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Biomedical subjects

R Gourgon

Publications and source records attributed to R Gourgon.

At least 19 recordsLinked to original sources
PubMed1995

Prolonged kinetics of recovery of oxygen consumption after maximal graded exercise in patients with chronic heart failure. Analysis with gas exchange measurements and NMR spectroscopy.

BACKGROUND: Patients with chronic heart failure (CHF) often complain of prolonged dyspnea after exercise. The determinants of oxygen consumption after exercise in these patients are unknown. We hypothesized that the kinetics of oxygen consumption recovery after graded exercise was prolonged in parallel with the recovery of muscle energy stores, was not affected by the exercise level, and could be used to assess the circulatory response to exercise. METHODS AND RESULTS: Seventy-two patients with CHF in Weber's class A (n = 28), B (n = 21), and C/D (n = 23) and 13 healthy subjects performed maximal upright bicycle exercise with breath-by-breath respiratory gas analysis. Kinetics of recovery of ventilation (VE), oxygen consumption (VO2), and CO2 production (VCO2) after exercise were characterized by T1/2, the time to reach 50% of the peak value. T1/2 VO2 (seconds) increased with the severity of CHF (97 +/- 17 for CHF A [P < .05 versus CHF B, P < .05 versus CHF C/D], 119 +/- 22 for CHF B [P < .05 versus control subjects, P < .05 versus CHF A, and P < .05 versus CHF C/D], 155 +/- 55 for CHF C/D [P < .05 versus control subjects, P < .05 versus CHF A, and P < .05 versus CHF B] compared with 77 +/- 17 for control subjects). T1/2 VCO2 and T1/2 VE also increased similarly with the worsening of CHF. T1/2 VO2 was correlated negatively with peak VO2 (r = .65) and was reproducible (r = .96). To study the relation between T1/2 VO2 and the duration of exercise, 10 healthy subjects and 22 patients underwent a second graded test at 75% and/or 50% of peak workload. T1/2 VO2 was minimally shortened, at only 50% of peak workload (P = .02). Finally, 19 patients underwent 31P nuclear magnetic resonance spectroscopy of the anterior compartment of the leg during exercise; the half-time of recovery of the ratio of inorganic phosphate to creatine phosphate (T1/2 Pi/PCr), reflecting the level of involvement of oxidative metabolism in the restoration of energetic metabolites after exercise, was linearly correlated with the half-time of VO2 recovery (r = .70, P < .01). CONCLUSIONS: Postexercise T1/2 VO2 increases when CHF worsens, perhaps in part a result of slower kinetics of recovery of muscle energy stores. The time course of oxygen consumption recovery may represent a simple new criterion for measuring the impairment of the circulatory response to exercise in CHF, even submaximal exercise.

Adult↗
PubMed1995

Comparison using dynamic vectorcardiography and MIBI SPECT of ST-segment changes and myocardial MIBI uptake during percutaneous transluminal coronary angioplasty of the left anterior descending coronary artery.

The quantitative relation between ST-segment changes and the severity and extent of myocardial ischemia during coronary occlusion remains unclear. This study assesses whether ST-segment changes during percutaneous transluminal coronary angioplasty (PTCA) correlate with the amount of myocardium at risk, measured with technetium-99m hexakis 2-methoxyisobutyl isonitrile (MIBI; also called sestamibi) single-photon emission computed tomography (SPECT). Quantitative continuous dynamic vectorcardiography was performed during PTCA of the left anterior descending coronary artery in 11 patients (mean age 64.3 years) without previous myocardial infarction. Change in the magnitude of the ST vector (STc-VM) was continuously recorded. A standardized protocol of balloon inflations was used and technetium-99m MIBI was injected intravenously at the onset of the third inflation. SPECT imaging was performed 60 minutes later and compared to a rest acquisition. SPECT was quantified by bull's-eye analysis using: (1) the change in the pathologic/normal area count ratio (delta P/N) as an index of the severity of ischemia; and (2) planimetered defect size during PTCA as an indicator of the size of the area at risk. The delta P/N from baseline to balloon occlusion (22 +/- 11%) was correlated, albeit loosely, to the maximum value of STc-VM (245 +/- 186 microV, r = 0.62, p < 0.05), but there was no correlation between the size of the scintigraphic defect and STc-VM. Likewise, the sum of ST-segment elevation was correlated to delta P/N (r = 0.72, p < 0.02), but not to the size of the scintigraphic defect.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Influence of preload reserve on stroke volume response to exercise in patients with left ventricular systolic dysfunction: a Doppler echocardiographic study.

OBJECTIVES: This study evaluated the role of preload reserve in the stroke volume response to exercise in patients with left ventricular systolic dysfunction by assessing the relation between stroke volume and late left ventricular diastolic filling during exercise. BACKGROUND: In patients with left ventricular diastolic dysfunction, the absence of left ventricular distension is the fundamental mechanism explaining the nonaugmentation of stroke volume during exercise. METHODS: In 32 patients with left ventricular systolic dysfunction and 16 healthy control subjects, mitral and aortic velocities were recorded by Doppler echocardiography at rest and during submaximal supine bicycle exercise. Stroke volume, peak early (E) and late (A) mitral velocities, A/E ratio and end-diastolic filling were measured at rest and during exercise. RESULTS: Stroke volume increased significantly in control subjects but did not change in patients. Peak early mitral velocity increased significantly and to the same extent in both groups, whereas peak late mitral velocity and end-diastolic filling increased significantly in both groups but more so in control subjects; the A/E ratio increased significantly in control subjects but did not change in patients. In addition, stroke volume correlated significantly with peak late mitral velocity during exercise in patients (r = 0.72, p < 0.001). CONCLUSIONS: Compared with control subjects, patients with left ventricular systolic dysfunction exhibited limited increases in both stroke volume and late left ventricular filling during exercise. Furthermore, their stroke volume response correlated with the capacity of the left ventricle to increase late diastolic filling, that is, preload reserve.

Adolescent↗
PubMed1995

Detection of coronary artery disease in diabetic patients.

Coronary artery disease may be difficult to detect in diabetic patients. This study was designed to determine the specificity and sensitivity of three noninvasive tests. Accordingly, the results of 48-h ambulatory electrocardiogram (ECG) monitoring, maximal ECG exercise test, and intravenous dipyridamole myocardial thallium scintigraphy were compared in 59 middle-aged diabetic patients who were consecutively selected for suspected coronary artery disease. All patients also underwent coronary angiography, which was performed regardless of the results of the non-invasive tests. Twenty patients (34%) had significant coronary lesions, i.e. stenosis equal to or greater than 70%, and 16 of these 20 patients (80%) had double or triple vessel disease. Sensitivity and specificity were, respectively, 25% and 88% for ambulatory ECG monitoring, 75% and 77% for the exercise test and 80% and 87% for thallium myocardial scintigraphy. This observation strongly supports the use of non-invasive tests for the detection of coronary artery disease in those diabetic patients at high risk of such disease. As the exercise test is cheaper and more widely available than thallium myocardial scintigraphy it should be used as a first line examination. Dipyridamole myocardial scintigraphy may provide an alternative solution for those patients who cannot perform maximal exercise, or with atypical clinical presentation.

Adult↗
PubMed1994

Peak oxygen uptake during exercise in mitral stenosis with sinus rhythm or atrial fibrillation: lack of correlation with valve area. A study in 70 patients.

Although the haemodynamic response during submaximal supine exercise in mitral stenosis has been well described, the determinants of peak oxygen uptake during maximal upright exercise are poorly characterized and may differ in sinus rhythm and atrial fibrillation. Seventy patients with isolated mitral stenosis underwent Doppler-echocardiography and bicycle exercise with respiratory gas analysis. Forty-two patients were in sinus rhythm (Group I) and 28 in atrial fibrillation (Group II). Peak oxygen uptake was 21.3 +/- 5.6 ml.min-1.kg-1 in group I and 18.1 +/- 5.1 ml.min-1.kg-1 in group II (P < 0.05). There was no significant correlation between indices of exercise tolerance (exercise duration, ventilatory threshold, peak oxygen uptake, indexed peak oxygen uptake, peak oxygen pulse) and valve area or gradient in either group. Indexed peak oxygen uptake was not correlated to delta oxygen pulse but was linearly related (r = 0.43) to delta heart rate (delta heart rate = peak heart rate/rest heart rate) in Group I but not in Group II. Thus, in patients with mitral stenosis, no correlation was found between the mitral valve area or the gradient at rest and maximal upright exercise tolerance, suggesting that peripheral adaptation and, in sinus rhythm, chronotropic reserve, are important compensatory mechanisms.

Atrial Fibrillation↗
PubMed1994

Eligibility for reperfusion therapy and outcome in elderly patients with acute myocardial infarction.

Reperfusion therapy by thrombolysis or angioplasty was considered in 260 unselected patients consecutively admitted within 6 h of the onset of Q wave myocardial infarction. Rates of reperfusion and in-hospital mortality were compared in 206 patients < 70 years and 54 patients > or = 70 years. Early reperfusion was obtained in 86.4% of the patients under 70 years and in 72.2% of those over 70 (P < 0.01). Thrombolysis was more frequently used in the younger group (66.0% vs 31.5%, P < 10(-5)), and primary angioplasty in the older (44.4% vs 29.6%, P < 0.05). Overall in-hospital mortality was higher in the older group (22.2% vs 4.4%, P < 10(-5)). After successful reperfusion, mortality was 12.8% in the patients over 70 and 3.9% in those under 70. After failed or unproven reperfusion, mortality was 46.7% in the patients over 70 and 7.1% in those under 70. Reperfusion therapy is feasible in the majority of patients over 70 years, but failure to attempt or to achieve reperfusion is associated with a poor outcome. Although not controlled, this study provides an incentive for attempting early reperfusion therapy as often as possible in the elderly with acute myocardial infarction.

Age Factors↗
PubMed1994

[Functional capacity after cardiac transplantation].

Cardiac transplantation has transformed the prognosis of NYHA Class IV severe cardiac failure. However, despite a "new heart", the exercise tolerance of transplanted patients remains poor for a long time. Cardiac denervation which decreases the chronotropic reserve, diastolic left ventricular dysfunction and intrinsic muscular abnormalities related to lack of training and to treatment are the underlying causes.

Cardiovascular Deconditioning↗
PubMed1994

[Incidence and prognosis of early primary cardiogenic shock in myocardial infarction].

The aim of this retrospective study was to analyse the results of coronary reperfusion on the incidence and short and medium term prognosis of early primary cardiogenic shock in acute myocardial infarction. Of 339 consecutive patients admitted within 6 hours of the onset of acute myocardial infarction, 25 (7.4%) had cardiogenic shock from the onset. The majority of patients (18) underwent direct angioplasty with a successful result in 16 cases. Intravenous thrombolysis was instituted in 5 cases followed by emergency coronary angiography leading to "rescue" coronary angioplasty in 3 cases, which was successful in 2 cases. Two patients had no coronary revascularisation because of a double contra-indication to thrombolysis and catheterization by the femoral approach. Intra-aortic balloon pumping was used in 17 cases. Complementary emergency surgical revascularization was necessary in 5 patients (20%). In all, early reperfusion of the infarct-related artery was obtained in 80% of cases (20 patients). The hospital mortality was 72% (18 patients) due to refractory cardiac failure in nearly all cases. After an average follow-up of 17 months, 3 of the 7 survivors of the hospital period have died and of the 4 remaining patients, 2 are in the NYHA classes III or IV. Recent therapeutic advances have not influenced the incidence of cardiogenic shock but have significantly increased the proportion of very early cardiogenic shock, whereas the late cardiogenic shocks of more progressive onset, have nearly disappeared (4/339, 1.2% in this series). The prognosis of these early shocks, caused by severe myocardial damage, remains catastrophic and hardly improved by emergency coronary reperfusion by angioplasty and intraaortic balloon pumping.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

[Critical analysis of scales of quality of life in cardiology; applications to cardiac insufficiency].

Scales of quality of life have only recently been imposed in cardiology. Essentially an Anglosaxon invention, they have been used for evaluating most treatment of cardiac failure. The main qualities of a good quality of life questionnaire are its sensitivity, its reproducibility and its validity. The contents of the questionnaire, particularly the relationship between items concerning symptoms and those concerning the psychological aspects of the disease, have a great influence on the quality of results. The "Living with Heart Failure Questionnaire" of the University of Minnesota is the most validated questionnaire at present. As with most other methods of therapeutic assessment in cardiology, the most recently obtained results from large multicenter trials, seem to show a much smaller benefit of drugs reputed to be effective in this condition, with respect to the quality of life of patients. This justifies: the continuation of validation of these questionnaires, a reflection on the efficacy of classical management of these patients.

Heart Diseases↗
PubMed1994

[What is the appropriate treatment for myocardial infarction with left ventricular dysfunction?].

The essential goal of medical treatment following myocardial infarction with left ventricular dysfunction must be the prevention of secondary cardiac failure. The existence of left ventricular dysfunction, in particular when it is not accompanied by clinical cardiac failure, is a virtually formal indication for beta-blocker treatment after an infarction. Beta-blockers with intrinsic sympathomimetic activity (ISA) are possibly better tolerated in this context. However, experience shows that cardiologists and general practitioners often remain reluctant to prescribe beta-blockers whenever left ventricular function is impaired. Converting enzyme inhibitors decrease the risk of onset of secondary cardiac failure, reduce sudden deaths by ventricular arrhythmias, reduce recurrences of myocardial infarction or unstable coronary insufficiency, and more generally reduce overall and cardiovascular mortality. This is a class effect. While there is no urgency to prescribe them during the acute phase, it is generally considered that it is extremely useful to give them fairly quickly, i.e. during the first 72 hours. At the end of the hospital phase, around two weeks, it is desirable, whenever possible, to prescribe a dose of the order of 75 mg/day of captopril or 2.5 mg/day of ramipril. The administration of aspirin can be considered virtually routine. Oral anticoagulants are desirable in the presence of a large akinetic pocket, a frequent starting point of thrombosis and/or systemic emboli, or in the presence of atrial fibrillation. Digitalis/diuretic treatment does not appear to be indicated at this stage. Other types of anti-ischemic treatment are not theoretically indicated as a matter of principle at this stage in the absence of residual ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1994

[Abnormal peripheral circulation in heart failure].

Left ventricular failure leads to circulatory failure which causes clinical symptoms and in which regional blood flow changes play an important role. An abnormality of systemic vasodilatation on exercise or on pharmacological intervention has been shown. This affects both the resistance and conductive vessels and is mainly functional, related to neurohormonal stimulation with a predominance of vasoconstrictive factors amongst which increased adrenergic tone probably plays an essential part. A modification of the endothelium-dependent response has recently been confirmed. The presence of structural vascular abnormalities (increase in parietal sodium and water concentrations, "remodelling" remains debatable in the human. These abnormalities have a common factor in their chronicity and take time to regress with medical treatment or after cardiac transplantation. Physical training seems to induce more marked and, above all, more rapid effects.

Endothelium, Vascular↗
PubMed1994

Left ventricular-arterial coupling in systemic hypertension: analysis by means of arterial effective and left ventricular elastances.

OBJECTIVE: To clarify the spectrum of the left ventricular responses in hypertension in man by means of coupled analysis of elastances. In the present study we analysed the 'functional' coupling of the left ventricle and the arterial system in terms of the arterial effective elastance (E(a)) divided by a value of end-systolic left ventricular elastance approximated by the end-systolic pressure-volume ratio (E(lv)). METHODS: Twenty-five normotensive and 19 hypertensive males without heart failure underwent a haemodynamic and angiographic study. The hypertensives were divided into three subgroups: group 1 had normal ejection fraction, group 2 had ejection fraction > 70% and group 3 had ejection fraction 50-58%. RESULTS: The ejection fraction was similar in hypertensives and controls and E(lv) was significantly increased in the hypertensives. E(a) was identical in the three hypertensive subgroups, which differed only for E(lv). Hypertensives with a normal ejection fraction (n = 8) had a normal E(a)/E(lv) ratio and end-systolic stress, and a significantly increased E(lv), related mainly to an increase in the left ventricular mass divided by the end-diastolic volume (m/VED) with normal systolic function of the left ventricular muscle. The significantly increased systolic pump function of group 2 (n = 5) seems to be related to a significant increase in both m/VED and left ventricular muscle contractility. Group 3 (n = 6) was more heterogeneous, some patients having insufficient hypertrophy and others impaired muscle function. CONCLUSIONS: The left ventricle and the arterial system remain correctly coupled in hypertensives overall, but with marked heterogeneity of the systolic pump (and sometimes muscle) function and mainly of the geometry of the left ventricle. Regarding the relatively unequivocal changes in Ea, the differences in ejection fraction and in left ventricular-arterial coupling in hypertensives are related mainly to changes in the left ventricular systolic pump function.

Adult↗
PubMed1994

[Role of digitalis glycosides in the treatment of cardiac failure].

While no doubt has ever been cast on the usefulness of digitalis in cardiac failure with atrial fibrillation and a fast ventricular rate, they are periodically brought into question regarding chronic cardiac failure in sinus rhythm. While they have not been supplanted by new positive inotropic agents, they are in competition with converting enzyme inhibitors. Recent therapeutic trials have shown that digitalis preparations, alone or in association with converting enzyme inhibitors, have beneficial effects on symptoms and exercise duration in patients with symptomatic impaired left ventricular systolic function. While the effects of digitalis preparations on mortality remain unknown, a large North American study should soon provide an answer to this question.

Chronic Disease↗
PubMed1993

Cardiopulmonary response during exercise of a beta 1-selective beta-blocker (atenolol) and a calcium-channel blocker (diltiazem) in untrained subjects with hypertension.

The effects of beta-blockers and calcium-channel blockers on cardiopulmonary response during exercise are not well characterized. Sixteen sedentary patients with essential hypertension underwent a randomized, double-blind, cross-over study comparing atenolol and diltiazem sustained-release 300 mg, each administered during 6 weeks, after a 15-day run-in placebo period. Neither atenolol nor diltiazem significantly affected maximal exercise duration, maximal oxygen uptake, ventilatory threshold, or any of the ventilatory parameters during exercise. With atenolol, the maximal oxygen pulse was significantly increased and compensated for the decrease in heart rate during exercise. Atenolol and diltiazem do not limit maximal exercise tolerance in untrained hypertensive subjects, but the circulatory profile is more preserved with diltiazem.

Adult↗
PubMed1993

[Effects of aging on left ventricle-arterial coupling in man].

Twenty-five normotensive men without any cardiac or arterial pathology, aged 22 to 68 years, 12 less than 45 year old, 13 over 45 years, underwent cardiac catheterisation and angiography. The following parameters were calculated: 1) a global index of arterial function (Ea) and its determining factors (Ea = LVESP/SV where LEVSP = left ventricular end systolic pressure and SV = left ventricular stroke volume); Ea = (HR x SVR) + Ea' where HR = heart rate, SVR = total systemic vascular resistance and Ea' = (LVESP - MAP/SV) (MAP = mean arterial pressure); 2) an index of global left ventricular pump function: ELV (ELV = LVESP/LVESV, where LVEDV = left ventricular end systolic volume; 3) an index of LV-arterial coupling: the Ea/ELV ratio. With aging, both Ea (by increase in SVR) and Ea' and ELV increased significantly. Ea/ELV (inverse of the ejection fraction-1) increased with age but ELV less than Ea. Ea/ELV was significantly higher in patients over 45 years of age but the correlation between ejection fraction and age was not statistically significant (p = 0.10). These results suggest that with aging, the improvement in LV pump function approximately corresponds to the degradation in arterial transport function: the left ventricular-arterial coupling as assessed by the Ea/ELV ratio (and therefore the ejection fraction) is maintained in the majority of cases.

Adult↗