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Biomedical subjects

Y Marquis

Publications and source records attributed to Y Marquis.

At least 19 recordsLinked to original sources
PubMed1997

Mitral balloon valvuloplasty in pregnancy: limiting radiation and procedure time by using transesophageal echocardiography.

A 35-year-old female with mitral stenosis was admitted to hospital in her 23rd week of gestation for management of disabling dyspnea and paroxysmal nocturnal dyspnea. She was in New York Heart Association functional class III and underwent successful percutaneous balloon mitral valvuloplasty with significant improvement of her symptoms. To limit radiation exposure and procedure time, transesophageal echocardiography was used in combination with pulsed fluoroscopy. The remainder of her pregnancy was uncomplicated and she gave birth to a healthy baby at 38 weeks' gestation.

Adult↗
PubMed1984

Patient-management problems as a learning tool for the continuing medical education of general practitioners.

The value of Patient-Management Problems (PMPs as a learning tool for continuing medical education was studied by using two frequently seen cardiovascular problems (angina and high blood pressure) and a province-wide sample of full-time general practitioners. The results indicate that PMPs can be a motivating and effective means of CME for the general practitioner; that knowledge was gained through the successive resolution of three pmps; that corrective feedback enhanced learning; and, that most of the knowledge gained on the paper cases was transferred to practice as reported by the participants on a questionnaire. Furthermore, while cueing may be a confounding factor when PMPs are used for evaluation purposes, it was shown to facilitate learning in the present learning context.

Education, Medical, Continuing↗
PubMed1983

Predictive value of atrial pacing test for survival of patients with coronary artery disease.

There is evidence that patients with signs of poor left ventricular function or marked ischemia at low work load during an exercise test have a poor prognosis for survival. To determine whether a pacing test can provide similar information, the 6-yr survival rate was computed in 118 medically-treated patients who had undergone a standardized atrial pacing test. Among the 118 patients, 80 had significant coronary artery disease (CAD). The variables measured for the atrial pacing test were: induced angina, myocardial lactate extraction (MLE), maximal heart rate (MHR) and left ventricular end-diastolic pressure (LVEDP) changes. There was no death in 38 patients without significant CAD. The 6-yr survival rate of the 80 patients with CAD was 84 +/- 4% (+/- SEM). Of all the variables, the combinations of MHR less than or equal to 150 beats min-1 during pacing associated with a LVEDP increase greater than or equal to 5 mmHg immediately after pacing or with MLE less than or equal to 0% during pacing constituted the best predictors. Patients with a MHR less than or equal to 150 beats min-1 and a LVEDP increase greater than or equal to 5 mmHg had a 6-yr survival of 56 +/- 12% in comparison to 92 +/- 3% for the remaining patients (P less than 0.001). Patients with a MHR less than or equal to 150 beats min-1 and MLE less than or equal to 0% during pacing had a 6-yr survival of 64 +/- 11% in comparison to 91 +/- 4% for the remaining patients (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Computer assisted instruction for retraining family doctors in hypertension and hyperlipoproteinemia.

In an attempt to retrain family doctors in hypertension and hyperlipoproteinemia, computer assisted instruction (CAI) was assessed in fourteen doctors (Group 1) and its efficiency was compared to that of traditional lectures given to twenty-one doctors (Group 2). The same objectives, contents and illustrations were used in both teaching approaches. There was no significant difference for age, year of graduation and type of practice in the two groups. Comparison between pre-test and immediate post-test revealed a significant gain of knowledge for hyperlipoproteinemia (group 1, 33% and group 2, 22%) and hypertension (group 1, 16% and Group 2, 19%). A year later a similar post-test was done in both groups, and no significant difference was found between this late post-test and the pre-test. CAI applied to family doctors is as efficient for learning as traditional lectures, and both approaches failed to show retention of knowledge after one year. This is perhaps the result of having selected instructional objectives of theoretical more than practical value.

Canada↗
PubMed1976

Effects of practolol on exercise tolerance and cardiac haemodynamics and metabolism in patients with coronary artery disease.

Sixteen male patients with typical angina pectoris secondary to coronary atherosclerosis performed two daily standardized exercise tests during two consecutive days. Three hours before each exercise they received placebo or 400 mg practolol administered orally in double-blind fashion in order to complete a cross-over design. Practolol significantly prolonged the exercise duration by 30.6% and delayed the appearance time of ischaemic electrocardiographic changes by 67.7%. Maximal heart rate, systolic pressure, and pressure-rate product were also reduced after medication. In order to investigate further the effects of this beta blocking agent, myocardial function and metabolism at rest and during supine exercise were assessed in 12 male patients with coronary artery disease before and after practolol 30 mg, iv. At rest, practolol produced a decrease in tension-time index (18%), cardiac index (17%), heart rate (10%), and stroke index (7%). A significant reduction was also observed in resting stroke work index (14%) and systolic and mean aortic pressure (6%). Left ventricular end-diastolic pressure remained unchanged. During supine exercise, only time-tension index (12%), heart rate (12%), and cardiac index (10%) were significantly reduced after the beta blocking agent. Practolol did not significantly change the arterial glucose, lactate, inorganic phosphate, potassium, calcium, magnesium, pH, PCO2, or PO2. The beta blocking agent did not modify the myocardial extraction of any of these substrates at rest or during exercise. In the dosage used in both studies, practolol significantly improved the exercise tolerance and reduced the ischaemic manifestations. The efficacy of practolol in angina pectoris may result mostly from its ability to decrease heart rate and systolic pressure during exercise.

Adult↗
PubMed1975

Comparison of changes in myocardial balances of lactate, glucose potassium, and inorganic phosphate during pacing-induced angina.

During an atrial pacing test, a correlative study in myocardial lactate, glucose, potassium, and inorganic phosphate balances was done in 34 patients with clinical evidence of ischemic heart disease. Electrocardiogram was continuously monitored while left ventricular end-diastolic pressure (LVEDP) was measured before and immediately after pacing. Coronary angiograms performed after the pacing test revealed atherosclerotic narrowings in all patients. During pacing, 16 patients developed anginal pain, and their LVEDP increased significantly. The other 18 patients had no angina and no significant change in LVEDP. In these 18 patients, there were no significant changes throughout the pacing study in myocardial balances of lactate, glucose, potassium, and inorganic phosphate. In contrast, the 16 patients with induced angina during pacing showed a significant myocardial production of lactate and a loss of potassium. Myocardial inorganic phosphate loss was not statistically significant. There was no significant change in myocardial glucose extraction during angina, although a slight increase was observed during the 1st min afer pacingmthere was no correlation between the arterial concentration and the myocardial extraction of these substances. N stoichiometric relationship was found between glucose and lactate or between potassium and inorganic phospahte balance; Myocardial extraction and production of lactate correlated best with inorganic phosphate uptake and loss. In the preset study, lactate was a more reliable metabolic indicator of myocardial ischemia than potassium and inorganic phosphate, although these last two substances may be helpful in acheiving a greater accuracy for biochemical diagnosis of ischemia. Myocardial glucose balance was of no value as a metabolic indicator of ischemia in this pacing study.

Adult↗
PubMed1975

Assessment of myocardial free fatty acid metabolism in humans during heparin infusion.

Free fatty acids (FFA) have been shown to be a major myocardial substrates during the postabsorptive state in humans. In order to document the utilization of these substrates by the heart while heparin was infused, the following study was designed. During heparin infusion, total and individual FFA were measured in arterial and coronary sinus plasma during the postabsorptive state in 13 patients with coronary artery disease and in 4 patients with no evidence of cardiac disease. Oleic-1-14C acid bound to albumin was infused at a constant rate for at least 7 min into the left coronary artery. Left coronary blood flow was determined in all patients. It was assumed the oleic-1-14C acid behaves like endogenous FFA. Arterial FFA concentration was high (mean and SEM: 1 +/- 0.21 mumoles/ml) and varied by less than 10% during the course of the study in 14 of the 17 patients. Oleic acid constituted 44% of all arterial FFA. The relative concentrations of the various individual FFA were similar in arterial and coronary sinus plasma. The average FFA extraction was 19.9 +/- 2.1%. In contrast, the oleic-1-14C acid extraction was relatively more steady during the infusion, and the mean extraction of this tracer was 36.0 +/- 2.1%. Myocardial uptake for the entire group was 52.3 +/- 6.3 mumoles/min. Although a definite plateau for 14CO2 release from oleic-1-14C acid oxidation was not obtained, at least 31.8 +/- 4.3% of the removed FFA was oxidized, representing 49.3 +/- 6.4% of myocardial oxygen consumption. The failure of oleic-1-14C acid oxidation to reach a steady state was not due to delay in the myocardial CO2 pool, since 14CO2 release from infused NaH 14CO3 and lactate-1-14C in 11 other subjects revealed that in equilibrium was obtained within 5 min. These findings indicate that the generation of 14CO2 from oleic-1-14C acid oxidation is relatively slow, and the uptake of labeled FFA is partly matched by release of unlabeled FFA, suggesting that the human heart has important lipid pools.

Adult↗
PubMed1975

[Values of glucose, potassium and inorganic phosphate as metabolic indicators of myocardial ischemia in humans].

In 34 patients with coronary atherosclerosis a pacing test was performed with measurement of the lactate, glucose, potassium and inorganic phosphate coronary arterio-venous differences. Eighteen of these 34 patients felt no pain during the pacing test. In this group of asymptomatic patients, there was no significant change of the lactate, glucose, potassium and inorganic phosphate myocardial extraction. In the 16 patients who felt an anginal pain during the pacing test, there was a significant myocardial production of lactate, but the myocardial loss of potassium and inorganic phosphate was not continuously statistically significant. Myocardial extraction of glucose during the pacing-induced angina did not increase. Although, in some patients, both the potassium and the inorganic phosphate might be used to assess a condition of myocardial ischaemia, the lactate remains the best metabolic criterion for pacing-induced ischaemia.

Angina Pectoris↗
PubMed1970

[Ethacrynic acid].

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Ethacrynic Acid↗