Stroke Subtype, Discharge Location Influence Use of Cardiac Rhythm Monitoring

Joint guidelines of the American Heart Association and American Stroke Association recommend extended rhythm monitoring (approximately 30 days) within six months after cryptogenic stroke (those whose mechanism is unclear). Yet rhythm monitoring is costly and can be invasive, and previous studies have suggested it is underutilized.

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Shaan Khurshid, MD, MPH, electrophysiology fellow, and Steven A. Lubitz, MD, MPH, cardiac electrophysiologist in the Telemachus & Irene Demoulas Family Foundation Center for Cardiac Arrhythmias and researcher in the Cardiovascular Research Center at Massachusetts General Hospital, and colleagues determined that only 71% of patients hospitalized with cryptogenic stroke received cardiac rhythm monitoring within six months. What's more, the use of monitoring was unrelated to the estimated risk of atrial fibrillation (AF). Their report appears in The American Journal of Cardiology.

Study Methods

The study team retrospectively studied 493 patients hospitalized for acute ischemic stroke at Mass General between October 2018 and June 2019. Patients were included only if they did not have AF detected before or during their hospitalization.

All patients underwent routine assessment for the cause of the stroke, which was categorized for this study as cardioembolic, cryptogenic or other/undocumented. AF risk was estimated using the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE)-AF score.

Cumulative Use of Monitoring

The primary study outcome was cardiac monitor use within six months from stroke admission with a 24- to 48-hour Holter/ECG monitor, two- to four-week event/patch monitor or implantable loop recorder (ILR). The overall cumulative use was 37%, but use differed by stroke subtype, discharge location and AF risk:

• Cryptogenic stroke—71%
• Cardioembolic stroke—48%
• Other/undocumented cause—23%
• Discharged home—46%
• Discharged to rehabilitation—25%
• Low AF risk—31%
• Intermediate AF risk—34%
• High AF risk—37%

Multivariable-adjusted Associations with Monitoring

• Cryptogenic stroke vs. other/undocumented—HR, 4.53 (P<0.01)
• Cardioembolic stroke vs. other/undocumented—HR, 2.43 (P<0.01)
• Discharged to home vs. rehabilitation—HR, 1.80 (P<0.01)
• CHARGE-AF score (per 1 SD decrease)—HR, 1.08 (P=0.33)

Use of ILRs

At six months, the cumulative incidence of ILR use was 10%. Only 28% of patients with cryptogenic strokes received an ILR.

Incident and Recurrent Stroke

By 12 months after stroke, 20 patients had developed incident AF. Eight of them (40%) had had strokes not classified as cardioembolic or cryptogenic, and only three (38%) had received monitors within 12 months.

Increasing CHARGE-AF score was strongly associated with incident AF (HR, 1.56 per 1 SD increase).

Opportunities to Improve Care

• Calculating a CHARGE-AF or other AF risk score could increase the efficiency of cardiac rhythm monitoring, as patients less likely to have undiagnosed AF could avoid the cost and potential harms associated with invasive or prolonged monitoring
• Patients with cryptogenic stroke in this study were more likely than others to receive monitoring, but there remains a pronounced gap between consensus guidelines and clinical practice
• Additional research is needed to understand whether low monitor use among patients discharged to rehabilitation is an opportunity to improve care or a reasonable response when patients are receiving an ongoing evaluation or have a poor prognosis

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