Editors' Note: Prolonged Cardiac Monitoring and Stroke Recurrence: A Meta-analysis

Abstract

The American Heart Association recommends extended cardiac monitoring for the diagnosis of subclinical atrial fibrillation (AF) among patients with acute ischemic stroke and no clear source of embolism. In this meta-analysis by Dr. Tsivgoulis and colleagues, investigators pooled high-quality observational cohort and randomized clinical trial data involving nearly 3,000 patients to evaluate the probability of identifying AF, initiation of anticoagulation, and stroke recurrence risk. Although all cardiac monitors increased the risk of AF detection and anticoagulation initiation, implantable loop recorders were associated with the highest probability of AF detection and anticoagulation initiation. Compared with patients who underwent conventional monitoring, those with prolonged monitoring were associated with a lower risk of recurrent stroke, although this risk was driven by patients monitored in observational (nontrial) cohort studies (relative risk [RR] 0.29, 95% CI 0.15–0.59 vs RR of stroke in randomized clinical trials 0.72, 95% CI 0.49–1.07). Dr. Meinel emphasizes that intracranial and systemic hemorrhages ought to be considered along with recurrent ischemic stroke in the decision to anticoagulate a patient with AF. The investigators acknowledge that intracranial hemorrhages are a highly fatal complication after anticoagulation, and although the risk of death due to major extracranial hemorrhage is also considerable, the mortality rate is far lower than what is seen among intracranial hemorrhages. Fortunately, most bleeding events and deaths due to such events are generally low (<5%). Owing to lack of available data on bleeding rates and mortality in many studies reported in this meta-analysis, the investigators cannot be certain of the low risks across all populations. That said, there were no significant differences in all-cause mortality with prolonged vs conventional cardiac monitoring in 2 of the included studies. Dr. Scharf also comments that the burden of subclinical AF and etiologies of recurrent stroke (e.g., small vessel or large vessel atherosclerosis) are also integral to evaluating the efficacy of anticoagulation in these patients. All authors eagerly await the results of randomized trials evaluating the potential benefit of anticoagulation after AF detection through prolonged cardiac monitoring. The American Heart Association recommends extended cardiac monitoring for the diagnosis of subclinical atrial fibrillation (AF) among patients with acute ischemic stroke and no clear source of embolism. In this meta-analysis by Dr. Tsivgoulis and colleagues, investigators pooled high-quality observational cohort and randomized clinical trial data involving nearly 3,000 patients to evaluate the probability of identifying AF, initiation of anticoagulation, and stroke recurrence risk. Although all cardiac monitors increased the risk of AF detection and anticoagulation initiation, implantable loop recorders were associated with the highest probability of AF detection and anticoagulation initiation. Compared with patients who underwent conventional monitoring, those with prolonged monitoring were associated with a lower risk of recurrent stroke, although this risk was driven by patients monitored in observational (nontrial) cohort studies (relative risk [RR] 0.29, 95% CI 0.15–0.59 vs RR of stroke in randomized clinical trials 0.72, 95% CI 0.49–1.07). Dr. Meinel emphasizes that intracranial and systemic hemorrhages ought to be considered along with recurrent ischemic stroke in the decision to anticoagulate a patient with AF. The investigators acknowledge that intracranial hemorrhages are a highly fatal complication after anticoagulation, and although the risk of death due to major extracranial hemorrhage is also considerable, the mortality rate is far lower than what is seen among intracranial hemorrhages. Fortunately, most bleeding events and deaths due to such events are generally low (<5%). Owing to lack of available data on bleeding rates and mortality in many studies reported in this meta-analysis, the investigators cannot be certain of the low risks across all populations. That said, there were no significant differences in all-cause mortality with prolonged vs conventional cardiac monitoring in 2 of the included studies. Dr. Scharf also comments that the burden of subclinical AF and etiologies of recurrent stroke (e.g., small vessel or large vessel atherosclerosis) are also integral to evaluating the efficacy of anticoagulation in these patients. All authors eagerly await the results of randomized trials evaluating the potential benefit of anticoagulation after AF detection through prolonged cardiac monitoring.