SUMMARYThe families of 41 patients with surgically proved isolated bicuspid aortic valves were examined. There were 275 first degree relatives of whom 220 were living, and 188 (85.5%) of thesewere examined. Seven first degree relatives were found to have aortic valve disease, and in a further 11 there was 'doubtful' evidence of bicuspid aortic valves. In 6 families there was more than 1 affected member and in an additional 7 families there was 1 or more 'doubtful' first degree relative. The minimum family incidence was therefore 14-6 per cent, or 31-7 per cent if 'doubtful' cases were included. The inheritance is most probably multifactorial, but occasionally the condition may occur as an autosomal dominant.The difficulties of diagnosing bicuspid aortic valves before the development of obstruction of left ventricular outflow were encountered and are discussed. The association of a bicuspid aortic valve with asymmetric septal hypertrophy, hypertrophic cardiomyopathy, and Marfan's syndrome was also noted. Peacock (1866) was the first to recognise the role of congenitally bicuspid aortic valves in the development of aortic stenosis, but he neither appreciated the frequency of this lesion nor realised that most cases of isolated aortic stenosis were congenital. The delay in recognition of the prevalence of bicuspid aortic valves has been partly caused by difficulty in diagnosis before the development of stenosis with the clinical signs of obstruction to left ventricular outflow; this may not occur until the third or fourth decade or even later, by which time the bicuspid nature of the valve has often become obscured by calcification. Koletsky (1941) reported a frequency of 0-54 per cent from 3300 consecutive necropsies and Roberts (1970) 0 9 per cent from 1440 necropsies. These figures, if representative, suggest that the incidence for all types of congenital heart disease in the population usually quoted as between 0 7 and 1-0 per cent may be an underestimate 'Present address:

Seven patients with miscellaneous cardiac disorders are described in whom asymmetric septal hypertrophy was revealed by echocardiography. In one of these patients coexisting hypertrophic cardiomyopathy was excluded histologically; thus asymmetrical septal hypertrophy is not confined to patients with hypertrophic cardiomyopathy.During the past four years echocardiography has proved of diagnostic value in hypertrophic cardiomyopathy with or without obstruction. Moreyra et al. (1969) were the first to study patients with hypertrophic cardiomyopathy and described a cluster of echoes of varying thickness impinging on the anterior mitral leaflet echoes during diastole. They suggested that the thickened interventricular septum was responsible for this appearance. Sometimes they observed a reduction of the slope of the anterior mitral leaflet echoes, and they attributed this to decreased left ventricular filling as a result of reduced left ventricular compliance. However, these early recordings were lacking in definition and did

0. (1974). Thorax, 29,[713][714][715][716][717][718][719] Hypertrophic cardiomyopathy and hyperthyroidism. The combination of hypertrophic cardiomyopathy and hyperthyroidism gives rise to a complex clinical picture as some of the symptoms and signs may be common to both conditions. The presentation and investigation of three patients are reported. In one patient there was evidence of progression from the hypertrophic obstructive phase to that associated with loss of outflow tract obstruction. The echocardiogram was especially useful in assessing the presence or absence of hypertrophic disease in the thyrotoxic subject. It is suggested that the long continued high-output circulatory state in clinically undetected hyperthyroidism may prove to be a stimulus for unrestrained cardiac muscle hypertrophy.Three patients are described, each of whom, at one time, had evidence of both hypertrophic cardiomyopathy and hyperthyroidism. Although the association of the two conditions may be fortuitous, the combination has not previously been reported, and the symptoms and signs pose problems in diagnosis which merit discussion. In addition, the extra work-load inherent in the maintenance of the hyperkinetic circulation in thyrotoxicosis might have some bearing on the aetiology of hypertrophic cardiomyopathy. Abnormal echocardiograms were recorded in each, and this technique proved a useful and simple method of screening these thyrotoxic patients when cardiomyopathy was suspected and prior to more detailed investigation by cardiac catheterization and angiography. CASE REPORTS PATIENT 1. A 38-year-old woman was referred to the cardiac clinic in 1958 because of a murmur. This had been noted by the general practitioner in 1956 but had not previously been commented upon at earlier routine examinations. Clinically an anxious woman of average build, the only physical abnormality was a grade 3/4 mid-to-late apical systolic murmur which ceased before the second sound. The blood pressure was 130/80 mmHg. The chest radiograph was normal. The electrocardiogram revealed sinus rhythm, frontal plane QRS axis -15°, a small Q in aVF, PR interval 0-12 sec. In 1959 she had attacks of paroxysmal supraventricular tachycardia, and a year later chest pain and shortness of breath on exertion occurred. In 1961 the electrocardiogram showed a pre-excitation type B pattern, PR interval 0-08 sec, frontal plane QRS axis +10°(repeated records remained almost identical henceforward). There was no alteration in the physical signs in the cardiovascular system but hyperthyroidism was suspected because of undue anxiety, tachycardia, and a small midline thyroid nodule. However, relevant investigations were negative (BMR 9%, 1'I thyroid uptake 25% at 4 hours and 50% at 48 hours).The patient was followed up routinely and in 1968 typical thyrotoxicosis developed, thyroid enlargement becoming more obvious, although there were no eye signs. The diagnosis was confirmed with thyroid function studies (protein-bound iodine 9-5 and 11 2 ,ug/ 100 ml, 13'I thyroid uptake 68 %...

No abstract