Systolic time interval characteristics in children with Duchenne's progressive muscular dystrophy.

Systolic time interval (STI) characteristics of 17 boys with Duchenne's muscular dystrophy (DMD) were compared with those of 80 normal boys who served as control subjects. The heart rate decreased linearly with age in normal control subjects (r = -.47, P less than .01). By contrast, heart rate was significantly higher in patients with DMD (P less than .001) and tended to increase further with age. Each STI variable for normal control subjects increased significantly with age (P less than or equal to .01); QII, left ventricular ejection time (LVET), and pre-ejection period (PEP), in addition, decreased with increasing heart rate (P less than or equal to .05). In dystrophic patients QII and LVET decreased with increasing heart rate (P less than .001) but were not influenced by age. None of the other STI values in dystrophic patients was significantly influenced by either age or heart rate. Mean QII, LVET, and QI were shorter and PEP, isometric contraction time (ICT), and PEP/LVET ratio were longer (P less than .001) for DMD patients than for normal control subjects. In 13/17 patients, QII and LVET were below the 95% confidence interval of the normal mean, whereas PEP, ICT, and PEP/LVET exceeded the upper limits of normal in 8, 9 and 11 patients, respectively. For dystrophic patients, the difference (delta) between the observed values and those predicted from regression equations for normal control subjects was lower for QII, LVET, and QI (P less than .01) but higher for PEP (P less than .04), ICT, and PEP/LVET ratio (P less than .001). delta QII and delta LVET increased with age (P = .001 and .032, respectively). Duchenne's muscular dystrophy is thus documented to be associated with substantial alterations in STI characteristics that suggest a compromise of global left ventricular performance. Some of these abnormalities increase with age, probably reflecting the progressive cardiomyopathy characteristics of this disease.

Successful surgical treatment of atrial, junctional, and ventricular tachycardia unassociated with accessory connections in infants and children.

Five children with severe, life-threatening tachydysrhythmias were treated successfully with surgery. Three had atrial ectopic automatic tachycardia (AET), one had AV junctional (his bundle) automatic ectopic tachycardia (JET), and one had ventricular reentry tachycardia (VT). The mechanism and site of the tachycardia were diagnosed preoperatively using intracardiac electrophysiologic studies (EPS). Medical management with all available drugs failed to control the tachycardia in each patient. The two patients with left atrial AET underwent cryoablation of the focus using cardiopulmonary bypass. The patient with right atrial AET had removal of the anterior one third of the right atrial appendage and cryoablation of the edges. The patient with AV JET first had incision and suture ligation of the bundle of His and implantation of a ventricular pacemaker, but the tachycardia recurred 2 weeks later. Cryoablation of the bundle of His prevented further recurrences. Tachycardia stopped in the patient with VT during incision of a tumor in the apex of the left ventricle. No patient had tachycardia after surgery and none has required medical treatment.

Mitral valve prolapse syndrome in children with Duchenne's progressive muscular dystrophy.

Myocardial function was evaluated prospectively by noninvasive methods in 20 boys with clinical, biochemical, muscle biopsy, and electromyographic evidence of Duchenne's progressive muscular dystrophy. Auscultatory evidence of a nonejection systolic click suggested mitral valve prolapse (MVP) syndrome in seven patients. Phonocardiography disclosed that the click was mid-systolic in four patients and early in three. Echocardiographic features consistent with this diagnosis were identified in all seven patients and in an additional four. One of these had an apical pansystolic murmur, suggestive of mitral regurgitation, whereas in the other three, prolapse of the mitral valve was "silent". Echocardiographic findings included an abrupt midsystolic, posterior motion (greater than 3 mm beyond the CD line) in five patients, multiple sequence echoes in six, and posterior coaptation of the mitral valve near the left atrial wall in six. The features most characteristic of MVP syndrome was a smooth, pansystolic, anteriorly concave (hammock-like) posterior motion deviating more than 3 mm beyond the CD line. Among the remaining nine patients who did not have echocardiographic evidence of prolapsing mitral valve, none had an early, middle or late nonejection systolic click or a heart murmur, although four patients in this group had moderate to severe scoliosis. These observations document of occurrence of MVP syndrome in children with Duchenne's muscular dystrophy and indicate that its prevalence is high. We speculate that prolapse of the mitral valve in these patients is an expression of the underlying cardiomyopathy characteristic of Duchenne's muscular dystrophy rather than an isolated, dystrophic involvement of the mitral valve leaflets.

Pericardial disease in children.

This article discusses the etiology, clinical presentation, diagnosis and treatment of pericardial disease in the pediatric age group. Purulent pericarditis is a medical and surgical emergency. Prompt surgical drainage and intravenous antibiotic therapy may be lifesaving. The pathogenesis and hemodynamic consequences of pericardial effusion, cardiac tamponade, pericardial constriction and pneumopericardium are also discussed. The key to intelligent management of pericardial disease is an appreciation of the fact that the abnormal hemodynamics resulting from these disorders can frequently only be relieved by cardiac decompression.