Subclinical Atrial Fibrillation in Older Patients

Jeff S Healey; Marco Alings; Andrew Ha; Peter Leong-Sit; David H Birnie; Jacob J de Graaf; Michel Freericks; Atul Verma; Jia Wang; Darryl Leong; Hisham Dokainish; Francois Philippon; Walid Barake; William F McIntyre; Kim Simek; Michael D Hill; Shamir R Mehta; Mark Carlson; Frank Smeele; A Shekhar Pandey; Stuart J Connolly; ASSERT-II Investigators

doi:10.1161/CIRCULATIONAHA.117.028845

Subclinical Atrial Fibrillation in Older Patients

Circulation. 2017 Oct 3;136(14):1276-1283. doi: 10.1161/CIRCULATIONAHA.117.028845. Epub 2017 Aug 4.

Authors

Jeff S Healey¹, Marco Alings², Andrew Ha², Peter Leong-Sit², David H Birnie², Jacob J de Graaf², Michel Freericks², Atul Verma², Jia Wang², Darryl Leong², Hisham Dokainish², Francois Philippon², Walid Barake², William F McIntyre², Kim Simek², Michael D Hill², Shamir R Mehta², Mark Carlson², Frank Smeele², A Shekhar Pandey², Stuart J Connolly²; ASSERT-II Investigators

Affiliations

¹ From Population Health Research Institute, Hamilton, ON, Canada (J.S.H., J.W., D.L., H.D., K.S., S.R.M., S.J.C.); McMaster University, Hamilton, ON, Canada (J.S.H., J.W., D.L., H.D., W.F.M., S.R.M., A.S.P., S.J.C.); Amphia Ziekenhuis, Breda, the Netherlands (M.A.); WCN-Dutch Network for Cardiovascular Research (M.A.); University of Toronto, ON, Canada (A.H., A.V.); University of Western Ontario, London, Canada (P.L.-S.); University of Ottawa Heart Institute, ON, Canada (D.H.B.); Nij Smellinghe Hospital, Drachten, the Netherlands (J.J.d.G.); Ikazia Ziekenhuis, Rotterdam, the Netherlands (M.F.); Institut Universitaire de Cardiologie et de Pneumologie de Québec, QC, Canada (F.P.); University of Alberta, Edmonton, Canada (W.B.); University of Calgary, AB, Canada (M.D.H.); St. Jude Medical, Sylmar, CA (M.C.); Slingeland Ziekenhuis, Doetinchem, the Netherlands (F.S.); and Cambridge Cardiac Care Centre, ON, Canada (A.S.P.). [email protected].
² From Population Health Research Institute, Hamilton, ON, Canada (J.S.H., J.W., D.L., H.D., K.S., S.R.M., S.J.C.); McMaster University, Hamilton, ON, Canada (J.S.H., J.W., D.L., H.D., W.F.M., S.R.M., A.S.P., S.J.C.); Amphia Ziekenhuis, Breda, the Netherlands (M.A.); WCN-Dutch Network for Cardiovascular Research (M.A.); University of Toronto, ON, Canada (A.H., A.V.); University of Western Ontario, London, Canada (P.L.-S.); University of Ottawa Heart Institute, ON, Canada (D.H.B.); Nij Smellinghe Hospital, Drachten, the Netherlands (J.J.d.G.); Ikazia Ziekenhuis, Rotterdam, the Netherlands (M.F.); Institut Universitaire de Cardiologie et de Pneumologie de Québec, QC, Canada (F.P.); University of Alberta, Edmonton, Canada (W.B.); University of Calgary, AB, Canada (M.D.H.); St. Jude Medical, Sylmar, CA (M.C.); Slingeland Ziekenhuis, Doetinchem, the Netherlands (F.S.); and Cambridge Cardiac Care Centre, ON, Canada (A.S.P.).

PMID: 28778946
DOI: 10.1161/CIRCULATIONAHA.117.028845

Abstract

Background: Long-term continuous electrocardiographic monitoring shows a substantial prevalence of asymptomatic, subclinical atrial fibrillation (SCAF) in patients with pacemakers and patients with cryptogenic stroke. Whether SCAF is also common in other patients without these conditions is unknown.

Methods: We implanted subcutaneous electrocardiographic monitors (St. Jude CONFIRM-AF) in patients ≥65 years of age attending cardiovascular or neurology outpatient clinics if they had no history of atrial fibrillation but had any of the following: CHA₂DS₂-VASc score of ≥2, sleep apnea, or body mass index >30 kg/m². Eligibility also required either left atrial enlargement (≥4.4 cm or volume ≥58 mL) or increased (≥290 pg/mL) serum NT-proBNP (N-terminal pro-B-type natriuretic peptide). Patients were monitored for SCAF lasting ≥5 minutes.

Results: Two hundred fifty-six patients were followed up for 16.3±3.8 months. Baseline age was 74±6 years; mean CHA₂DS₂-VASc score was 4.1±1.4; left atrial diameter averaged 4.7±0.8 cm; and 48% had a prior stroke, transient ischemic attack, or systemic embolism. SCAF ≥5 minutes was detected in 90 patients (detection rate, 34.4%/y; 95% confidence interval [CI], 27.7-42.3). Baseline predictors of SCAF were increased age (hazard ratio [HR] per decade, 1.55; 95% CI, 1.11-2.15), left atrial dimension (HR per centimeter diameter, 1.43; 95% CI, 1.09-1.86), and blood pressure (HR per 10 mm Hg, 0.87; 95% CI, 0.78-0.98), but not prior stroke. The rate of occurrence of SCAF in those with a history of stroke, systemic embolism, or transient ischemic attack was 39.4%/y versus 30.3%/y without (P=0.32). The cumulative SCAF detection rate was higher (51.9%/y) in those with left atrial volume above the median value of 73.5 mL.

Conclusions: SCAF is frequently detected by continuous electrocardiographic monitoring in older patients without a history of atrial fibrillation who are attending outpatient cardiology and neurology clinics. Its clinical significance is unclear.

Clinical trial registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01694394.

Keywords: atrial fibrillation; monitoring, physiologic; stroke.

MeSH terms

Aged
Aged, 80 and over
Atrial Fibrillation / epidemiology*
Cardiovascular Diseases / epidemiology*
Female
Humans
Male
Risk Factors

Associated data

ClinicalTrials.gov/NCT01694394