Doppler Echocardiography in Familial Hypertrophic Cardiomyopathy

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Abstract
Familial hypertrophic cardiomyopathy (HCM) has been poorly studied, although it may represent 50% of all HCM. We studied 346 subjects belonging to 20 unrelated families. Patients were considered affected in view of left ventricular (LV) wall thickness. One hundred twenty‐seven adults were considered affected, id est. had a left ventricular wall thickness (LVWT) > 13 mm, whereas 123 had a LVWT > 15 mm, suggesting that the cut‐off value is usually not critical. Within affected patients, 95% had an asymmetrical HCM (interventricular septum/left posterior wall thickness > 1.3 mm), whereas 84% had a ratio > 1.5. Distribution of the affected patients according with Maron's classification are in keeping with published studies about sporadic forms. Doppler derived isovolumetric relaxation time was prolonged in HCM (105 ± 23 vs 88 ± 16 msec, P < 0.001), and the ratio peak velocity of A wave over peak velocity of E wave was significantly lower in affected individuals (0.99 ± 0.56 vs 0.83 ± 0.46, P < 0.05). None of the 24 children studied (10 ± 3 years) were considered affected according to echocardiographic criteria. Conclusion: Echocardiography is the obligatory first step during genetic study for recognizing familial HCM. It allows classification in adults but not in children. Doppler estimate ofdiastolic function may be helpful in the future to recognize genetically affected subjects with normal or subnormal echocardiographic examination.