Physiological Versus Right Ventricular Outcome Trial Evaluated for Bradycardia Treatment Upgrades

Physiological Versus Right Ventricular Outcome Trial Evaluated for Bradycardia Treatment Upgrades

Guidelines for patients having first-time implants advocate that even when heart function is only mildly impaired, modern pacing approaches should be utilised to avoid the potentially damaging effects of RV pacing to preventing symptoms from pacing induced or worsened cardiomyopathy.

However, once a traditional (RV) pacemaker is implanted, development of impaired heart function does not prompt a device upgrade. Even at the end of battery life, physicians simply replace it like-for-like.

This trial tests whether such patients have better symptoms and quality of life if changed to a modern physiological pacing strategy from the traditional RV pacing approach.

In this crossover trial, participants will be upgraded to a physiological pacing strategy.

After their procedure, they will have a one-month run-in period to recover from the procedure (their pacemaker will be programmed to continued RV pacing).

They will be have 2 one-month blinded time periods, randomised to physiological pacing or right ventricular pacing alternately. They will subsequently undergo two six-month blinded randomised time periods.

Patients will document symptoms monthly on a mobile phone application or computer. At the end of each time period, they will have measurements of heart function, a walking test and quality-of-life questionnaires including the SF-36 questionnaire.

The investigators hypothesise that upgrading to physiological pacing strategies will improve patients' quality of life.

Patients with an RV pacemaker and LVEF 35-50% and a high burden of right ventricular pacing (>40%) who are clinically indicated for a cardiac resynchronisation therapy upgrade procedure and:

1. EF reduced by >5% of increase in LVESV by 10ml since implant
2. NT-proBNP >250ng/L in sinus rhythm
3. NT-proBNP > 750 Ng/L if AF
4. Left atrial volume index > 30ml/m2
5. Regular loop diuretics prescribed
6. Decline in daily patient activity by >1 hour per day since implant
7. Decrease in device measured thoracic impedance
8. Patient reported decline in functional class or exercise tolerance

Exclusion Criteria:

• Those unable to provide informed consent
• Patients under age 18
• Pregnant women