Mid-Term Results of Dual-Chamber Pacing in Children with Hypertrophic Obstructive Cardiomyopathy.

BACKGROUND: Permanent dual-chambered pacing (DDD) is an alternative to surgical treatment in patients with severe hypertrophic obstructive cardiomyopathy (HOCM) who do not have a satisfactory response to medical treatment. METHODS: Five children with severe HOCM still symptomatic despite medical treatment underwent permanent DDD pacing and were followed for 21 +/- 9.7 months. RESULTS: All patients improved their functional class. Doppler echocardiographic studies showed an early reduction of the left ventricular outflow tract gradient from 66 +/- 40 to 40 +/- 20 mmHg (P < 0.05) and to 30 +/- 11 mmHg (P < 0.05 and NS for comparison with the baseline and the early post-DDD pacing gradients, respectively) at mid-term follow-up. There was no evidence of left ventricular systolic dysfunction, and the results of left ventricular filling studies ruled out deleterious effects on diastolic function. Doppler echocardiography played a key role in the initial and subsequent assessment of these patients. CONCLUSIONS: Permanent DDD pacing is a reasonable alternative to surgery in children with HOCM who are still symptomatic despite medical therapy.

Clinical features of hypertrophic cardiomyopathy in the young.

BACKGROUND: We analysed the experience with hypertrophic cardiomyopathy in two paediatric centres to establish the differences from older patients. METHODS: Out of 45 young patients seen from 1974 to 1999, we included 38. Criterions for exclusion were secondary forms, or association with severe congenital cardiac disease which could alter the outcome. RESULTS: The patients presented at the age of 5.7 years, and were followed for 7.0 years. The 34 patients referred because of a murmur or cardiomegaly were older than the four with heart failure, presenting at 6.2 as opposed to 2.1 years of age, p = 0.08. Of the patients, 29 (76%) had primary cardiomyopathy, while 9 (24%) had secondary forms associated with Noonan's and LEOPARD syndromes. Familial tendency was ascertained in 7 patients (18%). The septal thickness in mm/m2 at presentation was greater in patients under 2 years than in older children (29 vs 18, p = 0.02). Obstructive hypertrophic cardiomyopathy was found in 17 patients (45%), with six of these having mild associated congenital cardiac defects. Nine had symptomatic arrhythmias. Overall, treatment was medical in 31, with DDD pacing used in 5, and surgery, radiofrequency ablation, and transplantation in one patient each. Total mortality was 24%, at a rate of 4.3% per year. Four patients died in heart failure and 5 had sudden death. Those in failure were significantly younger (p = 0.01). CONCLUSIONS: Hypertrophic cardiomyopathy in the young is characterized by referral for murmur or heart failure; frequent secondary forms; the obstructive variant being as common as the non-obstructive form; a mortality rate similar to that for adults attending tertiary centres; and less frequent familial forms than in older populations.

Cardiovascular findings, and clinical course, in patients with Williams syndrome.

AIMS: We investigated the incidence and outcome of cardiac malformations in 53 patients with Williams syndrome. METHODS AND RESULTS: The mean age, and period of follow-up, were 3.6 and 5.3 years, with standard deviations of 4.0 and 5.6 years, respectively. Of the patients, 45 (85%) had cardiovascular anomalies, often combined. Males presented earlier than females, at the ages of 2.1 years, with standard deviation of 2.8 years, as opposed to 4.5 years, with standard deviation of 4.2 years (p < 0.01). Supravalvar aortic stenosis occurred in 32 patients (71%), pulmonary arterial stenosis in 17 (38%), and mitral valvar prolapse in 12 (27%), 9 of these having regurgitant valves. Pulmonary valvar stenosis, ventricular septal defect, coarctation of the aorta, persistent patency of the arterial duct, hypertrophic cardiomyopathy, and subaortic stenosis all occurred less frequently. In 21 patients (47%), 24 surgical or catheter interventions had been made, most often for repair of supravalvar aortic stenosis, undertaken on 16 occasions with just one recurrence, and in 4 along with surgery to the mitral valve. Other lesions requiring intervention were pulmonary valvar stenosis, pulmonary arterial stenosis, coarctation of the aorta, and subaortic stenosis. We lost 3 patients (7%), with severe supravalvar aortic stenosis and moderate or severe mitral regurgitation, 2 early and one late after surgery. CONCLUSION: The most frequent cardiovascular anomalies in Williams syndrome were supravalvar aortic stenosis, pulmonary arterial stenosis, and mitral valvar prolapse, which occurred more frequently in our patients than previously observed. Patients with left ventricular pressure and volume overload were at greater risk.