T. Miele

Heart rate variability is a weak predictor of sudden death in children and young patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) carries a relatively high risk of sudden death, particularly in young people.1,2 To date, the clinical significance of heart rate variability (HRV) in patients with HCM is still controversial.3,4 Our study aimed to analyse HRV in a relatively large cohort of children and young patients with HCM, and to assess potential correlations with clinical markers of sudden death. In all, 53 patients diagnosed with HCM between the ages of 18 and 40 years and body surface area-matched controls were included in this study. The diagnosis of HCM was based on echocardiographic evidence of increased wall thickness, 2 standard deviations (SD) or more compared with age, sex and body surface area-matched people. Maximal ventricular wall thickness (MWT) was defined as the greatest thickness in any segment and measured as the absolute value and as Z score. At the time of the study, age of patients ranged from 1 to 220 months (mean 75.6 (SD 73.7)). Patients with HCM underwent physical examination, rest electrocardiography, conventional echocardiography, exercise test and 24-h …

A standard echocardiographic and tissue Doppler study of morphological and functional findings in children with hypertrophic cardiomyopathy compared to those with left ventricular hypertrophy in the setting of Noonan and LEOPARD syndromes

BACKGROUND Several clinical and echocardiographic studies describe morphological and functional findings in patients with hypertrophic cardiomyopathy. Less is known regarding morphological and functional characteristics of the left ventricular hypertrophy found in the setting of the Noonan and LEOPARD syndromes. OBJECTIVE To compare non-invasively the morphological and functional findings potentially affecting symptoms and clinical outcome in children with hypertrophic cardiomyopathy as opposed to Noonan and LEOPARD syndromes. PATIENTS AND METHODS We studied by echo-Doppler 62 children with left ventricular hypertrophy, dividing them into two subgroups matched for age and body surface area. The first group, of 45 patients with a mean age of 7.5 +/- 5.2 years and body surface area of 0.9 +/- 0.44 mq, had idiopathic hypertrophic cardiomyopathy. The second group, of 17 patients, all had left ventricular hypertrophy in the setting of Noonan or LEOPARD syndromes. Their mean age was 6.6 +/- 5 years, and body surface area was 0.8 +/- 0.36 mq. In all patients, we assessed the left ventricular maximal mural thickness, expressed as a Z-score, along with any obstructions in the left and right ventricular outflow tracts. In addition, to define left ventricular diastolic function, we used mitral flow and pulsed Tissue Doppler to record the Ea, Aa, Ea/Aa, E/Ea indexes in the apical 4-chamber view at the lateral corner of the mitral annulus. We also measured the diameters of the coronary arteries in the diastolic frame. RESULTS Compared to those with hypertrophic cardiomyopathy, those with syndromic left ventricular hypertrophy showed a significantly increased Z-score for mural thickness, and a higher prevalence of obstruction in the left ventricular outflow tract. In addition, the patients with Noonan or LEOPARD syndromes showed a significantly decrease of Ea and increase of Aa, with a decreased Ea/Aa ratio, all suggestive of left ventricular abnormal relaxation. Moreover, the E/Ea ratio was significantly increased in these patients. The presence of right ventricular hypertrophy, mainly associated with dynamic obstruction in the outflow tract, was detected in only 5 of the 17 patients with Noonan or LEOPARD syndromes, as was dilation of the coronary arteries. CONCLUSIONS Compared to children with hypertrophic cardiomyopathy, those with left ventricular hypertrophy in the setting of Noonan or LEOPARD syndromes show more ventricular hypertrophy and diastolic dysfunction, due to both abnormal relaxation and reduced compliance. They also exhibit an increased prevalence of obstruction of the left ventricular outflow tract, along with dynamic obstruction of the right ventricular outflow tract and dilated coronary arteries. These morphological and functional findings could explain the different symptoms and clinical events, and potentially define the more appropriate therapeutic options in children with left ventricular hypertrophy of different aetiology.