Catheter ablation in atrial fibrillation and heart failure with preserved ejection fraction improves peak pulmonary capillary wedge pressure, exercise capacity and quality of life: RCT STALL HFpEF

Introduction

Atrial fibrillation (AF) frequently accompanies heart failure with preserved ejection fraction (HFpEF). AF exacerbates HFpEF through adverse haemodynamic effects. In turn, HFpEF promotes AF through adverse left atrial remodelling. Observational data suggest sinus rhythm restoration improves outcomes in patients with AF and HFpEF. However, there are no randomised data examining the effects of rhythm control with catheter-based AF ablation on HFpEF outcomes.

Purpose

To compare the effects of AF ablation versus usual medical therapy on markers of HFpEF severity, including exercise haemodynamics, natriuretic peptide levels and patient symptoms.

Methods

Patients with symptomatic AF and HFpEF underwent exercise right heart catheterization (RHC) and cardiopulmonary exercise testing (CPET). HFpEF diagnosis was based on left ventricular ejection fraction (LVEF) ≥50%, elevated natriuretic peptide and echocardiographic diastolic impairment. HFpEF was confirmed on exercise RHC based on peak exercise pulmonary capillary wedge pressure (PCWP) of ≥25mmHg. Patients were randomised to AF ablation versus medical therapy, with investigations repeated at 6 months. The primary outcome was change in PCWP on follow-up.

Results

31 patients aged 66.1±7.5 years were randomized to AF ablation (16) versus medical therapy (15), with 51.6% female and 80.6% persistent AF. Baseline characteristics were comparable across groups. Paired analyses of ablation cohort showed significant reductions in peak PCWP (29.6±3.7 vs 25.9±4.6 mmHg, p<0.01), PCWP indexed for workload (39.0±57.9 vs 33.0±50.5 mmHg/W/kg, p<0.01), and BNP (146.2±80.5 vs 82.2±75.4 pg/mL, p=0.01); and increased resting cardiac output (4.6±0.9 vs 5.6±1.2 L/min, p=0.01), peak cardiac output (9.6±4.2 vs 10.4±3.7 L/min, p=0.02), peak (30s averaged) VO2 (1875.1±759.2 vs 2193.7±878.1 mL/min, p<0.01), peak absolute VO2 (1937.3±739.3 vs 2216.3±861.9 mL/min, p<0.01), peak (30s averaged) relative VO2 (19.4±5.9 vs 22.9±7.4 ml/kg/min) and peak workload (162.0±81.1 vs 184.4±83.4 W, p<0.01). Quality of life scores improved: AFEQT (45.3±20.9 vs 75±20.7, p<0.01) and MLHF (53±23.3 vs 17.5±22.8, p<0.01). Reversal of HFpEF by PCWP criteria occurred in 31.2% following AF ablation, and 50% among those free from arrhythmia recurrence. In the medical arm, there were no significant differences in RHC, CPET, and natriuretic peptide outcomes on follow-up versus baseline. Repeated measures mixed ANOVA testing showed significant time-randomisation interaction on peak VO2, absolute peak VO2, peak relative VO2, AFEQT/ MLHF scores, suggesting that significant improvements in these parameters were related to AF ablation.

Conclusion

In patients with concomitant AF and HFpEF, AF ablation improves invasive exercise haemodynamic parameters, increases exercise capacity, and enhances quality of life. Successful AF ablation may reverse the clinical syndrome of HFpEF in a subset of cases.

Funding Acknowledgement

Type of funding sources: None.

High power short duration (HPSD) versus lower power longer duration (LPLD) atrial fibrillation ablation: a multi-centre randomised controlled trial (HiLo-HEAT study)

Funding Acknowledgements

Type of funding sources: None.

Background

 Lower power (25W) longer duration (LPLD) radiofrequency (RF) ablation has conventionally been used on the posterior wall during pulmonary vein isolation (PVI) for atrial fibrillation (AF), to attenuate the risk of esophageal thermal injury (ETI). High power (40-50 W) short duration (HPSD) RF ablation results in shorter procedural times with no increase in ETI. However evidence had been limited by non-randomised studies.

Purpose

 To compare HPSD versus LPLD ablation and the effects on esophageal thermal injury (ETI) and procedural outcomes.

Methods

 In this multi-centre, prospective, randomised control trial, 88 patients with paroxysmal/persistent AF undergoing their first RF ablation procedure were randomised 1:1 to HPSD or LPLD ablation. Anterior wall ablation was done in both arms using 40-50 W, with ablation target of AI 500-500/ LSI 5-5.5. Posterior wall ablation was done using 40-50W (HPSD group) versus 25 W (LPLD group), with target AI 400/ LSI 4. Ablation involves wide antral circumferential PVI using contact force sensing ablation catheters, with additional ablation lines as per operator discretion. Circa multi-sensor esophageal temperature monitoring (ETM) probe was utilized. Endoscopy was performed within 24 hours to assess for ETI. The primary outcome was incidence of ETI, with secondary outcomes including acute procedural endpoints.

Results

 Mean age of the cohort was 61+/-9 years, with 31% females. 36 (41%) had PAF. PVI was achieved in 100% of patients, with posterior wall isolation (PWI) added in 19 PsAF patients (21.6%). There were more hypertensive patients in HPSD (p = 0.02). Significant esophageal luminal temperature rises (≥ 38 c) were seen in 93.2% of patients, with no difference between groups (p = 0.69). First pass isolation rates for left and right PVs were 85% and 61% respectively, with similar rates in both groups (p = 0.37, p = 0.65 respectively). HPSD group had shorter RF time (1613 vs 2303 secs, p <0.04), and fluoroscopy times (11.4 vs 13.1 mins, p = 0.05). Procedural times were lower in HPSD, although not significant (133.7 vs 150.8 mins, p = 0.10). Post ablation endoscopy showed 4 cases of ETI (4.5%), with equal occurrence in HPSD and LPLD (p = 1.0). All ETIs were class 2a (superficial ulcer), and treated with PPI therapy. Esophageal injuries not attributable to RF ablation occurred in 9 (10%), with no difference between groups (p = 0.29). There was no difference in AF recurrence between the 2 groups (post 3 months blanking period) after a mean follow up of 6.3 months (p = 0.71).

Conclusion

 HPSD ablation was associated with lower RF ablation and fluoroscopy times compared to LPSD, with comparably low rates of ETI on post ablation endoscopy. Our findings suggest that HPSD ablation is a safe and efficacious approach to PVI. However clinicians should be cognisant of the potential injury risk related to esophageal instrumentation from transesophageal echo/ ETM probes.

P574Accuracy of wrist-worn heart rate monitors for chronotropic assessment in atrial fibrillation

Introduction

Wrist-worn fitness and heart rate (HR) monitors are increasingly popular. Previous studies in healthy participants with sinus rhythm (SR) have yielded variable results depending on HR, activity levels and device tested. A paucity of data exists on their accuracy in atrial fibrillation (AF) in ambulatory patients.

Purpose

We sought to assess the HR accuracy of 2 commercially available smart watches (Fitbit Charge HR [FB] and Apple Watch Series 3 [AW]) compared with Holter monitoring in an ambulant patient cohort.

Methods

Patients aged >18 years referred for 24-hour Holter monitoring were prospectively recruited. The Holter monitor was the criterion measure. Each patient was randomly allocated to either a FB or AW along with their Holter monitor. The study protocol was approved by the institutional review board.

Statistical analysis: Pearson (r) correlation coefficients and Bland-Altman comparison with 95% limits of agreement (LoA) were evaluated to assess criterion validity and agreement between the smart watch and Holter ECG-HR. Bias was the calculated mean difference between the smart watch and ECG-HR. A ± 10-beat different between Holter-HR and SW-HR was used as a clinically relevant range to establish the accuracy of HR estimation by SW.

Results

Across all devices, 53,288 hear rate values were recorded from 32 patients. Twenty six patients were in persistent AF and six were in SR. Twelve patients wore the FB while 20 wore the AW. In the FB arm, nice patient were in persistent AF and three in SR. In the AW arm, persistent AF was the rhythm in seventeen and SR in three. Patients in SR demonstrated overall strong agreement compared to Holter monitoring (Mean Bias <1 beat, LoA −11 to 11 beats) and a correlation coefficient of 0.87 (p<0.001). In AF, both devices underestimated HR measurements (Overall Bias −9 beats, LoA −41 to 23, r=0.60, p<0.001). The AW had lower bias and narrower LoA compared to FB (−5 beats vs −13 beats, LoA −31 to 21 beats vs −50 to 22 beats). Using a ± 10-beat range against ECG-HR for clinical accuracy, both the AW and FB performed satisfactorily in SR with 95.2% of AW and 92.2% of FB HR readings considered valid. In AF, however, the AW-HR readings were within the ± 10-beat threshold in 76.5% of the time compared with only 56.1% of FB readings.

Conclusion

In ambulatory patients, smart watches were accurate in HR estimation when compared to Holter monitor in SR; however tended to underestimate HR in AF. Further improvements in device technology are needed before the widespread consumer adoption of this nascent technology for chronotropic assessment in arrhythmias.