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Biomedical subjects

R Prakash

Publications and source records attributed to R Prakash.

At least 127 records · Page 7Linked to original sources
PubMed1977

Sustained hemodynamic and antianginal effect of high dose oral isosorbide dinitrate.

Twenty-one patients with documented coronary atherosclerotic heart disease were studied to determine the effect of high dose oral isosorbide dinitrate (ISDN) on heart rate, blood pressure, and exercise time until angina pectoris. Patients were tested in two phases, initially with 0.4 mg of sublingual nitroglycerin and with sublingual placebo, and then with oral ISDN, mean dose 29 mg, and oral placebo. Both phases of the study were conducted in a randomized, double-blind, crossover manner. After ISDN was compared to oral placebo, heart rate increased at 30 to 300 min (P less than 0.01) (peak increase 18 beats/min at 60 min), and systolic blood pressure decreased from 45 to 300 min (P less than 0.005) (peak decrease 18 mm Hg at 60 min). Exercise time at 2 min after sublingual nitroglycerin increased 51% as compared to oral placebo, exercise time increased 54% at 1 hr (P less than 0.005), 37% at 3 hr (P less than 0.01), and 12% at 5 hr (NS). Twelve of 21 patients (57%) improved their exercise time until angina larger than or equal to 25% at 1 hr after oral ISDN. The exercise response to sublingual nitroglycerin was a good predictor of this response to oral ISDN.

Administration, Oral↗
PubMed1977

Effect of marijuana and placebo-marijuana smoking on psychological state and on psychophysiological cardiovascular functioning in anginal patients.

Ten male anginal patients with angiographically documented coronary artery disease, in a randomized double-blind crossover study, smoked one marijuana cigarette (containing 18 mg of delta-9-THC) on one morning and one placebo marijuana cigarette (containing 0.05 mg of delta-9-THC) on a successive morning. Significant increases occurred in average cognitive and intellectual impairment scores, derived from the objective content analysis of 5 min of speech, 30 mins after smoking the marijuana cigarette as compared to the placebo marijuana cigarette, and these scores decreased to near presmoking levels 60 min after smoking. No significant average changes occurred in anxiety or three hostility scale scores following smoking marijuana. Sizable individual differences were noted in the psychological responses to marijuana smoking due, presumably, to personality differences and/or differences in THC pharmacokinetics. Significant psychocardiovascular hemodynamic correlations, as measured by echocardiography, were observed during placebo-marijuana smoking between hostility inward scores and systolic blood pressure and ejection fraction, overt hostility outward scores and diastolic blood pressure, as well as between anxiety scores and stroke volume and left ventricular end-diastolic dimension and left ventricular diastolic volume. These significant psychophysiologic correlations were all eliminated during marijuana smoking. In view of associated findings that marijuana smoking decreased myocardial oxygen delivery, decreased exercise time until the onset of anginal pain, and increased myocardial oxygen demand in anginal patients, the use of marijuana by such patients is clearly inadvisable.

Adult↗
PubMed1976

First heart sound: a phono-echocardiographic correlation with mitral, tricuspid, and aortic valvular events.

We evaluated the relationship of S1 recorded by phonocardiography at the mitral area with motion of the mitral, tricuspid, and aortic valves, recorded by simultaneous echocardiography in 20 cardiac patients with a normal PR interval. The first major component of S1 coincided with mitral valve closure in 20 of 20 patients (100%) and also with tricuspid valve closure in 14 of 20 patients (70%). The second major component of S1 coincided with aortic valve opening in 20 of 20 patients and also with tricuspid valve closure in six of 20 patients (30%). We conclude that the first major component of S1 coincides with mitral valve closure in all patients but may also coincide with tricuspid valve closure in many patients, and the second major component of S1 coincides with aortic valve opening in all patients but may also coincide with tricuspid valve closure in some patients.

Adult↗
PubMed1976

Clinical implications of left ventricular function in patients with acute myocardial infarction.

Correlation of left ventricular filling pressure (55 patients) with the left ventricular stroke work index (61 patients) provided a rapid means of objectively determining ventricular performance after myocardial infarction. Pressure was monitored by means of the Swan-Ganz balloon-tipped catheter and thermal indicators were used for measuring cardiac output. A hemodynamic grouping of these myocardial infarction patients on the basis of the stroke work index showed close correlation with morbidity and mortality and provided a more accurate prognostic indicator than did the commonly used clinical predictors. Serial assessment of ventricular function further aided in defining the prognosis when it was not clear on admission. Thus, the levels of normal or abnormal ventricular function and the effect of therapeutic measures can be rapidly evaluated by determining the pressures and flows in patients with acute myocardial infarction.

Cardiac Output↗
PubMed1976

Enlarged left atrium causing possible false positive echocardiographic diagnosis of pericardial effusion.

Echocardiographic examination in a patient with IHSS, mitral insufficiency, and cardiomegaly suggested the possibility of a pericardial effusion. Echocardiographic M-mode scanning documented the continuity of the space posterior to the pericardium with an enlarged left atrium. Subsequent cineangiographic studies confirmed an enlarged left atrium and the absence of pericardial effusion. Left atrial enlargement may cause a false positive echocardiographic diagnosis of pericardial effusion.

Angiography↗
PubMed1975

Left ventricular filling pressures in cardiac patients.

Pulmonary artery end-diastolic pressure (PADP), pulmonary artery wedge pressure (PAWP), and pre-"a" wave left ventricular diastolic pressure (LVDP) were correlated with post-"a" wave left ventricular end-diastolic pressure (LVEDP) in 51 patients with coronary disease and in 43 cardiac patients with non-coronary disease, excluding mitral stenosis. In patients with coronary disease, the PADP was more closely correlated with PAWP (r=0.83) and LVDP (r=0.84) than with LVEDP (r=0.62). In patients with non-coronary disease, the PADP also was more closely correlated with PAWP (r=0.82) and LVDP (r=0.77) than with LVEDP (r=0.70). In patients with coronary disease, the PAWP was well correlated with LVDP (r=0.94) and with LVEDP (r=0.84). In patients with non-coronary disease, the PAWP was well correlated with LVDP (r=0.81) and with LVEDP (r=0.81). The PADP and PAWP may be helpful in evaluating left ventricular function at the bedside.

Blood Pressure↗
PubMed1975

Left ventricular end-diastolic pressure in anginal patients: lack of correlation with New York Heart Association's functional classification.

The New York Heart Association (NYHA) recently designated functional classifications I, II, and III, for angina. In the authors' series of 80 male anginal patients, observations were made on the mean left ventricular end-diastolic pressure (LVEDP) at rest and after left ventriculography and on the percentage of anginal patients with an abnormal LVEDP under these respective circumstances. The findings indicated no significant differences on the basis of NYHA classifications I, II, III. In the author's opinion, the NYHA functional classification cannot be used to distinguish the presence of abnormal left ventricular function in class I, II, and III anginal patients.

Angina Pectoris↗
PubMed1975

Effect of sublingual nitroglycerin on ejection fraction and left ventricular asynergy in coronary disease.

After sublingual nitroglycerin, the ejection fraction increased at least 8 percent in 10 of 19 patients (53 percent), changed less than 8 percent in 5 of 19 patients (26 percent), and decreased at least 8 percent in 4 of 19 patients (21 percent). After sublingual nitroglycerin, 16 of 21 areas (76 percent) of hypokinesis improved, 2 (10 percent) did not change, and 3 (14 percent) became worse. After sublingual nitroglycerin, 6 of 6 akinetic areas did not change. After sublingual nitroglycerin, 2 of 3 dyskinetic areas did not change and one improved. Left ventriculography performed before and after sublingual nitroglycerin may be useful in predicting viable areas of ischemic myocardium.

Aged↗
PubMed1975

The effect of isometric exercise on the systolic murmur of patients with idiopathic hypertrophic subaortic stenosis.

The effect of isometric handgrip exercise on the systolic murmur and bifid pulse in patients with idiopathic hypertrophic subaortic stenosis (IHSS) was evaluated. During handgrip exercise, the systolic murmur became inaudible or decreased in intensity by auscultation and disappeared or decreased in amplitude in phonocardiographic recordings in nine of nine patients with IHSS. During handgrip exercise, the bifid pulse observed in seven patients with IHSS disappeared or markedly decreased. Handgrip exercise may be helpful in the bedside diagnosis of IHSS.

Adult↗