Given the high risk of stroke in patients with atrial fibrillation (VHF), current guidelines, such as those of the European Society of Cardiology (ESC), recommend screening for VHF in certain patient groups.[1] ECG is considered the standard method of VHF identification. But simple, low-threshold screening methods outside the clinic and practice can also lead to the goal, emphasized renowned experts at a digital press briefing organized by Bristol Myers Squibb/Pfizer and the Kompetenznetz Vorhofflimmern e.V. (AFNET). And, patients whose VCF was diagnosed early may benefit from early rhythm-maintaining therapy.
Atrial fibrillation (VHF), as the most common sustained cardiac arrhythmia, is associated with a high risk of ischemic stroke and other thromboembolic events.[2] Cardiac arrhythmia increases with age and the risk of developing it is further increased by factors such as hypertension, cardiovascular disease, or diabetes mellitus. VCF is often asymptomatic and episodic and therefore frequently goes undetected. Therefore, in a relevant proportion of stroke patients with VCF, the diagnosis unfortunately occurs only after the event.[3,4] Therefore, early detection of VCF is important so that affected patients can receive adequate stroke prophylaxis in time.
Diagnostic methods for VHF detection are palpation of the pulse and resting ECG; repeated and prolonged ECG recordings may increase the diagnostic rate. The gold standard is considered to be the long-term ECG, which continuously records an ECG for 24 hours or longer. According to the experts, simple opportunistic screening methods such as a thumb ECG or low-threshold pharmacy-based screening programs can also reliably identify VCF.
VHF detection: thumb ECG beats gold standard
The B-SAFE study [5] compared two methods of detecting VCF: the 24-hour Holter ECG versus a thumb ECG triggered twice daily for two weeks by patients themselves and evaluated in a central database. The noninterventional, prospective, multicenter study included 1,500 patients aged > 70 years without known VCF at increased risk who had at least one risk factor in addition to hypertension. “In the context of opportunistic screening, it became clear that the thumb ECG beats the gold standard,” said Ralph Bosch, MD, Cardio Centrum Ludwigsburg, Germany, and regional chairman of the Bundesverband Niedergelassener Kardiologen e. V. (BNK) in Baden-Württemberg. With a detection rate of 4%, the thumb ECG was significantly superior to the Holter ECG at 2.2% (odds ratio: 1.85; p=0.0045). Overall, nearly 78% of newly diagnosed VHF patients received subsequent oral anticoagulation (OAC). In general, the acceptance of the thumb ECG is very high among older patients, who also consider the handling to be technically uncomplicated, explains Dr. Bosch. Thus, the thumb ECG could be a simple yet effective screening method in everyday life.
Low-threshold screening identifies VHF and associated mortality risk.
“Pharmacy-based screening using an ECG wand over the duration of one minute can also easily and quickly identify previously unknown atrial fibrillation and indicate a possible increased risk of mortality or cardiovascular-related hospitalization in the elderly,” explained Matthias Zink, MD, Department of Cardiology, Angiology and Internal Intensive Care Medicine, RWTH Aachen University Hospital. “The willingness of the participating pharmacies for this type of screening was very high and was very positively received by the population due to its ease of use,” added Dr. Zink. These are the findings of the prospective Aachen Pharmacy Study, whose data were collected as part of the “Aachen Against Stroke” campaign.[6] In a total of 7,107 subjects over 65 years of age, heart rhythm was recorded once for 60 seconds with a mobile 1-lead ECG and automatically analyzed. VHF was diagnosed in 6.1% of the participants, and it was a first-time diagnosis for 3.6% of the total group, according to Dr. Zink, who co-led the study with Prof. Nikolaus Marx, MD. Over the follow-up duration of 400 days, 2.3% of patients with detected VCF died compared with 0.8% in the group with normal ECG (hazard ratio [HR]: 2.94; 95% CI: 1.49-5.78; p=0.002). The hospitalization rate due to cardiovascular problems was twice as high in the VHF group as in the comparison group (10.6% vs. 5.5%; HR: 2.08; 95% CI: 1.52-2.84; p<0.001). “The study shows that low-threshold simple screening can identify atrial fibrillation and that previously unidentified individuals have a significantly increased risk of mortality in the following year compared with individuals without atrial fibrillation,” Dr. Zink concluded. “This type of VCF screening can set the stage for timely stroke prevention. The hope is that widespread screening can reduce mortality and lower subsequent costs in the health care system. However, further studies would have to show this.”
Early rhythm-maintaining therapy improves prognosis of VHF patients
Professor Paulus Kirchhof, MD, Director of the Department of Cardiology, University Medical Center Eppendorf (UKE) and Chairman of the Board of the Kompetenznetz Vorhofflimmern e.V. (AFNET) pointed out that despite improved management of the disease, VHF patients remain at high risk for cardiovascular complications. Can early rhythm control reduce this risk of stroke, heart failure, or angina? This question was investigated by the EAST-AFNET trial [7], which included 2,789 patients with early VCF (diagnosed within 1 year before randomization) and cardiovascular problems. When compared with standard treatment of VHF-related symptoms (“usual care”), early rhythm maintenance with antiarrhythmic drugs or catheter ablation (within 36 days of diagnosis) proved superior in most study end points. After a follow-up of five years, the combination of cardiovascular death, stroke, and hospitalization for decompensated heart failure or acute coronary syndrome occurred significantly less frequently under early rhythm control than in the control group (incidence per 100 patient-years: 3.9% vs. 5.0%; HR: 0.79; 95% CI: 0.66-0.94; p=0.005). “This corresponds to a relative risk reduction of 21 percent,” explained study leader Prof. Kirchhof. Differences were also consistently significant (cardiovascular death, stroke) or marked (hospitalization) for the individual components of the primary end point. There was no significant difference between the two groups with regard to the primary safety end point (stroke, death from any cause, serious complications during rhythm-maintaining treatment). The benefit of rhythm-maintaining therapy was found in patients:with heart failure regardless of left ventricular function.[8] A recent subanalysis of the study now showed that asymptomatic patients (800 patients, 30.4% of the total population) also benefited from early rhythm maintenance[9]: The relative risk for the primary study endpoint was reduced by 24% (HR: 0.76; 95% CI: 0.57-1.03; p=0.848). The results of the EAST-AFNET study may help to change the recommendations for action in patients with recently diagnosed VCF and to choose early rhythm control as a new strategy, Prof. Kirchhof summarized.
Sources
[1] Hindricks G and Potpara T et al. Eur Heart J. 2021; 42(5):373-498. doi: 10.1093/eurheartj/ehaa612
[2] Camm AJ et al. Eur Heart J. 2010; 31(19):2369-2429. doi: 10.1093/eurheartj/ehq278
[3] Haeusler KG et al. Int J Stroke. 2012; 7(7):544-550. doi: 10.1111/j.1747-4949.2011.00672.x
[4] Leyden JM et al. Stroke. 2013; 44(5):1226-1231. doi: 10.1161/STROKEAHA.113.675140
[5] Bosch R. Management of thumb-ECG detected subclinical atrial fibrillation in high risk patients – The B-SAFE Study; Late Breaking Clinical Trials I (V433), 87th Annual Meeting of the DGK, April 7, 2021.
[6] Zink MD et al. Europace 2021; 23:29-38. doi: 10.1093/europace/euaa190
[7] Kirchhof P et al. N Engl J Med 2020; 383:1305-1316. doi: 10.1056/NEJMoa2019422
[8] Rillig A, et al. Circulation. 2021;144:845–858.doi: 10.1161/CIRCULATIONAHA.121.056323
[9] Willems S. et al. Eur Heart J. 2021; 00:1-12. doi: 10.1093/eurheartj/ehab593
