Holter electrocardiogram should be systematic in Duchenne muscular dystrophy

Abstract

Duchenne muscular dystrophy (DMD) is due to mutations in the dystrophin gene on chromosome Xp21.1. Dystrophin is a sarcolemmal protein which binds actin to extra cellular matrix. A deficiency in dystrophin leads to breakdown of muscle membrane and muscular alteration [ [1] Finsterer J, Stollberger C. The heart in human dystrophinopathies cardiology. 2003; 99: 1-19. Google Scholar ]. The disease is clinically characterized by proximal weakness and wasting, leading to loss of ambulation by 12 years of age. The heart is affected to various degrees, depending on the stage of the disease. The most common cardiac abnormality in DMD is dilated cardiomyopathy. Conduction system disease and tachyarrhythmias may occur in some patients. Death occurs in early adulthood secondary to respiratory or cardiac failure [ [2] American Academy of Pediatrics Section on Cardiology and Cardiac Surgery Cardiovascular health supervision for individuals affected by Duchenne or Becker muscular dystrophy. Pediatrics. Dec 2005; 116: 1569-1573 Crossref PubMed Scopus (169) Google Scholar ], even if recent advances in the use of inspiratory and expiratory muscle aids have greatly reduced the risk of pulmonary morbidity and mortality rates [ [3] Bach J.R. Ishikawa Y. Kim H. Prevention of pulmonary morbidity for patients with Duchenne muscular dystrophy. Chest. 1997; 112: 1024-1028 Crossref PubMed Scopus (412) Google Scholar ].The typical initial manifestation of cardiac involvement in DMD is sinus tachycardia [ [1] Finsterer J, Stollberger C. The heart in human dystrophinopathies cardiology. 2003; 99: 1-19. Google Scholar ]. Cardiac involvement is due to progressive replacement of the cardiomyocytes and the Purkinje system by connective tissue or fat [ [1] Finsterer J, Stollberger C. The heart in human dystrophinopathies cardiology. 2003; 99: 1-19. Google Scholar ]. Impairment of cardiac autonomic function in patients with DMD is well known. Kirchmann found sinus tachycardia in 26% and reduced heart rate variability in 51% [ [4] Kirchmann C. Kececioglu D. korinthenberg R. Dittrich S. Echocardiographic and electrographic finding of cardiomyopathy in Duchenne and Becker-Kiener muscular dystrophies. Pedriatr Cardiol. janv-feb 2005; 26: 66-72 Crossref PubMed Scopus (79) Google Scholar ]. In human cardiac purkinje fibers, immunocytochemical staining showed that dystrophin was localised to the membrane surface of the purkinjer fiber [ [5] Bies R.D. Friedman D. Roberts R. Perryman M.B. Caskey C.T. Expression and localization of the dystrophin in human cardiac purkinje fibers. Circulation. 1992; 86: 147-153 Crossref PubMed Scopus (52) Google Scholar ].The cardiac rhythm abnormalities play a significant role in morbidity and mortality in this disease [ [6] Corrado G. Lissoni A. Beretta S. et al. Prognostic value of electrocardiograms, ventricular late potentials, ventricular arrhythmias, and left ventricular systolic dysfunction in patients with Duchenne muscular dystrophy. Am J Cardiol. 2002; 89: 838-841 Abstract Full Text Full Text PDF PubMed Scopus (128) Google Scholar ]. Supraventricular ectopy or couplets are reported to indicate increasing severity of arrhythmia with the progression of disease [ [7] Yanagisawa A. Miyagawa M. Yotsukura M. et al. The prevalence and prognostic significance of arrhythmias in Duchenne muscular dystrophy. Am Heart J. 1992; 124: 1244-1250 Abstract Full Text PDF PubMed Scopus (44) Google Scholar ]. 33% of DMD patients had ventricular premature beats in a study including 45 Duchenne muscular dystrophy patients without congestive heart failure and followed up for 3 years [ [8] Chenard A.A. Becane H.M. Tertrain F. de Kermadec J.M. Weiss Y.A. Ventricular arrhythmia in Duchenne muscular dystrophy: prevalence, significance and prognosis. Neuromuscul Disord. May 1993; 3: 201-206 Abstract Full Text PDF PubMed Scopus (85) Google Scholar ]. Patients who died suddenly were more likely to have had documented complex ventricular arrhythmias (6 of 9; 66%) [ [8] Chenard A.A. Becane H.M. Tertrain F. de Kermadec J.M. Weiss Y.A. Ventricular arrhythmia in Duchenne muscular dystrophy: prevalence, significance and prognosis. Neuromuscul Disord. May 1993; 3: 201-206 Abstract Full Text PDF PubMed Scopus (85) Google Scholar ].Shortened PQ interval and prolonged QT interval are also reported. In a controlled series including 328 DMD patients, 62% had conduction abnormalities like shortened PQ interval and prolonged QT interval by age 10 years [ [9] Nigro G. Comi L. Politan L. Brain R.J. The incidence and evolution of cardiomyopathy in Duchenne muscular dystrophy. Int J Cardiol. 1990; 26: 271-277 Abstract Full Text PDF PubMed Scopus (480) Google Scholar ]. Conduction system disease was also reported. Indeed, complete atrioventricular block was reported in the literature in 1997 [ [10] Takano N. Honke K. Hasui M. Ohno I. Takemura H. A case of pacemaker implantation for complete atrioventrivular block associated with Duchenne muscular dystrophy. No to Hattatsu. Nov 1997; 29: 476-480 PubMed Google Scholar ]. Holter electrocardiogram should be systematic periodically in the following of the DMD patients because of possible occurring conduction system disease and tachyarrhythmias. According to American paediatrics recommendations, periodic Holter monitoring should be considered for patients with demonstrated cardiac dysfunction [ [2] American Academy of Pediatrics Section on Cardiology and Cardiac Surgery Cardiovascular health supervision for individuals affected by Duchenne or Becker muscular dystrophy. Pediatrics. Dec 2005; 116: 1569-1573 Crossref PubMed Scopus (169) Google Scholar ].