RCT of Implantable Defibrillators in Patients With Non Ischemic Cardiomyopathy, Scar and Severe Systolic Heart Failure

Overview

BRITISH is a UK multicentre trial of patients who have been diagnosed with heart failure due to Non-Ischemic Cardiomyopathy (NICM, or heart failure that is not caused by blocked heart arteries. Participants will be randomised into two groups. Half the participants will receive an Implantable Cardioverter-Defibrillator (ICD) and the other half will not. The aim of the study will be to compare all-cause mortality (death from any cause) between these two groups at 36 months, and longer-term to 10 years. The study has the potential to change international heart failure treatment guidelines and to improve how patients with this condition are managed.

Patients with Non-Ischemic Cardiomyopathy (NICM) have a higher risk of experiencing serious abnormal heart rhythms that might be life-threatening. Current guidelines recommend fitting a device that can correct these serious heart rhythms (Implantable Cardioverter-Defibrillator (ICD)). However, research studies have shown that 90% of patients who have an ICD will never use it because they won't experience any serious heart rhythms. A recent large trial (DANISH) of over one thousand patients with severe Non-Ischemic Cardiomyopathy has called the current guidelines into question. The trial concluded that for patients who received an ICD, there was no difference in the likelihood of dying when compared to patients that didn't have an ICD fitted. As a result, many doctors are choosing not to implant an ICD in patients with this type of heart failure, as they believe there is no overall survival benefit. However, there are clues that some patients with NICM may still benefit from an ICD, even though the headline results suggest they are not necessary. It's likely that it's the patients who are at increased risk of having a serious abnormal heart rhythm that stand to benefit from ICDs. But having an ICD fitted carries with it a significant risk of problems developing e.g. bleeding, infection, lead problems, and inappropriate shocks. These risks may not outweigh the benefits and it is this question which BRITISH will address. The study will randomly assign (like the toss of a coin), half the study participants to receive an ICD and the other half to no ICD. Both groups will be followed up to decide whether having an ICD fitted reduces the chances of dying.