Available online 9 January 2024, 108106

Author links open overlay panel, , , , , , , , , , ABSTRACTBackground

Atrial fibrillation (AF) is an established risk factor for acute ischemic stroke (AIS). It remains unclear if new-onset AF confers a higher risk of AIS than longer-standing AF.

Methods

We retrospectively analyzed all stroke-free patients who underwent transthoracic echocardiography (TTE) in the Henry Ford Health System between March 6 and September 6, 2016. Incident AIS and new-onset AF were ascertained by the presence of new diagnostic codes in the electronic medical record over a follow-up period of up to 5 years. Cox proportional hazards regression was used to identify risk factors for new-onset AF or AIS.

Results

Of 7,310 patients who underwent baseline TTE the mean age was 65 years, 54% were female, 51% were Caucasian, and 46% had left atrial enlargement (LAE). Of at-risk patients, 10.9% developed new-onset AF and 2.9% experienced incident AIS. The risk of new-onset AF among at-risk patients was 3.1 times higher among patients with any degree of LAE compared to those with normal LA size (95% CI 2.6-3.6, P<0.0001). New-onset AF, more than established AF, in turn had a powerful association with incident AIS. The cumulative 5-year risk of AIS was 3.5% in those without AF, 5.9% in those with established AF prior to TTE, and 20.1% in those with new-onset AF (P<0.0001). In multivariable analysis new-onset AF had the strongest association with incident AIS (P<0.0001), followed by increasing age (P=0.0025), black race (P=0.0032), and smoking (P=0.0063).

Conclusions

New-onset AF has a strong relationship with incident AIS. LAE was present in nearly half of stroke-free patients undergoing TTE, and was associated with a significantly higher likelihood of new-onset AF during follow-up. Vigilant cardiac monitoring for AF in individuals with LAE, coupled with the timely initiation of anticoagulation, may be an important strategy for the primary prevention of AF-related stroke.

Section snippetsINTRODUCTION

Atrial fibrillation (AF) is the most common clinically significant arrhythmia in adults, occurring in more than 10% of people above the age of 80. [1], [2] AF increases the risk of acute ischemic stroke (AIS) by 5-fold and is directly responsible for almost 15% of all strokes. [3], [4] Anticoagulation is highly effective for reducing the risk of embolic stroke in patients with AF. [5] For this reason AF is routinely ruled out in patients presenting with AIS. [5] Outside of AIS, there are few

Study Setting and Population

This is a retrospective analysis of a prospectively-collected cohort that has been previously published. [13] All patients who underwent transthoracic echocardiography (TTE) within the Henry Ford Health System (HFHS) between March 6th and September 6th, 2016 were included, regardless of the indication for testing setting (i.e. inpatient versus outpatient). A standard list of indication for ordering TTE in our EMR is shown in Supplemental Table S1. HFHS is composed of five acute care hospitals,

Baseline Variables

Of 7,310 patients meeting the inclusion criteria (Fig. 1), mean age was 65 ± 17 years, 3,966 (54%) were female, 3,498 (51%) were white, and 2,911 (43%) were black. On baseline TTE 3,964 (54%) had a normal left atrium (LA), 907 (12%) had mild LAE, 959 (13%) had moderate LAE, and 1,480 (20%) had severe LAE (Table 1). Patients with any degree of LAE were significantly older and more often female, white, hypertensive, diabetic, and had a history of peripheral vascular disease (Table 1). Severity of

DISCUSSION

The global burden of AIS is expected to increase dramatically in the coming years. An estimated 77 million patients will be diagnosed with stroke by 2030. [15] It is therefore of utmost importance to identify high risk patients through the use of predictive factor analysis, in order to mitigate the negative effects of this disabling disease. [16]

AF is the most commonly encountered cardiac arrhythmia and carries a significant risk for stroke development. [1] Chronic hypertension and CHF increase

Sources of Funding

None

Disclosures

None

CRediT authorship contribution statement

Aboul-Nour Hassan: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Mayer Stephan A.: Conceptualization, Investigation, Supervision, Validation, Visualization, Writing – original draft, Writing – review & editing. Gagi Karam: Data curation, Writing – original draft, Writing – review & editing. Affan Muhammad: Conceptualization, Data

Declaration of Competing Interest

Authors have no conflicts of interest to report.

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