deCODE AF™

A DNA-based test enabling stroke prevention through more effective screening for atrial fibrillation. Targets outpatient Holter monitoring towards those stroke patients most likely to have intermittent AF. Treating AF patients with warfarin reduces their risk of stroke by 70%.

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Screening and prevention

How deCODE AF™ can help.

Diagnosing a larger proportion of AF

Between 15 and 20 percent of all strokes are cardiogenic, the subtype with the highest morbidity and mortality. Atrial fibrillation is the leading cause of cardiogenic stroke, but because it is often intermittent it is under diagnosed and undertreated in those who receive only in-patient cardiac monitoring following a stroke.

Targeted screening

Monitoring all ischemic stroke patients in an ambulatory setting may be considered impractical or too expensive. deCODE AF™ addresses this problem by identifying those stroke patients who are more likely to have AF. These patients may therefore benefit most from outpatient cardiac monitoring.

Better prevention

Two studies have shown that an extra week of ambulatory cardiac monitoring using an automated digital event recorder following a stroke may identify AF in another 5.6-14.3% of stroke survivors. For those in whom AF is detected, treatment with warfarin can reduce the risk of a secondary AF-related stroke by 70%.

deCODE AF™ is based on scientifically validated results from studies of tens of thousands of patients and controls.

The association of the deCODE AF™ markers with the risk of developing atrial fibrillation has in the case of those of European descent been repeatedly confirmed in multiple cohorts including more than 20,000 patients and many more thousands of controls(3-13). Studies in people of East Asian origin have confirmed highly significant association of the 4q25 markers with risk of AF. This includes a study of 333 AF patients and 2836 controls and further supportive evidence from two additional studies(4,7,11).

The initial discovery of genetic risk markers for atrial fibrillation was made by deCODE scientists in 2007. (Nature 2007: Variants conferring risk of atrial fibrillation on chromosome 4q25)(4). To identify genetic variants conferring risk of AF in the general population, deCODE conducted a genome-wide analysis of more than 300,000 SNPs across the entire genome in a cohort of a total of 5,000 Icelandic AF patients and healthy controls. Alleles (or versions) of two SNPs, rs2200733 and rs100233464, both located near the PITX2 gene on chromosome 4q25, were found to be significantly more common in AF patients than in control subjects. The PITX2 gene is known to play a role in cardiac development. These findings were then validated in studies of a total of more than 18,000 patients with all forms of AF and controls, including cohorts from Iceland, Sweden, the Massachusetts General Hospital in Boston, and, for the strongest of the variants, a cohort of Han Chinese from Hong Kong. The deCODE AF™ test measures the at-risk versions of these two SNPs. deCODE’s findings have subsequently been confirmed by several groups in additional cohorts in addition to the discovery of additional risk markers that are also included in the deCODE AF™ test(3,5-13).

Two studies have shown that an extra week of ambulatory cardiac monitoring using an automated digital event recorder following a stroke may identify AF in another 5.6 to 14.3% of stroke survivors(14,15). These include many who would originally be given the diagnosis of stroke of unknown etiology as well as carotid atherosclerosis-related stroke. Monitoring all ischemic stroke patients in an ambulatory setting is often considered too expensive. Roughly one-third of post-stroke and post-TIA patients are at high risk for atrial fibrillation, especially when the etiology is not clear. deCODE AF™ may identify patients who have intermittent AF and who are thus at high risk of recurrent stroke. It has been shown that treatment with warfarin can reduce the risk of stroke in those with AF by about 70%.(1). Warfarin treatment of these cases may decrease the future costs of morbidity and mortality that more than outweighs the extra cost of testing and monitoring.

This content was last reviewed on March 16, 2011.