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Chip inserted under the skin may better identify patients at risk of recurrent stroke

STROKE AF trial results indicate that an inserted chip can improve detection of irregular heart rate

June 1, 2021
Massachusetts General Hospital
A small chip inserted under the skin can monitor patients after common forms of stroke to predict those at high risk of a recurrent stroke. The chip may help physicians identify patients who could benefit from stroke prevention therapies.

For patients who have experienced certain common types of stroke, a small chip inserted under the skin may help physicians predict their likelihood of experiencing a second stroke, and therefore their likelihood of benefiting from preventive therapy. The findings come from a recent clinical trial published in the Journal of the American Medical Association and led by investigators at Massachusetts General Hospital (MGH) and Northwestern University Feinberg School of Medicine.

Each year, approximately 800,000 strokes occur in the United States, and as many as one-fourth occur in people who experienced a previous stroke. Investigators have been searching for ways to identify patients who are likely to experience a recurrent stroke, as these individuals could be candidates for taking certain medications such as blood thinners. One group of patients who face an elevated risk of recurrent strokes are those with atrial fibrillation -- an irregular and often rapid heart rate -- that often goes undetected and untreated. (Irregular heartbeats can allow blood to pool in the heart, which can cause clots to form and travel to the brain.)

Recent research has shown that a small chip inserted under the skin can monitor the heart rate and rhythm, and help physicians detect atrial fibrillation in patients who previously experienced what's called a cryptogenic stroke, one with no identified cause despite thorough patient testing. Now investigators have tested the chip -- less than 1¾? long and 1/6? thick and called an insertable cardiac monitor -- in patients who experienced a stroke caused by narrowing of a large artery like the carotid artery, or blockage of a small artery deep in the brain where atrial fibrillation would be unexpected.

In the Stroke of Known Cause and Underlying Atrial Fibrillation (STROKE AF) trial, 492 patients were randomized and completed 12 months of follow-up after receiving either an insertable cardiac monitor within 10 days of an initial stroke or usual care consisting of external cardiac monitoring through electrocardiograms or other tracking methods.

The chip detected atrial fibrillation in 12.1% of patients, compared with 1.8% detected through usual care. The team noted that the episodes of atrial fibrillation were not brief, with most lasting at least one hour. Most stroke experts would recommend that patients with this degree of atrial fibrillation start taking blood thinners to prevent a future stroke.

"We found that a significant minority of patients with stroke not thought to be related to atrial fibrillation actually have atrial fibrillation, but we can only find it with an implantable monitor," says lead author Richard A. Bernstein, MD, PhD, a professor of Neurology at Northwestern University Feinberg School of Medicine.

Adds senior author Lee H. Schwamm, MD, C. Miller Fisher Chair of Vascular Neurology at MGH: "Based on the study findings, we believe that patients with stroke who are similar to those in the STROKE AF Trial should now undergo long-term cardiac monitoring with an insertable cardiac monitor to identify unsuspected atrial fibrillation."

Schwamm notes that for every eight patients monitored, clinicians could expect to find atrial fibrillation in one of them in the first year. "This could dramatically change the treatment recommendations by their doctor," he says.

Next steps in this research include identifying patient factors that predict the development of atrial fibrillation and the duration and extent of the arrhythmia. Additional studies are being explored to further understand the association of silent atrial fibrillation and recurrent stroke of all types.

Story Source:

Materials provided by Massachusetts General Hospital. Note: Content may be edited for style and length.

Journal Reference:

  1. Richard A. Bernstein, Hooman Kamel, Christopher B. Granger, Jonathan P. Piccini, Pramod P. Sethi, Jeffrey M. Katz, Carola Alfaro Vives, Paul D. Ziegler, Noreli C. Franco, Lee H. Schwamm, Indrani Acosta, Pradipkumar Jamnadas, Sushma Manda, Rizwan Alimohammad, Valerie Arias, Kristi Tempro, Kathleen Ward, Khaled Asi, Indrajit Choudhuri, Waldo Guerrero, Junaid Kalia, Imran Niazi, Rehan Sajjad, Varoon Thavapalan, Manish Assar, Javier Banchs, James Black, Peter Cheung, Alan Donsky, Dion Graybeal, Rashedul Hasan, Osman Mir, Claude Nguyen, Gregory Olsovsky, Jennifer Rasmussen, Sanjeev Hasabnis, Russell Reeves, Chris Rowley, Jitendra Sharma, Macey Smith, Kay Bonyak, Matthew Sackett, James Allred, Pramod Sethi, Richard Jung, Jennifer Lynch, Steven Rowe, Subasini Dash, Taya Glotzer, Sameer Jamal, Glauco Radoslovich, Gunjan Shukla, John Zimmerman, Haitham Hussein, Dennis Zhu, Kristopher Krueger, Matthew Ostrander, Darwin Ramirez, Jeffrey Shultz, Jay Simonson, Brett Cucchiara, Rajat Deo, David Frankel, Judy Jia, Scott Kasner, Jeanie Luciano, Steven Messe, Michael Mullen, Pasquale Santangeli, Robert Schaller, Qingyang Yuan, Don Bledsoe, Christian Cajavilca, David Chiu, Rajan Gadhia, Maranda Randi Grimes, Larry Katz, Stacy Moye, Tapan Rami, Abraham Thomas, John Volpi, Ali Al Balushi, Clara Boyd, Subbarao Choudry, Mandip Dhamoon, Srinivas Dukkipati, Davida Goltz, Qing Hao, Deborah Horowitz, Gurmeen Kaur, Jacob Koruth, Christeena Kurian, Marie-Noelle Langan, Ivan Matos Diaz, Marc Miller, Vivek Reddy, Kara Sheinart, Laura Stein, Aaron Tansy, Stanley Tuhrim, Jesse Weinberger, William Whang, Jonathan Cross, Howard Kreger, Marc Saltzman, Kenneth Zide, Sandeep Bansal, Matthew Bernabei, Murray Flaster, Conor Barrett, Mark Etherton, E. Kevin Heist, Steven Lubitz, Robert Regenhardt, Richa Sharma, Scott Silverman, Kelly Sloane, Anand Viswanathan, Amit Doshi, William Logan, Maheen Malik, David Rempe, Rohan Arora, Stuart Beldner, Laurence Epstein, Haisam Ismail, Ram Jadonath, Jeffrey Katz, Richard Libman, Mohammad Moussavi, Anand Patel, Apoor Patel, Jonathan Willner, Paul Wright, Frances Caprio, Susan Kim, Scott Mendelson, Rod Passman, Ilana Ruff, Mohammad Alsorogi, Gauhar Chaudhary, Kent Morris, Savannah Mullins, Nadeem Talpur, Kevin Thomas, Breehan Chancellor, Larry Chinitz, Andre Culpepper, Michael Fara, Koto Ishida, Kaitlyn Lillemoe, Aaron Lord, Jose Torres, Cen Zhang, Freddy Abi-Samra, Michael Bernard, Jacqueline Carter, Himanshu Chokhawala, Amanda Downey, Samuel Khatib, Daniel Morin, Glenn Polin, Paul Rogers, Gabriel Vidal, Richard Zweifler, Gary Belt, Robert Felberg, Steve Furer, John Hanna, Angela McCall-Brown, Susan Seeger, Ramakota Reddy, Elaine Skalabrin, Diane Soik, Michael Wilder, Michelle Kearney, Eugene LaFranchise, Brett Parker, Robert Andrew (Drew) Pickett, Heather Bonaguidi, Douglas Gibson, Mary Kalafut, Beth Mattera, Nicholas Olson, Mary Parker, John Rogers, Poulina Uddin, Cherylee Chang, Sarah Graner, Joseph Kipta, Rony Salem, David Singh, Ahmed Al-Awwad, Bahar Beaver, Shuchi Chaudhary, Stephen Clayton, Claire Delpirou Nouh, Paul Garabelli, David Gordon, Aneesh Pakala, Bappaditya Ray, Scott Saucedo, Evgeny Sidorov, Stavros Stavrakis, Marilou Ching, Christopher Deline, J. Maurice Hourihane, Amit Kandel, Chee Kim, Rakesh Magun, Ashkan Mowla, Robert Sawyer, Donald Switzer, Nitish Badhwar, Randall Lee, Karl Meisel, Wade Smith, Moayd Alkahalifah, Sushanth Aroor, Negar Asdaghi, Nirav Bhatt, Victor Del Brutto, George Dillon, Paul Gadient, Sebastian Koch, Litsa Lambrakos, Amer Malik, Erika Marulanda-Londono, Zeeshan Memon, Ivan Mendoza, Raul Mitrani, Gustavo Ortiz, Jose Ramano, Nicole Sur, Luis Torres, James Daniels, Mark Johnson, Alejandro Magadan, Ty Shang, Nancy Mcclelland, Theodore Merriam, Karah Neisen. Effect of Long-term Continuous Cardiac Monitoring vs Usual Care on Detection of Atrial Fibrillation in Patients With Stroke Attributed to Large- or Small-Vessel Disease. JAMA, 2021; 325 (21): 2169 DOI: 10.1001/jama.2021.6470

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Massachusetts General Hospital. "Chip inserted under the skin may better identify patients at risk of recurrent stroke." ScienceDaily. ScienceDaily, 1 June 2021. <>.
Massachusetts General Hospital. (2021, June 1). Chip inserted under the skin may better identify patients at risk of recurrent stroke. ScienceDaily. Retrieved June 17, 2024 from
Massachusetts General Hospital. "Chip inserted under the skin may better identify patients at risk of recurrent stroke." ScienceDaily. (accessed June 17, 2024).

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