{"id":1280,"date":"2017-04-19T12:03:13","date_gmt":"2017-04-19T12:03:13","guid":{"rendered":"http:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/?p=1280"},"modified":"2017-08-21T10:17:07","modified_gmt":"2017-08-21T10:17:07","slug":"primary-care-corner-with-geoffrey-modest-md-the-elusive-search-for-afib-in-stroke-patients-and-an-app","status":"publish","type":"post","link":"http:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/2017\/04\/19\/primary-care-corner-with-geoffrey-modest-md-the-elusive-search-for-afib-in-stroke-patients-and-an-app\/","title":{"rendered":"Primary Care Corner with Geoffrey Modest MD: The elusive search for afib in stroke patients; and an app"},"content":{"rendered":"
\u200b\u200b\u200b\u200bby Dr Geoffrey Modest<\/span><\/strong><\/div>\n
\n

Atrial fibrillation is an important risk factor for current ischemic strokes, but may be hard to diagnose in\u00a0those presenting in\u00a0sinus rhythm. A reasonably large German study found that prolonged\u00a0Holter\u00a0monitoring picked up many more cases of atrial fibrillation than standard monitoring, the Find-AFRANDOMISED<\/sub>\u00a0trial\u00a0(see\u00a0Wachter\u00a0R.\u00a0Lancet\u00a0Neurol\u00a02017; 16: 282\u201390).<\/p>\n

Details:<\/p>\n

–398 patients were recruited from 2013-2014 in 4\u00a0German centers, all with acute ischemic stroke and\u00a0symptoms for 7 days or less, aged 60 years or older, in\u00a0sinus rhythm and no history of atrial fibrillation (AF).<\/p>\n

— Mean age 73, 40% women, 80% hypertension\/27% diabetes\/41% hyperlipidemia\/18% current smoker\/29% previous smokers\/20% previous ischemic stroke\/8% previous TIA\/5% heart failure\/10% MI\/15% CAD\/7% with ejection fraction <50%<\/p>\n

— lacunar\u00a0lesion on brain imaging found in\u00a040%, cardioembolism 20%\/small vessel disease 30%\/stroke of unknown cause 50%, mean CHA2<\/sub>DS2<\/sub>-VASC score 4.8\u00a0(most in the 4-6 range), mean CHADS2<\/sub>\u00a0score 3.5 (50% in the 4-6 range). 197 patients were classified as having cryptogenic stroke; 201 as non-cryptogenic, mostly small vessel occlusion (118 pts) and cardioembolic stroke (75 pts)<\/p>\n

— Those with severe ipsilateral carotid or intracranial artery stenosis were excluded<\/p>\n

— patients were randomized into standard monitoring (at least 24 hours of rhythm monitoring: 188 of 198 patients had stroke unit telemetry for a median duration of 73 hours, and 149 of the 198 patients received additional\u00a0Holter\u00a0monitoring for a median of 24 hours) versus 10-day\u00a0Holter\u00a0monitoring at baseline, at 3 months, and at 6 months of follow-up. The initial Holter was done at\u00a0a median of 3.5 days after symptom onset<\/p>\n

— primary endpoint was the occurrence of atrial fibrillation or atrial flutter (lasting\u00a030 seconds or longer) within 6 months after randomization and before stroke recurrence.<\/p>\n

—\u00a0secondary endpoints included: the detection of AF within 12 months, recurrence of\u00a0stroke, systemic embolism or death within 12 months.<\/p>\n

Results:<\/p>\n

— after 6 months, 13.5 % were found to have atrial fibrillation in the enhanced monitoring group versus 4.5% in the standard group, absolute difference 9.0%, p=0.002, number needed to screen=11<\/p>\n

— no patient with detected atrial fibrillation had a recurrent stroke or systemic embolization before the detection of atrial fibrillation within 6 months [by the way, this and another recent study I saw challenged the prior conventional wisdom that recurrrent strokes were much more common within the first week or two after the initial event]<\/p>\n

— one of 27 patients in the enhanced monitoring group had atrial flutter<\/p>\n

— the median duration of the longest AF episode during\u00a0Holter\u00a0monitoring was 5 hours, though one third lasted more than 24 hours and slightly less than one third <\u00a06 minutes, and the number of episodes of atrial fibrillation detected ranged from 1 to 12<\/p>\n

—\u00a0review of their graph shows that the 1st<\/sup>\u00a010 day\u00a0Holter\u00a0monitor picked up 18 patients, about \u00bd \u00a0were picked up in the 1st<\/sup>\u00a05 days; the 2nd<\/sup>\u00a0\u00a010-day\u00a0monitor\u00a0picked\u00a0up an additional 6 with 2 picked up in the 1st<\/sup>\u00a05 days;\u00a0and the 3rd<\/sup>\u00a0picked up one\u00a0on the 8th<\/sup>\u00a0day<\/p>\n

—\u00a0oral anticoagulation was given to all of the 39 patients\u00a0who developed AF, more in the intervention group since more AF was picked up there<\/p>\n

–clinical sequelae were found in\u00a08 patients in\u00a0the intervention group (5 recurrent strokes and 3 TIAs) and 14 in the control group (9 recurrent strokes and 5 TIAs), for rates of 3.7% vs 5.4%, nonsignificant (though this trial was underpowered for clinical outcomes, this finding does mirror that of the CRYSTAL-AF trial,\u00a0which used an implantable cardiac monitor to pick up AF, finding\u00a021% fewer events after 12 months). No cases of systemic embolization. No difference in picking up AF by age, sex, CHADS2<\/sub>, NIH Stroke Scale,\u00a0symptoms at admission, or if the stroke was considered “cryptogenic”)\u200b<\/p>\n

Commentary:<\/p>\n

— The rationale for looking aggressively for atrial fibrillation is that strokes from AF can be more severe, there is a high risk of recurrent strokes, and the detection of AF really changes therapy\u00a0from antiplatelet drugs to oral anticoagulants, the latter\u00a0decreasing\u00a0the risk of recurrent strokes by 60 to 70%.\u00a0 Since\u00a0there are significant adverse events associated with these anticoagulants, it seems that\u00a0their indications need to be pretty clear.<\/p>\n

— The European Society of Cardiology recommends at least 72 hours of\u00a0to\u00a0monitoring, and also gives a Class IIa\u00a0recommendation for implantable cardiac monitors (see\u00a0Eur\u00a0Heart J 2016; 37: 2893\u2013962.)<\/p>\n

— Review of the timing of AF pickups in the above study found\u00a0that most (18\/25, 72%) happened on the first 10-day cycle, and the pickup was reasonably evenly spread throughout the 10-day period; 6\/25, (24%) were picked up in the second 10-day monitoring, again spread throughout the 10-day period; and one (4%) was near the end of the third\u00a010-day period. This suggests to me\u00a0that the monitoring should be for the entire 10-day periods, and that it is unlikely that a 4th<\/sup>\u00a010-day period would be useful.\u00a0The researchers in the above study suggested 7-10 days of monitoring within the first few days of symptom onset, and then repeating if higher risk (repeated\u00a0cryptogenic strokes or embolic stroke of unknown source, frequent supravenrtricular ectopies, elevated natriuretic peptides, left atrial enlargement, or reduced atrial contractility).<\/p>\n

–Holter monitoring has the advantage of being cheap, noninvasive, available, and able to be done within days of a cerebrovascular event.<\/p>\n

so, very interesting study finding a significant number of patients having a stroke do in fact have AF on monitoring, and the more monitoring , the higher the pickup rate. \u00a0But hard to come to firm conclusions without a larger study powered sufficiently to assess clinical outcomes in order to\u00a0see if AF pickup and treatment mattered (eg, is AF causative, or is it an innocent bystander which we know is common as age\u00a0increases? and we also know that strokes themselves can cause cardiac arrhythmias, so which came first?)\u00a0The other issues the larger trial could assess include:<\/p>\n

\u200b–\u00a0what defines risky AF: eg, do really short episodes of AF matter (and what length does seem to matter?), and is this age-dependent?<\/p>\n

—\u00a0is there a number of AF episodes per 10-day monitoring that increase risk of stroke\/TIA (and does that number vary depending on the length of AF episodes)? and, is this age-dependent?<\/p>\n

—\u00a0at what age should we do more aggressive monitoring (and should there be scaled amounts of monitoring based on different age groups, since AF is more common with increasing\u00a0age)? is there an age where monitoring stops being clinically useful (either the AF doesn’t really increase risk that much, or the risks start to outweigh the benefits)?<\/p>\n

the bottom line to me is that if we can show that picking up AF\u00a0leads to improved clinical outcomes, \u00a0I\u00a0would support more aggressive monitoring than the recommendations of the study authors: even though there were\u00a0only 1 pickup during the\u00a0third\u00a010-day period, given how devastating a recurrent stroke can be, my inkling would be to support the 3 monitoring periods.<\/p>\n

See here\u00a0<\/a>which argues for enhanced screening for atrial fibrillation overall (not just in people with\u00a0strokes)<\/p>\n

and \u00a0there are many blogs on atrial fibrillation treatment (\u00a0type atrial fibrillation in the search window)<\/p>\n

—————————————————————————————————————-<\/p>\n

As an aside, there is a free app for iphones called Cardiio which displays\u00a0one\u2019s pulse (just place a finger lightly on the camera on the back of the iphone). In Europe, it is approved to diagnose AF, but the FDA has\u00a0not\u00a0approved it in the US at this point. But one can see one’s\u00a0rhythm, and patients could be shown how to use it and assess for abnormalities which might be AF. Basically, a study found that in 1013 patients with hypertension, diabetes, and\/or aged >65, the sensitivity for the full Cardiio (Cardio Rhythm) was 92.9% and the specificity\u00a0was 97.7%, as compared to single-lead ECG\u00a0tracings reviewed by 2 cardiologists (see\u00a0Chan P-H. J Am Heart Assoc. 2016;5:e003428, or \u00a0doi: 10.1161\/JAHA.116.003428), though the positive predictive value in this study was only 53.1%. I have played with the app\u00a0a little and seems pretty impressive to me (ie, I can see a clear waveform, documentation of the pulse, and, at least for the few times I\u2019ve done it, I seem to be in normal sinus rhythm. Though not sure what I\u2019d find with three\u00a010-day Holter monitor recordings\u2026)<\/p>\n<\/div>\n

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the elusive search for afib in stroke patients; and an app […]<\/p>\n

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