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Biomedical subjects

H C Mehmel

Publications and source records attributed to H C Mehmel.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1983

[Prognostic value of preoperatively determined end-systolic left ventricular diameter in patients with chronic aortic insufficiency--an echocardiographic study].

Serial echocardiographic studies of Henry et al. (Circulation 61, 471 [1980]) in patients with chronic aortic regurgigation (AR) indicate that preoperative left ventricular end-systolic dimension (ESD) greater than 55 mm and fractional shortening (FS) less than 25% may identify patients with reduced postoperative survival. We retrospectively analyzed the onedimensional echocardiograms of 33 patients with AR without coronary artery disease who underwent operation from 1977 to 1981. Twenty-three patients with ESD less than or equal to 55 mm (group A, mean age 48 +/- 10 years) were followed 36 +/- 14 months postoperatively, ten patients with ESD greater than 55 mm (group B, eight patients with FS less than 25%; mean age 48 +/- 12 years) 40 +/- 10 months. In both groups there were no perioperative or late deaths. In group A the average preoperative NYHA functional class decreased from 2.6 to 1.4 postoperatively, in group B from 3.0 to 1.5 (A vs. B: NS). Preoperative FS was 35 +/- 8% in group A and 22 +/- 3% in group B, preoperative ESD 44 +/- 5 mm in group A and 62 +/- 7 in group B. Three years after operation, end-diastolic dimension was 54 +/- 8 mm compared with 68 +/- 5 mm preoperatively in group A (p less than 0.001) and 61 +/- 11 mm compared to 79 +/- 8 mm preoperatively in group B (p less than 0.001). According to these data, a significant postoperative decrease of end-diastolic dimension can be expected in most patients with AR and ESD greater than 55 mm. The long-term prognosis of this subgroup is not so impaired as to recommend aortic valve replacement to asymptomatic patients a priori.

Aortic Valve Insufficiency↗
PubMed1982

Intracoronary thrombolysis in acute myocardial infarction: duration of ischemia as a major determinant of late results after recanalization.

To define the effect of duration of myocardial ischemia on the late results after successful thrombolysis in patients with acute transmural myocardial infarction, data on 39 patients treated with intracoronary infusion of streptokinase were analyzed. Patients with successful recanalization of infarct vessel and a time lag between onset of symptoms and reperfusion less than 4 hours were assembled in group A1 (n = 15), and patients with successful recanalization but a time lag of more than 4 hours (n = 17) in group A2. Group B consisted of 7 patients with unsuccessful thrombolysis. Coronary anatomy, left ventricular volume, ejection fraction, and regional ejection fraction of infarct area were determined before and 4 weeks after thrombolysis with cineangiography. Serum creatine kinase activity was serially measured. Before intervention, the groups were comparable with regard to age, Killip class, localization of infarction, incidence of previous infarction, Gensini score of coronary anatomy, left ventricular volume, ejection fraction, regional ejection fraction of infarct area, and serum creatine kinase activity. Four weeks after the intervention, patients in group A1 had a higher ejection fraction (59%) and regional ejection fraction of infarct area (39%) than patients in group A2 (ejection fraction: 49%, p less than 0.05; regional ejection fraction: 26%, p less than 0.05) and group B (ejection fraction: 44%, p less than 0.05; regional ejection fraction: 25%, p = 0.05). Peak serum creatine kinase activity measured during the acute illness was lower in group A1 (764 U/liter) than in group A2 (1,580 U/liter, p less than 0.05) and group B (2,106 U/liter, p less than 0.05). Thus, contraction of infarct area was improved and enzymatic estimate of infarct size was reduced after early as compared with late reperfusion in patients with acute myocardial infarction.

Aged↗
PubMed1982

The effect of aortic valve replacement on survival.

We retrospectively studied 252 operated and 47 unoperated patients with isolated aortic valve disease. Aortic valve replacement (AVR) was recommended to all patients based on clinical and hemodynamic data. Preoperative hemodynamic and angiographic data were similar in operated and unoperated cohorts. Seventy-one percent of patients received a Björk-Shiley prosthesis. Operative mortality was 7% for the entire surgical series. For patients with predominant aortic stenosis (AS), survival at 3 years was 87% in operated and 21% in unoperated patients (p less than 0.001). For patients with predominant aortic insufficiency (AI), the 5-year survival rate was 86% in operated and 87% in unoperated patients (NS). AVR improved long-term survival in patients with AS who had normal or impaired left ventricular (LV) function. In patients with AI and normal LV function, survival was not improved after AVR, but those with LV dysfunction who were operated on tended to survive longer (NS). Long-term survival of unoperated patients with AI was better than that in unoperated patients with AS. We conclude that AVR improves long-term survival in patients with AS who were normal or abnormal LV function, and that AVR does not change long-term survival in patients with AI, although those with LV dysfunction tended to survive longer.

Adult↗
PubMed1981

[Angina pectoris syndrome in patients with normal coronary arteriograms (X syndrome) (author's transl)].

In 37 patients with typical exercise-dependent angina pectoris but with normal coronary arteriograms and normal left ventricular function at rest (X syndrome), the dipyridamole-induced dilatory reserve of the coronary vascular system was reduced significantly to about 50% of control values (P less than 0.001). There were no changes in the small vessels causing the reduced dilatory reserve, but ultrastructural changes in the mitochondria were demonstrable. In the patients with X syndrome there was a significant reduction of lactate extraction (P less than 0.05) after electrical atrial stimulation (150/min) and in most cases lactate production was demonstrable. In the control group the myocardial lactate uptake was unchanged. Left ventricular function in patients with X syndrome was normal at rest whereas during exercise it was significantly reduced (P less than 0.001). These results show that X syndrome consists of a particular form of ischaemic heart disease with still normal left ventricular function at rest, but disordered pump activity during physical stress.

Adult↗
PubMed1981

[Direct contrast medium demonstration of acute and chronic pericardial effusion and of the pericardium (author's transl)].

After aspiration of the pericardial space 10 to 20 ml of contrast medium were injected into the pericardial sac in 11 patients with in part large pericardial effusions. Thus the effusion became directly visible on fluoroscopy and a satisfactory position of the aspiration cannula in the pericardial sac was ascertained. Complete drainage of the pericardial effusion could be well observed by fluoroscopy. The pericardial effusion dyed by contrast medium and the surrounding structures could be filmed by kinecardiography with a 35 mm camera ("pericardiography"). In contrast to echocardiography pericardiography resulted in additional important diagnostic information in two patients. Direct contrast medium demonstration of pericardial effusions and of the pericardium improves the safety during pericardial aspiration and enlarges the diagnostic possibilities particularly in ill-defined pericardial diseases and septated pericardial processes.

Adult↗
PubMed1981

Reduced coronary dilatory capacity and ultrastructural changes of the myocardium in patients with angina pectoris but normal coronary arteriograms.

Hemodynamic and metabolic studies were performed in 15 patients without heart disease (controls, group A), in 21 patients with typical stress-induced anginal pain but normal coronary and left ventricular angiograms (angina pectoris with normal arteriogram, group B), and in 10 patients with angiographically proved coronary artery disease (CAD, group C). Coronary dilatory capacity, determined by measuring total myocardial blood flow at rest and during maximal coronary vasodilatation (dipyridamole, 0.5 mg/kg i.v.), was markedly reduced in group B and C patients. In group B patients, left ventricular catheter biopsy specimens revealed no evidence of small-vessel disease, but did show histologic alterations of mitochondria. During atrial pacing, the control subjects showed no changes in myocardial lactate uptake, whereas in group B patients, myocardial lactate production occurred. In contrast to controls, patients in group B showed a significant decline in ejection fraction and circumferential fiber shortening during isometric exercise. These findings suggest that myocardial ischemia is the cause of angina pectoris in patients who have angina but normal coronary arteriograms.

Adult↗
PubMed1981

The linearity of the end-systolic pressure-volume relationship in man and its sensitivity for assessment of left ventricular function.

The linearity and sensitivity of the end-systolic pressure-volume (P-Ves) relation to the inotropic state of the left ventricle were investigated in 11 patients with coronary heart disease and one patient with congestive cardiomyopathy. To minimize autonomic reflex responses, propranolol, 0.15 mg/kg, and atropine, 1 mg, were administered i.v. at the beginning of the study. Three ventriculograms were performed: at rest, after oral isosorbide dinitrate, 10 mg (systolic pressure decrease greater than or equal to 15 mm Hg), and during infusion of methoxamine, 2 mg/min (systolic pressure increase greater than or equal to 10 mm Hg). The three points of the Pv-Ves relation showed linearity (r greater than or equal to 0.96). The relation between the slope k of the P-Ves relation and the left ventricular ejection fraction at rest was best described by an exponential function (r = 0.94). The use of peak systolic pressure instead of end-systolic pressure showed equally good results. The intercept of the P-Ves line on the abscissa, which represents the theoretical end-systolic volume at zero pressure, was not related to the ejection fraction under control conditions. The P-Ves relation in postextrasystolic beats was displaced toward the left (smaller end-systolic volumes) and became steeper.

Atropine↗
PubMed1981

A new orally active positive inotropic substance: AR-L 115 BS.

In the course of diagnostic cardiac catheterisation in 6 patients suspected of having coronary heart disease 2-[(2-methoxy)-4-methylsulfinyl)phenyl]-1H-imidazol[4,5-b]pyridine (AR-L 115 BS) was administered to see whether an improvement in left ventricular function could be achieved. 30 min after oral administration of the drug there was an increase in the ejection fraction (EF) and in the rate of circumferential fibre shortening (FSR) and a decrease in the end-systolic volume (ESV) and end-diastolic pressure (EDP). There was no significant change in heart rate (HR) and systolic blood pressure. The investigation confirmed the positive inotropic effect of AR-L 115 BS following oral administration: this substance could, therefore, be of value in the treatment of cardiac insufficiency.

Blood Pressure↗
PubMed1981

[The end-systolic pressure-volume relationship in the assessment of left ventricular function (author's transl)].

This investigation was undertaken to determine whether the left ventricular (LV) end-systolic pressure and end-systolic volume, as measured under clinical conditions, are linearly correlated and whether the slope of the end-systolic pressure-volume relationship (P-Ves) is a meaningful parameter in the assessment of left ventricular function. The studies were performed in twelve patients (eleven with coronary artery disease and one with congestive cardiomyopathy) during which autonomic reflex responses were minimized by propranolol (0.15 mg/kg i.v.) and atropine (1 mg i.v.). Three left ventricular angiograms (at rest, after 10 mg isosorbide dinitrate and during an infusion of 2 mg/min methoxamine) were obtained from which the three respective P-Ves data points were calculated and subjected to linear regression analysis (r greater than or equal to 0.96). The slope k of the linear P-Ves relation correlated most closely with the resting ejection fraction (EF) as an exponential function (r = 0.94). The end-systolic pressure could be interchanged with the peak systolic pressure which is more easily obtained. The theoretical end-systolic volume at end-systolic pressure = 0 (V0) was not related to the resting ejection fraction. Post-extrasystolic potentiation, resulting in an acute inotropic incrementation, shifted the P-Ves toward similar volumes and steepened its slope.

Atropine↗