title: Exercise-induced intranodal atrioventricular block.
abstract: Exercise-induced atrioventricular (AV) block in patients with normal AV conduction at rest is rare. Herein, we describe the case of a 67-year-old woman with normal 1 : 1 AV conduction at rest, who developed complete AV block during a treadmill test. Our patient complained of effort-related dizziness and dyspnea, which had been ongoing for 3 months. The patient's physical examination was normal. The resting electrocardiogram showed left anterior fascicular block with a PR interval of 0.19 seconds. The echocardiogram was normal except for mild aortic valve regurgitation. During the treadmill test, the patient developed complete AV block at a sinus rate of 90 beats/min, which was followed by 2 : 1 AV block associated with dyspnea and dizziness. The patient's coronary angiogram was normal, and the ergonovine provocation test was negative. Electrophysiological studies demonstrated rate-dependent intranodal AV block. The patient received implantation of a permanent dual chamber (DDD) pacemaker and had no further symptoms during the follow-up period.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Pohang St. Mary's Hospital, Pohang, Korea.
authors.forename: Mi-Youn
authors.initials: MY
authors.lastname: Park
authors.forename: Woo-Seung
authors.initials: WS
authors.lastname: Shin
authors.forename: Byung-Ju
authors.initials: BJ
authors.lastname: Shim
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Jae-Hong
authors.initials: JH
authors.lastname: Park
authors.forename: Yoon-Seok
authors.initials: YS
authors.lastname: Koh
authors.forename: Jong-Min
authors.initials: JM
authors.lastname: Lee