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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 e397 CLINICAL STATEMENTS AND GUIDELINES 4.2.2. Exercise Electrocardiographic Testing in Patients With Documented or Suspected Bradycardia or Conduction Disorders Recommendations for Exercise Electrocardiographic Testing in Patients With Documented or Suspected Bradycardia or Conduction Disorders Referenced studies that support recommendations are summarized in Online Data Supplement 2. COR LOE Recommendations IIa B-NR 1. In patients with suspected chronotropic incompetence, exercise electrocardiographic testing is reasonable to ascertain the diagnosis and provide information on prognosis.S4.2.2-1,S4.2.2-2 IIa C-LD 2. In patients with exercise-related symptoms suspicious for bradycardia or conduction disorders, or in patients with 2:1 atrioventricular block of unknown level, exercise electrocardiographic testing is reasonable.S4.2.2-3,S4.2.2-4 Synopsis Although there is no routine role for exercise electrocardiographic testing in the evaluation of patients with suspected or documented bradycardia/conduction disorder, it may be useful in selected patients. Limited observational data suggest that it can be useful in evaluating those whose symptoms occur during or immediately after exercise, including those suspected of chronotropic incompetence and exercise-induced, neurally mediated syncope. Occasionally, patients manifest conduction disorders precipitated by myocardial ischemia during exercise electrocardiographic testing. Exercise testing can be helpful in evaluating the impact of parasympathetic withdrawal and sympathetic activation on cardiac conduction (eg, distinguishing atrioventricular nodal versus conduction disturbances in the His Purkinje system below the atrioventricular node [infranodal] in the setting of 2:1 atrioventricular nodal block).S4.2.2-5 Recommendation-Specific Supportive Text 1. Exercise electrocardiographic testing is integral to the diagnosis of chronotropic incompetence, a condition broadly defined as an inability to increase heart rate commensurate with the increased metabolic demands of physical activity.S4.2.2-6 Chronotropic incompetence, often considered as failure to achieve 80% of age-predicted maximal heart rate but in practice much more difficult to define particularly in the presence of comorbidities can contribute to exercise intolerance and connotes an adverse prognosis.S4.2.2-1,S4.2.2-2,S4.2.2-7 Although estimates of prevalence range broadly from 9% to 89% it appears to be common in individuals with cardiovascular disease, including one-third of those with congestive heart failure.S4.2.2-6 2. In patients with exercise-related symptoms, the development or progression of atrioventricular block may occasionally be the underlying cause. Because worsening atrioventricular block with exercise is usually attributable to infranodal disease, exercise electrocardiographic testing may also be helpful for defining the site of atrioventricular block when unclear by ambulatory electrocardiographic monitoring.S4.2.2-4,S4.2.2-5,S4.2.2-8 Only rarely does exercise testing uncover otherwise occult and clinically significant conduction disorders. Although typically associated with signs and symptoms of ischemia during the test, exercise-induced conduction disorders have been reported without evidence of ischemia.S4.2.2-4 Conduction disorders elicited by exercise electrocardiographic testing in rare cases may be precipitated by myocardial ischemia or coronary vasospasm.S4.2.2-9–S4.2.2-13 In a review of 2 200 consecutive exercise tests to assess the significance of transient intraventricular conduction abnormalities associated with myocardial ischemia, only 10 (0.45%) patients manifested both ischemia and intraventricular conduction abnormalities. Subsequent coronary angiography revealed significant stenosis of the left anterior descending coronary artery at or before the first septal branch in all 10.S4.2.2-11 In patients presenting with syncope without exercise related symptoms, the yield of exercise electrocardiographic testing even with additional imaging modalities is low.S4.2.2-14 4.2.3. Ambulatory Electrocardiography in Patients With Documented or Suspected Bradycardia or Conduction Disorders Recommendation for Ambulatory Electrocardiography in Patients With Documented or Suspected Bradycardia or Conduction Disorders Referenced studies that support the recommendation are summarized in Online Data Supplement 3. COR LOE Recommendation I B-NR 1. In the evaluation of patients with documented or suspected bradycardia or conduction disorders, cardiac rhythm monitoring is useful to establish correlation between heart rate or conduction abnormalities with symptoms, with the specific type of cardiac monitor chosen based on the frequency and nature of symptoms, as well as patient preferences.S4.2.3-1–S4.2.3-12 Synopsis The intermittent nature of most symptomatic bradycardia and conduction disorders often necessitates a more prolonged form of electrocardiographic monitoring to correlate rhythm disturbances with symptoms. For those with daily symptoms, a 24- or 48-hour continuous ambulatory ECG (Holter monitor) is appropriate Downloaded from http://ahajournals.org by on October 7, 2026