Solutions to the Challenges of Conduction System Pacing

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

• 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 [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 [Time frame: From enrollment until 6 months after recruitment of last patient]