Electrocardiographic changes in cases of duchenne muscular dystrophy

BackgroundDuchene muscular dystrophy is an x-linked recessive progressive muscular disease. It presents in first year of life and is fatal by second decade mostly because of respiratory involvement and in 10% case because of cardiac failure. The cardiac involvement usually occurs after 10 years age. The incidence of cardiac involvement increases with increasing age affecting all patients by age of 18 years.Duchene muscular dystrophy(DMD) usually leads to dilated cardiomyopathy (DCM), congestive cardiac failure, arrhythmias, & sudden cardiac death. DMD may be associated with various ECG changes like sinus tachycardia, reduction of circadian index, decreased heart rate variability, short PR interval, right ventricular hypertrophy, S-T segment depression and prolonged QTc. Rarely it might be associated with Wolf Parkinson White syndrome(WPW syndrome). WPW syndrome is characterized by short PR interval, delta wave, and wide QRS complex and is a surface evidence of accessory pathway. It might be associated with supraventricular tachycardia and sudden cardiac death from ventricular tachycardia.AimTo study ECG findings in cases of Duchenne muscular dystrophy. Materials and methodsThe study was conducted at Pediatric cardiology department, Prince Salman Heart Centre Riyadh. All patients diagnosed as Duchenne muscular dystrophy were included in the study. The diagnostic criteria were clinical, biochemical and confirmed by PCR. All patients underwent 12 lead ECG and long lead II in recumbent posture and 24h holter monitoring and echocardiogram. The 24h holter was applied to all patients. The were given a diary to record any symptoms like palpitation, syncope, chest pain or dyspnea during 24 holter monitoring. The holters were reviewed for heart rate and presence of any ectopics or arrhythmias. The electrocardiogram of all patients were reviewed and following parameters were noted ; characteristics heart rate, R waves, waves, R–S ratio, PR interval, delata wave, Q waves, QT interval, T wave, ST segment. The aforementioned ECG parameters were studied and measured manually and compared with published standard age matched normal values. The abnormal were findings were defined if were away from minimal or maximal limits for that age.ResultsA total of 20 patients were studied. All were male. The mean age of patients was 10 years. The mean weight of patients was 34.5kg. Majority of patients (75%) were where wheelchair bound and 25% were ambulatory. The ECG abnormalities were noted in 80% of patients. Sinus tachycardia was present in 60% of patients. Tall R waves were present in 45% of patients with RS ratio more than 1 in lead V1 as well as deep S waves in leads V5 and V6.Short PR interval was noted in 3(15%) of patients. One patient had was diagnosed as WPW syndrome and had short PR interval, delta wave and wide QRS complex. 24h holter monitoring was normal in all patients.DiscussionThe most frequent electrocardiographic findings described in cases of Duchenne muscular dystrophy are sinus tachycardia and tall R waves in right precordial leads as seen in our study. Similar findings are also observed in female carriers of Duchenne muscular dystrophy gene. The presence of sinus tachycardia may suggest cardiac dysfunction or autonomic dysregulation in these cases. Other interesting finding in our cases was short PR interval in 3 cases(15%) and presence of WPW syndrome features in one patient. We planned further study in these patients to correlate clinical, biochemical, echo and ECG findings

Giant right coronary artery aneurysm secondary to Kawasaki disease in an infant

Kawasaki disease (KD) is a potentially decapacitating multisystemic vasculitis with unknown etiology that acquired worldwide attention due to associated coronary aneurysms leading to life-threatening complications in very young babies including thrombosis, ischemia, and rupture. High levels of suspicion for early diagnosis and prompt treatment are crucial in preventing serious complications. We report here one of the patients who developed a giant coronary aneurysm but fortunately not a life-threatening complication after 5 years of follow-up. We conclude that later intravenous immunoglobulins (IVIG) treatment could be an important factor—among others—that precipitate into such complications. Keywords: Coronary artery, Echocardiogram, Giant coronary artery aneurysm, Infant, Kawasaki diseas

Genetic Insights from Consanguineous Cardiomyopathy Families

Inherited cardiomyopathies are a prevalent cause of heart failure and sudden cardiac death. Both hypertrophic (HCM) and dilated cardiomyopathy (DCM) are genetically heterogeneous and typically present with an autosomal dominant mode of transmission. Whole exome sequencing and autozygosity mapping was carried out in eight un-related probands from consanguineous Middle Eastern families presenting with HCM/DCM followed by bioinformatic and co-segregation analysis to predict the potential pathogenicity of candidate variants. We identified homozygous missense variants in TNNI3K, DSP, and RBCK1 linked with a dilated phenotype, in NRAP linked with a mixed phenotype of dilated/hypertrophic, and in KLHL24 linked with a mixed phenotype of dilated/hypertrophic and non-compaction features. Co-segregation analysis in family members confirmed autosomal recessive inheritance presenting in early childhood/early adulthood. Our findings add to the mutational spectrum of recessive cardiomyopathies, supporting inclusion of KLHL24, NRAP and RBCK1 as disease-causing genes. We also provide evidence for novel (recessive) modes of inheritance of a well-established gene TNNI3K and expand our knowledge of the clinical heterogeneity of cardiomyopathies. A greater understanding of the genetic causes of recessive cardiomyopathies has major implications for diagnosis and screening, particularly in underrepresented populations, such as those of the Middle East