Korean Circ J.  2012 Oct;42(10):698-701. 10.4070/kcj.2012.42.10.698.

Exercise-Induced Intranodal Atrioventricular Block

• Park MY
• Shin WS
• Shim BJ
• Lee SJ
• Park JH
• Koh YS
• Lee JM

• KMID: 1826467
• DOI: http://doi.org/10.4070/kcj.2012.42.10.698

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.

Keyword

Atrioventricular block; Exercise test; Electrophysiologic techniques, cardiac

MeSH Terms

Aged
Aortic Valve
Atrioventricular Block
Bundle-Branch Block
Dizziness
Dyspnea
Electrocardiography
Electrophysiologic Techniques, Cardiac
Ergonovine
Exercise Test
Female
Follow-Up Studies
Humans
Physical Examination
Ergonovine

Figure

• 

  Fig. 1 Treadmill exercise test. A: at rest-normal AV conduction. B: stage 1-high degree AV block. C: stage 2-complete AV block. D: at recovery-normal AV conduction. AV: atrioventricular.

• 

  Fig. 2 Twenty-four-hour Holter monitoring. A: 2 : 1 AV block (atrial rate, 80 beats/min). B: normal AV conduction (atrial rate, 54 beats/min). AV: atrioventricular.

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  Fig. 3 Electrophysiologic study. A: basic sinus cycle length. B: HRA pacing at a cycle length of 780 msec-2 : 1 AV block. C: HRA pacing at a cycle length of 500 msec-high-grade 2nd degree AV block. D: intravenous atropine induced sinus rate acceleration-complete AV block. HRA: high right atrium, AV: atrioventricular.

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