Emergency pacemaker implantation in nonagenarians with complete heart block: is single chamber pacing sufficient?

Background

In ambulatory patients with complete heart block and preserved sinus node activity (CHBs), dual chamber pacing confers well-established physiological benefits versus single chamber pacing. There is limited evidence as to whether these benefits extend to very frail patients, especially those over 90 years of age.

Purpose

In nonagenarians presenting with emergent CHBs from 2016–2019, we compared the clinical characteristics of patients selected for single versus dual chamber pacemakers (PPM), and evaluated the symptomatic and prognostic implications of these devices.

Methods

Baseline characteristics were discerned from electronic records, and physiological data extracted from serial PPM interrogations. Frailty was quantified according to the Rockwood clinical frailty scale (1–9). Cause of death was provided by the patients' General Practitioner. Cox proportional hazards analysis (HR, 95% CI) examined associations with all-cause mortality and death from congestive cardiac failure (CCF).

Results

168 consecutive patients were included (44.3% Male, Median age: 91 (2) years) and followed-up for 26.9±14.6 months. 22 patients (13.1%) were implanted with single chamber pacemakers (all programmed VVIR); when compared with patients receiving dual chamber devices, these patients had similar median age (93 (3) versus 91 (2) years, p=0.15) and LV systolic function (LVEF: 49.2% ±9.7 versus 50.7% ±10.1, p=0.71), but were more frail (Rockwood scale: 5.2±1.8 versus 4.3±1.1, p=0.004) and more likely to have severe cognitive impairment (27.3% versus 9.2%, p=0.018). Post implant, patients who received single chamber devices had higher average respiratory rates (21.3±2.4 breaths per minute versus 17.5±2.6 breaths per minute, p=0.002), lower average heart rates (65.5±10.1 bpm versus 71.9±8.6 bpm, p=0.002), and lower daily activity levels (0.57±0.3 hours of activity versus 1.5±1.1 hours of activity, p=0.016) than those with dual chamber devices. Death from CCF was more common in patients receiving single chamber devices (40.9% versus 6.2%, log rank p<0.0001); this association persisted when adjusting for age, frailty and cognitive impairment (adjusted HR: 6.2 (2.2–17.3, p=0.0005). However, in this age group, single chamber pacing was not independently associated with all-cause mortality when compared with dual chamber pacing (adjusted HR: 1.9 (0.95–3.6, p=0.07).

Conclusions

In nonagenarians with CHBs, dual chamber pacing was associated with improved symptomatic outcomes and a reduced risk of death from CCF, but did not affect all-cause mortality when compared with single chamber pacing.

Funding Acknowledgement

Type of funding sources: None.

Cardiac implantable electronic device infections: prognostic value of the PADIT score and its cost-utility implications for antimicrobial envelope use in the United Kingdom

Background

The incidence of cardiac implantable electronic device (CIED) infections is rising.

Purpose

We examined the factors associated with CIED infection, assessed the prognostic power of the PADIT risk score, and modelled the cost-utility of selective TYRX antimicrobial envelope use for preventing CIED infections.

Methods

Data were extracted from 2016 to 2019, and included all de novo implants, generator changes and lead interventions for transvenous CIEDs at a high-volume UK centre. CIED infection was defined as hospitalisation for device infection within 12 months of a procedure. Cost-utility analysis was informed by standardised tariffs, and quality adjusted life year (QALY) and efficacy data was extrapolated from analysis of the WRAP-IT trial.

Results

6,035 patients underwent 7,383 procedures; CIED infection occurred in 59 individuals (0.8%). In addition to the constituents of the PADIT score, lead extraction (HR 3.3 (1.9–6.1), p<0.0001), C-reactive protein >50mg/l (HR 3.0 (1.4–6.4), p=0.005), re-intervention within two years (HR 10.1 (5.6–17.9), p<0.0001), and procedure duration over two hours (HR 2.6 (1.6–4.1), p=0.001) were independent predictors of infection. Increased PADIT score was strongly associated with infection (AUC: 0.82, HR per point increase: 1.36 (1.27–1.47), p<0.0001). A cost-utility model assigning TYRX envelopes to patients with PADIT scores ≥6 predicted a reduction in infections (number needed to treat: 72) and a cost per QALY gained within the UK's (NICE) cost-effectiveness threshold (£25,107).

Conclusions

The PADIT score was a powerful predictor of CIED infections in a heterogeneous population,and may facilitate cost-effective TYRX envelope allocation in selected high-risk patients.

Funding Acknowledgement

Type of funding sources: None.

Feasibility of using his bundle pacing with boston scientific generators

Introduction

His bundle pacing (HBP) aims to deliver physiological activation of the ventricles via the native His-Purkinje conduction system. A challenge of HBP is the limited market of implantation tools, pacing leads and specifically designed pacing algorithms.

Purpose

Over the last three years both Medtronic (MDT) and Boston Scientific (BSC) generators have been used for HBP in a large tertiary centre. We examined whether there was any difference between lead parameters and battery longevity depending on the type of manufacturer used.

Methods

Patients implanted with a MDT Select Secure model 3830 lead were included in this retrospective study. Data collected included HBP thresholds (analysed at 1ms pulse width) at implant and at the most recent device check, HBP percentages and battery longevity (months). Battery longevity were calculated by adding duration of follow up and estimated battery life at last follow up.

Results

A total of 31 patients were included for data analysis (58% male and mean age 72 years). 18 patients had MDT generators of which 3 were PPMs, 5 were CRT-Ps and 10 were CRT-Ds. 13 patients had BSC generators of which 5 were PPMs, 5 were CRT-Ps and 3 were CRT-Ds. Mean follow up of the cohort was 12.7±9.02 months.

Mean HBP percentages were 77±37% and 72.2±42.1% for MDT and BSC, respectively (p=0.430). Mean HBP threshold (Volts) at implant was significantly lower with BSC vs MDT (0.85±0.58 vs 1.84±1.06, p=0.01), and similar after follow up (1.01±0.91 vs 1.32±0.73, p=NS). There were no statistically significant differences between mean HBP threshold at implant compared to follow up for both manufacturers.

Interestingly, mean battery longevity for BSC vs MDT generators was significantly higher (136±29.3 vs 90.5±29.1, p<0.001). Longevity was also compared for PPM/CRT-P and CRT-D separately. For PPM/CRT-P, BSC generators had significantly higher longevity as compared to MDT (141.6±33.1 vs 91.6±34.5, p=0.009). This difference was not observed for CRT-Ds between the 2 manufacturers (p=0.068).

Conclusion

Our results suggest HBP with MDT Select Secure 3830 lead is feasible with BSC generators. There is potentially greater battery longevity with BSC compared to MDT generators. Further studies are needed with greater numbers and longer follow up to confirm this finding.

Funding Acknowledgement

Type of funding sources: None.