Key result
Serial electrocardiograms in a patient with Kearns-Sayre syndrome revealed alternating bundle branch block patterns best explained by triple pathway longitudinal dissociation in the His bundle.
Why the study?
Alternating bundle branch block and specific intraventricular conduction abnormalities in Kearns-Sayre syndrome had not been previously reported.
Case Report (n=1)
No
This case report suggests that triple pathway longitudinal dissociation in the His bundle can explain the complex alternating bundle branch block patterns observed in a patient with Kearns-Sayre syndrome.
Answers are grounded in this paper and cite their sources.
Alerts clinicians to rare His-bundle mechanisms in Kearns-Sayre alternating BBB; hypothesis-generating for longitudinal dissociation, needs prospective validation.
Kearns-Sayre症候群（以下，KSS）は進行性外眼筋麻痺，網膜色素変性，心伝導ブロックを3主徴とする予後不良の疾患である．症例は現在27歳，KSSの男性である．19歳時にとられた心電図において，初めに洞調律，左軸偏位−70°，PR間隔0.16秒，QRS幅0.16秒で，完全右脚ブロック型【A】を示し，その数十秒後に左軸偏位−60°，PR時間0.15秒，QRS幅0.15秒の完全左脚ブロック型【B】を示す狭義の交代性脚ブロックを認めた．さらには，26歳時の心電図で，QRS軸±0°と先のA，Bより右方に偏位し，PR時間0.22秒，QRS幅0.15秒で，V1誘導はrSr’型で右脚ブロック型に近似しているが，V5，V6誘導にS波を認めない非特異的心室内伝導障害と考えられる波形【C】を認めた．【A】，【B】のみならず，【C】のQRS軸シフトを考慮すると，左右脚の伝導性の差のみでは説明困難であり，われわれはヒス束内縦解離による解析を行い，ヒス束内triple pathway縦解離がこれらの心電図変化の機序と考えられた．多彩な伝導障害を示すKSS症例の中で，われわれが知る限り，従来報告されていない所見と考えられたので報告する．
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Sato et al. (2023) conducted a case report in Kearns-Sayre syndrome (n=1). Electrocardiographic observation was evaluated on Electrocardiographic conduction patterns. Serial electrocardiograms in a patient with Kearns-Sayre syndrome revealed alternating bundle branch block patterns best explained by triple pathway longitudinal dissociation in the His bundle.
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