open access

Vol 18, No 3 (2011)
Interesting electrocardiograms
Published online: 2011-06-09
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Progressive conduction disturbance in myotonic dystrophy

Jorge Palazzolo, Emilce Trucco, Mauricio Arce, Andrés Ricardo Pérez Riera, Francisco Femenía
Cardiol J 2011;18(3):322-325.

open access

Vol 18, No 3 (2011)
Interesting electrocardiograms
Published online: 2011-06-09

Abstract

Myotonic dystrophy (DM), the commonest dystrophy in adults, is an autosomal dominant disease characterized by a variety of multisystemic features. Two main genetically distinct forms of DM have been identified: type 1 (DM1), the classic form first described by Steinert, and type 2 (DM2), identified by Ricker. DM1 is caused by trinucleotide expansion of cytosine- -thymine-guanine (CTG) in the myotonic dystrophy protein kinase gene, whereas in DM2 the expansion of tetranucleotide repeats (CCTG) in the zinc finger protein 9 gene was identified. Both mutations are dynamic and are located in non-coding parts of the genes. Phenotype variability of DM1 and DM2 is caused by a molecular mechanism due to mutated RNA toxicity. DM1 is characterized by myotonia and multi-organ damage with major cardiac involvement. The disease is usually slowly progressive and life expectancy is reduced by the increased mortality associated with cardiopulmonary complications. Sudden death can occur as a consequence of cardiac-conduction abnormalities. We present the ECG of a 26 year-old male with DM1 and progressive conduction system disturbance characterized by syncopal episodes. (Cardiol J 2011; 18, 3: 322–325)

Abstract

Myotonic dystrophy (DM), the commonest dystrophy in adults, is an autosomal dominant disease characterized by a variety of multisystemic features. Two main genetically distinct forms of DM have been identified: type 1 (DM1), the classic form first described by Steinert, and type 2 (DM2), identified by Ricker. DM1 is caused by trinucleotide expansion of cytosine- -thymine-guanine (CTG) in the myotonic dystrophy protein kinase gene, whereas in DM2 the expansion of tetranucleotide repeats (CCTG) in the zinc finger protein 9 gene was identified. Both mutations are dynamic and are located in non-coding parts of the genes. Phenotype variability of DM1 and DM2 is caused by a molecular mechanism due to mutated RNA toxicity. DM1 is characterized by myotonia and multi-organ damage with major cardiac involvement. The disease is usually slowly progressive and life expectancy is reduced by the increased mortality associated with cardiopulmonary complications. Sudden death can occur as a consequence of cardiac-conduction abnormalities. We present the ECG of a 26 year-old male with DM1 and progressive conduction system disturbance characterized by syncopal episodes. (Cardiol J 2011; 18, 3: 322–325)
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Keywords

myotonic dystrophy; syncope; atrioventricular block; sudden death

About this article
Title

Progressive conduction disturbance in myotonic dystrophy

Journal

Cardiology Journal

Issue

Vol 18, No 3 (2011)

Pages

322-325

Published online

2011-06-09

Bibliographic record

Cardiol J 2011;18(3):322-325.

Keywords

myotonic dystrophy
syncope
atrioventricular block
sudden death

Authors

Jorge Palazzolo
Emilce Trucco
Mauricio Arce
Andrés Ricardo Pérez Riera
Francisco Femenía

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