Results from a nationwide atrial fibrillation screening effort in Belgium

Introduction

Atrial Fibrillation (AF) is associated with an increased risk of stroke that can be mitigated with anticoagulation therapy. Opportunistic screening for AF for primary stroke prevention is recommended in subjects above 65. However, the paroxysmal and asymptomatic nature of AF hampers early detection with a single time point screening. Multiple time point measurements are superior to single time point measurements for the detection of AF. New technologies such as photoplethysmography (PPG) enable large scale AF screening with repetitive measurements at low-cost using only a smartphone.

Purpose

To explore an entirely online AF screening program in subjects with an elevated stroke risk.

Methods

The Belgian Heart Rhythm Association launched a digital marketing campaign, to promote AF screening during “The Belgian Week of the Heart Rhythm”. Candidates were referred to an online questionnaire to calculate their CHADS-VASC score. Subjects older than 18 with a CHADS-VASC score of 2 or more were allowed to enter the screening program. AF screening was performed with a PPG-based smartphone application. A 60-second PPG trace is captured by placing a fingertip on the smartphone's camera. The smartphone application analyses the PPG trace with an artificial intelligence software. Subjects were instructed to perform measurement twice daily and while experiencing symptoms over the course of 7 days. Measurements were classified as AF or non-AF by the algorithm and were reviewed by medical technicians.

Results

Of the 12.602 candidates who completed the questionnaire, 6.020 subjects met the inclusion criteria and were offered screening. However, only 2.111 (35%) participated in the screening program. The mean age of participants was 63±11 years, 37.3% was male, median CHADS-VASC was 2 (2–3). 257 participants (12.2%) were previously known with AF. In total 25.362 PPG recordings of 60 seconds were performed of which 258 demonstrated AF. AF was detected in 56 participants (2.7%). This was a new finding in 36 participants (1.7%) meaning that 64.3% of participants demonstrating AF were not previously known with AF. The number needed to screen was 58.6 to detect AF in a population without a history of AF and the number needed to invite was 167.2. Only 20 participants (7.8%) with a history of AF demonstrated AF during the screening program.

Conclusions

AF screening in subjects with an elevated stroke risk is feasible with an entirely online screening program without the need for medical hardware or medical personnel with an acceptable number needed to screen. However, this approach failed to target subjects in the highest age groups and since almost two thirds of the subjects interested in the screening program failed to commence screening, approaches to increase this response (specifically in high-risk groups) needs to be explored.

Funding Acknowledgement

Type of funding sources: None.

Relationship between mortality after ICD implantation and center volume in Belgium

Introduction

In Belgium ICD implantation is restricted to 23 centers. A previous analysis of our group based on aggregated results per center showed that 3y mortality varied significantly between centers ranging from 7.5 to 23.4%. Multivariate analysis demonstrated that volume, infection rate and a higher proportion of implantations in primary prevention were predictors of 3y-mortality. These findings needed to be confirmed on a patient level since they could be caused by inter-patient rather than inter-hospital differences.

Methods

The QERMID-ICD database is a retrospective database of all patients implanted with an ICD in Belgium managed by the governmental health care institution (RIZIV/INAMI). Participation is mandatory for reimbursement. We analyzed data of 9896 new implantations performed between 2010 and 2016. Following patient characteristics were available: demographics (gender, NYHA class, primary vs secondary prevention, underlying heart disease, type of device, QRS duration, age and ejection fraction (EF)), comorbidities (atrial fibrillation, diabetes, COPD, neurological disease, oncological disease and renal failure), volume of center (low < median of 65 primo-implantations/year vs high >65 implantations/year) and the average income of the arrondissement in which the patient lived (low income < p25, median p25-p75, high > p75). The primary endpoint was 3y-mortality. Chi-squared test and Mann-Whitney U test with correction for multiple testing were used and multivariate logistic regression was performed to determine the corrected odds ratio for 3-year mortality. Finally, Kaplan-Meier survival analysis was performed.

Results

Low volume centers treated different patients than high volume centers. They implant more primary prevention (66.5 vs. 61.6%), more often patients with ischemic cardiomyopathy (49.8 vs 47.9%), less often arrhythmogenic heart disease (13.2 vs 16.6%) and patients with more co-morbidities and from communities with lower average income. High volume centers used more cardiac resynchronization therapy (26.8 vs 22.5%) despite no difference in QRS width. 1 and 3-y mortality were significantly higher in the low volume centers, respectively 5.6 vs. 4.4% and 16 vs. 11.1%. This was also confirmed in Kaplan Meier survival analysis. In multivariate logistic regression underlying heart disease, income, age, EF, NYHA class, CRT, indication and most comorbidities were significantly associated with mortality, but center volume remained an independent risk factor for 3-y mortality (OR = 0.749 (0.702–0.937), p<0.001).

Conclusion

Patients treated in low and high-volume centers in Belgium are different. However, there remained an association between volume and mortality of centers when controlling for these differences. Further research to elucidate if this association is due to statistical limitations of our analysis, referral bias or differences in quality of care is necessary.

Funding Acknowledgement

Type of funding source: None

New approach to improve the calibration of main fatty acids by near-infrared reflectance spectroscopy in ruminant meat

This study aims to investigate alternative near-infrared reflectance spectroscopy (NIRS) strategies for predicting beef polyunsaturated fatty acids (PUFA) composition, which have a great nutritional interest, and are actually poorly predicted by NIRS. We compared the results of NIRS models for predicting fatty acids (FA) of beef meat by using two databases: a beef database including 143 beef samples, and a ruminant database including 76 lamb and 143 beef samples. For all the FA, particularly for PUFA, the coefficient of determination of cross-validation (R2CV) and the residual predictive deviation (RPD) of models increased when the ruminant muscle samples database was used instead of the beef muscle database. The R2CV values for the linoleic acid, total conjugated linoleic acid and total PUFA increased from 0.44, 0.79 and 0.59 to 0.68, 0.9, 0.8, respectively, and RPD values for these FA increased from 1.33, 2.14, 1.54 to 1.76, 3.11 and 2.24, respectively. RPD above 2.5 indicates calibration model is considered as acceptable for analytical purposes. The use of a universal equation for ruminant meats to predict FA composition seems to be an encouraging strategy.

Prospective evaluation of a simplified approach for common atrial flutter radio frequency ablation with only two catheters

Intra-atrial conduction block within the inferior vena cava-tricuspid annulus isthmus (IVCT) has been shown to predict successful common atrial flutter ablation. However, its demonstration requires the use of several electrode catheters and mapping of the line of block. The aim of this study was prospectively to test the feasibility of a simplified ablation procedure using only two catheters.

METHODS

Radio frequency (RF) ablation of common atrial flutter was performed in 30 patients with the sole use of a catheter for atrial pacing and a RF catheter. RF ablation lesions were created in the IVCT. Surface ECG criteria were used to monitor the conduction within the IVCT. The end point during low lateral atrial pacing was an increment in the interval between the pacing artefact and the peak of the R wave in surface lead II >50 ms and clockwise rotation of the P wave axis beyond -30 degrees and inferiorly. Then, the line of lesions was mapped during atrial pacing with the RF catheter. Additional RF lesions were applied if mapping disclosed a zone of residual conduction. Otherwise the procedure was stopped if mapping showed parallel double potentials all along the line. Finally, the block was reassessed with a 'Halo' catheter.

RESULTS

Surface ECG criteria were met in 26 patients. Mapping the line of lesions showed a complete corridor of parallel double potentials in these 26 cases and in 3 of the 4 patients in whom ECG criteria were not met. Conduction evaluated with the Halo catheter showed bi-directional complete block in these 29 patients. After a follow-up of 16 +/- 4 months there was no recurrence of atrial flutter.

CONCLUSION

Surface ECG criteria combined with mapping of the line of block demonstrate evidence of bi-directional IVCT block. This simplified RF ablation of common atrial flutter is feasible with a low recurrence rate.

Existence and characterization of double salts in indium trihalide – potassium halide – water systems at 21 °C (halide = Cl, Br)

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Existence and characterization of double salts in indium trihalide – potassium halide – water systems at 21 °C (halide = Cl, Br)

The degree of hydration of stable hydrates is discussed on the basis of early literature results and our determination of the phase diagrams for the systems InCl3–KCl–H2O and InBr3–KBr–H2O at 21 °C The existing double salts are formulated: 3KCl•InCl3•H2O and 2KCl•InCl3•H2O in the chloride system, and 3KBr•InBr3•1.5H2O, 2KBr•InBr3•H2O, KBr•InBr3•2H2O, and 3KBr•2InBr3 in the bromide system. All of them are incongruently saturating at 21 °C. A summary of their crystallographic and Raman spectroscopic data is given.