Atrial fibrillation in sub-Saharan Africa: The knowns and unknowns?

Atrial Fibrillation in Heart Failure: Epidemiology, Quality of Life and Clinical Characteristics in the Iron Deficiency and ANaemia in Heart Failure (IDAN-HF) Study in Ogbomoso, Nigeria

Background

The cluster of atrial fibrillation (AF) with heart failure (HF) may be associated with a poorer prognosis. Its epidemiology and impact on clinical outcomes and quality of life among HF subjects in Africa have not yet been fully described. This study aimed at describing the epidemiology of AF among HF subjects, its impact on quality of life, clinical characteristics, and associations.

Methods

140 HF subjects were recruited by stratified random sampling method, and 12-lead electrocardiography was done to diagnose AF. Statistical analysis was done with SPSS 21.0. Informed consent was obtained from all participants.

Results

The frequency occurrence of AF was 28 (20.0%) of the HF subjects and were similar in age, systolic blood pressure, diastolic blood pressure, right ventricular internal dimension, packed cell volume, and gender distribution with those in sinus rhythm. The mean (S.D) six minutes walk test distance was significantly lower among HF subjects with AF compared to those without AF (171.1± 88.9 vs. 225.8 ± 102.1m respectively, p <0.05). Pulmonary hypertension, intracardiac clots, and kidney dysfunction were more frequent among HF subjects with AF than among those without AF. HF subjects with AF had a higher frequency of clusters of comorbidities than those without AF. AF was most prevalent and left atrial dimension was highest among subjects who had HF with reduced ejection fraction, compared to other HF phenotypes.

Conclusion

AF is common in HF among Nigerians and is associated with poor quality of life and poorer functional status compared to those with sinus rhythm.

Performance of a Mobile Single-Lead Electrocardiogram Technology for Atrial Fibrillation Screening in a Semirural African Population: Insights From "The Heart of Ethiopia: Focus on Atrial Fibrillation" (TEFF-AF) Study

Background

Atrial fibrillation (AF) screening using mobile single-lead electrocardiogram (ECG) devices has demonstrated variable sensitivity and specificity. However, limited data exists on the use of such devices in low-resource countries.

Objective

The goal of the research was to evaluate the utility of the KardiaMobile device’s (AliveCor Inc) automated algorithm for AF screening in a semirural Ethiopian population.

Methods

Analysis was performed on 30-second single-lead ECG tracings obtained using the KardiaMobile device from 1500 TEFF-AF (The Heart of Ethiopia: Focus on Atrial Fibrillation) study participants. We evaluated the performance of the KardiaMobile automated algorithm against cardiologists’ interpretations of 30-second single-lead ECG for AF screening.

Results

A total of 1709 single-lead ECG tracings (including repeat tracing on 209 occasions) were analyzed from 1500 Ethiopians (63.53% [953/1500] male, mean age 35 [SD 13] years) who presented for AF screening. Initial successful rhythm decision (normal or possible AF) with one single-lead ECG tracing was lower with the KardiaMobile automated algorithm versus manual verification by cardiologists (1176/1500, 78.40%, vs 1455/1500, 97.00%; P<.001). Repeat single-lead ECG tracings in 209 individuals improved overall rhythm decision, but the KardiaMobile automated algorithm remained inferior (1301/1500, 86.73%, vs 1479/1500, 98.60%; P<.001). The key reasons underlying unsuccessful KardiaMobile automated rhythm determination include poor quality/noisy tracings (214/408, 52.45%), frequent ectopy (22/408, 5.39%), and tachycardia (>100 bpm; 167/408, 40.93%). The sensitivity and specificity of rhythm decision using KardiaMobile automated algorithm were 80.27% (1168/1455) and 82.22% (37/45), respectively.

Conclusions

The performance of the KardiaMobile automated algorithm was suboptimal when used for AF screening. However, the KardiaMobile single-lead ECG device remains an excellent AF screening tool with appropriate clinician input and repeat tracing.

Trial Registration

Australian New Zealand Clinical Trials Registry ACTRN12619001107112; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378057&isReview=true