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Biomedical subjects

C M Schannwell

Publications and source records attributed to C M Schannwell.

At least 19 recordsLinked to original sources
PubMed2001

[Can pathological left ventricular hypertrophy in arterial hypertension be distinguished from physiological hypertrophy caused by sports?].

BACKGROUND AND OBJECTIVE: Patients with hypertensive heart disease and left ventricular hypertrophy demonstrate impaired left ventricular diastolic filling. Aim of this study was to find out if physiological left ventricular hypertrophy induced by endurance training causes abnormal left ventricular systolic and diastolic filling. METHODS: We examined 42 athletes with left ventricular hypertrophy due to endurance training (aged 25 +/- 7 years), 31 patients with left ventricular hypertrophy due to hypertensive heart disease (aged 28 +/- 6 years) and 20 untrained, healthy subjects (controls, aged 26 +/- 8 years) by conventional echocardiography and calculated left ventricular muscle mass and fractional shortening. In addition the following Doppler-echocardiographic parameters were measured: maximal early and late velocity of diastolic filling, ratio of maximal early and late velocity of diastolic filling, acceleration and deceleration time and isovolumetric relaxation time. RESULTS: All three study groups showed normal fractional shortening. Conventional echocardiography revealed a higher left ventricular muscle mass in the two study groups as compared to the controls (controls: 119 +/- 12 g, athletes: 225 +/- 18 g*; hypertensive patients: 216 +/- 16 g*; * p < 0.01 versus controls). In the athletes with physiological left ventricular hypertrophy a normal left ventricular diastolic filling pattern was documented (VE: 0.64 +/- 0.1 m/s; VA: 0.51 +/- 0.2 m/s). In hypertensive heart disease a diastolic dysfunction in terms of a delayed relaxation pattern with a decrease of maximal early velocity of diastolic filling (VE: 0.45 +/- 0.09 m/s) and a compensatory increase of the maximal late velocity of diastolic filling (VA: 0.54 +/- 0.1 m/s) was demonstrated. CONCLUSION: In pathological left ventricular hypertrophy due to hypertensive heart disease a pathological diastolic filling pattern was documented. In athletes with physiological left ventricular hypertrophy a normal left ventricular diastolic filling pattern was revealed. Thus Doppler-echocardiographic parameters of left ventricular diastolic function can be of diagnostic importance for discriminating between pathological and physiological left ventricular hypertrophy.

Adolescent↗
PubMed2001

[Left ventricular diastolic function parameters after PTCA and stent implantation].

UNLABELLED: This study was designed to determine the effect of successful coronary revascularisation on left ventricular diastolic function. METHODS: We consecutively studied the time course of diastolic function by Doppler echocardiography in 100 patients with one-vessel disease before and 48 hours after elective coronary angioplasty. Three abrupt vessel closures occurred within 24 hours after intervention. These three patients were excluded from the study. 58 patients were initially successful treated with coronary angioplasty (residual stenosis < 40%). In 39 patients stents were used to improve an inadequate result after coronary angioplasty. The following parameters of left ventricular diastolic function were evaluated before and 48 hours after coronary intervention: peak early (VE, m/s) and peak late diastolic (VA, m/s) flow velocity, E/A ratio, acceleration time (AT, ms), deceleration time (DT, ms) and isovolumetric relaxation time (IVRT, ms). Ejection fraction (EF; %) was determined and used to characterise systolic left ventricular function. RESULTS: Both patient groups (58 patients with coronary angioplasty and 39 patients with combined coronary angioplasty and stent implantation) showed no relevant differences concerning sex, age, atherosclerotic risk factors, exercise capacity and results of exercise electrocardiography. All patients who underwent stent implantation showed an early improvement of left ventricular diastolic function 48 hours after revascularisation. Surprisingly there was no significant short-term improvement (48 hours) of diastolic function in patients with initially successful angioplasty. CONCLUSION: We suppose that stent implantation faster normalises coronary blood flow than coronary angioplasty.

Angioplasty, Balloon, Coronary↗
PubMed2001

[Left ventricular diastolic function in pregnancy in patients with arterial hypertension. A prospective study with M-mode echocardiography and Doppler echocardiography].

INTRODUCTION: During pregnancy eminent cardiovascular changes occur. The aim of the following study was to investigate the course of hemodynamic parameters under increased volume load during pregnancy in women suffering from mild arterial hypertension. METHODS: Altogether 47 women (age: 25 +/- 4 years) with mild arterial hypertension detected during pregnancy underwent echocardiography at the 9th, 24th and 33rd week of gestation. Furthermore echocardiography was performed postpartum at weeks 1 and 8. The control group comprised 45 healthy pregnant women. In all patients left ventricular muscle mass index and systolic shortening fraction were measured. The following Doppler echocardiographic parameters were ascertained: peak early diastolic and peak late diastolic flow, VE/VA ratio, acceleration time, deceleration time and isovolumetric relaxation time. RESULTS: During pregnancy all patients had an increase of left ventricular muscle mass index and a decrease of fractional shortening. All patients developed a relevant diastolic dysfunction. While the control group developed signs of disturbed relaxation as reduction of peak early diastolic flow (0.89 +/- 0.07 versus 0.82 +/- 0.08 m/s*), VE/VA ratio and an increase of isovolumetric relaxation time (72 +/- 12 versus 123 +/- 7*) at the 33rd week of gestation (* p < 0.01), all pregnant women with mild arterial hypertension developed a diastolic dysfunction with signs of delayed relaxation already at the beginning of gestation. 26 pregnant women with arterial hypertension developed a restrictive diastolic filling pattern at 24 weeks of gestation. The other 21 pregnant women only showed restriction for a short time at the end of gestation. In healthy pregnant women, volume load results in a reversible physiologic left ventricular hypertrophia, a significant alteration of diastolic left ventricular function in terms of a disturbed relaxation pattern and a temporary decrease of systolic function. In comparison hypertensive pregnant women show a delayed relaxation at the beginning of pregnancy and 50% developed early signs of restrictive cardiomyopathy. These changes may predispose to critical complications during pregnancy.

Adult↗
PubMed2001

[Prognostic relevance of left ventricular diastolic function parameters in dilated cardiomyopathy].

Patients with dilated cardiomyopathy (DCM) generally have an impaired functional capacity and poor long-term out-comes. A mortality of 5-15% per year has been described actually. Aim of this study was to verify the prognostic relevance of invasive and non-invasive parameters of diastolic function in patients with DCM. In 33 patients with DCM, cardiac catheterization was performed and left ventricular systolic (ejection fraction (EF; %)); left ventricular enddiastolic pressure (LVEDP; mmHg) and diastolic function (time constant of relaxation (T, ms); the constant of myocardial stiffness (b) were derived from biplane laevocardiography and simultaneous micromanometric registration of pressure-volume curves. For evaluation of clinical out-come, the follow-up period was defined as beginning on the day after cardiac catheterization and ending on the most recent date or with a cardiac event (death or cardiac transplantation). All patients were reevaluated for NYHA functional class and completed a standard questionnaire. The following hemodynamic parameters were evaluated: invasive parameters of left ventricular diastolic function (constant of relaxation: tau (ms), constant of myocardial stiffness: b)), as well as parameters of systolic function (ejection fraction (EF; %)), left ventricular pressure (LVEDP; mmHg), left ventricular muscle mass index (LVMMI; g/m2), left ventricular enddiastolic volume index (LVEDVI; ml/m2) and non-invasive parameters of morphological data, left ventricular systolic (fractional shortening (FS, %) and ejection fraction) and diastolic parameters with echocardiography. During the follow-up period of 36 months, 11 of 33 patients experienced a major cardiac event (cardiac death n = 8, heart transplantation n = 3). The major cause of death was progressive pump failure. The remaining 22 patients were further classified with respect to changes in functional status. While clinical symptoms could be improved medically in patients with moderate increase of myocardial stiffness, patients with severe increase of myocardial stiffness (b: 76.1 +/- 12.1 vs 17.9 +/- +8.1, p < 0.001) could not be improved and suffered more cardiac events. Doppler echocardiographic measurements in these patients showed a restrictive filling pattern (VE 0.91 +/- 0.21 vs 0.64 +/- 0.18 m/s; p < 0.01; VA 0.52 +/- 0.23 vs 0.57 +/- 0.24 m/s; p < 0.01, deceleration time 129 +/- 17 vs 211 +/- 14 ms; p < 0.01). The medical heart failure therapy was comparable in both groups. In patients with cardiac events, the diastolic left ventricular variables did not significantly differ between patients who underwent heart transplantation and those who died. Patients who demonstrated a sole impairment of relaxation (tau: > 50 ms) suffered no cardiac events. Impaired diastolic function contributes to the clinical picture of congestive heart failure. Parameters of left ventricular diastolic function are powerful and important predictors of major cardiac events in patients with DCM, like heart transplantation and non-sudden death, and may indicate future clinical success of medical treatment. Invasive and non-invasive parameters of diastolic function reveal comparable information for the estimation of prognosis of patients with DCM in order to initiate early therapy.

Adult↗
PubMed2001

Morphological differences of the internal thoracic artery in patients with and without coronary artery disease--evaluation by duplex-scanning.

OBJECTIVE: The internal thoracic artery is an established arterial graft for myocardial revascularisation, especially of the left anterior descending artery because of a higher patency rate compared to venous grafts. It has never been investigated, whether there are morphological differences in this vessel between patients with or without coronary artery disease or if they are comparable to morphological changes in the common carotid artery. METHODS: We investigated the internal thoracic artery and the common carotid artery of 24 patients (12 with coronary artery disease, 12 without coronary artery disease) with an ultrasonic system on both sides. The intima-media thickness and the diameter of both vessels were estimated. RESULTS: The intima-media-thickness of the internal thoracic artery was comparable in all patients, independent of the presence of a coronary artery disease (0.51+/-0.11 mm with coronary artery disease, 0.50+/-0.17 mm without coronary artery disease, P>0.05). Compared with this the intima-media-thickness of the common carotid artery was thicker in patients with coronary artery disease (0.84+/-0.13 mm with coronary artery disease, 0.73+/-0.07 mm without coronary artery disease, P< or or =0.014). There was no correlation between the thickness of the internal thoracic artery and the common carotid artery (r=0.018, P>0.05). CONCLUSIONS: It could be demonstrated for the first with non-invasive ultrasound, that the intima-media-complex of the internal thoracic artery is protected of the influence of arteriosclerosis. There are no morphological differences like the intima-media-thickness of the common carotid artery. The proven protective mechanism underlines the widespread use of the internal thoracic artery as a coronary artery bypass graft.

Aged↗
PubMed2000

[Differences in the clinical performance and initial diagnosis in women with suspected coronary artery disease].

BACKGROUND AND OBJECTIVE: Although coronary heart disease (CHD) is a major cause of morbidity and mortality, it is still being underestimated in women. This prospective study was undertaken to ascertain special features of the symptoms and in the initial diagnosis of CHD in women. PATIENTS AND METHODS: Between January 1996 and August 1998, a total of 5000 patients (2500 women, 2500 men; mean age 61 [39-83]) were admitted for their initial invasive investigation of suspected CHD. All data relating to history, laboratory tests, resting and exercise ECG, and coronary angiography were recorded and analysed. RESULTS: Typical angina pectoris as initial symptom was recorded in 40% of women, 57% of men, atypical symptoms in 48% vs. 24%. Typical angina pectoris in the presence of demonstrated CHD were found in 32% of women, compared with 69% in men. The interval from initial symptoms to established diagnosis was 68 months in women and 9 months in men, 71% of women but only 5% of men having consulted at least two specialists. Both women and men with CHD had comparable risk factors. Anginal symptoms prematurely ended an exercise ECG test in 49% of women and 44% of men. Significant S-T segment changes were noted in 19% of women, 30% of men with CHD. The positive predictive value of clinical symptoms and ergometric results with regard to CHD was much lower in women than in men: 33% vs 85%. CONCLUSIONS: Clinical symptoms and the exercise ECG are much less diagnostically reliable in women than in men and had a very low predictive value. Women often have typical anginal symptoms even in the absence of CHD. They, therefore, require more sensitive methods than the exercise ECG for the initial diagnosis of CHD, especially in the face of prolonged symptom-to-diagnosis intervals.

Adult↗
PubMed2000

[Cardiac complications in diabetes mellitus].

Diabetes mellitus as a disease of epidemiological impact leads to diabetic cardiopathy by modulation of myocardial, vascular and metabolic components. This includes the development of a coronary microangiopathy and a decrease of diastolic and systolic function of the left ventricle as well as the development of an autonomic diabetic neuropathy. Patients with diabetes show an increased mortality concerning cardiovascular events. They more often suffer from myocardial infarction as non-diabetics mostly with a more serious course. Moreover, the post-infarction course is affected with a worse prognosis as in non-diabetics. For diagnosis of cardial involvement in diabetes electrocardiographic and echocardiographic procedures are of use. Special tests of the autonomic function complete the diagnostic ensemble. An early therapy with ACE-inhibitors and beta blocking agents as well as a strong diabetes therapy, in particular with insulin, can influence the mortality favorably. Moreover, the diagnosis and therapy of additional cardiovascular risk factors (arterial hypertension, dyslipidemia) are very important, because these are correlated with a for diabetic patients markedly increased risk of mortality. The clinical relevance of the term diabetic cardiopathy is justified by the 6 factors: macroangiopathy, microangiopathy, disturbances of the myocardial metabolism, myocardial fibrosis, autonomic diabetic neuropathy and disturbances of the coagulability. Diagnostic and therapeutic goals are discussed.

Arteriosclerosis↗
PubMed2000

[Left ventricular diastolic function in normal pregnancy. A prospective study using M-mode echocardiography and Doppler echocardiography].

BACKGROUND AND OBJECTIVE: During pregnancy many substantial changes occur in the cardiovascular system. Aim of this study was to examine how physiological preload alterations influence left ventricular haemodynamic parameters. PATIENTS AND METHODS: During the 9th, 24th and 33rd weeks of pregnancy and 8 weeks after childbirth 36 patients underwent echocardiographic studies. 36 young not pregnant women (25 +/- 7 years) served as controls. The following Doppler echocardiographic parameters were measured: peak early diastolic flow velocity (VE, ms); acceleration (AT; ms) and deceleration time (DT; ms) of flow velocity in early diastole; peak late diastolic flow velocity (VA; m/s) and isovolumetric relaxation time (IVRT; ms). In all women the left ventricular muscle mass index (LVMMI), fractional shorting (FS; %) and the ratio between septum and posterior ventricular wall were calculated. RESULTS: During pregnancy all women showed an elevation of the left ventricular muscle mass index (LVMMI: from 66 +/- 6 to 100 +/- 9 g/m2; p < 0.01) and a decrease of fractional shortening (FS: from 38 +/- 4 to 31 +/- 3%). All patients developed a relevant diastolic dysfunction: reduced early diastolic flow velocity (VE: from 0.89 +/- 0.11 to 0.83 +/- 0.19 m/s; P < 0.01), reduced E/A ratio (1.7 +/- 0.4 to 1.2 +/- 0.4; P < 0.01), prolonged IVRT (72 +/- 12 to 114 +/- 12 ms; P < 0.01) and deceleration time (DT: to 189 +/- 17 to 227 +/- 18 ms; P < 0.01). Eight weeks after childbirth all parameters of left ventricular systolic and diastolic functions were normal. CONCLUSION: Preload alterations during normal pregnancy lead to reversible physiological left ventricular hypertrophy. Furthermore, we found a short-time reduction of systolic function just before childbirth and a significant alteration of the left ventricular diastolic filling pattern (abnormal relaxation pattern). While left ventricular systolic function was normal in all patients one week after childbirth, left ventricular hypertrophy and left ventricular diastolic dysfunction persisted for nearly two months.

Adult↗
PubMed2000

Non-invasive assessment of graft patency using transcutaneous Doppler echocardiography for the validation of functional improvement after PTCA of the LAD via internal thoracic artery graft.

Percutaneous transluminal coronary angioplasty (PTCA) of a native coronary artery via internal thoracic artery (ITA) graft after bypass surgery is a relatively rare procedure. Our current study evaluates the flow velocity patterns of the graft before and after PTCA. After intervention the mean diastolic flow velocity increased under rest and stress conditions. In addition, the graft patency was proved not before control angiography after 6 months. It could be verified that the measurement of flow velocity patterns under rest and stress conditions is a useful non-invasive procedure for monitoring long-term patency and PTCA-results of this vessel.

Angioplasty, Balloon, Coronary↗
PubMed1999

[Early decrease in diastolic function in young type I diabetic patients as an initial manifestation of diabetic cardiomyopathy].

INTRODUCTION: The early determination of the myocardial manifestation is of considerable importance, since the prognosis of patients (P) with insulin dependent diabetes mellitus (IDDM) is generally masked by secondary cardiac complications. The aim of this study was to investigate whether young, asymptomatic P with IDDM and persisting normal systolic left ventricular (LV) function already show a diastolic LV dysfunction. METHODS: An echocardiographical examination of 92 IDDM patients (age: 25 +/- 4 years) without known cardiac disease and of 50 control persons (C) of similar ages was carried out. P with a cardiac disease or long-term diabetic syndrome were excluded. Using M-mode echocardiography, morphological parameters and systolic time-intervals (fractional shortening; ejection fraction) were determined. Doppler indices were then measured: maximal early and late diastolic flow velocity (VE; VA), E/A ratio, acceleration and deceleration time (DT), isovolumetric relaxation time (IVRT). RESULTS: Although the left atrial and left ventricular dimensions, as well as the systolic functional parameters of all P with IDDM were normal, they showed a diastolic dysfunction with a reduction of the early diastolic filling (VE; 0.54 +/- 0.07 m/s vs 0.72 +/- 0.04 m/s; p < 0.01) and the E/A ratio (0.9 +/- 0.15 vs 1.99 +/- 0.22; p < 0.01), an increase in the atrial filling (VA; 0.76 +/- 0.05 m/s vs 0.39 +/- 0.04 m/s, p < 0.01), an extension of the IVRT (129 +/- 23 ms vs 78 +/- 6 ms, p < 0.01), and an increased DT (248 +/- 27 ms vs 188 +/- 8 ms, p < 0.01). CONCLUSION: Even young P with IDDM, with a normal systolic ventricular function, suffer a diastolic dysfunction which serves as a marker of a diabetic cardiomyopathy. Therefore, echocardiography with measurements of systolic and diastolic functional parameters appears to be a sensible method for evaluating the course of diabetic cardiomyopathy.

Adult↗
PubMed1999

[PTCA of the LAD via the internal thoracic artery graft with Doppler ultrasonic control of the results: a case report and review of the literature].

The report presents a transluminal angioplasty (PTCA) of a severe stenosis of the left anterior descending artery (LAD) behind the anastomosis; the internal thoracic artery (ITA) graft was used as a conduit. Before and after the PTCA the changing of velocity flow patterns under rest and stress conditions with a handgrip-maneuver were measured with a noninvasive transthoracic ultrasound Doppler system. The mean diastolic velocity, which represent coronary perfusion through the ITA graft, increased after successful PTCA at rest and under stress conditions. An additional increasing of the mean diastolic velocity at rest and under stress conditions was seen after six months before the catheterization proposing no signs of restenosis. For this reason the vessel could be classified prospectively patient. This could be confirmed during coronary angiography. We also present a review of the published reports concerning PTCA of ITA grafts and PTCA of the native vessel using the ITA as a conduit. In this review 286 cardiac interventions on 273 patients with a primary rate of success of 87% could be counted, the documented rate of restenosis was 30%, and the rate of complication was approximately 1%. The PTCA in ITA grafts or of the native vessel via ITA grafts, respectively, represent an alternative to reoperation. The ultrasound-duplex measurements are gaining an increasing significance for the noninvasive patency rate and post-interventional monitoring of the long-term PTCA result. With the augmentation of the ITA as a coronary bypass and expected increase of post-operative interventions, a noninvasive tool is necessary.

Angina Pectoris↗
PubMed1998

[Diastolic function parameters and atrial arrhythmias in patients with arterial hypertension].

OBJECTIVE: To investigate in patients with arterial hypertension (HT) the extent of left ventricular (LV) hypertrophy and diastolic function in relation to atrial arrhythmias. PATIENTS AND METHODS: In 112 hypertensive patients (40 women, 72 men; mean age 50 +/- 6.6 years) with a mean systolic blood pressure for the cohort of 170 +/- 5 mmHg, their first invasive coronary angiography was performed between July 1995 and October 1997 because of angina pectoris and/or an abnormal stress electrocardiogram. After excluding coronary heart disease LV dimensions and diastolic function were measured by echocardiography; in 59 of the 112 patients LV hypertrophy was demonstrated. In addition, long-term blood pressure monitoring, exercise and long-term electrocardiography, late-potential analysis and measurement of heart rate variability were undertaken. The control group consisted of 51 patients without arterial hypertension after exclusion of coronary heart disease. RESULTS: Even in the hypertensive patients without LV hypertrophy diastolic LV function and ergometric exercise capacity were reduced. The risk of LV arrhythmias was significantly higher in patients with LV hypertrophy than those without and in the control group, as measured by the complexity of atrial arrhythmias (P < 0.001), the incidence of abnormal late potentials (P < 0.001) and reduction in heart rate variability (29.3 +/- 5.3 ms vs 47.8 +/- 12.1 ms vs 60.7 +/- 6.6 ms; P < 0.001). There were similar results regarding severe complex atrial arrhythmias (38.5 vs 15.0 vs 0%; P < 0.001). The incidence of atrial arrhythmias correlated with the LV diameter (r = 0.68, P < 0.001), LV morphological dimensions and diastolic function (isovolumetric relaxation time r = 0.44, P < 0.001) and the ratio of early to late diastolic inflow (r = 0.46; P < 0.001). CONCLUSIONS: Hypertensive patients have a higher risk of atrial and ventricular arrhythmias, depending on the degree of LV hypertrophy. But atrial arrhythmias, in contrary to ventricular arrhythmias, are also closely related to abnormalities in LV diastolic function.

Adult↗
PubMed1998

[Internal thoracic artery bypass--basic principles of Doppler ultrasound for pre- and postoperative diagnosis].

During the last 25 years the internal thoracic artery has become a well established conduit for coronary revascularization. Next to angiography, duplex-sonography is increasingly used as a non-invasive imaging procedure for the evaluation of this graft vessel. Preoperative investigation in 117 patients has yielded a high level of agreement between angiography and duplex-sonography. While the preoperative flow-pattern is dominated by systolic flow as it is typical for vessels supplying skeletal muscle, the postoperative findings show an adaptation to the coronary vascular bed as the diastolic flow increases. These non-invasive measurements are well matched with invasive intravascular recordings. Coronary angiography and duplex-sonography of the internal thoracic artery yielded comparable findings in respect to the procedural result. Considering the increasing use of the internal thoracic artery in coronary artery bypass surgery, this non-invasive method should gain increasing relevance.

Blood Flow Velocity↗
PubMed1998

[Antithrombotic therapy in chronic coronary syndromes--value of thrombocyte aggregation inhibition, anticoagulation and chronic thrombolysis].

Antithrombotic therapy is a basic part in the treatment of acute as well as chronic coronary syndromes. The rationale is an enhanced platelet activity with predomination of procoagulatory mechanisms in coronary artery disease. The current status of antiplatelet drugs, anticoagulation, and chronic thrombolysis used in the treatment of chronic coronary syndromes is discussed. It is concluded that low-dose aspirin is the current drug of choice for long term oral treatment in patients with stable chronic coronary artery disease. In contrast, oral anticoagulation with coumadin should be considered in patients with higher risk for atrial or ventricular thrombosis. The impact of long-term intermittent urokinase therapy in patients with end-stage coronary artery disease and refractory angina pectoris leads to a marked improvement of clinical symptoms. Oral blockade of platelet membrane glycoprotein IIb/IIIa receptor and clinical trials regarding antiischemic effects of low-molecular weight heparins in chronic coronary syndromes are expected for the future.

Anticoagulants↗
PubMed1998

[Assessment of the anti-ischemic effect in patients with therapy refractory angina pectoris in end-stage coronary heart disease--results of chronic intermittent urokinase therapy].

Patients with refractory angina pectoris and end-stage coronary artery disease represent an increasing clinical problem. Numbers of these patients will increase in the future for improved survival due to effective secondary prevention of coronary artery disease. Next to the evaluation of clinical symptoms non-invasive objective parameters of myocardial ischemia are of major relevance before initiation of alternative treatment modalities and for verification of antiischemic effectiveness. Based on our own experience it can be shown that in these patients testing which is mainly based on the patients physical exercise capacity is only of limited value due to the early occurrence of clinical symptoms. Furthermore diffuse perfusion abnormalities reduce the sensitivity of electrocardiographic and scintigraphic detection of ischemic changes. In contrast indirect measures of ischemia relating to the systolic or diastolic function of the left ventricle like doppler-echocardiography and radionuclide ventriculography seem to be promising approaches. This is confirmed by the results from the application of long-term intermittent urokinase therapy. Long-term intermittent urokinase therapy leads to an absolute enhancement of myocardial perfusion, which makes this approach superior to other medical interventions which are mainly based on a reduction of cardiac work-load.

Angina Pectoris↗
PubMed1998

Effect of implantable cardioverter/defibrillator lead placement in the right ventricle on defibrillation energy requirements. A combined experimental and clinical study.

OBJECTIVES: The effect of implantable cardioverter/defibrillator (ICD) lead placement in the right ventricle (RV) on defibrillation efficacy has not been thoroughly investigated. Therefore, the goal of this combined experimental and clinical study was to evaluate the effect of a septal and a non-septal position of the right ventricular endocardial spring lead on defibrillation energy. METHODS: In 12 isoflurane-anaesthetized swine and subsequently in 8 patients who underwent ICD implantation, two different positions of the distal spring lead in the RV were investigated in randomized order: non-septal position (free wall of the RV) and septal position (interventricular septum). For each position, separate 50% probability determinations of energy (E50), peak voltage (V50) and peak current (A50) were calculated using the three reversal up/down defibrillation procedure. The E50, V50, A50 and impedance (I) were averaged and compared using the two-sided t-test for paired samples. RESULTS: Both the experimental study and the clinical study demonstrated that placing the distal defibrillation lead near to the septum rather than near to the ventricular free wall resulted both in the swine and in the patients in significantly lower E50-31.6%/ - 37.1%, V50-16.1%/-20.9% and A50 -10.0%/ - 24.2%, respectively. Defibrillation impedances were significantly reduced only in the experimental study. CONCLUSIONS: Defibrillation efficacy depends on the position of the distal spring electrode in the RV. A septal position significantly reduces the energy requirements compared to a non-septal position. The decrease in energy requirements might be explained by an increase in current flow through the septum and the posterolateral wall of the left ventricle. reserved

Animals↗