Conduction system pacing is a new way of stimulating the heart using pacemaker wires. Traditional pacemakers stimulate the heart muscle which causes disordered heart beats: the walls of the heart move at different times. This wears down the heart over time. Conduction system pacemakers stimulate the heart's electrical system directly producing natural heart beats that are much less disordered. Unfortunately, these pacemakers can only be implanted by a small group of experts at specialised centres with specialist equipment. This study aims to allow conduction system pacemakers to be offered to any patient at any hospital by simplifying the process of inserting the pacemaker wires and the improving the pacemaker's ability to interpret electrical traces. Firstly, the best locations in the heart for conduction system pacemaker wires using specialised electrical traces, MRI and ultrasound scans will be identified. Features that can be seen on X-ray to guide doctors to these locations will then be identified. Secondly, the investigators will collect electrical information from the pacemaker wires and additional electrical traces to develop an algorithm that can make the interpretation the electrical traces more accurate.
Study A: 100 patients will be prospectively recruited. These patients will be further divided into a derivation and validation group. The derivation group will consist of the first fifty patients recruited (patients 1-50) and the validation group will consist the second fifty patients recruited (patients 51-100). All 100 patients will have an indication for pacemaker insertion and will undergo a conduction system pacemaker implant. The derivation group will undergo the research protocol which will include additional measurements from: 1. Ultra-high frequency ECG. A non-invasive surface ECG that detects, isolates and amplifies high frequency components that are filtered out in conventional ECGs. 2. Electro-anatomical mapping. In majority of participants, the invasive mapping catheter will be inserted from the same venous access point to collect detailed electrical and anatomical data. In a small subset of patients, activation maps of the left ventricle will be collected, where the access will be through the femoral artery in the groin. Non invasive mapping will also be performed in a subgroup of patients with ECGi, where the participants will wear a 252 electrode ECG vest during the procedure. These patients will undergo a pre-procedural CT scan with the vest. 3. Echocardiography. Participants will undergo either transthoracic echocardiography, transoesophageal echocardiography or intracardiac echocardiography. Additional venous access from the femoral vein in the groin will be sought for patients undergoing intracardiac echocardiography. 4. Haemodynamic assessment Invasive blood pressure will be obtained in patients who already have arterial access for the left ventricular electro- anatomical maps. The sheath will be connected to the pressure inducer. Non invasive beat-by-beat blood pressure will be obtained by a high precision finger cuff (finometer). A further 50 patients will be prospectively recruited that will make up the validation cohort for Study A. These patients will undergo a conduction system pacemaker as standard clinical practice. The step-by-step algorithm will be prospectively derived from the above to implant the conduction system lead using standard equipment alone; fluoroscopy, PSA and 12-lead ECG. The success rate, conduction system capture threshold, procedure time and fluoroscopy time will be assessed. Although all operators will be highly experienced device implanters, these implants will include operators who are new to conduction system lead implantation. Study B: In patients 1-50 undergoing implantation of conduction system pacemakers, 2-lead surface ECG alongside conventional lead data will be collected. A surface 12-lead ECG will be collected as well. The patients will undergo the standard pacing manoeuvres for conduction system pacing. The patient will be paced using the PSA and a 12-lead ECG and 2-lead ECG will be collected via Bard, a computer software that is able to collect highly accurate ECG traces of the heart using mapping catheters placed inside the heart and the surface ECG. Prospective data from 200 patients with a chronic conduction system lead implant under device follow-up to obtain EGM, 12 -lead ECG and the 2-lead ECG recordings of multiple pacing and sensing configurations will also be collected. These patients will be attending for routine appointments. The pacing and sensing configurations are undertaken as part of routine checks
Study Type
OBSERVATIONAL
Enrollment
300
Imperial College Healthcare Trust; Hammersmith Hospital
London, United Kingdom
RECRUITINGA1: Success rates of conduction system lead implant (novel workflow vs conventional methods)
Time frame: From enrollment until 6 months after recruitment of last patient
B1: The number of patients with morphology change seen during decrementing output threshold test of 2-lead ECG when compared to gold standard 12-lead ECG
Time frame: From enrollment until 6 months after recruitment of last patient
A2: Procedure and fluoroscopy times of the streamlined workflow to current conventional methods of His-bundle and Left-bundle pacing
Time frame: From enrolment to until completion of PPM insertion of the last patient recruited into Study A (patient 100); average total of 3 years
A2: Procedure and fluoroscopy times of the streamlined workflow of conduction system implant to current right ventricular pacing
Time frame: From enrolment to until completion of PPM insertion of the last patient recruited into Study A (patient 100); average total of 3 years
A2: Assess capture threshold of conduction system pacing from the optimised workflow to that of conventional methods of conduction system implantation
Threshold is measured through the device, looking to achieve the minimum energy (in V) required to safely and reliably capture the cardiac tissue target. In this outcome, the investigators will compare the minimum threshold required to achieve capture of conduction system pacing to that of conventional right ventricular pacing and asses if this the same, higher or lower.
Time frame: From enrollment until 6 months after recruitment of last patient
A2: Define left bundle area capture diagnostics and delineate differences between left ventricular septal pacing.
Time frame: From enrollment until 6 months after recruitment of last patient
B2: Improvement in device battery life measured in days and months with novel device algorithm applied
Device battery time is given upon device interrogation and is dependent on percentage of the time the patient is paced and the energy delivered. Battery life will increase if less energy is required. The investigators will assess if there is a increase in days or months in the battery life of the pacemaker with introduction of the novel algorithm.
Time frame: From enrollment until 6 months after recruitment of last patient
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