医師国家試験 第114回 問31
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A 26-year-old woman presented to the emergency room with palpitations and shortness of breath that started suddenly while she was eating breakfast. Although the health-screening examination performed three weeks ago showed delta waves in her ECG, echocardiography taken at a nearby hospital showed no abnormal findings. At presentation, she was slightly hypotensive with a blood pressureof96/68mmHg. HerECGonadmissionshowedanarrowQRS-complex tachycardia at a rate of 180/min. Neither ST elevation nor T wave abnormality was present. What is the most probable diagnosis of the arrhythmia?
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Supraventricular tachycardia
健診の心電図でデルタ波を認めていることからWPW症候群があり、今回は突然発症した心拍数180/分のnarrow QRS頻拍です。QRS幅が狭いことから心室起源ではなく、副伝導路と房室結節を旋回する房室回帰性頻拍などの上室性頻拍(supraventricular tachycardia)と考えられます。洞頻脈では180/分の突然発症は説明しにくく、洞不全症候群や完全房室ブロックは徐脈性不整脈です。