I read with great interest the report by Biagini et al concerning the prognostic value of the Doppler restrictive filling pattern in hypertrophic cardiomyopathy (HC). The investigators concluded that the Doppler pattern of restrictive left ventricular filling is a strong predictor of sudden death and HC-related death. Their report raises the following concerns.

Family histories of sudden death were present in 21% of patients with restrictive filling. Also, 21% of patients with restrictive filling showed nonsustained ventricular tachycardia on Holter monitoring compared to 6% of patients without restrictive filling. Moreover, unexplained syncope was present in 14% of patients with restrictive filling patterns compared to 8% of patients without restrictive filling. Considering that history of sudden death, unexplained syncope, and ventricular tachycardia affect prognosis in HC, it would be interesting to assess the prognostic value of the restrictive filling pattern in patients who did not display these 3 parameters.

The Doppler mitral inflow pattern is affected by left ventricular outflow tract obstruction, load conditions, and heart rate. It would be interesting to know the impact of drugs (diuretics, β blockers, and calcium channel inhibitors) in patients with HC regarding the mitral inflow pattern.

Considering that right ventricular pacing can influence the mitral inflow pattern, I would like to know the numbers of patients with pacemaker implantation in the 2 groups.