Undiagnosed AF, Subclinical Strokes May Be Common in Preserved-EF Heart Failure: ARIC

September 30, 2015

NATIONAL HARBOR, MD — Many patients with heart failure and preserved ejection fraction (HFpEF) have unrecognized atrial fibrillation (AF) that is associated with small, subclinical cerebral infarcts leading to cognitive dysfunction, propose researchers based on their analysis of participants in the long-running Atherosclerosis Risk in the Community (ARIC) cohort study[1]. It may therefore be wise to screen patients with HFpEF for paroxysmal AF that would be missed by standard ECG at periodic clinic visits, they conclude.

Speaking with heartwire from Medscape, lead author Dr Rebecca J Cogswell (University of Minnesota, Minneapolis) said that in addition to current efforts to put everyone with AF on oral anticoagulant therapy to prevent large, clinically disastrous strokes, "maybe we [also] need to be thinking about preventing smaller subclinical infarcts, which we know cause cognitive decline."

Cogswell presented the ARIC analysis, based on 1527 participants, in poster form here at the Heart Failure Society of America 2015 Scientific Meeting.

She pointed to data from ARIC and other sources suggesting that subclinical cerebral infarcts can develop long before AF is detected. In the current analysis, ARIC participants were broken out into four groups: whether they had HFpEF or no heart failure and AF or no recognized AF. Unsurprisingly, those without heart failure or known AF had the lowest rate of subclinical cerebral infarcts by MRI, about 17%.

The two groups with AF, one with HFpEF and one without heart failure of any kind, had an intermediate prevalence of such infarcts. And those with HFpEF but no AF diagnosis had the highest prevalence, about 29%, which was independently and significantly increased compared with the lowest rate.

"It's not to say that patients with HFpEF can't have some other reason [than AF] to have subclinical infarcts—for example, they may have carotid disease—but it's very suggestive that there's atrial fibrillation that we've missed," Cogswell said.

Subclinical Infarct Prevalence and Adjusted* Odds Ratio (95% CI) by HFpEF and AF Status in ARIC

Parameter No HF, no known AF (n=1273) No HF, AF diagnosis (n=53) HFpEF, no known AF (n=167) HFpEF, AF diagnosis (n=34)
Subclinical infarcts by MRI (%) 17.3 24.5 29.3 23.5
OR (95% CI) 1.00 1.24 (0.64–2.40) 1.60 (1.08–2.36) 1.06 (0.46–2.46)
*Adjustments include age, race, sex, body-mass index, hypertension, diabetes, coronary artery disease, warfarin use, and enrolling center

Scores on a range of validated cognitive function tests were reduced in both heart-failure groups that had subclinical infarcts, compared with both heart-failure groups without such infarcts. Cognitive deficits tracked with the infarcts and with AF, but not with whether there was HFpEF or no heart failure, pointing to the thrombogenic AF as the source of the deficits, not heart failure per se, according to the group.

Standard tests of cognitive abilities used in the study included Delayed Word Recall (DWR), the Mini-Mental State Examination (MMSE), Trail-Making Tests (TMT) A and B, the Decision Support System (DSS), Word Fluency, and the Language Modalities Test A.

Cogswell had no relevant financial relationships.

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