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Kusumoto et al 2018 Bradycardia Clinical Practice Guidelines

August 20, 2019 Circulation. 2019;140:e382–e482. DOI: 10.1161/CIR.0000000000000628 e410

CLINICAL STATEMENTS AND GUIDELINES in the setting of acute SND, in the absence of spinal cord injury or post-heart transplantation. However, a Cochrane systematic review of 5 randomized trials evaluating the use of aminophylline in the setting of out of hospital asystolic or bradycardic arrest did not show improved survival or return of spontaneous circulation.S5.3.2.4-10 Refer to Table 8.

Sinus bradycardia attributable to autonomic denervation, surgical trauma, ischemia, rejection, and prior amiodarone use is common after heart transplant.S5.3.2.4-11–S5.3.2.4-13 In contrast to normal heart rate values, bradycardia in heart transplant recipients are sometimes defined as a heart rate persistently <70 or 80 bpm.S5.3.2.4-13 Because of an acute reduction in sympathetic tone, severe sinus bradycardia is common in the acute recovery phase after spinal cord injury; both incidence and severity of bradyarrhythmias are related to the level and severity of spinal cord injury.S5.3.2.4-14 Cardiac arrest, most often attributable to sinus arrest and asystole, during the first 2 to 4 weeks after injury was observed in 16% of patients with severe cervical spinal injury.S5.3.2.4-15

Recommendation-Specific Supportive Text

1.	 Sinus bradycardia is common after heart transplant, and sinus rates of <70 to 80 bpm may be inadequate for postoperative demand. Chronotropic incompetence usually improves in the early postoperative period but can be clinically significant and require therapy in a few patients. Atropine is ineffective for treatment of post-heart transplant SND because of denervation.S5.3.2.4-16–S5.3.2.4-18 The use of terbutaline to treat sinus bradycardia after heart transplant has also been described, but data are more limited. Four small observational studies have shown improved heart rate and sinus node function after transplant using the methylxanthines aminophylline or theophylline. In 2 studies of 15 and 29 patients, oral theophylline was associated with restoration of a sinus rate of 90 bpm, and 1 study showed a reduction in PPM implantation compared with historical controls.S5.3.2.4-2,S5.3.2.4-4 The evidence for aminophylline is more limited; in invasive EPS, aminophylline infusion had variable effects on sinus node function and heart rate in heart transplant recipients.S5.3.2.4-1,S5.3.2.4-3 2.	 Sinus bradycardia requiring medical therapy is a common complication of spinal cord injury and can be persistent and refractory to atropine and other adrenergic drugs. Although an inciting cause is not always noted, common triggers for bradycardia episodes are tracheal suctioning and turning the patient.S5.3.2.4-14,S5.3.2.4-19 Although atropine and inotropes are often used to treat bradycardia and hypotension caused by autonomic dysreflexia, these drugs are not always effective. Because the primary heart rate abnormality is attributable to unopposed parasympathetic stimulation, adenosine receptor blockade by theophylline or aminophylline target the underlying pathology and has been shown to be effective in case series. Although data regarding the use of methylxanthines in this clinical condition is limited, 3 case series of 2 to 6 patients have shown beneficial effects on heart rate and avoidance of PPM implantation.S5.3.2.4-5–S5.3.2.4-7 Treatment usually can be withdrawn after 4 to 6 weeks, and side effects or adverse events are rare.S5.3.2.4-14,S5.3.2.4-19 Temporary pacing is another potential approach for treating hemodynamically significant sinus bradycardia associated with spinal cord injury.

5.3.3. Temporary Pacing for Bradycardia Attributable to SND Temporary pacing is used to acutely treat bradycardia causing hemodynamically significant instability, such as prolonged and symptomatic pauses, life-threatening ventricular arrhythmias mediated by bradycardia, or severe symptomatic bradycardia attributable to a reversible cause with the goal to avoid PPM implantation. Temporary pacing can be implemented transcutaneously,S5.3.3-1 via a transesophageal approachS5.3.3-2,S5.3.3-3 or by insertion of a transvenous pacing electrodeS5.3.3-4 or pulmonary-arterial pacing catheter.S5.3.3-5 Emergency temporary pacing for treating bradycardia associated with hemodynamic instability generally involves pacing the right ventricle (RV) because of ease of access from the venous system and rate support whether bradycardia is attributable to SND or atrioventricular block. In rare cases, temporary pacing of the right atrium (alone or in conjunction with ventricular pacing) is used when maintenance of atrioventricular synchrony is critical.

Recommendations for Temporary Pacing for Bradycardia Attributable to SND Referenced studies that support recommendations are summarized in Online Data Supplements 18, 19, 20, and 21.

COR LOE Recommendations

IIa C-LD 1.  In patients with persistent hemodynamically unstable SND refractory to medical therapy, temporary transvenous pacing is reasonable to increase heart rate and improve symptoms until a PPM is placed or the bradycardia resolves.S5.3.3-3–S5.3.3-17

IIb C-LD 2.  In patients with SND with severe symptoms or hemodynamic compromise, temporary transcutaneous pacing may be considered to increase heart rate and improve symptoms until a temporary transvenous or PPM is placed or the bradycardia resolves.S5.3.3-1,S5.3.3-18–S5.3.3-22

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