[Left ventricular systolic and diastolic functions in hypertrophic cardiomyopathy: with special reference to clinical symptom and the effects of calcium blocking agent (nifedipine)].

To assess left ventricular (LV) diastolic function in hypertrophic non-obstructive cardiomyopathy (HCM), biplane angiograms and pressures (catheter-tip manometer) were analyzed in 23 patients with HCM and 10 normal subjects (N). The effects of calcium antagonist on LV diastolic function was also evaluated by sublingual administration of 20 mg of nifedipine in 17 patients with HCM. Frame-by-frame (20 msec) analysis of angiograms was performed. LV relaxation was assessed by the time constant (T) of isovolumic LV pressure decline. 1. As compared with N, HCM showed greater increase in LV end-diastolic pressure and time constant (T). There was a significant prolongation of time from end-systole to the peak filling rate (PFR) during rapid filling period in HCM, while PFR did not differ between N and HCM. Left and upward shifts of LV diastolic pressure-volume relations were noted in HCM. Thus, abnormal LV diastolic function in HCM was characterized by impaired relaxation, delayed early diastolic filling and decreased LV compliance. 2. Clinical symptom of chest pain in HCM was associated with a decreased normalized PFR (PFR/SV and PFR/EDV). This finding suggested that an abnormal LV diastolic filling may be one of the contributing factors of chest pain in HCM. 3. Sublingual nifedipine (20 mg) did not always improve impaired relaxation and diminished LV compliance in HCM. Further study will be needed in the treatment of abnormal LV diastolic function in HCM with calcium blocking agents.