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Optimisation of Pacemaker Therapy for Cardiac Function

Gierula, John (2017) Optimisation of Pacemaker Therapy for Cardiac Function. PhD thesis, University of Leeds.

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Abstract

Patients with right ventricular (RV) pacemakers are at increased risk of left ventricular (LV) systolic dysfunction (LVSD) and chronic heart failure (CHF). I aimed 1) to establish the prevalence of LVSD in patients with long-term RV pacemakers listed for pulse generator replacement (PGR), 2) to evaluate the effects on LV function of reprogramming existing pacemakers to reduce RV pacing (RVP) and 3) to investigate whether upgrade to cardiac resynchronization therapy (CRT) at the time of PGR is beneficial in patients with unavoidable RV pacing and LVSD. Data were collected on 491 patients listed for PGR. Reduced left ventricular ejection fraction (LVEF) <50% was observed in 40%. Multivariable analysis revealed %RVP, serum creatinine and previous myocardial infarction (MI) to be independently related to the presence of LVSD. An audit was performed to investigate the effects of optimising pacemaker programming to avoid RV pacing in 66 patients. At 6m, RV pacing was reduced by a mean of 49%, with a mean improvement in LVEF of 6% and no reduction in exercise capacity, NT-pro-BNP or quality of life. Fifty patients with unavoidable RV pacing, LVSD, and mild symptoms of CHF, listed for PGR were randomized 1:1 to either standard RV-PGR or CRT. At 6 months there was a difference in change in median LVEF, improvements in exercise capacity, quality of life, and NT-proBNP in those randomized to CRT. After 809 days, 17 patients had died or been hospitalized (6 CRT and 11 PGR) and two patients in the PGR arm required CRT for deteriorating CHF. In summary, LVSD is common in patients with standard RV pacemakers and relates to cardiovascular co-morbidities, careful reprogramming to avoid unnecessary RV pacing can improve LVEF without adversely affecting exercise capacity and quality of life and upgrading patients with unavoidable RV pacing to CRT at PGR improves LV function, and exercise tolerance and may reduce admissions and further upgrades.

Item Type: Thesis (PhD)
Keywords: Pacemaker, heart failure, PGR, CRT, upgrade
Academic Units: The University of Leeds > Faculty of Medicine and Health (Leeds)
The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Medicine (Leeds)
Identification Number/EthosID: uk.bl.ethos.721819
Depositing User: Dr John Gierula
Date Deposited: 16 Aug 2017 09:57
Last Modified: 25 Jul 2018 09:55
URI: http://etheses.whiterose.ac.uk/id/eprint/17864

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