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Biomedical subjects

H C Mehmel

Publications and source records attributed to H C Mehmel.

At least 19 recordsLinked to original sources
PubMed1991

[Left bundle-branch block and primary benign heart tumor].

The electrocardiogram (ECG) of a 56-year-old woman suffering from insomnia and nervousness revealed left bundle branch block, an ECG two years previously having been normal. Echocardiography showed a perimyocardial space-occupying lesion in the area of the left ventricle. Magnetic resonance imaging demonstrated a 6 x 6 x 7 cm solid tumour, which could not be separated from the myocardium of the dorsal portion of the ventricle and the left atrial wall. Coronary angiography demonstrated a few small atypical vessels originating from the right coronary artery. An endomyocardial biopsy was equivocal. An exploratory thoracotomy revealed a large, livid tumour which could not be resected because it involved a large area of the left ventricle and left atrium. Surgical biopsy showed a cavernous haemangioma. The subsequent course (ten months' follow-up) has so far been unremarkable.

Bundle-Branch Block↗
PubMed1989

[Cor triatriatum in adulthood].

Cor triatriatum was diagnosed in a 32-year-old woman (Case 1) and a 36-year-old man (Case 2). The definitive diagnosis in Case 1 was made by transthoracic 2-D echocardiography, in Case 2 (after a chance finding) only after additional transoesophageal echocardiography. Colour Doppler echo in Case 1 provided information on the number and localization of membrane openings, while in Case 2 simultaneous measurement of maximal flow velocity and normal right-sided pressures indicated that the anomaly was haemodynamically insignificant owing to the size of the central opening in the membrane (maximal diameter 2.1 cm). In Case 1, abnormal haemodynamic findings on right-heart catheterization provided the indication for surgery and the membrane was successfully removed. Postoperatively the patient was much improved and cardiac catheterization demonstrated normal values.

Adult↗
PubMed1988

[Acute myocardial infarct: myosin-light-chain liberation and ventricular function].

Infarct size can be estimated noninvasively by analysis of circulating CK-MB and/or cardiac myosin light chains. To investigate whether myosin light chains release is correlated with the impairment of left ventricular function in acute myocardial infarction, this marker protein was determined by liquid phase radioimmunoassay in serial blood samples of 25 patients. Likewise CK-MB was measured in the same blood samples. From the serum concentration changes the cumulative appearance was calculated as an estimate of infarct size. Left ventricular end diastolic pressure, global and regional ejection fraction were measured immediately and 3 weeks after admission. Particularly during the chronic phase of myocardial infarction a close correlation was found between serological estimates of infarct size and impairment of left ventricular function. The cumulative appearance of myosin light chains was superior to CKMB in assessing the hemodynamic impact of myocardial infarction in the acute and chronic stage. Therefore, myosin light chains are an appropriate serological indicator for the hemodynamic significance of myocardial infarction during the acute and chronic stage and might allow an assessment of the patients' risk.

Cardiac Output↗
PubMed1988

Low-fat diet and regular, supervised physical exercise in patients with symptomatic coronary artery disease: reduction of stress-induced myocardial ischemia.

The effects of physical exercise and normalization of serum lipoproteins on stress-induced myocardial ischemia were studied in 18 patients with coronary artery disease, stable angina pectoris, and mild hypercholesterolemia (total serum cholesterol 242 +/- 32 mg/dl). These patients underwent a combined regimen of low-fat/low-cholesterol diet and regular, supervised physical exercise at high intensity for 12 months. At 1 year serum lipoproteins has been lowered to ideal levels (serum cholesterol 202 +/- 31 mg/dl, low-density lipoproteins 130 +/- 30 mg/dl, very low-density lipoproteins 22 +/- 15 mg/dl, serum triglycerides 105 [69 to 304] mg/dl) and physical work capacity was improved by 21% (p less than .01). No significant effect was noted on high-density lipoproteins, probably as a result of the low-fat/high-carbohydrate diet. Stress-induced myocardial ischemia, as assessed by thallium-201 scintigraphy, was decreased by 54% (p less than .05) despite higher myocardial oxygen consumption. Eighteen patients matched for age and severity of coronary artery disease served as a control group and "usual medical care" was rendered by their private physicians. No significant changes with respect to serum lipoproteins, physical work capacity, maximal rate-pressure product, or stress-induced myocardial ischemia were observed in this group. These data indicate that regular physical exercise at high intensity, lowered body weight, and normalization of serum lipoproteins may alleviate compromised myocardial perfusion during stress.

Body Weight↗
PubMed1987

[Balloon dilatation in unstable angina pectoris and acute myocardial infarct].

Early results after percutaneous transluminal coronary angioplasty (PTCA) in patients with unstable angina or acute myocardial infarction were compared with those in patients with stable angina. The primary success rate in 115 patients with unstable angina was 72%, in 73 with acute myocardial infarction 78%, and in 213 with stable angina 79%, i.e. there was no difference between the three groups. In patients with acute myocardial infarction and primary successful PTCA control angiography was performed one month after PTCA, in patients with unstable and stable angina 6 months after PTCA. Angiographic findings were identical in the three groups. But the results after successful balloon dilatation were dependent on the extent of primary success: in all three groups, patients in whom the post-dilatation control angiography revealed recurrence of stenosis the primary results were worse than in those without. There was no difference between those patients with lasting success and those with recurrence as regards cholesterol level, arterial hypertension, diabetes, and smoking habits. It is concluded that in every patient with acute symptoms of coronary heart disease the indication for PTCA should be considered.

Angina Pectoris↗
PubMed1985

Amelioration by nitroglycerin of left ventricular ischemia induced by percutaneous transluminal coronary angioplasty: assessment by hemodynamic variables and left ventriculography.

Increasingly longer balloon inflation times during coronary angioplasty can create significant left ventricular ischemia, amelioration of which was attempted in this study using nitroglycerin. Hemodynamic variables were assessed during inflation of an angioplasty balloon in the proximal left anterior descending coronary artery of 10 patients. Regional wall motion was assessed by left ventriculography during a separate balloon inflation. Nitroglycerin (200 micrograms) was then administered intravenously, and hemodynamic and ventriculographic assessments during balloon inflations were repeated. Balloon inflation resulted in a marked increase in left ventricular end-diastolic pressure (from 9.2 +/- 2.1 to 19.4 +/- 2.9 mm Hg) and time constant of left ventricular relaxation (from 44.2 +/- 6.2 to 62.3 +/- 11.3 ms) and a decrease in distal coronary artery perfusion pressure (from 54 +/- 9 to 33.1 +/- 4 mm Hg). Time to onset of angina was 29 +/- 3 seconds and time to ST segment depression of 1 mm or greater was 30 +/- 3 seconds. Regional wall motion analysis 30 seconds after onset of balloon inflation revealed marked hypokinesia and akinesia in the anteroapical segments with graduated depression of inferior wall motion, greatest at the apex. After the administration of nitroglycerin, balloon inflation resulted in a smaller increase in end-diastolic pressure (from 5.0 +/- 2.7 to 8.3 +/- 2.6 mm Hg) and time constant (from 47.9 +/- 4.7 to 54.4 +/- 9.2 ms; both p less than 0.01 versus standard balloon inflation). Distal coronary artery pressure remained similar to standard balloon inflation (32 +/- 3 mm Hg) despite lower mean arterial pressure (89 +/- 5 mm Hg, p less than or equal to 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1984

Estimation of left ventricular myocardial function by the ejection fraction in isolated, chronic, pure aortic regurgitation.

In patients with aortic regurgitation (AR), the left ventricular (LV) ejection fraction (EF) may not adequately reflect depressions of myocardial contractility due to decreased aortic impedance. The sensitivity of end-systolic pressure-volume relations and stress-volume relations in detecting myocardial depression in patients with AR was studied. In 12 patients with normal valvular function but with varying LV function (due to coronary heart disease in 9 patients and dilated cardiomyopathy in 3 patients) (group 1), and in 8 patients with AR (group 2), LV angiography was performed before and after sublingual application of isosorbide dinitrate. Heart rate was kept constant by right atrial pacing. In group 1, the slope k of the end-systolic pressure-volume relation was to EF at rest: k = 0.091.e0.051 EF; r = 0.88. In AR, this relation was shifted significantly to the right: k = 0.019.e0.066 EF; r = 0.92. This shift persisted when the end-systolic stress-volume relation instead of the end-systolic pressure-volume relation was calculated. Thus, in patients with AR the end-systolic pressure-volume relation is flatter than that in patients with intact valvular function at a given EF. The same is true for the end-systolic stress-volume relation. The data indicate that EF overestimates myocardial contractility in AR compared with end-systolic pressure-volume or stress-volume relations. This overestimation is probably a result of decreased aortic impedance in AR.

Adult↗
PubMed1984

Ventricular arrhythmias before and late after aortic valve replacement.

The influence of aortic valve replacement on the incidence of ventricular arrhythmias was studied by 24-hour Holter electrocardiographic monitoring in 45 patients immediately before and 14 +/- 7 months after operation. Ventricular arrhythmias were graded according to the Lown criteria. Preoperative left ventricular (LV) ejection fraction (EF) was determined by angiography and postoperative LVEF by gated blood pool scintigraphy. Repetitive ventricular arrhythmias (Lown grade 4A/B) were associated with a reduced LVEF (less than 55%) before and after operation. In 24 patients with preoperative normal LVEF (greater than or equal to 55%) (group A), mean LVEF remained unchanged after operation (72% vs 71%). Pre- and postoperative ventricular premature complex (VPC) frequency (45 +/- 99 vs 39 +/- 94 VPC/24 hours) and grade (1.3 vs 1.4) were not significantly different. However, in 17 patients with preoperative impaired LVEF (less than 55%) (group B, LVEF preoperatively 40 +/- 8%) and marked postoperative improvement (greater than 10%) (LVEF postoperatively 64 +/- 7%), mean VPC frequency decreased from 536 to 69 VPCs/24 hours and mean VPC grade was reduced from 3.8 to 1.5. Complex VPCs were found preoperatively in all 17 patients of group B, but in only 5 patients after operation. Four patients had a reduced LVEF preoperatively and it did not improve postoperatively (group C). Postoperative Holter monitoring detected ventricular tachycardia in all 4 patients. This study indicates that repetitive VPCs are infrequent in patients with normal LVEF before and late after aortic valve replacement. In patients with impaired LVEF and complex VPCs preoperatively, the postoperative improvement of LV function is usually accompanied by a reduction of frequent and complex VPCs.

Adolescent↗
PubMed1984

Ventricular arrhythmias in idiopathic dilated cardiomyopathy.

Twenty four hour ambulatory electrocardiograms were recorded in 60 patients with idiopathic dilated cardiomyopathy. The diagnosis was based on clinical, laboratory, and cardiac catheterisation findings. All patients had a left ventricular ejection fraction less than 0.55; in 39 it was less than 0.40. Ventricular extrasystoles were evident in all patients: they were rare in 11 (18%), moderately frequent in 24 (40%), and frequent in 25 (42%). Multiform extrasystoles were recorded in 57 patients (95%), paired ventricular extrasystoles in 47 (78%), and non-sustained ventricular tachycardias consisting of three to 19 beats in 25 (42%) of the 60 patients studied. Eight patients had more than five episodes of ventricular tachycardia a day. Patients with atrial fibrillation had the same frequency and grade of ventricular arrhythmias as those with sinus rhythm. Patients with infrequent and frequent ventricular extrasystoles could not be differentiated on the basis of the clinical or haemodynamic findings. The mean values of NYHA functional class, cardiac index, left ventricular end diastolic pressure, and ejection fraction were, however, significantly different in patients with and without ventricular tachycardia. During follow up of 12 +/- 5 months seven patients died; all seven had an ejection fraction less than 0.40. In four patients who died of congestive heart failure, but in only one of the three patients who died a sudden cardiac death, ventricular tachycardia was recorded during ambulatory monitoring. High grade ventricular arrhythmias are often seen in patients with idiopathic dilated cardiomyopathy; patients with ventricular tachycardia have more impairment of left ventricular function than patients without ventricular tachycardia; and ambulatory monitoring may be of little help in identifying patients at increased risk of sudden cardiac death.

Adolescent↗
PubMed1984

[Function of the right ventricle in mitral valve defects before and after surgical correction].

To ascertain whether surgical correction of mitral valve lesions can lead to postoperative improvement of right ventricular function, investigations were carried out in 17 patients with mitral valve disease, clinical severity grade III and IV, before and at an average of 18 months postoperatively. Six subjects without heart disease served as controls. Preoperatively, all patients underwent catheterization and cineangiographic evaluation of both the right and left ventricles. The right ventricular ejection fraction (RV-EF) was also determined from the radionuclide ventriculogram before and after the surgical intervention (closed mitral commissurotomy in five patients and mitral valve replacement in twelve). The patients were studied at rest and during bicycle ergometry in the supine position. As compared with control subjects, before surgery at rest, patients with mitral valve disease had significantly higher values for mean left atrial pressure (22 +/- 7 vs 8 +/- 2 mm Hg), mean pulmonary artery pressure (39 +/- 17 vs 17 +/- 5 mmHg), pulmonary arteriolar resistance (361 +/- 260, increased 5-fold, vs 69 +/- 27 dyn . s . cm-5) and right ventricular systolic pressure (55 +/- 20 vs 24 +/- 6 mmHg) while the values for right ventricular end-diastolic pressure, mean right atrial pressure, left ventricular end-diastolic pressure and left ventricular systolic pressure did not differ (Table 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1984

[Thrombolysis in acute transmural heart infarction: length of ischemia as a determinant of late results after 15 months].

In 28 patients the effect of coronary artery reperfusion in acute transmural myocardial infarction was evaluated by the clinical and hemodynamic results obtained after 15 months. Patients with successful reperfusion within 4 hours after onset of symptoms were assembled in group A1 (n = 11), patients with successful reperfusion after more than 4 hours in group A2 (n = 7). Group B consists of 10 patients with unsuccessful reperfusion. Left ventricular ejection fraction (radionuclide ventriculography) and the perfusion defect (thallium-201 scintigraphy) were measured acutely and after 15 months (at rest and during exercise). The coronary anatomy and the regional ejection fraction of infarct area were determined acutely and after 4 weeks by cineangiography. Serum creatine kinase activity was measured serially during the acute phase of the infarction. Before the acute intervention, the patients of the 3 groups were comparable with regard to killip class, location of infarction, number of previous infarctions, coronary anatomy, left ventricular ejection fraction, thallium-201 perfusion defect and base-line serum creatine kinase activity. During acute infarction peak creatine kinase activity tended to be lower in group A1 (1296 U/l) than in group A2 (2100 U/l, NS) and in group B (2240 U/l, NS). After 4 weeks regional ejection fraction of infarct area was higher in group A1 (36%) than in groups A2 (24%, NS) and B (20%, p less than 0.05). After 15 months the thallium-201 perfusion defect was smaller in group A1 (7%) than in groups A2 (28%, p less than 0.05) and B (34%, p less than 0.01). At the same time left ventricular ejection fraction was higher in group A1 (52%) than in groups A2 (34%, p less than 0.05) and B (35%, p less than 0.05). Fifteen months after acute infarction patients in group A1 tended to reach a higher workload during exercise (118 watts) compared with patients of groups A2 (82 watts, NS) and B (86 watts, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1984

[Is the quotient: systolic peak pressure/end-systolic volume a useful parameter in the assessment of left ventricular function?].

The quotient: peak systolic pressure/end-systolic volume (SP/ESVI) has been proposed as a parameter of LV function and as a substitute for the slope k of the end-systolic pressure-volume relation (P-Ves), because SP/ESVI is much easier to obtain. Therefore, the relation between SP/ESVI and k and the relation between SP/ESVI and ejection fraction (EF) were investigated. In 18 patients P-Ves was obtained after vegetative blockade (1.5 mg atropine and 0.15 mg/kg propranolol) from three LV angiograms at three different afterloads (control, isosorbide dinitrate, methoxamine). - SP/ESVI and slope k showed a moderate correlation: SP/ESVI = 0.50k + 2.35; r = 0.76. SP/ESVI and EF were correlated best in an exponential way: SP/ESVI = 0.267 X e0. 045EF ; r = 0.82.- An essential disadvantage of the quotient SP/ESVI resides in the fact, that the P-Ves line has varying intercepts on the abscissa. Secondly, any quotient may belong to several P-Ves lines. The quotient SP/ESVI may be used only with caution and under specific conditions as a substitute of the slope k of the P-Ves.

Blood Pressure↗
PubMed1984

[Improvement of the non-invasive diagnosis of coronary heart disease using a new double-isotope method for the noninvasive determination of coronary transit times].

In conventional myocardial Thallium-201 scintigraphy, regional myocardial Thallium-201 activity is compared to the area of normal, i.e., maximal activity. In the presence of multivessel coronary artery disease, this mode of evaluation may yield false negative results. -In 87 patients suffering from coronary artery disease and in 26 controls, after simultaneous i.v. injection of Thallium-201 and Technetium-99m coronary transit times of Thallium-201 were determined as the interval between arrival of the tracer in the aortic root and the onset of its extraction in different myocardial areas. - Patients with hemodynamically significant coronary artery stenoses (greater than or equal to 75%) revealed a significant increase in coronary transit times over septum, apex, or posterolateral wall of the left ventricle. Using maximal coronary transit times, i.e., the largest of the regional values, an excellent discrimination between patients with severe coronary artery stenoses and controls was achieved. Following coronary vasodilatation with dipyridamole, even subcritical (50-75%) coronary artery stenoses could be detected with high sensitivity, since the shortening of coronary transit times in patients with subcritical stenoses was less pronounced as compared to controls. - Especially in the presence of diffuse three-vessel coronary artery disease, the quantitative assessment of regional coronary transit times yields important parametric data in addition to those obtained by conventional Thallium-201 scintigraphy combining static imaging with rapid sequence analysis of time-activity curves.

Coronary Disease↗