Showing papers by "Heart and Diabetes Center North Rhine-Westphalia published in 2005"

Effect of cardiac resynchronization therapy on global and regional oxygen consumption and myocardial blood flow in patients with non-ischaemic and ischaemic cardiomyopathy.

Abstract: Aims We studied the effects of cardiac resynchronization therapy (CRT) on global and regional myocardial oxygen consumption (MVO2) and myocardial blood flow (MBF) in non-ischaemic (NICM) and ischaemic dilated cardiomyopathy (ICM). Methods and results Thirty-one NICM and 11 ICM patients, all of them acute responders, were investigated. MVO2 and MBF were obtained by 11C-acetate PET before and after 4 months of CRT. In NICM global MVO2 and MBF did not change during CRT, while the rate pressure product (RPP) normalized MVO2 increased ( P =0.03). Before CRT regional MVO2 and MBF were highest in the lateral wall and lowest in the septum. Under therapy, MVO2 and MBF decreased in the lateral wall ( P =0.045) and increased in the septum ( P =0.045) resulting in a more uniform distribution. In ICM, global MVO2, MBF, and RPP did not change under CRT. Regional MVO2 and MBF showed no significant changes but a similar tendency in the lateral and septal wall to that in NICM. Conclusion CRT induces changes of MVO2 and MBF on a regional level with a more uniform distribution between the myocardial walls and improved ventricular efficiency in NICM. Based on the investigated parameters, CRT appears to be more effective in NICM than in ICM.

Attenuation Correction of Myocardial SPECT Perfusion Images with Low-Dose CT: Evaluation of the Method by Comparison with Perfusion PET

Abstract: In cardiac SPECT, specificity is significantly affected by artifacts due to photon absorption. As the success of attenuation correction depends mainly on high-quality attenuation maps, SPECT low-dose CT devices are promising. We wanted to evaluate the usefulness of a SPECT low-dose CT device in myocardial perfusion scintigraphy. For the evaluation of attenuation correction systems, primarily comparisons with coronary angiography are used. Because the comparison of a method showing myocardial perfusion with an investigation displaying the morphology of vessels yields some difficulties, we chose perfusion PET with 13N-ammonia as the reference method. Methods: We prospectively analyzed 23 patients (6 women, 17 men) with known or suspected coronary artery disease. Rest studies and studies under pharmacologic stress with adenosine were performed. After simultaneous injection of 13N-ammonia and 99mTc-sestamibi, a dynamic PET acquisition was started. The SPECT study was performed about 2 h later. Based on 20-segment polar maps, SPECT with and without attenuation correction was compared with PET-derived perfusion values and ammonia uptake values. The PET uptake images were also smoothed to adjust their resolution to the resolution of the SPECT images. Results: The concordance of SPECT and PET studies was improved after attenuation correction. The main effect was seen in the inferior wall. Especially in the apex and anterolateral wall, there were differences between SPECT and PET studies not attributable to attenuation artifacts. Because these differences diminished after smoothing of the PET studies, they might be due to partial-volume effects caused by the inferior resolution of the SPECT images. Conclusion: The x-ray-derived attenuation correction leads to SPECT images that represent myocardial perfusion more accurately than nonattenuation-corrected SPECT images. The benefit of the method is seen primarily in the inferior wall. The low resolution of the SPECT system may lead to artifacts due to partial-volume effects. This phenomenon must be considered when perfusion PET is used as a reference method to investigate the effect of attenuation correction.

Three-dimensional, isotropic MRI: a unified approach to quantification and visualization in congenital heart disease.

Abstract: Purpose: Current standards in magnetic resonance imaging of congenital heart disease are based mostly on anisotropic protocols to image both morphology and function. Operator-dependent acquisition planning is typically needed to obtain the desired images. We propose to instead use operator-independent, three-dimensional, isotropic imaging protocols to acquire both morphology and function (cine and flow) of the entire heart in a few standardized acquisitions. Subsequently, due to the isotropic property of the data, any desired imaging plane can be “imaged” offline by interactive planar reformatting and used for qualitative and quantitative diagnostic evaluation. Materials and methods: Morphological data was acquired in patients using 3D steady state free precession (SSFP) protocols, and functional data in volunteers using multislice 2D or 3D cine SSFP as well as 3D, three-component phase-contrast velocity mapping with EPI readouts. Tools to integrate morphological and functional offline image evaluation based on interactive planar reformatting, volume rendering, and corresponding quantification tools were implemented and discussed. Results: We successfully acquired and integrated morphology and flow and demonstrated potential clinical applications. Conclusion: User independent acquisitions of morphological and functional isotropic 3D datasets with real-time, interactive planar reformatting, volume rendering, and integration of morphology and function, have the potential to replace conventional, user dependent, anisotropic 2D imaging in patients with cardiac malformations.

Global and regional myocardial oxygen consumption and blood flow in severe cardiomyopathy with left bundle branch block

Abstract: Objective: In patients with dilated cardiomyopathy (DCM), left bundle branch block (LBBB) is a common finding. The characteristic feature is an asynchronous septal wall motion and most frequently a delay of the lateral and/or posterior wall segments. With the onset of cardiac resynchronization therapy, there is a focus on the specific pathophysiology of a LBBB. However, quantitative data on regional myocardial oxygen consumption (MVO2) and blood flow (MBF) are missing. Methods: We studied 31 patients with severe DCM and LBBB (ejection fraction 22.1±7.1%) and 14 patients with mild to moderate DCM without LBBB (ejection fraction 46.7±7.9%). Global and regional MVO2 as well as MBF were determined from a dynamic 11C-acetate positron emission tomography (PET) study. Results: Global MVO2 and MBF were lower in the DCM group with LBBB than in the control group (P<0.05). Regionally, the LBBB group revealed a higher (P<0.05) MVO2 and MBF in the lateral wall than in the other walls. The control group did not show significant differences between the myocardial walls and demonstrated a smaller variability of the parameters. Conclusion: DCM patients with LBBB exhibit a more heterogeneous distribution of MVO2 and MBF among the myocardial walls than DCM patients without LBBB. Due to the LBBB associated electromechanical alterations, the highest regional values of MVO2 and MBF are found in the lateral wall.

Rosiglitazone plus metformin is effective and well tolerated in clinical practice: results from large observational studies in people with type 2 diabetes.

Abstract: This study investigated the efficacy during daily practice of rosiglitazone (RSG) added to metformin (MET) in poorly controlled type 2 diabetes mellitus. Two post-marketing observational studies were conducted in Germany over 6 months. RSG (4 mg/day titrated to 8 mg/day as required) was added to existing MET in 11,014 subjects. Subjects were maintained on diet and exercise. Addition of RSG to MET significantly reduced median HbA 1c by 1.3% (8.1 vs. 6.8%; p < 0.0001) and median fasting blood glucose (FBG) by 47.0 mg/dl (171.0 vs. 124.0 mg/dl; p < 0.0001) after 6 months. The proportion of subjects achieving HbA(1c) targets of < or = 6.5 and < or = 7.0% increased from 3.5 to 38.8% and from 13.5 to 63.7%, respectively. Mean systolic and diastolic blood pressure decreased by 7 and 3 mmHg, respectively (p < 0.0001). Mean weight decreased by 1.7 kg and was constant or reduced in most (74.1%) subjects. Addition of RSG to MET significantly reduces median HbA 1c and FBG in clinical practice and is generally well tolerated.

Beneficial effects of atorvastatin on myocardial regions with initially low vasodilatory capacity at various stages of coronary artery disease

Abstract: The aim of this study was to analyse non-invasively the regional effect of therapy with an HMG-CoA reductase inhibitor on myocardial blood flow in patients with coronary artery disease (CAD) with special reference to segments with initially substantially impaired vasodilation. The study included 26 patients with untreated hypercholesterolaemia. Coronary angiography revealed CAD in nine patients with stenosis >50% and wall irregularities or minimal stenosis <30% in 17 patients. Before and 4.6±1.8 months after atorvastatin therapy, 13N-ammonia positron emission tomography (PET) studies were performed at rest and under pharmacological stress. Minimum coronary vascular resistance (MCR) and coronary flow reserve (CFR) were determined. Segments were divided into those with normal or near-normal (MBF during adenosine ≥2.0 ml/min/g) and those with abnormal (MBF<2.0 ml/min/g) vasodilator flow response. In CAD patients, 156 segments were analysed, 85 of which had abnormal MBF; in the non-obstructive group, 59 of 297 segments had abnormal MBF. LDL cholesterol decreased after atorvastatin therapy from 186±43 mg/dl to 101±26 mg/dl (p<0.001). In normal segments no significant changes in MBF, CFR and MCR were found. However, initially abnormal segments showed significant improvements in MCR (15%, p<0.0001) and MBF during adenosine (30%, p<0.0001) after therapy. The improvement in regional coronary vasodilator function after atorvastatin in patients with coronary atherosclerosis may be caused, at least in part, by increased flow-mediated (endothelium-dependent) dilation of the total arteriolar and arterial vascular system. These data further support the concept of non-invasive management of stable CAD by statin therapy and life-style modification guided by PET.

Mechanical Ventricular Circulatory Support in Children; Bad Oeynhausen Experience

Abstract: INTRODUCTION Recently various mechanical circulatory support systems are being used all over the world, nevertheless the size of the devices limits the implantation in pediatric cases. Accordingly we report our experiences with assist devices applied for pediatric patients. PATIENTS AND METHODS Twenty-nine children underwent mechanical circulatory support implantation operation. The diagnoses of preoperation were dilated cardiomyopathy in 16, congenital heart disease in 12 and allograft dysfunction in 1. RESULTS From November 1987 to January 2004 we implanted 7 LVAD, 11 BVAD and 11 ECMO in pediatric patients. The 29 patients were supported from 11 to 231 days (mean 32.3 days). Three children were supported by Thoratec LVAD. Biventricular Thoratec VAD was used in 3 children. Three children were supported by Medos-HIA system LVAD, and 8 children by biventricular VAD using the Medos-HIA system. One child was supported by Novacor LVAD. Fourteen children were supported by ECMO. We succeeded in heart transplantation in 10 cases, but lost 16 children during the support. Bleeding occurred in 7 cases, thrombosis occurred in 6 cases, infection occurred in 8 cases, pneumothorax occurred in 3 cases and neurological deficit occurred in 2 cases. CONCLUSION The development of assist device for children which has long durability and small in size as a future subject is desired. Further clinical and experimental research and application of those assist devices for children are in progress.

Digital frequency analysis of valve sound phenomena in patients after prosthetic valve surgery: its capability as a true home monitoring of valve function.

Abstract: Background and aim of the study: Depending on the individual risk profile of a patient, disturbances of the functional integrity of mechanical heart valve prostheses occur in up to 2.5% of patients each year. The early phase of prosthetic dysfunction (due to thrombus formation, tissue ingrowth or endocarditis) usually remains undiagnosed, as patients do not present with symptoms in this situation, and imaging techniques (echocardiography, fluoroscopy) demonstrate normal occluder motion. The delay between the onset of prosthetic valve dysfunction and its clinical manifestation may result in complications (e.g. thromboembolism) or extended therapeutic options (e.g. reoperation rather than more intensive anticoagulation). Methods: A total of 291 patients with mechanical heart valves was allocated to four different subgroups, and each measured their valve sounds regularly with the ‘ThromboCheck’ device. Depending on the subgroup, the signals were compared with different reference signals. Patients in whom a suspicious signal was detected were immediately contacted and examined meticulously. Results: Fourteen patients were found to have suspicious signals. In 13 patients, valve dysfunction was confirmed by fluoroscopy, but in four cases neither transthoracic nor transesophageal echocardiography detected abnormal occluder motion or ‘musses’ adjacent to the prosthesis. Normal valve sounds returned in four patients who underwent thrombolytic therapy. All patients regularly recorded and passed on their signals. Surveys revealed high acceptance and easy handling of the Thrombocheck device. Conclusion: Home monitoring of sound pressure measurements of prosthetic valves by digital frequency analysis via a Fast Fourier transformation may detect even very mild alterations of prosthetic valve function. The next evolution of control systems, allowing for registration of flow, frequency spectrum and electrocardiography, opens potential applications for Internet-based, remote monitoring of cardiac patients.

Enhancement of perfusion reserve by cardiac resynchronization therapy: reply

Abstract: The letter from Dr Knaapen and co-workers raised an interesting and critical point about our conclusion that further studies have to clarify whether long-term cardiac resynchronization therapy (CRT) is able to improve myocardial perfusion and metabolism at a global level, suggesting a regression of cardiomyopathy. This conclusion was based on the observation that global resting MBF and MVO2, which were reduced in our cardiomyopathy patients, …

Abl05: spinal cord stimulation for refractory stable angina pectoris in patients with chronic pacemaker treatment

Abstract: Spinal cord stimulation (SCS) is a safe treatment modality in patients with severe angina pectoris. We studied possible interactions of procedures in patients treated with both, SCS for angina pectoris and permanent pacemaker (PPM) treatment for bradyarrhythmias. Methods used Since January 2001, we performed SCS in 61 patients (pts.) (48 men, 13 women, age 65±8 years, bmi 27±9 kg/qm). Nine pts. additionally needed PPM treatment for bradyarrhythmias. All pts. had severe angina pectoris (III to IV [39/22] according to Canadian Cardiovascular Society) under considered medication due to angiographically documented end-stage coronary artery disease (CAD), which could not be treated interventionally. After 3 to 5 days of successful test stimulation using an epidural lead a commercially available implantable pulse generator is placed in a subcutaneous pouch below the costal arch. Results In 58 pts. (95%) angina pectoris could be reduced significantly. In 3 pts. the lead was removed because of ineffectivity during the test period. There was no interaction between neurostimulation and PPM treatment during follow-up of 1 to 38 (mean 20±12) months. DDD pacemaker were used in bipolar sensing mode: n=4 Medtronic, n=3 Biotronik, n=2 Guidant. View this table: Conclusion SCS has proved to be a safe procedure in patients with severe angina pectoris and PPM treatment with bipolar sensing mode.