p.43 抽出テキスト

Kusumoto et al 2018 Bradycardia Clinical Practice Guidelines

August 20, 2019 Circulation. 2019;140:e382–e482. DOI: 10.1161/CIR.0000000000000628 e424

CLINICAL STATEMENTS AND GUIDELINES 6.4.1. General Principles of Chronic Therapy/ Management of Bradycardia Attributable to Atrioventricular Block

Recommendations for General Principles of Chronic Therapy/ Management of Bradycardia Attributable to Atrioventricular Block Referenced studies that support recommendations are summarized in Online Data Supplements 31, 32, 33, and 34.

COR LOE Recommendations

III: Harm C-LD 1.  In patients with first-degree atrioventricular block or second-degree Mobitz type I (Wenckebach) or 2:1 atrioventricular block which is believed to be at the level of the atrioventricular node, with symptoms that do not temporally correspond to the atrioventricular block, permanent pacing should not be performed.S6.4.1-1–S6.4.1-7

III: Harm C-LD 2.  In asymptomatic patients with first-degree atrioventricular block or second-degree Mobitz type I (Wenckebach) or 2:1 atrioventricular block which is believed to be at the level of the atrioventricular node, permanent pacing should not be performed.S6.4.1-4–S6.4.1-10

Synopsis

The presence or absence of symptoms is a major determinant on whether permanent pacing will be required in the setting of bradycardia associated with atrioventricular block. In addition to symptoms, there are 3 additional clinical issues that must be considered when deciding on the use of permanent pacing in patients with atrioventricular block. First, the site of atrioventricular block is critical because patients with infranodal disease who then later develop complete heart block will be dependent on unreliable ventricular escape rhythms. Second, significant amounts of right ventricular pacing are potentially deleterious. Finally, patients with atrioventricular block may have an associated systemic disease that leads to progressive atrioventricular block or has additional risk for ventricular arrhythmias.

Recommendation-Specific Supportive Text

1.	 In patients who have second-degree Mobitz type I (Wenckebach) or 2:1 atrioventricular block but with symptoms of dizziness or presyncope or even syncope that do not temporally correspond to the episode of atrioventricular block, it is unclear whether permanent pacing will improve symptoms or alleviate them. If the level of the block is at the atrioventricular node, then sudden progression to a higher degree of atrioventricular block is unlikely.S6.4.1-1,S6.4.1-3 If the symptoms do not correlate with the episodes of first-degree or second-degree Mobitz type I atrioventricular block, the episodes would be considered unrelated and a pacemaker would not be indicated.S6.4.1-1,S6.4.1-3 Given the procedural and long-term risks of PPMs, in the absence of mitigating circumstances, for patients with first-degree or second-degree Mobitz type I (Wenckebach) atrioventricular block that does not clearly correspond to symptoms, further monitoring and follow up should be implemented.S6.4.1-4–S6.4.1-7

2.	 Firstand second-degree Mobitz type I (Wenckebach) atrioventricular blocks (or 2:1 atrioventricular block, if the level of block is at the atrioventricular node) are typically benign in that they do not progress suddenly to complete heart block.S6.4.1-1,S6.4.1-3 Treatment of these conduction disorders with a pacemaker are typically reserved for significant symptoms that affect QOL. Occasionally second-degree Mobitz type I (Wenckebach) atrioventricular block is in fact infranodal, and in those instances a pacemaker may be considered even in the absence of symptoms.S6.4.1-1 Although a narrow QRS complex suggests that the block is at the level of the atrioventricular node, there are instances where it has been determined to be infranodal during an EPS. Symptoms may be difficult to correlate but ambulatory electrocardiographic monitoring or a treadmill exercise test may be useful. Improvement in atrioventricular conduction suggests that the site of block is at the atrioventricular node, whereas worsening atrioventricular conduction suggests infranodal block. If the symptoms do not clearly correspond to the episodes of atrioventricular block, the risks associated with the pacemaker in the absence of clear benefit make the overall risk-benefit ratio unfavorable.S6.4.1-11 Similarly, in patients with long-standing persistent or permanent AF with a low heart rate and appropriate chronotropic response, in the absence of symptoms, pacing for rate support is unlikely to be beneficial. Although PPM implantation is a relatively low-risk cardiac procedure, procedural complications and death directly related to implant can occur, and implanted leads have long-term management implications.S6.4.1-4–S6.4.1-7

6.4.2 Transient/Potentially Reversible Causes of Atrioventricular Block

Recommendations for Potentially Reversible or Transient Causes of Atrioventricular Block Referenced studies that support recommendations are summarized in Online Data Supplements 34, 35, 36, and 37.

COR LOE Recommendations

I C-LD 1.  In patients with symptomatic atrioventricular block attributable to a known reversible cause in whom the atrioventricular block does not resolve despite treatment of the underlying cause, permanent pacing is recommended.S6.4.2-1–S6.4.2-3

Downloaded from http://ahajournals.org by on October 7, 2026