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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 e447 CLINICAL STATEMENTS AND GUIDELINES 2. Given that regions of myocardium may not be irreversibly infarcted, and adequate reperfusion will improve electrical conduction, temporary atrioventricular block is common. The outcome is therefore determined primarily by the clinical presentation, location of infarct, and associated myocardial damage.S8.3-6,S8.3-7,S8.3-9–S8.3-11,S8.3-23 Anterior MI with associated atrioventricular conduction impairment generally confers a worse prognosis with a higher mortality than an inferior MI with a similar initial presentation.S8.3-1,S8.3-4,S8.3-6,S8.3-12,S8.3-24 Indications, therefore, for PPM implantation in the setting of an acute MI are based on the clinical situation, and adequate observation to allow for recovery of atrioventricular conduction, and to avoid unnecessary pacemaker implantation. Again, the clinician should carefully consider and generally avoid early permanent pacing (<72 hours), so as to potentially avoid unnecessary implantation of pacemakers.S8.3-10,S8.3-23 It may be reasonable to consider CIED with defibrillator capacity in patients with pacing requirement and low LVEF as indicated in other scientific society statements.S8.3-25,S8.3-26 3. Persistent evidence of infranodal conduction impairment is associated with more severe myocardial injury, and a worse prognosis. In the context of infranodal conduction block maintenance of ventricular systole depends on the presence of less reliable ventricular escape rhythms. It may be reasonable to consider CIED with defibrillator capacity in patients with pacing requirement and low LVEF as indicated in other scientific society statements.S8.3-25,S8.3-26 4. Autonomic derangements during an acute MI are common, and small case series suggest that atropine can be used to increase heart rate.S8.3-27 Atropine appears to be safe in those patients with atrioventricular nodal block in the absence of infranodal conduction system disease.S8.3-9,S8.3- 28,S8.3-29 In contrast, it is important to recognize that the use of atropine in patients with infranodal conduction disease or block can be associated with exacerbation of block and is potentially of harm. Aminophylline/theophylline has also been examined in this setting, and in the context of very limited data appears likely to be safe if atropine is ineffective.S8.3-10,S8.3-11,S8.3-30,S8.3-31 5. Given that the natural course of an MI with conduction system abnormalities is frequently associated with recovery of conduction, early and unnecessary pacing should be avoided.S8.3-1,S8.3- 4,S8.3-7,S8.3-12 Although PPM implantation is a relatively low risk cardiac procedure, complications including death range from 3% to 7% and there are significant long-term implications for pacing systems that use transvenous leads.S8.3-13–S8.3-16 6. Although injury to the fascicular system in the context of an acute MI indicates substantial myocardial injury (commonly through an anterior infarction), patients with injury to single bundle branches or fascicles have not been shown to benefit from permanent pacing.S8.3-1,S8.3-4,S8.3-6,S8.3-12,S8.3-24 8.4 Neurologic Disorders A number of neurologic disorders can be associated with bradycardia, for example increased intracranial pressure (often called Cushing’s reflex).S8.4-1 In these settings, bradycardia can be treated as described in the acute management sections (Sections 5.4. and 6.3.) if heart rate support is required. During chronic management of neurologic disorders, bradycardia can be observed in several settings. General recommendations for the management of cardiac involvement in patients with neuromuscular disorders including recommendations on surveillance and medical management have been provided in a recent AHA scientific statement.S8.4-2 Specific recommendations for permanent pacing in the setting of progressive neurologic disorders that affect atrioventricular and intraventricular conduction has been discussed in Sections 6.4.4. and 7.5. in this document and special considerations for permanent pacing in patients with neuromuscular disease is summarized in Table S4 in the Web Supplement. Traumatic spinal cord injury above the sixth thoracic spinal cord can result in autonomic dysreflexia characterized by sympathetic impairment and preserved parasympathetic responses via the vagus nerve. Profound bradycardia can be triggered by noxious stimuli such as bladder catheterization.S8.4-3 In a prospective multicenter study of 315 patients with spinal cord injury, bradycardia accounted for approximately 50% of the observed cardiovascular complications.S8.4-4 Because bradycardia resolves after either a few weeks or removal of the noxious stimulus, conservative therapy is generally successful for managing the bradycardia. However, in some cases where symptomatic bradycardia cannot be avoided by conservative measures permanent pacing can be considered using the standard recommendations for implantation outlined in Sections 5.4.4. and 6.4.4. 8.4.1 Epilepsy Recommendation for Patients With Epilepsy and Symptomatic Bradycardia Referenced studies that support the recommendation are summarized in Online Data Supplement 55. COR LOE Recommendation IIa C-LD 1. In patients with epilepsy associated with severe symptomatic bradycardia (ictal bradycardia) where antiepileptic medications are ineffective, permanent pacing is reasonable for reducing the severity of symptoms.S8.4.1-1–S8.4.1-4 Downloaded from http://ahajournals.org by on October 7, 2026