Repeated Early Holter ECG Spots AF Sooner After Stroke

Marlene Busko

October 24, 2018

MONTREAL — In patients who have had a stroke, more extensive and frequent Holter electrocardiogram (ECG) monitoring may detect by 6 months atrial fibrillation (AF) that would otherwise only be detected within 3 years with standard care, new research suggests.

Rolf Wachter, MD, from the University Hospital Leipzig, Germany, presented these results, which are from a secondary analysis of the Finding Atrial Fibrillation in Stroke – Evaluation of Enhanced and Prolonged Holter Monitoring (FIND-AF) trial, here at the 11th World Stroke Congress (WSC) 2018.

The primary findings, which were published last year, showed that at 6 months, AF was detected in significantly more patients who received the enhanced and prolonged Holter monitoring than patients who received standard care (14% vs 5%, P = .002).

Now the extended follow-up shows that whereas AF was detected early with the intervention, "in the end, the control arm nearly caught up with the intervention arm" at 3 years, Wachter told Medscape Medical News.

Expressed differently, this study shows that with extensive early Holter ECG monitoring, "we find AF in 3 months similar to what we usually find in 3 years" with standard care, and these patients receive anticoagulation, he noted.

However, it's unclear whether earlier detection of AF or earlier anticoagulation therapy translates into a lower risk for stroke or transient ischemic attack (TIA) or mortality during follow-up, he conceded, because the trial was not powered to detect hard clinical endpoints.

Nevertheless, there was a trend toward a lower rate of strokes, TIA, and death during follow-up with the intervention.

An adequately powered trial to investigate hard outcomes is needed, Wachter concluded.

In the meantime, he said, the current findings imply that "it's worth it to look for AF in all patients who are older than 60 years of age and have a stroke, irrespective of stroke etiology."

Session comoderator Robert Hart, MD, codirector of the McMaster/Hamilton Health Sciences Stroke Fellowship Program and a senior scientist at the Population Health Research Institute, told Medscape Medical News that key questions remain unanswered.

"I think an important question that remains is, What duration of intermittent Afib confers a higher stroke risk?"

Also, "we know in older people, if we monitor long enough, we find brief episodes of Afib in a third," he added. "So the next question is, How much Afib warrants anticoagulation?"

Hart says this study "makes it more urgent" to conduct the research to answer these questions.

Better AF Detection, Faster NOAC Therapy, Fewer Strokes?

"AF is a common risk factor for stroke and recurrent stroke," Wachter noted, "but paroxysmal AF often escapes the routine diagnostic workup."

Two previous randomized trials, EMBRACE and CRYSTAL-AF, established that prolonged monitoring detects more cases of AF than standard care or repetitive ECG — but the patients all had cryptogenic stroke and were followed to 90 days or generally less than 24 months in the two respective trials.

The Find-AF trial randomly assigned patients who had diverse types of stroke and followed them longer.

The investigators assigned 398 patients aged 60 years and older who had had strokes of different causes to receive the intervention (10-day Holter ECG monitoring at baseline, 3 months, and 6 months) or standard care (at least 24 hours of Holter ECG monitoring) at four centers in Germany.

At baseline, the mean age of the patients was 72 years, and 42% were women.

For half of the patients, the cause of the stroke was undetermined; 30% had small vessel occlusion, and 20% had cardioembolism.

At 6 months, patients who had experienced a cryptogenic or noncryptogenic stroke "benefited similarly from the intervention," Wachter said.

The extended secondary analysis revealed that over time, the rate of detection of AF increased in the standard-care group but not in the intervention group.

At 36 months, there was a similar number of cases of AF in both groups: 30 in the intervention group and 22 in the control group. The difference was not significant (P = .26).

Of the 30 cases of AF in the intervention group, 25 cases (83%) were discovered in the 6-month intervention.

The researchers plan to conduct a new study of more than 5000 patients at 50 stroke units in Germany to see whether recurrent strokes may be avoided by prolonged and extended Holter ECG monitoring after a first stroke.

FIND-AF was supported by an unrestricted grant from Boehringer Ingelheim. Dr Wachter receives research grants from Boehringer Ingelheim and is on the speaker's bureau for Bayer, Boehringer Ingelheim, BMS/Pfizer, and Daiichi.

11th World Stroke Congress (WSC) 2018. Presented October 18, 2018.

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