Purpose of the study: to assess the diagnostic value of the commonly adopted haemodynamic criteria for the diagnosis of obstructive and non-obstructive hypertrophic cardiomyopathy.
Patients: 16 cases of hypertrophic cardiomyopathy, 7 cases of the non-obstructive form, 16 fixed subaortic stenosis, 8 valvular aortic stenosis, and 7 cases of hypertensive heart disease.
Methods: left and right heart catheterisation, with particular attention to the pressure gradient and to the aortic pulse pressure by means of simultaneous pressure recording from the left ventricle and aorta under basal conditions, after a ventricular premature beat, during the Valsalva manoeuvre, during amyl nitrite inhalation, and isoproterenol administration.
Results and conclusion: the Valsalva manoeuvre increases significantly (p < 0.001) the pressure gradient, and the aortic pulse pressure in the post-extrasystolic beat decreases significantly (p < 0.001) in patients with hypertrophic obstructive cardiomyopathy. This response is significantly different from that of the other 3 disease groups. If the non-obstructive form is defined by strict criteria (i.e. no gradient above 30 mmHg even after provocative manoeuvres), then it cannot be separated from other forms of secondary left ventricular hypertrophy.