Long-term insertable cardiac monitoring after ischemic stroke improves AF detection
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Long-term insertable cardiac monitoring for atrial fibrillation among patients with ischemic stroke of atherosclerotic origin improved AF detection 10-fold compared with standard of care, a speaker reported.
In addition, factors including chronic HF, left atrial enlargement and BMI were prognostic of post-stroke AF at 36 months, according to a secondary analysis of the STROKE AF trial presented at the International Stroke Conference.
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“I think we've settled the question, what's a better way to find fibrillation in these patients? It's with an inserted device,” Lee H. Schwamm, MD, FAHA, professor of neurology at Harvard Medical School, C. Miller Fisher Chair in Vascular Neurology and director of the MGH Center for TeleHealth at Massachusetts General Hospital and vice president of digital patient experience and virtual care, Mass General Brigham, said during a presentation. “This is not a transient rise in fibrillation, which then diminishes or vanishes over the course of the next 3 years. This is a continuous and progressive detection of fibrillation. The total rate was 21.7%, one in five patients with this presumed stroke type has fibrillation detected in the subsequent 3 years, very similar to the 30% seen in CRYSTAL AF.
“What are the implications for this? First of all, 88% of these episodes are asymptomatic. Relying on patient's self-report to decide who to monitor is not a sensible or rational strategy. In addition, the burden of fibrillation that we detected was significant: 67% of the patients who had AF detected had at least one episode lasting more than an hour,” Schwamm said. “This is not a trivial little squiggle of something on an on an ECG that then goes away. This is of significant duration and significant burden such that the cardiologists who adjudicated these rhythm strips felt confident this was atrial fibrillation.”
STROKE AF was a prospective, randomized, controlled, multicenter trial, for which 492 patients (mean age, 67 years; 62% men) with ischemic stroke and no prior AF diagnosis were randomly assigned to either continuous monitoring with an insertable cardiac monitor (Reveal LINQ, Medtronic) or a control group who received site-specific standard of care for AF detection.
As Healio previously reported, at 12 months, the incidence rate of AF was 12.1% in the insertable cardiac monitor group compared with 1.8% in the control group (HR = 7.41; 95% CI, 2.6-21.28; P < .001).
For the present analysis of the STROKE AF trial, researchers compared the 3-year incidence of AF detected via long-term insertable cardiac monitoring in 148 patients compared with standard of care in 146 patients after ischemic stroke associated with ASCVD.
Schwamm reported that the incidence rates of AF following ASCVD-related ischemic stroke was approximately 10-fold during long-term insertable cardiac monitoring (21.7%) compared with standard of care (2.4%) at 36 months (HR = 10; 95% CI, 4-25.2; P < .001).
In addition, 88% of AF episodes detected with long-term insertable cardiac monitoring were asymptomatic, and the median time to first adjudicated AF episode was 284 days, according to the presentation.
“This really raises for us the important question, should we treat device-detected asymptomatic fibrillation differently than clinically symptomatic fibrillation with respect to future stroke risk,” Schwamm said during the presentation. “In being honest with ourselves, if we have no hesitation to pull the trigger and start anticoagulation because a cryptogenic stroke had device detected fibrillation 6 months later, should we decide that if you had a lacunar stroke, we can ignore that same device detected fibrillation? That's the fundamental problem for us. And I'm going to make a fairly radical statement, which is at some level, all stroke is cryptogenic. We never know for sure what caused the index stroke. We have hypotheses.”
Insertable cardiac monitoring also evaluated total daily AF burden, detecting the following:
- 33.9% of episodes lasting 6 minutes;
- 22% of episodes lasting 30 minutes;
- 20.5% of episodes lasting 1 hour;
- 11.6% of episodes lasting 6 hours; and
- 1.9% of episodes lasting 23 hours or more.
Researchers observed no significant difference in stroke recurrence in insertable cardiac monitoring and control groups at 12 months (HR = 0.67; 95% CI, 0.35-1.28; P = .23) or 36 months (HR = 1.1; 95% CI, 0.7-1.8; P = .71).
Moreover, patients with chronic HF, left atrial enlargement, BMI more than 30 kg/m2 and/or QRS more than 120 ms had an AF detection rate of 30% at 36 months compared with 8.6% among patients with neither (HR = 4.08; 95% CI, 1.72-9.7; log-rank P < .001).
“A substantial portion of patients who had a presumed ideology of atherosclerotic stroke were found to have device detected or subclinical fibrillation in this trial,” Schwamm said. “If this data doesn't convince you that fibrillation is present in this population, I don't think any data will, because it's consistent, it accumulates over time and it looks remarkably similar to a set of data that we've all been very comfortable with, which is the CRYSTAL AF data.
“We don't talk about device-detected hyperglycemia without symptoms of diabetes and say, we don't have to treat the sugar because the person doesn't have symptoms and evidence of diabetic complications,” Schwamm said. “We treat the diabetes because we know it's a risk factor for future strokes. We have to start to think differently about building probabilistic models of future stroke risk and then determining therapy based on that.”
Reference:
- Irregular heart rhythms detected in 1 in 5 stroke survivors, increasing risk of new stroke. newsroom.heart.org/news/irregular-heart-rhythms-detected-in-1-in-5-stroke-survivors-increasing-risk-of-new-stroke. Published on Feb. 8, 2023. Accessed on Feb. 8, 2023.
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Schwamm LH, et al. LB1. Presented at: International Stroke Conference; Feb. 8-10, 2023; Dallas (hybrid meeting).
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