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Biomedical subjects

H de Geest

Publications and source records attributed to H de Geest.

At least 19 recordsLinked to original sources
PubMed1993

Usefulness of echocardiography and Doppler in the detection of segmental myocardial ischemia.

Echocardiography and Doppler was performed in 20 patients during percutaneous transluminal coronary angioplasty of a right coronary artery to evaluate the usefulness of echocardiography and Doppler in the detection of segmental myocardial ischemia. Wall motion analysis was also compared to the occurrence of chest pain in relation to electrocardiographic and hemodynamic changes. Even in the case of small segmental myocardial ischemia, the two-dimensional echocardiographic evaluation of wall motion is superior to all other measured parameters. Contrary to this, the Doppler examination of transmitral flow is not sensitive enough in the detection of such small segmental myocardial ischemia, induced by right coronary artery occlusion.

Adult↗
PubMed1993

Changes in left ventricular filling after valve replacement for aortic stenosis.

In order to evaluate the short- and long-term effects of aortic valve replacement on the pattern of left ventricular inflow velocity, pulsed wave Doppler analysis was performed in 20 patients with isolated aortic stenosis. Complementary, left ventricular wall thickness was measured, using M-mode echocardiography. One week after operation, left ventricular wall thickness is not changed significantly. The Doppler findings suggest some improvement of left ventricular filling. Six months and 1 year postoperatively, there is a significant, but incomplete regression of left ventricular hypertrophy. Left ventricular filling improved only partially, compared to preoperatively.

Aged↗
PubMed1992

Isolated single coronary artery: a review of 50,000 consecutive coronary angiographies.

Single coronary artery is a rare congenital anomaly of the coronary arteries where only one coronary artery arises from the aortic trunk by a single coronary ostium, supplying the entire heart. A database consisting of the angiographic reports of 50,000 consecutive coronary angiographies performed in adult patients in the University Hospital of Leuven between March 1973 and August 1991 was searched for the diagnosis of single coronary artery. All films concerned were reviewed and classified according to their anatomical type. Thirty-three cases of single coronary artery were retrieved, yielding an incidence of 0.066%. Patient characteristics and clinical data are described, with a discussion on the pathological importance of this finding.

Adult↗
PubMed1991

Successful mitral valvuloplasty using the Inoue balloon in a patient with mitral stenosis associated with subvalvular fibrosis and reduced left ventricular inflow cavity: a case report.

Percutaneous transvenous mitral valvuloplasty (PTMV) was performed with two cylindric pigtail balloon catheters in a 52-year-old woman with symptomatic mitral stenosis. The subvalvular apparatus was fibrous with welded chordae and the subvalvular left ventricular space was markedly reduced. As a result of this distorted anatomy, during the inflations, the two balloons constantly slipped back into the left atrium before full inflation was obtained. After the procedure, the mitral valve area (MVA), as estimated by echo-doppler (ED), increased from 1.00 to 1.34 cm2. After 2 months of mild clinical improvement, the patient again became symptomatic and ED examination showed a MVA of 1.25 cm2. A second PTMV was performed with an Inoue balloon, the entire procedure taking less than 1 hour. A stable position of the Inoue balloon and complete dilatation were achieved. ED examination showed a mitral valve area of 2.30 cm2. There was no mitral regurgitation nor atrial septal defect. After 3 months, she has only N.Y.H.A. class I symptoms and MVA, as estimated by ED, was 2.40 cm2.

Catheterization↗
PubMed1991

Left ventricular function changes during pharmacological and physiological interventions and routine activities monitored in healthy volunteers by a portable radionuclide probe (VEST).

A miniaturized radionuclide cardiac probe incorporated in a semi-rigid plastic chest garment has made ambulatory left ventricular (LV) function evaluation possible, with gated nuclear data being stored on tape together with electrocardiographic data, for subsequent off-line processing. After red blood cell labelling with 555 MBq (15 mCi) 99mTc and standard gated blood pool imaging in 45 degrees LAO, we performed a continuous monitoring of LV function in 20 healthy male volunteers (age range: 22-25 years), in resting control conditions as well as during activities (standing, walking, climbing stairs) and after interventions (isosorbide dinitrate intake, Trendelenburg position, inflation of cuffs around the thighs). VEST-monitoring proved to be a reliable method that gave reproducible results: changes of ejection (EF) in basal conditions were lower than 5% in 95% of the patients. Changes in LV function caused by daily activities were easily demonstrated. While standing effected no significant EF changes, walking and climbing increased EF by 6.9% (p less than 0.05) and 21.2% (p less than 0.05) respectively. Changes in LV volumes caused by alterations in venous return were also demonstrated. Compared with baseline, Trendelenburg increased end-diastolic volume (EDV) by 2.9% while isosorbide dinitrate and inflation of cuffs decreased it by 5.7% and 2.2% respectively.

Adult↗
PubMed1991

The spectrum of left ventricular filling in severe aortic stenosis.

To assess left ventricular diastolic filling in valvular aortic stenosis, pulsed Doppler echocardiography was used prospectively in 35 patients with severe aortic stenosis (valve area less than 1 cm2) and in 38 age-matched normal subjects. Twenty-seven patients had a normal left ventricular systolic function at rest (ejection fraction greater than 0.50) and a normal or only slightly increased mean pulmonary capillary wedge pressure (mean 11 +/- 4 mm Hg). Eight patients had a poor left ventricular systolic function (ejection fraction: 0.28 +/- 0.10) and an elevated mean pulmonary capillary wedge pressure (mean: 36 +/- 9 mm Hg). The Doppler derived filling parameters were correlated with hemodynamic data, left ventricular wall thickness derived from M-mode echocardiograms, heart rate and atrio-ventricular (A-V) conduction delay using stepwise multiple correlation. The data of this study suggest that left ventricular filling is significantly impaired in patients with severe aortic stenosis and left ventricular hypertrophy with an increase in late diastolic (A-wave) velocity, an increase in the A/E ratio, a decrease in the first one-half filling fraction and a prolongation of early diastolic deceleration time. These changes in filling hemodynamics are associated with alterations in mean pulmonary capillary wedge pressure, left ventricular wall thickness, heart rate and A-V conduction delay. When heart failure develops as a result of impaired left ventricular systolic function, an increase in left atrial filling pressure is associated with a shift of left ventricular filling towards early diastole with a 'normalisation' of the transmitral flow velocity curve. In extreme cases, a progression towards a 'restrictive' filling pattern is found with a marked shortening of the left ventricular early diastolic deceleration time. In the presence of high filling pressures, increased left atrial driving pressure (derived from the mean pulmonary capillary wedge pressure) is associated with changes in the left ventricular filling pattern irrespective of the presence and the degree of myocardial hypertrophy.

Adolescent↗
PubMed1990

Effect of short atrioventricular delay on cardiac output.

Short atrioventricular (AV) delay modifies late diastolic filling dynamics. The effect of this change on cardiac output (CO) was studied in closed chest, AV blocked canine preparations (N:10), during AV sequential pacing (80 bpm). CO (thermodilution technique) and transmitral flow velocity (TMFV, pulsed-wave Doppler) were measured and compared (paired t-test) on the basis of TMFV pattern, when atrial contraction (A wave) started just after early diastolic transmitral flow deceleration (PR: 219 +/- 25 ms, mean +/- SD) and when A wave occurred at the end of late diastole and shortened due to the next ventricular contraction (PR: 56 +/- 11 ms). The short AV delay resulted in 12.0 +/- 5.9% decrease of CO, reflecting the interrupted late diastolic atrial transport. Properly timed atrial contraction is necessary for optimal AV sequential pacing.

Animals↗
PubMed1986

Effects of xamoterol a new beta-adrenoceptor partial agonist, in patients with angina pectoris.

The effects of xamoterol on exercise capacity have been evaluated in 10 patients with angina pectoris and well-preserved left ventricular function. Compared to placebo a single 200 mg dose of xamoterol produced a slight but insignificant increase in exercise capacity. At maximum work load, ST-T segment depression was reduced (3 mm and 2.19 mm after placebo and xamoterol, respectively; p less than 0.05). The changes paralleled an insignificant reduction in maximal heart rate and pressure-rate product. At rest, xamoterol increased the heart rate from 80 to 86 beats/min. Thus, at rest, when sympathetic tone is low, xamoterol acts as a beta-receptor agonist but during exercise, when sympathetic tone is high, xamoterol acts as an antagonist and reduces myocardial ischaemia.

Adrenergic beta-Agonists↗
PubMed1986

Coronary thrombolysis with recombinant single-chain urokinase-type plasminogen activator in patients with acute myocardial infarction.

Seventeen patients with acute transmural myocardial infarction and angiographically confirmed complete coronary occlusion were treated with heparin combined with intravenous single-chain urokinase-type plasminogen activator (scu-PA), obtained by expression of the cDNA encoding mature human scu-PA in Escherichia coli. In eight patients, recombinant scu-PA (rscu-PA) was given as a 10 mg bolus followed by 30 mg over 1 hr. Recanalization was obtained in six patients, but with persistent delayed opacification of the vessel in four of these patients. During infusion, a plateau level of rscu-PA antigen in plasma of 3.4 micrograms/ml (median value, range 1.4 to 5.5) was reached. At the end of the infusion the alpha 2-antiplasmin level had decreased to 54% (median, range 22% to 82%) of the preinfusion level, the fibrinogen level to 89% (median, range 26% to 101%), and fibrinogen degradation products (FDPs) to 20 micrograms/ml (median, range 8 to 387). In nine patients, rscu-PA was administered as a 10 mg bolus followed by 60 mg over 1 hr. This resulted in recanalization with normal distal filling of the vessel in seven patients, within 46 +/- 17 min (mean +/- SD). During infusion the concentration of rscu-PA in plasma increased to a median value of 7.4 micrograms/ml (range 4.0 to 13.3). At the end of the infusion the alpha 2-antiplasmin level was 22% of baseline (range 5% to 47%), the fibrinogen level 45% (range 4% to 94%), and the concentration of FDPs 87 micrograms/ml (range 6 to 1034). No significant bleeding or short-term side effects were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Pseudoaneurysm of the left ventricle following cardiac surgery. Report of 3 cases and review of the literature.

Three cases of pseudoaneurysms of the left ventricle after aneurysmectomy are presented. Pseudoaneurysm formation was evidently caused by infection in one case. In the 2 other cases the pathogenetic mechanism remains uncertain. Both local infection or a superimposed new myocardial infarction might have been responsible for pseudoaneurysm formation. In each instance diagnosis was suggested by one or more noninvasive techniques (echocardiography, isotopic ventriculography, CT-scanning) and confirmed by cineangiocardiography. Two patients were successfully reoperated while the third died shortly after surgery. Special attention is drawn to the pathogenetic mechanisms underlying postoperative pseudoaneurysm formation. Finally, the diagnostic value of non-invasive technique is discussed.

Adult↗
PubMed1985

Pacing in children.

Fourteen children had a permanent pacemaker implanted between May 1967 and July 1983. Postoperative complete heart block was the indication in nine cases, congenital complete heart block in three, and sick sinus syndrome in two. Two patients died, one suddenly and one after aortic valve replacement. A total of 48 pulse generators were implanted; five patients were given an isotopic pacemaker. Twelve patients had epicardial leads implanted initially, and two received a transvenous endocardial system. The lead system implanted initially remained without malfunction in only seven patients. In the other seven patients 20 lead malfunctions occurred. Psychological maturity and physical development seemed to be normal in all 14 children. Improvement in equipment and technique will improve the outlook for paced children in the future.

Cardiac Pacing, Artificial↗
PubMed1984

Coronary thrombolysis with tissue-type plasminogen activator in patients with evolving myocardial infarction.

Tissue-type plasminogen activator is a naturally occurring, clot-selective activator of fibrinolysis. We recently reported that human tissue-type plasminogen activator isolated from a Bowes-melanoma-tissue-culture supernate lysed coronary thrombi in dogs without depleting circulating fibrinogen or alpha 2-antiplasmin, in contrast to the case with streptokinase and urokinase. In the present study coronary thrombolysis, confirmed angiographically, was induced within 19 to 50 minutes with intravenous or intracoronary tissue-type plasminogen activator in six of seven patients with evolving myocardial infarction. Circulating fibrinogen, plasminogen, and alpha 2-antiplasmin were not depleted by this agent, in contrast to the case in the two patients subsequently given streptokinase. In the one patient in whom lysis was not inducible with tissue-type plasminogen activator, it was also not inducible with streptokinase. These observations indicate that clot-selective coronary thrombolysis can be induced in patients with evolving myocardial infarction by means of tissue-type plasminogen activator, without concomitant induction of a systemic lytic state. Definition of its therapeutic benefit must await greater availability of the agent and the performance of appropriate clinical trials.

Aged↗
PubMed1984

Coronary thrombolysis with intravenously administered human tissue-type plasminogen activator produced by recombinant DNA technology.

Coronary thrombolysis was induced by intravenous infusion of human tissue-type plasminogen activator (recombinant human t-PA or rt-PA) obtained by expression of the cloned gene in a mammalian cell system. Thrombolysis was detected by the appearance of reperfusion arrhythmia and confirmed by repeat angiography in anesthetized dogs with 1-hr-old thrombi of the left anterior descending coronary artery that were induced with a copper coil. Infusion of 1000 IU (10 micrograms)/kg/min intravenous rt-PA (n = 9) elicited reperfusion within 13.7 +/- 1.9 min (mean +/- SE) without producing systemic fibrinolysis or distal coronary embolization. Infusion of urokinase at the same rate elicited thrombolysis in seven of 10 dogs within an average of 19.3 +/- 2.2 min. However, distal coronary embolization occurred in two dogs and systemic fibrinolysis was observed in all. In three dogs treated with urokinase thrombolysis was obtained only with subsequent intracoronary infusion. Restoration of myocardial perfusion and metabolism assessed with positron-emission tomography was consistently noted in dogs treated with rt-PA. Thus, rt-PA, a clot-selective thrombolytic agent that does not activate the fibrinolytic system systemically and that is potentially available in large quantities, in view of its synthesis by recombinant DNA technology, offers a promising practical approach for coronary thrombolysis in patients with acute myocardial infarction.

Angiography↗
PubMed1980

Post-traumatic infarction due to blunt chest trauma. Report of two cases.

A myocardial infarction may be caused by a blunt chest trauma. The myocardium may be directly contused or a coronary artery may be occluded. The present paper describes a patient in whom no obstructive lesions of the coronary arteries were found after a posttraumatic infarction and a second patient with a posttraumatic occlusion of the left anterior descendents. The first patient had an abnormal connection between the right coronary artery and the circumflex artery, which is also thought to be posttraumatic.

Adult↗