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Kusumoto et al 2018 Bradycardia Clinical Practice Guidelines

Circulation. 2019;140:e382–e482. DOI: 10.1161/CIR.0000000000000628 August 20, 2019 e399 CLINICAL STATEMENTS AND GUIDELINES

and mobile continuous outpatient telemetry monitoring provide a higher diagnostic yield than 24- or 48-hour Holter monitoring because of the longer period of monitoring. These prolonged monitoring strategies can be useful in the evaluation of suspected bradycardia or conduction disorders.S4.2.3-1–S4.2.3-3,S4.2.3-5,S4.2.3-7–S4.2.3-12,S4.2.3-17 The characteristics of available ambulatory monitoring systems and their proper selection were recently reviewedS4.2.3-14,S4.2.3-18 and have been tabulated in the 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients with Syncope (Table 6).S4.2.3-19 Choice of device is predicated on frequency of symptoms and the degree to which symptoms incapacitate the patient.S4.2.3-13, S4.2.3-14,S4.2.3-18–S4.2.3-20 Whatever monitoring system is chosen, it is important for the appropriate infrastructure to be present to facilitate timely notification of the patient and healthcare provider when a potentially dangerous abnormality is identified.

4.2.4 Imaging in Patients With Documented or Suspected Bradycardia or Conduction Disorders

Recommendations for Cardiac Imaging in Bradycardia or Conduction Disorders Referenced studies that support recommendations are summarized in Online Data Supplements 3 and 4.

COR LOE Recommendations

I B-NR 1.  In patients with newly identified LBBB, seconddegree Mobitz type II atrioventricular block, high-grade atrioventricular block, or thirddegree atrioventricular block with or without apparent structural heart disease or coronary artery disease, transthoracic echocardiography is recommended.S4.2.4-1–S4.2.4-10

IIa B-NR 2.  In selected patients presenting with bradycardia or conduction disorders other than LBBB, second-degree Mobitz type II atrioventricular block, high-grade atrioventricular block, or third-degree atrioventricular block, transthoracic echocardiography is reasonable if structural heart disease is suspected.S4.2.4-3,S4.2.4-11–S4.2.4-13

IIa C-LD 3.  In selected patients with bradycardia or bundle branch block, disease-specific advanced imaging (eg, transesophageal echocardiography, computed tomography, cardiac magnetic resonance imaging [MRI], or nuclear imaging) is reasonable if structural heart disease is suspected yet not confirmed by other diagnostic modalities.S4.2.4-14–S4.2.4-22

III: No Benefit B-NR 4.  In the evaluation of patients with asymptomatic sinus bradycardia or firstdegree atrioventricular block and no clinical evidence of structural heart disease, routine cardiac imaging is not indicated.S4.2.4-22–S4.2.4-24

Synopsis

Because bradycardia or conduction disorders can be present in a wide variety of cardiovascular and systemic diseases and, because the prognosis of documented bradyarrhythmias is heavily influenced by the presence of underlying structural heart disease, assessment of cardiac structure and function is often clinically indicated. In an international survey of 43 medical centers belonging to the European Heart Rhythm Association’s electrophysiology research network, 66% reported that they “always or almost always” perform an echocardiogram in patients presenting with syncope. An additional 27% reported that they pursue such testing in “most cases.”S4.2.4-25 The ACCF/ASE/AHA/ASNC/HFSA/ HRS/SCAI/SCCM/SCCT/SCMR 2011 appropriate use criteria for echocardiography endorses the propriety of echocardiography in patients with symptoms suspected to be cardiac in origin, including symptoms potentially caused by bradycardia or conduction disorders such as syncope, or lightheadedness /presyncope with signs or symptoms of cardiovascular disease known to cause such symptoms (eg, aortic stenosis, hypertrophic cardiomyopathy or heart failure).S4.2.4-12 Advanced imaging, both cardiac and noncardiac, can be helpful in carefully selected patients suspected to have structural cardiac disease known to be associated with bradycardia or conduction disturbances that is not apparent on echocardiogram and those patients in whom heterotaxy syndromes such as polysplenia is suspected.

Recommendation-Specific Supportive Text

1.	 In unselected populations, those with LBBB have a higher prevalence of both cardiovascular and noncardiovascular comorbiditiesS4.2.4-6 and an increased likelihood of underlying structural heart disease.S4.2.4-4,S4.2.4-8,S4.2.4-10 Longitudinal, community-based and cohort studies suggest an associated increased risk of cardiovascular death, sudden death, and death from congestive heart failure, without an increase in all-cause mortality.S4.2.4-1,S4.2.4-2,S4.2.4-5,S4.2.4-9,S4.2.4-10,

S4.2.4-26,S4.2.4-27 Some also suggest increased incident coronary artery disease and congestive heart failure during follow-up.S4.2.4-1,S4.2.4-2, S4.2.4-8,S4.2.4-9 The clinical implications of asymptomatic LBBB in young, apparently healthy individuals may differ from those in an older or sicker population.S4.2.4-28,S4.2.4-29 Nonetheless, excluding associated structural heart disease in all patients with LBBB is prudent as the conduction disorder may not only be a harbinger of occult structural or ischemic heart disease but also connotes an elevated risk should they be presentS4.2.4-1,S4.2.4-7, S4.2.4-30–S4.2.4-36 and may influence management in some forms of structural heart disease. Most notably, LBBB helps identify candidates for resynchronization therapy in those with heart failure with reduced ejection fraction.S4.2.4-37,S4.2.4-38

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