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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 e405 CLINICAL STATEMENTS AND GUIDELINES

cardiovascular events including syncope, AF, and heart failure.S5.1-13 Moreover, the development of chronotropic incompetence with age is associated with increased risk of cardiovascular death and overall mortality.S5.1-14,S5.1-15 Although the underlying causes are not well understood, heart rate variability also decreases with age.S5.1-16

5.2 Clinical Presentation of SND

Symptoms attributable to SND can range from mild fatigue to frank syncope. The severity of clinical manifestations generally correlates with the heart rate or the pause duration. Syncope is a common manifestation and, in 1 trial,S5.2-1 was present in 50% of patients who received pacemakers for SND. Other clinical symptoms include dyspnea on exertion caused by chronotropic incompetence, lightheadedness, and chronic fatigue. Patients with SND may manifest symptoms attributable to sinus bradycardia, sinus arrest or sinoatrial exit block. Correlation between symptoms and bradycardia is considered to be the “gold standard” of diagnosis. However, it may be difficult to establish this correlation in some cases because of the presence of competing etiologies of symptoms as well as limitations in monitoring (eg, comorbid conditions that prohibit long-term monitoring because of fear of injuries).

5.3 Acute Management of SND

A master algorithm for the acute management of bradycardia is given in Figure 4. Specific subsections address acute management of drug toxicity for bradycardia attributable to SND or atrioventricular block, and reversible causes, acute medical therapies, and temporary pacing specifically in the setting of SND.

5.3.1 Acute Management of Reversible Causes of SND

Recommendation for Acute Management of Reversible Causes for Bradycardia Attributable to SND

COR LOE Recommendation

I C-EO 1.  In symptomatic patients presenting with SND, evaluation and treatment of reversible causes is recommended.

Synopsis

Most patients with SND present with chronic complaints that do not require acute treatment. In addi- tion, most causes of SND are chronic and irreversible. In some cases, sinus bradyarrhythmias are attributable to potentially reversible causes such as acute MI, atrial tachyarrhythmias, electrolyte abnormalities, hypothyroidism, medications, infections, and metabolic abnormalities (Table 7).

Figure 4. Acute bradycardia algorithm. Colors correspond to Class of Recommendation in Table 2. See Sections 5.3. and 6.3. for discussion. *Atropine should not be given in patients after heart transplant. †In patients with drug toxicity and severe symptoms, preparation for pacing should proceed simultaneously with pharmacologic treatment of drug toxicity. ‡Refer to Section 5.3.3., Figure 5. AADs indicates antiarrhythmic drugs; AV, atrioventricular; BB, beta blocker; CCB, calcium channel blocker; COR, Class of Recommendation; ECG, electrocardiographic; H+P, history and physical examination; IMI, inferior myocardial infarction; IV, intravenous; PM, pacemaker; S/P, status post; and VS, vital signs.

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