Development and validation of a questionnaire to assess knowledge in patients with Atrial Fibrillation

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Centre for Heart Rhythm Disorders

Background

Education is critical to empower individuals to self-monitor and manage their condition. Significant variability exists in the provision of education for atrial fibrillation (AF), whilst individual patient factors including health literacy and education level attainment may impact on knowledge levels. Objective assessment of knowledge  may help to target education to areas of need, and result in improved patient outcomes.

Objective

To describe the development and validation of a knowledge questionnaire for AF.

Methods

A multidisciplinary expert team of healthcare professionals developed the questionnaire, in conjunction with consumers, with question content based upon areas deemed most critical to AF and related self-management. The multiple choice questionnaire consists of 20 items, each worth 5 points, to give a total score out of 100. The questionnaire assesses five domains specific to AF: general knowledge, complications, medications, risk factors and action. The questionnaire was developed in English. The questionnaire was tested on 10 randomly selected patients with AF for face validity and 19 healthcare professionals for content validity. The final version was completed by 454 individuals with AF. Exploratory factor analysis was used to determine construct validity with factor loadings of 0.40 and above considered acceptable. Reliability was assessed using Cronbach’s alpha, with a value greater than 0.7 acceptable.

Results

Face and content validity were considered acceptable, after minor changes to wording. The cohort of 454 individuals with AF had a mean age of 66.9 ± 12 years and 43% were female. Mean (SD) total score was 57.7 ± 15.8. Exploratory factor analysis was undertaken using the principal components method. This resulted in a Kaiser–Meyer–Olkin Measure of Sampling Adequacy of .64 and a Bartlett"s Test of Sphericity being significant at 0.00. Seven factors were selected and analysed using principal component analysis with varimax rotation. All items loaded on one of the seven factors. Internal consistency demonstrated a Cronbach’s alpha of 0.65.

Conclusion

The Atrial Fibrillation Knowledge Questionnaire is a valid measure to assess knowledge in individuals with AF.

Incidence of new-onset atrial fibrillation after cavotricuspid isthmus ablation for isolated typical atrial flutter: a systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

There is a lack of consensus guidelines regarding the continuation of anticoagulant therapy following cavotricuspid isthmus (CTI) ablation for typical atrial flutter.  This is despite a significant number of patients developing new-onset atrial fibrillation (AF) following the procedure.  Furthermore, a summary of Kaplan-Meier estimates for drug-free, arrhythmia-free survival has never been reported.

Purpose

 To estimate the incidence of drug-free, new-onset AF stratified by rhythm monitoring strategy in patients undergoing  CTI ablation for isolated typical atrial flutter.

Methods

PubMed, Embase and MEDLINE databases were searched to identify relevant studies. Only studies where anti-arrhythmic drugs were discontinued post-ablation and that accounted for patient censoring by reporting results in the form of time to event data were included.  Data was extracted from published Kaplan-Meier curves using a digitizing software and confidence intervals for the survivor function were estimated based on the number at risk at the time point of interest. Results were pooled in a random effects model using the DerSimonian-Laird estimator.

Results

 Thirteen relevant studies incorporating 1712 patients (79 % male, mean age 63.2 +/-11.2 years,  LVEF 55.2 +/-10.8%) were identified. The estimated  freedom from  new-onset atrial fibrillation was 89.7% (95% CI: 80.3-90.1%) at 1 year and 86.2% (95% CI: 78.4-94.0%) at 2 years in patients undergoing predominantly symptom –based monitoring, 74.6% (95%CI: 67.0-82.3%) at 1 year and 69.5% (95%CI: 63.5-75.6%) at 2 years  in patients undergoing regular clinic follow-up with periodic Holter monitoring and 51.4% (95% CI: 41.8-61.0%) at 1 year and 22.7% (95% CI: 8.7% - 36.6%) at 2 years in patients with implantable loop recorders.

Conclusion

 With the advent of implantable loop recorders, it is apparent that most patients with isolated atrial flutter manifest new-onset AF following CTI ablation and the merits of discontinuing anticoagulation must be carefully considered in this population.  Symptom-based monitoring likely severely underestimates the incidence of new-onset AF and may lead to adverse outcomes, particularly in patients with a high risk of stroke.

Preweaning to postweaning rumen papillae structural growth, ruminal fermentation characteristics, and acute-phase proteins in calves

This study evaluated pre- to postweaning ruminal structural development, fermentation characteristics, and acute-phase protein levels in calves with a high milk replacer (MR) feeding rate prior to weaning. Six ruminally cannulated Holstein bull calves were fed MR (150 g/L) at 15% of body weight (BW) in 2 equal volumes daily. Volumes were adjusted weekly based on BW. Calves were weaned using a 1-step weaning method, with MR decreased by 50% at the end of wk 5 and full weaning at the end of wk 6. Calf starter, chopped straw, and water were offered ad libitum. Intake was recorded daily, and BW was recorded weekly. From wk 5 to 12, ruminal pH was continuously measured using a ruminal pH bolus. Ruminal fluid was collected weekly from wk 5 to 12 for measurement of short-chain fatty acid concentrations and quantification of total bacteria and protozoa. Rumen papillae were obtained at wk 5, 6, 7, 8, and 12 for histological analysis. Serum amyloid A and lipopolysaccharide-binding protein were measured weekly. Data were analyzed using GLIMMIX procedure of SAS (SAS Institute Inc., Cary, NC), with week as a fixed effect and calf as a random effect. During the weaning step-down, starter intake was 3-fold higher and continued to increase until wk 12. Body weight increased from birth to wk 12; however, BW did not change during wk 6, 7, and 8, possibly due to low metabolizable energy intake caused by the weaning strategy. Preweaning ruminal pH was below 5.8 for approximately 936.3 ± 125.99 min/d, implying ruminal acidosis. Furthermore, ruminal pH below 5.8 reached a peak at wk 8 with 1,203.9 ± 227.65 min/d below pH 5.8 and slowly decreased to 388.1 ± 189.82 min/d below pH 5.8 at wk 12. Papillae surface area, length, and width increased during wk 12 compared with wk 5. Corneum thickness increased by week, whereas spinosum/basale thickness only increased during wk 8 compared with wk 5. The acute-phase protein concentration was highest at wk 1 and then decreased and remained constant until wk 12. In conclusion, even before step-down weaning, calves experienced ruminal acidosis despite low starter intake. Further, the observed prolonged ruminal pH depression suggests that dietary rumen adaptation after weaning can take several weeks in calves with a high MR feeding rate preweaning. The prolonged depressed ruminal pH did not affect acute-phase proteins and this finding, along with the other results, suggests that rumen epithelium barrier integrity is not compromised during weaning.

P3794MOODS: a novel risk score to identify patients with atrial fibrillation and sleep apnoea

Background

Sleep-disordered breathing (SDB) is an important risk factor for developing atrial fibrillation (AF), and treatment of concomitant SDB can improve AF rhythm outcomes. Diagnosis of SDB requires sleep studies which can pose a significant time and resource burden. We sought to develop a prediction score based on clinical characteristics that can help identify AF patients who require further assessment for SDB.

Methods

Prospectively-collected data for 442 consecutive patients treated for AF from 2009 to 2017 were analysed. All patients were considered candidates for rhythm-control and therefore referred for sleep studies. The diagnosis of SDB was confirmed using in-lab polysomnography and classified using the apnoea-hypopnoea-index (AHI), with cut-offs of ≥15/hr and ≥30/hr indicating moderate-to-severe and severe SDB respectively. Patients treated up to 2015 formed the derivation cohort (n=311) and the remainder (n=113) formed the validation cohort. Multivariate logistic regression analysis was used to identify clinical variables predictive of moderate-to-severe SDB. A risk score model was developed based on regression coefficients and tested using receiver-operating-characteristics analyses on the validation cohort.

Results

Overall, mean age was 60±11 years, mean body mass index (BMI) was 30±5 kg/m2 and 69% were men. The prevalence of moderate-to-severe SDB was 33.7%. There were no significant differences in baseline characteristics between the derivation and validation cohorts. Male gender (score=1), overweight (BMI: 25–29 kg/m2, score=2), obesity (BMI≥30 kg/m2, score=3), diabetes (score=1), and stroke (score=2) were significantly independently predictive of moderate-to-severe SDB and formulated the score. The score performed well to predict moderate-to-severe SDB with a C-statistic of 0.73 (95% CI: 0.67–0.79, P<0.001) in the derivation cohort, and 0.67 (95% CI: 0.57–0.77, P<0.001) in the validation cohort. As a rule-out test, a score of ≤3 had a negative predictive value of 77% for moderate-to-severe SDB (91% for severe SDB). A score of ≥4 had an intermediate positive likelihood ratio (PLR) of 2 for moderate-to-severe SDB (2.2 for severe SDB), while a score of ≥5 had a high PLR of 6.5 and 6.8 for moderate-to-severe SDB and severe SDB respectively.

Sensitivity and specificity table

Conclusion

A novel risk score comprising clinical characteristics can identify patients with AF likely to benefit from further assessment for SDB. Application of this model may aid optimise resource utilisation and facilitate timely patient care.

P661Nocturnal hypoxemic burden in ambulatory patients with atrial fibrillation: a disease-orientated assessment of sleep-disordered breathing severity

Background

Studies investigating the relationship between sleep-disordered breathing (SDB) and atrial fibrillation (AF) have largely assessed SDB-severity by the apnea–hypopnea index (AHI). However, the AHI does not incorporate nocturnal hypoxemic burden, which may increase the risk of non-paroxysmal AF (nPAF) as the clinical manifestation of more progressed AF substrates. This investigation sought to systematically characterize and compare the composition of AHI and hypoxemic burden with the aim to defining a disease-orientated metric for SDB-severity best associated with prevalent nPAF.

Methods

Polysomnography including overnight oximetry data were obtained in 435 consecutive ambulatory AF patients to determine the composition of AHI (apneas vs. hypopneas), the number of acute episodic desaturations per hour (oxygen desaturation index, ODI) and the composition of total time spent below 90% oxygen saturation (T90Total) attributed to acute desaturations (T90Desaturation). Logistic regression analysis was used to characterize the association with prevalent nPAF.

Results

One hundred sixty-nine AF patients (38%) had nPAF and one third (n=149, 34%) had moderate-to-severe SDB (AHI>15). 82% of the median total AHI (9.4 [3.6–20.1]) could be attributed to hypopneas. Only 29% of events were associated with episodic desaturations, which contributed to 96% (T90Desaturation) of the variation in T90Total. The high variability in durations and nadirs of distinct desaturation events can expose patients to long T90Total, even if the AHI is low. Not AHI, but T90Total and ODI were associated with nPAF independent of gender and age. However, diabetes, hypertension and body mass index contributed more significantly to the overall risk of nPAF.

Conclusions

In AF patients, hypopneas constitute a majority of respiratory events during sleep. Patients with low AHI can still be exposed to high nocturnal hypoxemic burden, which is mainly a cumulative consequence of episodic desaturations. T90Total and ODI, but not AHI, were associated with nPAF independent of gender and age, but concomitant modifiable risk factors made a more significant contribution to the overall risk of nPAF versus PAF.