The His optimised pacing evaluated for heart failure trial

INTERVENTION: All patients will be implanted with a Pacemaker or Implantable Cardioverter Defibrillator with one of the leads positioned on the His bundle in order to obtain direct His‐bundle capture. If it is not possible to successfully implant a His‐bundle lead with selective direct His bundle capture or non‐selective capture with < 40ms prolongation of the QRS duration, then a lead will be implanted in a lateral branch of the coronary sinus as an alternative approach. Patients will then be allocated in random order to six month treatment periods in each of the following two states 1. No pacing 2. AV optimised direct His‐bundle pacing CONDITION: Topic: Cardiovascular disease; Subtopic: Cardiovascular (all Subtopics); Disease: Heart Failure ; Circulatory System ; Heart failure PRIMARY OUTCOME: Exercise capacity is determined by measuring peak oxygen uptake (VO2) at baseline, 6 and 12 months. SECONDARY OUTCOME: 1. Changes in B‐type Naturietic Peptide (BNP) are measured at baseline, 6 and 12 months; 2. Changes in Quality of Life Scores are measured at baseline, 6 and 12 months; 3. Cost effectiveness analysis is completed at baseline, 6 and 12 months; 4. Echocardiographic measurement of left ventricular function and remodeling is measured at baseline, 6 and 12 months; 5. Fluoroscopy time during device insertion is measured 2 months pre‐randomisation and during device insertion; 6. Percentage pacing, arrhythmia burden, pacing threshols, R wave amplitude and lead impedance are measured at baseline, 6 and 12 months INCLUSION CRITERIA: 1. Aged 18 or above 2. Ventricular Ejection Fraction (EF) < 35% 3. New York Heart Association (NYHA) class II‐IV 4. PR interval =200ms 5. Narrow QRS duration (=140ms) or prolonged QRS duration with typical Right Bundle Branch Block (RBBB) morphology on 12 lead ECG and sinus rhythm