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TOPICS TO READ

ATRIAL FIBRILLATION

 

 

 

 

 

https://www.medscape.com/viewarticle/892189

Catheter ablation of AF, as opposed to rhythm- or rate-control medical therapy, was followed by a significantly reduced rate of death or HF hospitalization in patients with both AF and HF and reduced ejection fraction in the randomized CASTLE-AF trial.[1] Growing evidence that ablation in patients with CHF may be preferable approach

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Patients with : Afib, symptomatic CHF and Low EF [<35%]

--- typical: 64 yr old symptomatic man

--- subgroup suggests EF < 24% may do worse

Intervention: ablation vs Rhythm control vs Rate control

--- low complication rate/ expert centres

Significant Improved mortality [47% benefit] , CHF, LV function @ 5 years

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2018 Feb :  Risk of CVA: Newman discussion

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Threshold cutoff burden to anticoagulate SCAF remains to be determined.

Consider the CHADSVASC score and underlying structural heart

  • Trials reporting anticoagulant benefits have been done in patients with clinically significant Afib, either symptomatic AF or AF long enough to be recorded on multiple ECGs, and have not taken into account the burden of the Afib or use of AA drugs, ablation or surgery.

  • Brief episodes of device detected sub-clinical/silent atrial fibrillation [SCAF] , ranging from 6minutes- 24 hours,  appear to be associated with a stroke risk, but SCAF is thought to be potentially different c/w clinical AFib in terms of its character and possibly a relatively lower risk of stroke. 

  • Initially, it was thought that the stroke risk was the same irrespective of burden, but we now believe that increased burden correlates with increased risk. and that lower burden correlates with lower risk, and that burden should be factored into our assessment of treatment. Further complicating this, is our belief that symptoms and short-term monitorring are not a reliable way to assess burden

  • “Silent atrial fibrillation has been identified.  Data is emerging that the burden on Afib maybe important in determining the risk. For  durations between 6 minutes and 24 hours there is no clear evidence yet as to the specific threshold burden that supports anticoagulation . Trials are ongoing.  Until evidence exists decisions are  individualized. After some discussion. it was recommended that…”

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Paroxysmal: < 7 days

Persistent: > 7 days

Permanent ' we wont try to convert to sinus rhythm

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http://stroke.ahajournals.org/content/strokeaha/47/2/570.full.pdf

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BURDEN appears to be important and should be taken into account

  • Old data: SPAF studies suggested that the stroke risk was similar for paroxysmal/persistent/permanent

  • New data: AVERROES study showed decreasing risk for permanent>persistent>paroxysmal

  • Unfortunately, symptoms and holters are not considered a reliable way to assess burden in patients who dont have an implanted device

  • Implantable devices/Long term monitoring provide a unique opportunity to assess burden

    • These device detected arrhythmias in otherwise asymptomatic pts is referred to as SCAF [subclinical atrial fibrillation]

    • AHRE [atrial high rate episodes] are associated with stroke: studies suggest 5min-24 hours​ burden

      • MOST: 5 minutes episode [74 yr olds with PM, 2 yrs, 50% prevalence of AHRE]

      • ASSERT: 6 minute episode = 1.8x risk  [65 yr olds with ICD or PM, 3 months, 10% prevalence]

      • TRENDS: 5.5 hrs per day burden

      • Capucci:  24 hr episode

    • No study done yet to prove that noac reduces this risk as it does with clinical Afib

      • Now have Artesia study​ being done

    • We may soon look to combine burden assessment with CHADS risk

      • Botto et al.​

        • low stroke risk: 0.8% per year

          • CHADS2 with zero AHRE

          • CHADS1 with <24hrs​ AHRE

          • CHADS0 with >24hrs AHRE

        • high stroke risk: 5% per year

          • CHADS 3​ with zero AHRE

          • CHADS 2 with <24 hrs AHRE

          • CHADS 1 with >24 hrs AHRE

        • So CHADS0 is low risk no matter what and CHADS 3 is high risk no matter what and CHADS 1 or CHADS 2 need some burden to be worth anticoagulating

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ARTESIA STUDY

..... David Says that the EP guys debated cutoffs for the Artesia study: they all agree that

  • <6minutes has no need for anticoagulation, and

  • they arbitrarily selected 24 hours as a definite significant threshold. The randomized studies to date used an abnormal ECG as an indicator which was thought to be reflective of 'long lasting afib', but there were no holter or SCAF patients in those days, so its impossible to know what the relevant duration was.

ARTESIA : ongoing Canadian study....indication: Dr Lashevsky

At least 1 episode of SCAF 6'-24hrs and

  • prior cva 

  • age 75

  • age 65 with 2 other risks [chadsvas 3]

  • age 55 with 3 other risks [chadsvas 3]

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2017 December: Dr Newman

It can 'take a while of looking' to catch the Afib spell

Reveal study: showing that the longer that you monitor in Chads 3 patients, the greater the chance that you see Afib [40% at 30 mnths].. meaning you could argue that we should monitor for a long time if unexplained CVA. Some Current strategy at sunnybrook is to do 2x 14 day holters

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Navigate ESUS study : trial of ASA vs Rivar in patients with embolic source of undetermined source showed no benefit to rivaroxaban, meaning we cant just assume afib was the cause

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Sunnybrook is studying patients with big LAvolume and >40pacs/hr

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