J Cardiovasc Ultrasound.  2013 Sep;21(3):148-151. 10.4250/jcu.2013.21.3.148.

Recurrent Syncope Episodes and Exercise Intolerance in Hypertrophic Cardiomyopathy Combined with Atrioventricular Conduction Disturbance

• Kim KH
• Yang DH
• Kim CY
• Kim NK
• Choi WS
• Bae MH
• Lee JH
• Park HS
• Cho Y
• Chae SC

• KMID: 1500196
• DOI: http://doi.org/10.4250/jcu.2013.21.3.148

Abstract

A 30-year-old female patient with known hypertrophic cardiomyopathy (HCMP) was admitted for recurrent syncope episodes. Electrocardiogram (ECG) showed 2 : 1 atrioventricular (AV) block. Stress echocardiography with bicycle showed high grade AV block at high stage of the exercise associated with exercise intolerance and dyspnea. Twenty-four hour ECG monitoring also revealed high grade AV block and 1 episode of non-sustained ventricular tachycardia. Implantable cardioverter/defibrillator-pacemaker (ICD-P) was inserted. After implantation of ICD-P, conduction disturbance and exercise intolerance were improved. AV block is a rare complication HCMP. There are just a few case reports that present symptoms caused by conduction disturbance in HCMP. This case describes repeated syncope episodes and exercise intolerance caused by conduction disturbance during exercise in HCMP patient. For evaluating the cause of syncope in HCMP, stress echocardiography can be helpful to understand the probable mechanism of syncope.

Keyword

Hypertrophic cardiomyopathy; Syncope; Atrioventricular block; Stress echocardiography

MeSH Terms

Adult
Atrioventricular Block
Cardiomyopathy, Hypertrophic*
Dyspnea
Echocardiography, Stress
Electrocardiography
Female
Humans
Syncope*
Tachycardia, Ventricular

Figure

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  Fig. 1 Baseline electrocardiogram (ECG) showed 2 : 1 atrioventricular conduction block with 36 beats/min of ventricular rate (A) and follow-up ECG after discontinuation previous medications showed normal sinus rhythm (B).

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  Fig. 2 Baseline echocardiogram showed asymmetric septal hypertrophy of left ventricle in parasternal view (A), systolic anterior motion of mitral valve presented by M-mode (B), and left ventricular outflow tract (LVOT) flow pattern with dagger shape and resting pressure gradient via LVOT (C).

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  Fig. 3 Simultaneous stress echocardiogram with abnormal mitral inflow pattern with multiple peaks in atrial phase (A), high grade atrioventricular block (B) and non-sustained ventricular tachycardia in 24-hour electrocardiogram monitoring (C) during exercise.

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  Fig. 4 Initial treadmill test revealed high grade atrioventricular block (A). After implantable cardioverter/defibrillator-pacemaker with ventricular pacing follow-up treadmill test (B), electrocardiogram showed no more conduction disturbance or ventricular arrhythmia during the exercise.

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