Copyright © Italian Federation of Cardiology. Unauthorized reproduction of this article is prohibited. Natural history of dilated cardiomyopathy: from asymptomatic left ventricular dysfunction to heart failure – a subgroup analysis from the Trieste Cardiomyopathy Registry Aneta Aleksova a , Gastone Sabbadini b , Marco Merlo a , Bruno Pinamonti a , Giulia Barbati a,c , Massimo Zecchin a , Rossana Bussani e , Furio Silvestri e , Anna M. Iorio a , Davide Stolfo a , Matteo Dal Ferro a , Andreea M. Dragos a , Gennaro Meringolo a , Stelios Pyxaras a , Francesco Lo Giudice a , Andrea Perkan a , Andrea di Lenarda d and Gianfranco Sinagra a Background Few data are available in the literature regarding the characteristics and prognosis of asymptomatic patients with idiopathic dilated cardiomyopathy (DCM). Aim To determine the frequency with which patients affected by DCM are diagnosed in the asymptomatic state as well as to evaluate the natural history of such patients and the factors influencing their outcome. Moreover, we sought to compare the outcome of asymptomatic patients with that of patients with signs of overt heart failure at the time of first evaluation. Methods and results We analyzed the data of 747 patients with DCM enlisted in the Heart Muscle Disease Registry of Trieste from 1978 to 2007. We divided our population into four groups; group 1 comprised 118 asymptomatic [New York Heart Association (NYHA) I] patients without a history of congestive symptoms (16%), group 2 comprised 102 asymptomatic (NYHA I) patients (14%) with a positive anamnesis for heart failure stabilized in medical therapy, group 3 comprised 327 patients (44%) with signs of mild heart failure (NYHA II) and group 4 comprised 200 patients (26%) in NYHA III–IV. During the follow-up of 112 W 63 months, 46 (21%) of 220 asymptomatic patients with DCM died or underwent heart transplantation. By Cox proportional model, left ventricular ejection fraction of 30% or less was a unique independent predictor either for death/ heart transplantation (hazard ratio 3.15, 95% confidence interval 1.5–6.7, P U 0.003) or for sudden death/major ventricular arrhythmias (hazard ratio 3.9, 95% confidence interval 1.7–9.3, P U 0.002). Patients from group 1 had a trend for a better outcome with respect to those from group 2(P U 0.06). In comparison with the asymptomatic patients, those with signs of overt heart failure at baseline had a worse prognosis. Conclusion The proportion of asymptomatic patients with DCM at the moment of first evaluation at our center is significant (30%). Among them, those without a previous history of heart failure had a less advanced disease and a trend for a better long-term outcome on optimal medical treatment. Therefore, early diagnosis may offer better long- term quality of life and even better survival. Further studies on larger populations are indicated. J Cardiovasc Med 10:699–705 Q 2009 Italian Federation of Cardiology. Journal of Cardiovascular Medicine 2009, 10:699–705 Keywords: asymptomatic left ventricular dysfunction, heart failure, idiopathic dilated cardiomyopathy, prognosis a Cardiovascular Department, ‘Ospedali Riuniti’ and University of Trieste, b Department of Clinical Morphological and Technological Sciences, University of Trieste, Trieste, c Department of Public Health and Microbiology, University of Torino, Torino, d Cardiovascular Center, Territorial Health Service of Trieste and e Department of Pathological Anatomy, University of Trieste, Trieste, Italy Correspondence to Gianfranco Sinagra, MD, FESC, Cardiovascular Department, ‘Ospedali Riuniti’ and University of Trieste, Strada di Fiume 447, 34100 Trieste, Italy Tel: +39 040 3994480; fax: +39 040 3994878; e-mail: gianfranco.sinagra@aots.sanita.fvg.it Received 26 August 2008 Revised 19 February 2009 Accepted 17 March 2009 Introduction Idiopathic dilated cardiomyopathy (DCM) is a myo- cardial disorder characterized by dilatation and impaired function of the left or both ventricles [1]. Despite recent advances in medical treatment, left ventricular dysfunc- tion associated with signs of congestive heart failure is characterized by significant mortality [2]. Patients may progress through an asymptomatic phase of left ventri- cular systolic dysfunction before the development of overt heart failure [3–5]. Studies [6–8] have demon- strated that left ventricular systolic dysfunction is as prevalent as overt heart failure in the general population. Left ventricular dysfunction has a progressive nature, and that is the reason for increasing interest regarding its preclinical state. The evidence for the clinical interest is its inclusion in the new American College of Cardiology/ Original article 1558-2027 ß 2009 Italian Federation of Cardiology DOI:10.2459/JCM.0b013e32832bba35