To the Editor:

We appreciate the interest in our article1 shown by Manovel-Sánchez et al.2 Certainly, the results of our series are not much different from those presented now. The high risk of recurrence in patients who have experienced resuscitated sudden death or sustained ventricular tachycardia is well recognized. There is agreement about the need to use an implantable cardioverter defibrillator for secondary prevention,3 but greater controversy about indicating a defibrillator for primary prevention, because it is not clear how many risk factors are needed for the indication.4 Even at institutions with specialized units for this condition, the percentage of patients who receive a defibrillator for prevention varies considerably and depends not only on differences in the criteria for indicating the implant, but also on the type of population being cared for.1,5,6

The possible discrepancies between the series of Manovel-Sánchez et al1 and ours may lie in the different proportion of patients in the primary and secondary prevention groups. Additionally, both series may have had patient selection bias, making comparison between them difficult. It is particularly difficult to draw conclusions about the usefulness of risk stratification when analyzing patients with a defibrillator implant as secondary prevention. Because these patients often do not undergo a complete risk assessment, which is not essential when deciding on whether a defibrillator is indicated, they may paradoxically have fewer risk factors than primary prevention patients, despite having more appropriate shocks.

Therefore, there are still many questions in terms of stratifying the risk of our patients and indicating whether a defibrillator is needed for primary prevention: How many risk factors are required? Do all factors have equal weight? How do risk factors work in older patients? How important are other factors that may have an impact, such as ischemic heart disease or atrial fibrillation? What role will genetics play? What will be the role of new imaging techniques such as magnetic resonance and tissue Doppler?

We share the belief that multicenter studies should be conducted. From the Hypertrophic Cardiomyopathy Working Group of the Sociedad Española de Cardiología (Spanish Society of Cardiology), we would like to encourage the development of an ambitious national registry of patients with this condition that covers various related diagnostic and therapeutic aspects. Because of its importance, a registry of patients with an implanted defibrillator is the section being developed first.

Lorenzo Monserrat is receiving research aid funds from the Aventis Foundation. Lorenzo Monserrat is funded by the Red Cardiovascular (Cardiovascular Network, RECAVA) of the Instituto de Salud Carlos III (C03/01).