Lone ventricular cardiomyopathy, 1993-1996.

Objective: To identify subjects with univentricular idiopathic structural and/or functional myocardial disorders (as defined) and to describe the characteristic features.

Design: Over a period of 4 years, 1993-1996, all adult subjects were obtained consecutively from a centralised referral cardiological service. The subjects had to fulfil a set of formulated diagnostic criteria for each isolated type of univentricular disease-symptomatic or asymptomatic. The subjects were diagnosed on the basis of clinical features, supported by electrocardiographic, radiological and echocardiographic evidence of lone ventricular disease, with a further definition of abnormalities based on appropriately selected standard left and right heart assessments, inter alia: (i) cardiac catheterisation, including coronary arteriography and pulmonary angiography; (ii) radio-isotope studies-mibiscan; (iii) ventilation perfusion scan; and (iv) laboratory tests to identify likely cause(s) of diffuse myocardial damage as well as to recognise nonspecific effects of tissue damage and organ dysfunction.

Setting: A referral cardiological service of a tertiary academic hospital, which provides a consultative service for inpatients and ambulatory cases. All subjects were studied on admission to hospital.

Participants: A set of criteria was formulated for each category of lone ventricular myopathy. A total of 30 patients were thus identified and included in the study-men and women ranging in age from 18 years to 84 years, with an average of 48 years. All were investigated after admission to hospital by means of a detailed set of investigations that rigorously excluded overt or occult causes of diffuse myocardial damage and any severe myocardial dysfunction secondary to haemodynamic conditions. Seven patients with significant coronary artery disease were excluded. Any subject with pulmonary or systemic hypertension was also excluded.

Main Outcome Measures: Total number of patients, number of patients in each subgroup were analysed by age, sex, clinical features, and by special investigation. The mode of presentation and electrocardiographic features were analysed separately.

Results: Twenty-two left ventricular and 8 right ventricular cases of lone ventricular cardiomyopathy were diagnosed. All but 1 patient with right ventricular disease were symptomatic and 5 subjects with left ventricular myopathy were incidentally discovered. There were 17 men and 13 women in the series. Of the 8 patients with right ventricular disease, 6 were women, while of the 22 patients with left ventricular cardiomyopathy, 15 were men.

Conclusion: The study supports the previously described existence of lone ventricular idiopathic cardiomyopathy. Further studies are, however, indicated in order to define its prevalence and nature more accurately, as well as to describe any relationship with univentricular cardiomyopathies, and define the characteristics of each category and the possible evolutionary patterns. Right ventricular cardiomyopathy is a new entity which may pose difficult diagnostic challenges, while left ventricular disease is generally accepted as a stage in the clinical spectrum of classic idiopathic dilated cardiomyopathy.