CRT in narrow QRS heart failure with MRI dyssynchrony assessment
Research type
Research Study
Full title
Cardiac resynchronisation therapy in patients with narrow QRS morphology and heart failure: mechanistic insights from cardiac MRI and electroanatomical mapping
IRAS ID
125230
Contact name
Aldo Rinaldi
Contact email
Sponsor organisation
King's College London
Research summary
Heart failure is the most common serious cardiac disease. It affects approximately 1 million people in the UK and has a 1-year mortality of over 30% following a hospital admission. Heart failure is when the efficiency of the heart pump is reduced and has multiple causes. A subgroup of these patients have delayed conduction of the electrical signal across the heart that causes the heart muscle to contract. This leads to an uncoordinated contraction of the left ventricle (LV-the chamber that pumps blood to the body) and a further reduction in efficiency. Specialist pacemakers can correct this dyssynchronous electrical activation by pacing the LV from both sides simultaneously, this leads to an improvement in efficiency of the LV that translates into a reduction in symptoms and reduced mortality in the majority of these patients; this is called cardiac resynchronisation therapy (CRT).
Electrical activation of the LV is measured on the surface ECG (heart tracing) by a pattern called the QRS complex. If the QRS complex is broad (>120ms) there is delayed conduction of the electrical signal across the LV. There is a group of patients who have heart failure, a normal QRS duration and evidence of mechanical dyssynchrony seen with ultrasound (echocardiography). Small studies have shown an improvement with CRT in these patients, but no studies have investigated the mechanisms by which they have mechanical dyssynchrony and why CRT might work.
We aim to use MRI to select patients with dyssynchrony and then perform an invasive electrophysiological study to examine the mechanisms as to why this should occur and who may have a positive response to CRT. In the patients who are planned for a defibrillator we will implant a permanent CRT system to assess for chronic improvement. This study will have implications for over 400 000 patients in the UK.
REC name
London - Dulwich Research Ethics Committee
REC reference
13/LO/1475
Date of REC Opinion
20 Dec 2013
REC opinion
Further Information Favourable Opinion