p.22 抽出テキスト

Kusumoto et al 2018 Bradycardia Clinical Practice Guidelines

Circulation. 2019;140:e382–e482. DOI: 10.1161/CIR.0000000000000628 August 20, 2019 e403 CLINICAL STATEMENTS AND GUIDELINES

4.	 The prevalence of undiagnosed sleep apnea may be high in patients referred for pacemaker implantation for asymptomatic bradycardia and in unselected recipients of cardiovascular implantable electronic devices (CIED).S4.2.7-10,S4.2.7-11 In a small, but illustrative, study, 7 patients with asymptomatic nocturnal bradyarrhythmias referred for pacemaker were queried for symptoms of sleep apnea. Suspicious symptoms prompted polysomnography that confirmed previously unsuspected obstructive sleep apnea in all. Over 22 months of follow-up, 86% remained free of bradyarrhythmia symptoms on treatment for sleep apnea but without a pacemaker.S4.2.7-10 A second illustrative study involved 98 consecutive patients with PPMs, implanted for a variety of indications, who were systematically screened with the Epworth Sleepiness Scale and polysomnography. Although only 25% of the group had Epworth Sleepiness Scale score >11 (normal, 0-10), 59% were diagnosed with sleep apnea by polysomnography. The sleep apnea was severe in 27% of the 69 subjects receiving a pacemaker for indications other than cardiac resynchronization.S4.2.7-11 Thus, conditions prompting consideration for CIED likely define a population at higher risk of sleep disordered breathing. This likely relates only partially to apnea-induced bradyarrhythmia. The complex interaction between sleep disordered breathing and a broad array of cardiovascular diseases likely contributes, as well.S4.2.7-25

4.3 Invasive Testing

4.3.1. Implantable Cardiac Monitor in Patients With Documented or Suspected Bradycardia or Conduction Disorders

Recommendation for Implantable Cardiac Monitor in Patients With Documented or Suspected Bradycardia or Conduction Disorders Referenced studies that support the recommendation are summarized in Online Data Supplement 6.

COR LOE Recommendation

IIa C-LD 1.  In patients with infrequent symptoms (>30 days between symptoms) suspected to be caused by bradycardia, longterm ambulatory monitoring with an implantable cardiac monitor (ICM) is reasonable if initial noninvasive evaluation is nondiagnostic.S4.3.1-1–S4.3.1-3

Synopsis

One of the most debilitating symptoms of bradycardia is syncope resulting in trauma. The suddenness and unpredictability of such events make the ICM an ideal diagnostic tool given its capacity for prolonged monitoring (up to 3 years) and its freedom of reliance on active patient participation. Early workS4.3.1-4 as well as subsequent randomized and nonrandomized studies evaluating the diagnostic efficacy of ICM were almost exclusively performed in patients presenting with unexplained syncope and/or presyncope and not specifically for identification of bradycardia.S4.3.1-5 In patients with ongoing or frequent symptoms of bradycardia, the 12lead ECG or external ambulatory electrocardiographic monitoring can usually document SND or atrioventricular conduction disease. However, when patients present with infrequent paroxysmal or infrequent symptoms, culprit bradycardias can evade the detection by standard external monitoring modalities. Longer duration of ambulatory monitoring with ICM may then be necessary to obtain correlation between bradycardia and symptoms.

Recommendation-Specific Supportive Text

1.	Several randomized controlled trials (RCTs) have demonstrated the diagnostic value of ICM in patients presenting with unexplained syncope or presyncope.S4.3.1-1–S4.3.1-3 Compared with investigation by conventional testing modalities such as 24-hour ambulatory electrocardiographic monitoring, 12-lead ECG, and treadmill stress test, the strategy of long-term rhythm monitoring with ICM was more effective in obtaining a clinical diagnosis. Many of the conditions diagnosed by ICM were found to be bradycardia-mediated (ie, high-grade atrioventricular block, SND, neurocardiogenic syncope with predominant cardio-inhibitory component) and were successfully treated with permanent cardiac pacing. Most patients with clinically significant bradycardia presenting with symptoms other than syncope (eg, fatigue, dyspnea on exertion) do not typically need prolonged ambulatory monitoring for diagnosis. Nevertheless, in some patients, the diagnosis may remain inconclusive or uncertain after initial noninvasive evaluation. External monitors will generally be the first-line choice of diagnostic tools in an effort to obtain potential correlation between bradycardia and symptoms but, for patients with very infrequent symptoms, initial ICM implantation may be the best and most cost-effective initial strategy.S4.3.1-2

Downloaded from http://ahajournals.org by on October 7, 2026