuming, and inaccurate. As a result, the
procedure may work in only half of all patients, and result in unnecessary damage to healthy
tissue, leading to later impairment of heart function.
The CPS project's overall goal is to increase the success rates of ablation therapy by
improving the accuracy and efficiency of locating the optimal region of tissue to eliminate
during the pace mapping procedure. Increasing ablation therapy success rates will mean that
patients will be unlikely to suffer from future heart rhythm disorders as a result of their
heart attack, increasing the life expectancy of heart attack patients. Excess damage caused
to the heart as a result of unnecessary ablation lesions will be limited, decreasing the
likelihood of future complications. In addition, dangerous heart rhythms do not need to be
induced in the patient, significantly decreasing the risk of death during the treatment.
