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Biomedical subjects

F D Maul

Publications and source records attributed to F D Maul.

At least 73 records · Page 4Linked to original sources
PubMed1985

[Follow-up studies in chronic aortic insufficiency].

In order to study the course of chronic aortic regurgitation 17 patients with various degrees of aortic valve incompetence were investigated twice with a time interval of 1.5 +/- 0.4 years. The following parameters were evaluated: NYHA class; electrocardiographic sum of the largest R-wave in V4-V6 plus the largest S-wave in V1-V3 (RS index); echocardiographic left ventricular end-diastolic diameter (EDD); roentgenographic heart volume (HV); scintigraphic left ventricular end-diastolic volume (EDV), regurgitated blood volume (RBV) and ejection fraction (EF). During the period of observation functional deterioration occurred in 5 cases, all suffering from moderate to severe aortic regurgitation. While EF did not change significantly (55 +/- 12% vs. 55 +/- 11%), all other parameters showed a significant increase: RS index 5.4 +/- 1.4 mVolt to 6.0 +/- 1.7 mVolt (p less than 0.01); EDD 6.3 +/- 0.7 to 6.8 +/- 0.9 cm (p less than 0.001); HV 1017 +/- 151 ml to 1099 +/- 261 ml (p less than 0.01); EDV 371 +/- 131 ml to 441 +/- 175 ml (p less than 0.001); RBV 117 +/- 57 ml to 151 +/- 77 ml (p less than 0.001). Cases with functional deterioration showed a higher initial EDV and EDD (487 +/- 143 vs. 322 +/- 93 ml, p less than 0.05; 7.1 +/- 0.7 vs. 6.1 +/- 0.5 cm, p less than 0.01). The increase of HV, EDV and RBV during the time of observation was higher than in the remaining patients (166 +/- 137 vs. 39 +/- 95 ml, p less than 0.05; 133 +/- 75 vs. 44 +/- 29 ml, p less than 0.01; 66 +/- 22 vs. 22 +/- 31 ml, p less than 0.01). On average it was less pronounced in cases with mild initial left ventricular dilation than in those with marked dilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1984

[Aortocoronary bypass operation in considerably reduced left-ventricular function caused by chronic ischemia].

Among a group of 18 patients with severe angina and an ejection fraction of less than 46%, cine-angiography was performed on 18, 2-D echocardiography on 18, radionuclide ventriculography on 13 and 201Thallium myocardial scintigraphy on 13 at rest, both pre-operatively and six months after an aortocoronary bypass operation. In nine patients there was a significant increase postoperatively in the ejection fraction (P less than 0.001) (group I), while it remained practically unchanged in the remainder (group II). Similar results were obtained with radionuclide ventriculography and echocardiography. Ischaemia at rest was demonstrated by myocardial scintigraphy preoperatively in an average of 10 out of 27 sectors in group I patients, but within six months postoperatively decreased to 3.1 (P less than 0.01). In group II patients the mean number of sectors with ischaemia at rest was pre-operatively 2.5, postoperatively 6.0. With one exception there was an improvement in left-ventricular function at rest in all patients with pre-operatively 7 or more sectors showing ischaemia at rest. These results suggest that myocardial scintigraphy makes it possible to identify those patients with severe ischaemic myocardial damage who would profit from revascularization.

Angina Pectoris↗
PubMed1984

Volumetric evaluation of aortic regurgitation by combined first-pass/equilibrium radionuclide ventriculography.

In 16 men with normal valvular function (group 1) and 23 men and one woman with isolated aortic regurgitation (group 2) effective stroke was determined by first-pass radionuclide ventriculography. Total left ventricular stroke volume was derived from equilibrium radionuclide ventriculography using a geometric approach for the end-diastolic volume multiplied by the ejection fraction. The difference between the two stroke volumes as a fraction of total left ventricular stroke volume was taken as radionuclide regurgitant fraction. Radionuclide lv/rv stroke count ratio was calculated as the ratio of end-diastolic-end-systolic count-rate differences from the left and right ventricles. All patients underwent left heart catheterization. Angiographic regurgitant fraction was evaluated by the method of Sandler and Dodge in 16 patients of group 2. In the others, aortic regurgitation was quantified in 5 grades of severity. Group l was classified correctly by both radionuclide regurgitant fraction and lv/rv stroke count ratio (specificity 100%). In group 2 the radionuclide regurgitant fraction was elevated in all (from + 20% to +88%, sensitivity 100%), radionuclide lv/rv stroke count ratio in 19 of 24 cases (from 0.6 to 5.6, sensitivity 79%). The angiographic regurgitant fraction correlated well with the radionuclide regurgitant fraction (r = 0.78), whereas no significant correlation was found between the angiographic stroke volume ratio (i.e. left ventricular stroke volume/cardiac output per beat) and radionuclide stroke count ratio (r = 0.10) due to the high rate of false-negative results of the latter method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Limitations of scintigraphically determined left-ventricular/right-ventricular stroke volume in the evaluation of the severity of aortic valve insufficiency].

Noninvasive evaluation of aortic regurgitation can be performed by the radionuclide determination of the left/right ventricular stroke volume ratio. This ratio proved to have a relatively low sensitivity. Therefore, we conducted a study comprising 25 patients with angiographically verified aortic regurgitation in order to look for characteristics of patients with false-negative results. In 5 patients with aortic regurgitation the scintigraphically determined left/right ventricular stroke volume ratio was within normal range. In 3 other patients with severe regurgitation the radionuclide ratio was distinctly lower when compared with the angiographic stroke volume ratio (calculated from the left ventricular stroke volume and effective stroke volume). Left heart failure was observed in all these 8 patients, 7 of 8 patients showed additional right heart failure. Only 2 of the other 17 patients had signs of left heart failure. In the 8 patients with discrepant results, the roentgenographically determined heart volume was increased (1617 vs 1057 ml; 2p less than 0.001), left ventricular ejection fraction decreased (31 vs 60%; 2p less than 0.001), and mean pulmonary artery and right atrial pressure were elevated (38 vs 18 mm Hg; 2p less than 0.001; 11 vs 6 mm Hg; 2p less than 0.001). We conclude that in patients with aortic regurgitation, congestive heart failure associated with functional pulmonic and tricuspid regurgitation and geometric reasons can lead to a reduced sensitivity of the radionuclide left/right ventricular stroke volume ratio.

Aortic Valve Insufficiency↗
PubMed1983

Fully automated sectorial equilibrium radionuclide ventriculography. Proposal of a method for routine use: exercise and follow-up.

A fully automated computer program is described for processing equilibrium radionuclide ventriculography data with regard to global and sectorial left ventricular ejection fraction. The precise identification of the left ventricular outline, a prerequisite for reproducible determination of sectorial ejection fraction, was achieved by using morphological and functional criteria in a sequential edge detection technique. The high reproducibility of this method (correlation coefficient r: global ejection fraction r = 0.96, sectorial ejection fraction r = 0.82-0.97) allows the evaluation of a mean normal sectorial ejection fraction profile and its adaptation to the individual left ventricle. Computerized comparison between individual and adjusted normal sectorial ejection fraction permits quantitation of the degree and localization of functional impairment at rest, sectorial comparison between ejection fraction at rest and during peak exercise is used for the detection of ischemic functional impairment. The success rate of end diastolic left ventricular edge detection of 96% and the processing time of 150 s makes this method suitable for routine use.

Cardiac Output↗
PubMed1983

Noninvasive assessment of left ventricular performance following transluminal coronary angioplasty.

We studied 36 patients with successful transluminal coronary angioplasty (group 1) noninvasively using exercise electrocardiography, exercise T1-201 myocardial scintigraphy and equilibrium radionuclide ventriculography before and 3-5 days after the procedure. Six patients who underwent aortocoronary-bypass surgery (group 2) and 10 patients with stable angina pectoris (group 3) served as controls. All patients had arteriographically documented coronary artery disease at least in one major coronary vessel (stenosis greater than or equal to 70%). In group 1, average coronary stenosis was 81.1 +/- 8.4% before dilatation and 44 +/- 13.7% after the procedure (P less than 0.001). Ischemia score in the exercise electrocardiography decreased from 2.4 +/- 2.7 before dilatation to 0.4 +/- 0.8 after the procedure (P less than 0.001). Myocardial perfusion in computerized T1-201 myocardial scintigraphy 5-10 min after exercise expressed as vitality index (the ratio of T1-201 uptake in the ischemic region to the region of maximal uptake in the same image analyzed carefully in the same view in 2 studies) increased from 72.9 +/- 8.4% before dilatation to 79.9 +/- 11.7% after the procedure (P less than 0.001). Ejection fraction at rest increased from 47.2 +/- 9.2% to 51.0 +/- 9.7% (P less than 0.001) and during exercise from 39.9 +/- 10.5% to 49.4 +/- 10.9% (P less than 0.001) before and after the procedure. In group 2, noninvasive studies showed a tendency to improvement after surgery. In group 3 no significant changes were noted. We conclude that transluminal coronary angioplasty improves both coronary perfusion to ischemic areas supplied by critical coronary artery stenoses and left ventricular function, especially during exercise, if luminal diameter is dilated by greater than 20%.

Adult↗
PubMed1983

[Current status of scintigraphic diagnosis in liver diseases].

The methods and the radioisotopes used in scintiscanning of the liver have recently seen major advances. The clinical indications for scintigraphy in focal and diffuse diseases of the liver are discussed. Scintigraphy compares favorably with other imaging techniques with regard to sensitivity and specificity.

Budd-Chiari Syndrome↗
PubMed1983

[Global and regional computer-assisted functional topography of the thyroid. A simple self-calibrating method for supplementing gamma-camera-thyroid-gland scintigraphy].

A semiautomatic computer program is described for the quantification of global and regional 20 min 99mTc-thyroid uptake. The procedure is self-calibrating by the activity remaining in the empty syringe. The standardized definition of the thyroid ROI by an isocontour in the interpolative background corrected thyroid image results in an excellent inter-observer variability. The very short processing time of 30 sec makes this procedure suitable for routine use.

Calibration↗
PubMed1982

[Combined first-pass-/equilibrium radionuclide ventriculography for non-invasive evaluation of aortic valve incompetence].

In 15 patients with pure aortic valve incompetence and 5 patients with normal valvular function we determined cardiac output by first-pass-radionuclide ventriculography. In addition, left ventricular stroke volume was evaluated by equilibrium radionuclide ventriculography. The difference between those two volumes in relation to left ventricular stroke volume is the regurgitant fraction. Stroke volume index was calculated as the ratio of enddiastolic-endsystolic count differences of left and right ventricle. Patients with aortic insufficiency demonstrated a regurgitant fraction between 20 and 88%, whilst controls never exceeded 10% (on average-2%). Sensitivity therefore was 100%. In contrast, 2 of 15 patients with aortic valve incompetence showed a stroke volume index within normal range (sensitivity 87%). Regurgitant fraction correlated well with aortographically determined severity of valvular incompetence (r = 0.94). We conclude that combined first-pass-/equilibrium radionuclide ventriculography is a highly sensitive quantitative method for evaluation of aortic insufficiency.

Adult↗
PubMed1981

[Improved myocardial function after transluminal coronary angioplasty (author's transl)].

To assess the results of transluminal coronary angioplasty (TCA), 42 patients (mean age 50 years) with for coronary artery disease were investigated at rest and during exercise with the ECG (n = 40), thallium-201 myocardial scintigraphy (n = 23) and equilibrium-radionuclide ventriculography (n = 32). Each method of stress testing was quantified: the exercise ECG by means of an ischemia score, incremented with increasing ST-segment depression and decremented as a function of duration of exercise and workload in watts; thallium-201 scintigraphy by means of an index for minimal to maximal perfusion region (vitality index) and redistribution factors; equilibrium-radionuclide ventriculography by means of global ejection fraction and maximum systolic volume change with respect to the end-diastolic volume. The patients were divided into three groups: 30 had successful TCA defined as demonstrating at least a 20% reduction in the stenosis; six underwent aortocoronary bypass operation (nine grafts; complete revascularization in four patients); and in six patients TCA was unsuccessful. TCA was successful in 24 LAD stenoses, 5 RCA stenoses, and in one proximal anastomosis of an aortocoronary bypass graft. Dilatation could not be achieved in three LAD stenoses and three stenoses of the RCA. In those in whom it was successful, TCA yielded an average reduction of coronary artery stenosis from 84 to 43%. Both TCA and bypass operation (OP) led to comparable degrees of functional improvement. The ischemia score decreased from 2.8 to 0.9 after TCA and from 1.6 to 0 after OP. The vitality index increased from 67 to 77% and from 74 to 81% after TCA and OP respectively while the corresponding redistribution factors decreased (TCA: at 1 hour from 5 to 1% and at 3.5 hours from 11 to 4%; OP: at 1 hour from 2.2 to 1.4% and at 3.5 hours from 7.6 to 4.1%. The global ejection fractions at rest improved from 46 to 52% and from 38 to 45% and during exercise from 42 to 50% and from 36 to 43% after TCA and OP respectively. The maximum--dV/dt/EDV increased at rest (TCA: from 2.7 to 3.5 per second; OP: from 2.1 to 3.8 per second) and during exercise (TCA: from 3.1 to 4.0 per second; OP: from 2.6 to 3.3 per second). In the group with unsuccessful TCA, no significant differences in the latter parameters were observed. Ten of the 30 patients who had undergone successful dilatation were reinvestigated after three months. Maintenance of good functional results could be documented in eight while deterioration was seen in two patients, one with a significant restenosis and one who developed a new narrowing distal to the successfully dilated stenosis. Thus, the results show that in selected cases, TCA can render improved ventricular function and perfusion comparable to that of aortocoronary artery bypass surgery.

Adult↗