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Biomedical subjects

H T Chou

Publications and source records attributed to H T Chou.

6 recordsLinked to original sources
PubMed1990

Left ventricular reserve of the hypertrophied heart in patients with systemic hypertension and hypertrophic cardiomyopathy--relation to age and left ventricular relative wall thickness.

To determine the effects of aging and concentric hypertrophy on the reserve of the left ventricle (LV), 36 patients with hypertension (HT), 22 with hypertrophic cardiomyopathy (HCM) and 25 age-matched normal subjects (N) were studied by isoproterenol (ISP) infusion echocardiography. The end-diastolic LV relative wall thickness (RWT), fractional shortening (FS), peak mitral flow velocity during the rapid filling phase (R) and atrial systole (A), and the A/R ratio were measured. At rest, the RWT and A/R were larger in groups HT and HCM than in group N. There were no significant differences in age, heart rate (HR), and FS among the groups. The A/R of all groups showed a good positive correlation with increasing age. The A/R of the HT group was also positively correlated with RWT. During ISP infusion, the HR, R, A, A/R and FS increased in all groups. The changes in R and FS were smaller in groups HT and HCM than in group N. The change in HR in groups N and HT, and the change in FS in all groups during ISP infusion were all inversely correlated with increasing age. The change in FS during ISP infusion was inversely correlated with RWT in the HT group, but not in HCM. Thus, it was suggested that the impairment of LV reserve in patients with HCM is not only caused by concentric hypertrophy and the aging process, but also by other myocardial factors.

Adolescent↗
PubMed1989

[Genesis of systolic anterior motion (SAM) of the mitral valve in patients with aortic regurgitation].

This study was performed to evaluate the incidence and genesis of systolic anterior motion (SAM) of the mitral valve apparatus in patients with aortic regurgitation (AR). The study population consisted of 44 patients with non-rheumatic AR, without significant aortic stenosis or mitral regurgitation. The presence and location of SAM in the short-axis view were determined by M-mode echocardiography guided by two-dimensional echocardiography. The extent and direction of the regurgitant jet were decided by pulsed or two-dimensional Doppler echocardiography. SAM was observed in 21 (48%) of the 44 patients, and it was more frequently observed in patients with an etiology of aortic valve prolapse or annuloaortic ectasia than in those of other etiology (10/14 vs 10/30; p less than 0.05). Twenty-eight patients whose regurgitant jet was directed posteriorly and impinged on the mitral valve apparatus had a significantly higher incidence of SAM than did the other 16 patients (18/28 vs 3/16; p less than 0.01). In eight of 10 patients in whom the direction of the regurgitant jet could be precisely observed by two-dimensional Doppler echocardiography. SAM was observed at the place where a regurgitant jet was directed along the anterior mitral valve in the short-axis view. M-mode measurements (LVDd, LVDs, %FS, LVDd-LVDs) of the patients with SAM had greater values than those of patients without SAM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[Prognosis of hypertrophic cardiomyopathy: echocardiographic and postmortem histopathologic study of 30 patients].

To clarify the influence of cardiac function of myocardial histologic lesions on the prognosis of hypertrophic cardiomyopathy (HCM), most recent echocardiographic findings of 30 deceased patients were reviewed. In 12 patients, histological sections from the left ventricular transverse plane made at necropsy were examined. According to the main causes of death, patients were categorized into four groups as sudden death (17 cases), heart failure death (four cases), embolic death (four cases), and non-cardiac death (five cases). 1. Clinically, atrial fibrillation and heart failure (NYHA III, IV) were frequently observed in heart failure and embolic groups. 2. Echocardiographically, left ventricular wall thickness did not differ among the four groups, but percent fractional shortening was significantly smaller in heart failure group than in non-cardiac group, and left ventricular end-diastolic dimension (LVDd) and left atrial dimension were significantly greater in heart failure group than in non-cardiac group. The normalized rapid filling rate was less in heart failure, embolic, sudden death and non-cardiac groups in that order. 3. Histopathologically, the mean myocyte diameter (MD) and percent area of disarray (%D) did not differ among the four groups, but % area of massive fibrosis (MF) greater than 2 mm2 was larger in heart failure, embolic, sudden death and non-cardiac groups in that order, especially in heart failure group. 4. Comparison of echocardiographic and histopathological findings: Though MD and %D did not correlate with any echocardiographic indices, %MF correlated significantly with LVDd (r = 0.83, p less than 0.005), and correlated inversely with the normalized rapid filling rate (r = -0.80, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

[Pulsed Doppler echocardiographic findings in 117 professional cyclists].

To investigate the effect of long-term athletic training on the heart, pulsed Doppler echocardiography was performed in 117 male professional cyclists (Group C: 20-59 years of age), and 40 age- and sex-matched untrained normal controls (Group N). According to age, the subjects in each group were categorized in two subgroups: 74 cyclists (Group CI), 20-39 years of age and 43 cyclists (Group CII), 40-59 years of age; 24 control subjects (Group NI), 20-39 years of age and 16 control subjects (Group NII), 40-59 years of age. The average durations as professional cyclists were eight years in Group CI and 29 years in Group CII. The ratios of pre-ejection period to ejection time (LV-PEP/ET, RV-PEP/ET) as obtained from Doppler flow velocity patterns of the left and right ventricles (LV, RV) were used as parameters of systolic function. The peak flow velocities during rapid filling (LV-R, RV-R) and atrial systole (LV-A, RV-A), and the ratio of A to R (LV-A/R, RV-A/R) were used as parameters of diastolic filling dynamics. The parameters of systolic function of both ventricles and those of diastolic filling dynamics of the RV did not differ between Group C and Group N, Group CI and Group NI, and Group CII and Group NII. Study of the diastolic filling dynamics of the LV disclosed that Group C had a significantly higher LV-A/R (p less than 0.05) than did Group N; therefore, no significant differences between Group CI and Group NI, and Group CII had a significantly lower LV-R (p less than 0.005) and a higher LV-A/R (p less than 0.005) than did Group NII. Twenty-four hour ambulatory ECG monitoring was performed for 49 cyclists. Thirty cyclists aged 20-39 years were categorized in two groups according to their LV-A/R values: eight cyclists (Group A) with the LV-A/R greater than the mean + SD value (0.69) in Group NI and 22 cyclists (Group B) with the LV-A/R lower than or equal to 0.69. Nineteen cyclists aged 40-59 years were separated into two groups according to the LV-A/R value: 11 cyclists (Group A) with the LV-A/R values greater than the mean + SD value (0.89) in Group NII, and eight cyclists (Group B) with the LV-A/R equal to or less than 0.89.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗