beating heart

Insertable cardiac monitoring cost-effectively detects irregular heartbeat or atrial fibrillation episodes and episode duration in patients who have had cryptogenic strokes (cause of stroke unknown), according to two studies presented at the American Stroke Association’s International Stroke Conference 2015.

Doctors cannot determine the cause of ischemic stroke in 20 percent to 40 percent of cases, despite conventional diagnostic tests. But they need to document atrial fibrillation in order to prescribe anticoagulant therapy to reduce recurrent stroke risk.

ICMs are inserted under the skin in a minimally invasive procedure to monitor patients’ heartbeats for three years, compared to electrocardiograms, which are tests given on the spot in doctors’ offices or hospitals, and Holter monitors, which patients wear from 24 hours to several days.

To help determine if an ICM is effective, researchers analyzed 1,247 cryptogenic stroke patients who received an ICM device post stroke.

They found:

  • Atrial fibrillation detection rate in the study population was 12.2 percent at 182 days; this was 37 percent higher than what was found in a recent randomized controlled trial (CRYSTAL AF) at the same time.
  • ICM detected the duration of each atrial fibrillation episode.
  • Half of the patients with detected atrial fibrillation had an episode that was at least 3.4 hours in duration.
  • Among the patients with atrial fibrillation, 25 percent had an episode that was longer than 11.8 hours.

Atrial fibrillation episodes of clinically important duration were detected with continuous ICM monitoring in a notable proportion of cryptogenic stroke patients, despite a relatively brief follow-up, the researchers said. These “real-world” data confirm what was observed in the CRYSTAL AF study, and researchers suggest that ICMs may have even greater clinical utility in detecting AF in real-world practice than in clinical trials.

In other research (abstract 14), scientists analyzed data from previous studies to determine if detecting atrial fibrillation with an ICM in cryptogenic stroke patients is cost-effective compared to standard of care.

They found:

  • ICM was associated with fewer recurrent strokes and increased quality of life.
  • While stroke-related costs were lower in the ICM group, overall costs were higher than in the standard of care group.

When researchers studied the ratio of added costs to added health-related quality of life benefits, they determined ICM use would be considered by payers to be a good value for the money and cost effective.