Cardiac involvement determines the prognosis of Duchenne muscular dystrophy
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《美国医学杂志》
Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Vienna, Austria
With interest we read the article by Gulati et al on cardiac involvement (CI) in 30 patients with Duchenne muscular dystrophy (DMD).[1] The authors conclude that cardiomyopathy in DMD is frequently subclinical or subtle with sinus-tachycardia already in the early stages of the disease, requiring echocardiography for comprehensive assessment of CI.[1] The study raises the following concerns:
It is known that approximately two thirds of the DMD cases are familial and only one third is sporadic.[2] How to explain that the family history of the presently investigated patients was positive in only one third of the cases
The authors mention enlargement of skeletal muscles in 13% of their cases. Usually, only the calf muscles are affected. Did the authors also find pseudohypertrophy of muscles other than those of the calves
Mean age at loss of ambulation was 8.1y but at the time of the study when mean age was 10.1y only 63% were non-ambulatory. How to explain this discrepancy How to explain that 10% of the patients had cardiac symptoms or signs already at onset of DMD (mean age at onset: 4.8y) although it is reported that CI usually manifests clinically after age 10y at the onset of the wheel chair bound stage.[3] How to explain that only 10% had symptoms or signs suggestive of CI whereas 64% had an EF <55%
Eighty percent of the patients had a deceleration time of <150ms, but all had an E/A ratio >1, which is compatible with a restrictive filling pattern. Which is the cause of this finding. Do the authors explain this unusual finding with early myocardial fibrosis were also the atria enlarged in patients with restrictive filling pattern. How many of the patients fulfilled the diagnostic criteria for dilative cardiomyopathy Since age of patients was quite variable, it is desirable that measurements presented in [Table 2] were related to body size. Also atrial size should be given.
Recently, it has been shown that left ventricular hypertrabeculation/noncompaction (LVHT) is a possible manifestation of CI in DMD.[4] Did the authors look for LVHT and how many of their patients presented with LVHT on echocardiography Did those patients who died during follow up undergo autopsy Which were the patho-anatomic findings in these patients Did any of the deceased patients present with LVHT
Compared to previous studies,[3],[5] how to explain the presence of ECG abnormalities in 93% of the cases already at a mean age of 10.1y Though CI in DMD increases with age, CI is clinically present in all DMD patients not earlier than at age 18y.[3] Some studies recommend β -blockers for sinustachycardia.[6] Did any of the presented patients also receive β -blockers instead of digitoxin, and if not which was the reason for not taking β -blockers
How to explain the origin of rhythm abnormalities in the posterobasal and inferior left ventricular wall
How to explain the absence of a correlation between clinical parameters, creatine-kinase levels, presence of dystrophin deletions, corticosteroid therapy, and CI How to explain the association between deletions and the cardio-thoracic ratio Recently, it has been reported that systolic function improves from corticosteroids in addition to skeletal muscle performance.[7] How to explain that there was no relation between corticosteroid therapy and CI
Overall, CI in DMD manifests at varying age and initially subclinically. Clinical CI develops at later stages and comprises ECG abnormalities and dilative cardiomyopathy. Development of CI in DMD over time is still an unsolved issue and requires comprehensive and long-term observations in a large number of genetically confirmed patients.
References
1.Gulati S, Saxena A, Kumar V, Kalra V. Duchenne Muscular dystrophy: prevalence and patterns of cardiac involvement. Indian J Pediatr 2005; 72: 389-393.
2.Bakker E, van Ommen GJB. Duchenne and Becker muscular dystrophy . In Emery AEH, ed. Neuromuscular disorders: Clinical and molecular genetics. Chichester; John Wiley & Sons, 1998
3.Nigro G, Comi LI, Politano L, Bain RJ. The incidence and evolution of cardiomyopathy in Duchenne muscular dystrophy. Int J Cardiol 1990; 26: 271-277. [PUBMED]
4.Finsterer J, St φllberger C, Gaismayer K Janssen B. Acquired noncompaction in Duchenne muscular dystrophy. Int J Cardiol 2005; (in press)
5.Sanyal SK, Johnson WW. Cardiac conduction abnormalities in children with Duchenne's progressive muscular dystrophy: electrocardiographic features and morphologic correlates. Circulation 1982; 66: 853-863. [PUBMED]
6.Bushby K, Muntoni F, Bourke JP. 107th ENMC International Workshop: the management of cardiac involvement in muscular dystrophy and myotonic dystrophy. 7th-9th June 2002, Naarden, the Netherlands. Neuromuscul Disord 2003; 13: 166-172
7.Markham LW, Spicer RL, Khoury PR, Wong BL, Mathews KD, Cripe LH. Steroid Therapy and Cardiac Function in Duchenne Muscular Dystrophy. Pediatr Cardiol 2005; (in press)(Finsterer Josef, Stollberger Claudia)
With interest we read the article by Gulati et al on cardiac involvement (CI) in 30 patients with Duchenne muscular dystrophy (DMD).[1] The authors conclude that cardiomyopathy in DMD is frequently subclinical or subtle with sinus-tachycardia already in the early stages of the disease, requiring echocardiography for comprehensive assessment of CI.[1] The study raises the following concerns:
It is known that approximately two thirds of the DMD cases are familial and only one third is sporadic.[2] How to explain that the family history of the presently investigated patients was positive in only one third of the cases
The authors mention enlargement of skeletal muscles in 13% of their cases. Usually, only the calf muscles are affected. Did the authors also find pseudohypertrophy of muscles other than those of the calves
Mean age at loss of ambulation was 8.1y but at the time of the study when mean age was 10.1y only 63% were non-ambulatory. How to explain this discrepancy How to explain that 10% of the patients had cardiac symptoms or signs already at onset of DMD (mean age at onset: 4.8y) although it is reported that CI usually manifests clinically after age 10y at the onset of the wheel chair bound stage.[3] How to explain that only 10% had symptoms or signs suggestive of CI whereas 64% had an EF <55%
Eighty percent of the patients had a deceleration time of <150ms, but all had an E/A ratio >1, which is compatible with a restrictive filling pattern. Which is the cause of this finding. Do the authors explain this unusual finding with early myocardial fibrosis were also the atria enlarged in patients with restrictive filling pattern. How many of the patients fulfilled the diagnostic criteria for dilative cardiomyopathy Since age of patients was quite variable, it is desirable that measurements presented in [Table 2] were related to body size. Also atrial size should be given.
Recently, it has been shown that left ventricular hypertrabeculation/noncompaction (LVHT) is a possible manifestation of CI in DMD.[4] Did the authors look for LVHT and how many of their patients presented with LVHT on echocardiography Did those patients who died during follow up undergo autopsy Which were the patho-anatomic findings in these patients Did any of the deceased patients present with LVHT
Compared to previous studies,[3],[5] how to explain the presence of ECG abnormalities in 93% of the cases already at a mean age of 10.1y Though CI in DMD increases with age, CI is clinically present in all DMD patients not earlier than at age 18y.[3] Some studies recommend β -blockers for sinustachycardia.[6] Did any of the presented patients also receive β -blockers instead of digitoxin, and if not which was the reason for not taking β -blockers
How to explain the origin of rhythm abnormalities in the posterobasal and inferior left ventricular wall
How to explain the absence of a correlation between clinical parameters, creatine-kinase levels, presence of dystrophin deletions, corticosteroid therapy, and CI How to explain the association between deletions and the cardio-thoracic ratio Recently, it has been reported that systolic function improves from corticosteroids in addition to skeletal muscle performance.[7] How to explain that there was no relation between corticosteroid therapy and CI
Overall, CI in DMD manifests at varying age and initially subclinically. Clinical CI develops at later stages and comprises ECG abnormalities and dilative cardiomyopathy. Development of CI in DMD over time is still an unsolved issue and requires comprehensive and long-term observations in a large number of genetically confirmed patients.
References
1.Gulati S, Saxena A, Kumar V, Kalra V. Duchenne Muscular dystrophy: prevalence and patterns of cardiac involvement. Indian J Pediatr 2005; 72: 389-393.
2.Bakker E, van Ommen GJB. Duchenne and Becker muscular dystrophy . In Emery AEH, ed. Neuromuscular disorders: Clinical and molecular genetics. Chichester; John Wiley & Sons, 1998
3.Nigro G, Comi LI, Politano L, Bain RJ. The incidence and evolution of cardiomyopathy in Duchenne muscular dystrophy. Int J Cardiol 1990; 26: 271-277. [PUBMED]
4.Finsterer J, St φllberger C, Gaismayer K Janssen B. Acquired noncompaction in Duchenne muscular dystrophy. Int J Cardiol 2005; (in press)
5.Sanyal SK, Johnson WW. Cardiac conduction abnormalities in children with Duchenne's progressive muscular dystrophy: electrocardiographic features and morphologic correlates. Circulation 1982; 66: 853-863. [PUBMED]
6.Bushby K, Muntoni F, Bourke JP. 107th ENMC International Workshop: the management of cardiac involvement in muscular dystrophy and myotonic dystrophy. 7th-9th June 2002, Naarden, the Netherlands. Neuromuscul Disord 2003; 13: 166-172
7.Markham LW, Spicer RL, Khoury PR, Wong BL, Mathews KD, Cripe LH. Steroid Therapy and Cardiac Function in Duchenne Muscular Dystrophy. Pediatr Cardiol 2005; (in press)(Finsterer Josef, Stollberger Claudia)