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Biomedical subjects

Y L Doi

Publications and source records attributed to Y L Doi.

48 records · Page 3Linked to original sources
PubMed1982

Effect of oral propranolol on left ventricular performance in patients with ischemic heart disease. Ear densitographic study during uninterrupted treadmill exercise.

The effect of oral propranolol on left ventricular performance during early upright exercise was evaluated by ear densitography in patients with arteriographic coronary artery disease (CAD). Measurements of systolic time intervals differentiated 10 unmedicated patients with CAD (group 1) and 15 patients with CAD taking propranolol (group 3). The patients in group 3 had less shortening of preejection period at 1 minute and 4 minutes of exercise than group 1 patients (p less than 0.001 and p less than 0.005, respectively), with propranolol appearing to prevent the abnormal shortening of preejection period seen in the unmedicated group. Group 3 patients, in contrast to group 1 patients, showed reduction of heart rate and heart rate-blood pressure product both at rest and during exercise. Furthermore, PEP/LVET and percentage change in PEP/LVET from control responses were similar to those of subjects free of CAD (group 2). These results indicate that propranolol effects a favorable change in LV performance by postponing early exhaustion of cardiac reserve, despite significant CAD. There was relatively large overlap in percentage change in PEP/LVET from control between group 2 and group 3 in contrast to the clear separation among unmedicated patients. Thus, the excellent diagnostic accuracy of systolic time intervals recorded during exercise is greatly reduced by beta-adrenoceptor blockade.

Administration, Oral↗
PubMed1981

Elucidation of physiologic lengthening of left ventricular ejection time during early upright exercise.

To elucidate the relationship between heart rate (HR) and left ventricular ejection time (LVET) during early exercise, 30 patients with chest pain were studied at 1 (1') and 4 minutes (4'). Mean results for control leads to 1' exercise: HR 79 to 105 beats per minute, LVET 247 to 260 msec. Thus instead of shortening as predicted by the HR change at 1' of exercise, LVET rose significantly (p less than 0.001). Subsequently LVET fell as HR continued rising, and by 4' had fallen toward control level. This phenomenon is comparable to the paradoxical decline in LVET as HR decreases early post-exercise and is comparably explained by transiently disproportionate change in determinants of LVET, stroke volume, and ejection rate. Absence of difference in response of exercise-positive (ST depression greater than or equal to 1 mm) and exercise-negative patients, also supports this initial paradoxical lengthening in LVET as a physiologic response.

Adult↗
PubMed1981

Noninvasive assessment of left ventricular performance in patients with ischemic heart disease: ear densitographic study during uninterrupted treadmill exercise.

Among 738 consecutive patients with chest pain referred for exercise testing, only 17 men fulfilled strict criteria for this pilot study: (1) achievement of at least 90 percent of age-predicted maximal heart rate or electrocardiographic criteria for a positive test; (2) subsequent coronary angiography; (3) exclusion of prior heart disease; and (4) absence of medication. Measurements of systolic time intervals obtained with ear densitography during early exercise differentiated 10 patients with coronary artery disease (Group 1) from 17 men (7 patients plus 10 normal volunteers) with normal coronary arteries (Group 2). Despite nearly identical heart rate and blood pressure responses in both groups, men in Group 1 had a significantly greater reduction of preejection period (PEP) at 1 minute and 4 minutes as well as a greater decrease in PEP/LVET (left ventricular ejection time) ratio. Differences were most significant when expressed as percent change of PEP/LVET ratio from control value (p less than 0.001 at both 1 minute and 4 minutes). After 4 minutes, men in Group 1 had no further decrease in PEP/LVET ratio and in 8 of the 10 men PEP/LVET ratio then increased to peak exercise. By contrast, PEP/LVET ratio continued to decrease to peak exercise in men in Group 2. The early floor in PEP/LVET ratio in Group 1 represents limited functional reserve and the subsequent increase suggests functional deterioration. Thus, densitographic systolic time interval measurements during uninterrupted exercise in unmedicated subjects appear to improve the sensitivity and specificity of the conventional treadmill test.

Adult↗
PubMed1981

Arrhythmia in hypertrophic cardiomyopathy. I: Influence on prognosis.

In order to examine the association between arrhythmia and subsequent prognosis, 72-hour ambulatory electrocardiographic monitoring was performed in 86 unselected patients with hypertrophic cardiomyopathy. During monitoring 23 patients experienced at least one episode of supraventricular tachycardia and 24 had ventricular tachycardia (of whom 10 had more than three episodes). The patients were then followed for a mean of 2.6 years (range one to four). Seven patients died suddenly. Of these, five had exhibited multiform and paired ventricular extrasystoles and ventricular tachycardia. These arrhythmias were significantly associated with sudden death whereas supraventricular arrhythmias were not. The patients who died suddenly were older and had experienced more symptoms than the survivors, and three had a family history of hypertrophic cardiomyopathy and sudden death. This experience provides the basis for the assessment of treatment in patients with hypertrophic cardiomyopathy and serious ventricular arrhythmia.

Adolescent↗
PubMed1981

Midsystolic closure of the aortic valve in primary pulmonary hypertension.

Echocardiographic examination in a patient with primary pulmonary hypertension demonstrated midsystolic closure of the aortic valve, which has often been described in hypertrophic cardiomyopathy with or without obstruction, in discrete subaortic stenosis, and in ruptured aneurysm of the right coronary sinus of Valsalva. A possible mechanism for this finding in primary pulmonary hypertension and differential diagnosis from other diseases are discussed.

Aortic Valve↗
PubMed1981

Motion of pulmonic valve and constrictive pericarditis.

Extreme respiratory variation in the depth of the "a" wave of the pulmonic valve echo was demonstrated in a patient with constrictive pericarditis; a mechanism for this finding is offered. Disparity in systolic and diastolic ventricular function in constriction is also useful in ruling out restrictive cardiomyopathy.

Aged↗
PubMed1980

Echocardiographic differentiation of hypertensive heart disease and hypertrophic cardiomyopathy.

The clinical differentiation of hypertensive heart disease from hypertrophic cardiomyopathy usually presents no problem but it is less clear whether an echocardiographic distinction can always be made and, if so, what those echocardiographic criteria of difference are. It can be inferred from recent publications that when echocardiographic criteria for hypertrophic cardiomyopathy are met in hypertensive subjects, both diagnoses may be made. This may be unjustified, and in order to clarify this problem that M-mode echocardiographic features of 37 patients with severe systemic hypertension were compared with those of 70 patients with hypertrophoic cardiomyopathy and normal blood pressure. Systolic anterior movement of the mitral valve and/or mid-systolic closure of the aortic valve were found in 82 per cent of patients with obstructive and 35 per cent of patients with non-obstructive hypertrophic cardiomyopathy. These features were not seen in patients with hypertension. The conventional echocardiographic features of left ventricular hypertrophy and function did not permit distinction between hypertensive heart disease and hypertrophic cardiomyopathy. The echocardiographic diagnosis of hypertensive heart disease from hypertrophic cardiomyopathy is, therefore, difficult unless systolic anterior movement of the mitral valve and/or mid-systolic closure of the aortic valve can be shown.

Adult↗