Detection of Atrial Fibrillation Using Insertable Cardiac Monitors in Patients With Cryptogenic Stroke in Japan (the LOOK Study): Protocol for a Prospective Multicenter Observational Study

Satoshi Suda; Takehiro Katano; Kazuo Kitagawa; Yasuyuki Iguchi; Shigeru Fujimoto; Kenjiro Ono; Osamu Kano; Hidehiro Takekawa; Masatoshi Koga; Masafumi Ihara; Masafumi Morimoto; Hiroshi Yamagami; Tadashi Terasaki; Keiji Yamaguchi; Seiji Okubo; Yuji Ueno; Nobuyuki Ohara; Yuki Kamiya; Masataka Takeuchi; Yukako Yazawa; Yuka Terasawa; Ryosuke Doijiri; Yoshifumi Tsuboi; Kazutaka Sonoda; Koichi Nomura; Takashi Shimoyama; Akihito Kutsuna; Kazumi Kimura

doi:10.2196/39307

Detection of Atrial Fibrillation Using Insertable Cardiac Monitors in Patients With Cryptogenic Stroke in Japan (the LOOK Study): Protocol for a Prospective Multicenter Observational Study

JMIR Res Protoc. 2023 Apr 13:12:e39307. doi: 10.2196/39307.

Authors

Satoshi Suda¹, Takehiro Katano¹, Kazuo Kitagawa², Yasuyuki Iguchi³, Shigeru Fujimoto⁴, Kenjiro Ono⁵, Osamu Kano⁶, Hidehiro Takekawa⁷, Masatoshi Koga⁸, Masafumi Ihara⁹, Masafumi Morimoto¹⁰, Hiroshi Yamagami¹¹, Tadashi Terasaki¹², Keiji Yamaguchi¹³, Seiji Okubo¹⁴, Yuji Ueno¹⁵, Nobuyuki Ohara¹⁶, Yuki Kamiya¹⁷, Masataka Takeuchi¹⁸, Yukako Yazawa¹⁹, Yuka Terasawa²⁰, Ryosuke Doijiri²¹, Yoshifumi Tsuboi²², Kazutaka Sonoda²³, Koichi Nomura²⁴, Takashi Shimoyama²⁵, Akihito Kutsuna²⁵, Kazumi Kimura¹

Affiliations

¹ Department of Neurology, Nippon Medical School, Tokyo, Japan.
² Department of Neurology, Tokyo Women's Medical University, Tokyo, Japan.
³ Department of Neurology, The Jikei University School of Medicine, Tokyo, Japan.
⁴ Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
⁵ Division of Neurology, Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan.
⁶ Department of Neurology, Toho University Faculty of Medicine, Tokyo, Japan.
⁷ Department of Neurology, Dokkyo Medical University, Tochigi, Japan.
⁸ Department of Cerebrovascular Medicine, National Cerebral and Cardiovascular Center, Osaka, Japan.
⁹ Department of Neurology, National Cerebral and Cardiovascular Center, Osaka, Japan.
¹⁰ Department of Neurosurgery, Yokohamashintoshi Neurosurgical Hospital, Kanagawa, Japan.
¹¹ Department of Stroke Neurology, National Hospital Organization Osaka National Hospital, Osaka, Japan.
¹² Department of Neurology, Japanese Red Cross Kumamoto Hospital, Kumamoto, Japan.
¹³ Department of Neurology, Ichinomiya Nishi Hospital, Aichi, Japan.
¹⁴ Department of Cerebrovascular Medicine, NTT Medical Center Tokyo, Tokyo, Japan.
¹⁵ Department of Neurology, Juntendo University Faculty of Medicine, Tokyo, Japan.
¹⁶ Department of Neurology, Kobe City Medical Center General Hospital, Hyogo, Japan.
¹⁷ Department of Neurology, Showa University Koto Toyosu Hospital, Tokyo, Japan.
¹⁸ Department of Neurosurgery, Seisho Hospital, Kanagawa, Japan.
¹⁹ Department of Stroke Neurology, Kohnan Hospital, Miyagi, Japan.
²⁰ Department of Neurology, Brain Attack Center Ota Memorial Hospital, Hiroshima, Japan.
²¹ Department of Neurology, Iwate Prefectural Central Hospital, Iwate, Japan.
²² Department of Neurosurgery, Kawasakisaiwai Hospital, Kanagawa, Japan.
²³ Department of Neurology, Saiseikai Fukuoka General Hospital, Fukuoka, Japan.
²⁴ Department of Neurology, Shioda Hospital, Chiba, Japan.
²⁵ Department of Neurology, New Tokyo Hospital, Chiba, Japan.

PMID: 37052993
PMCID: PMC10141259
DOI: 10.2196/39307

Abstract

Background: Paroxysmal atrial fibrillation (AF) is a probable cause of cryptogenic stroke (CS), and its detection and treatment are important for the secondary prevention of stroke. Insertable cardiac monitors (ICMs) are clinically effective in screening for AF and are superior to conventional short-term cardiac monitoring. Japanese guidelines for determining clinical indications for ICMs in CS are stricter than those in Western countries. Differences between Japanese and Western guidelines may impact the detection rate and prediction of AF via ICMs in patients with CS. Available data on Japanese patients are limited to small retrospective studies. Furthermore, additional information about AF detection, including the number of episodes, cumulative episode duration, anticoagulation initiation (type and dose of regimen and time of initiation), rate of catheter ablation, role of atrial cardiomyopathy, and stroke recurrence (time of recurrence and cause of the recurrent event), was not provided in the vast majority of previously published studies.

Objective: In this study, we aim to identify the proportion and timing of AF detection and risk stratification criteria in patients with CS in real-world settings in Japan.

Methods: This is a multicenter, prospective, observational study that aims to use ICMs to evaluate the proportion, timing, and characteristics of AF detection in patients diagnosed with CS. We will investigate the first detection of AF within the initial 6, 12, and 24 months of follow-up after ICM implantation. Patient characteristics, laboratory data, atrial cardiomyopathy markers, serial magnetic resonance imaging findings at baseline, 6, 12, and 24 months after ICM implantation, electrocardiogram readings, transesophageal echocardiography findings, cognitive status, stroke recurrence, and functional outcomes will be compared between patients with AF and patients without AF. Furthermore, we will obtain additional information regarding the number of AF episodes, duration of cumulative AF episodes, and time of anticoagulation initiation.

Results: Study recruitment began in February 2020, and thus far, 213 patients have provided written informed consent and are currently in the follow-up phase. The last recruited participant (May 2021) will have completed the 24-month follow-up in May 2023. The main results are expected to be submitted for publication in 2023.

Conclusions: The findings of this study will help identify AF markers and generate a risk scoring system with a novel and superior screening algorithm for occult AF detection while identifying candidates for ICM implantation and aiding the development of diagnostic criteria for CS in Japan.

Trial registration: UMIN Clinical Trial Registry UMIN000039809; https://tinyurl.com/3jaewe6a.

International registered report identifier (irrid): DERR1-10.2196/39307.

Keywords: atrial cardiomyopathy; atrial fibrillation; biomarker; cryptogenic stroke; insertable cardiac monitor.

©Satoshi Suda, Takehiro Katano, Kazuo Kitagawa, Yasuyuki Iguchi, Shigeru Fujimoto, Kenjiro Ono, Osamu Kano, Hidehiro Takekawa, Masatoshi Koga, Masafumi Ihara, Masafumi Morimoto, Hiroshi Yamagami, Tadashi Terasaki, Keiji Yamaguchi, Seiji Okubo, Yuji Ueno, Nobuyuki Ohara, Yuki Kamiya, Masataka Takeuchi, Yukako Yazawa, Yuka Terasawa, Ryosuke Doijiri, Yoshifumi Tsuboi, Kazutaka Sonoda, Koichi Nomura, Takashi Shimoyama, Akihito Kutsuna, Kazumi Kimura. Originally published in JMIR Research Protocols (https://www.researchprotocols.org), 13.04.2023.