BACKGROUND AND AIM OF THE STUDY:In patients with heart valve disease, the valve leaflets display a gapped, rough endothelial lining often covered with calcified areas. As a consequence, blood flow is disturbed and a stimulation of components of the hemostasis system is assumed. The possible mechanisms of this process are, however, unclear at present.METHODS:Platelet function was studied in 660 patients considered for isolated coronary artery bypass graft (CABG) surgery, and in 421 patients considered for single aortic valve replacement (AVR). Platelet function was monitored preoperatively using the platelet function analyzer device (PFA-100). The test results were reported as closure time of the membrane hole at the end of a capillary tube. The von Willebrand factor antigen, and its collagen-binding activity, were also determined among subgroups of 40 AVR and 50 CABG candidates.RESULTS:Platelet dysfunction was displayed by only 22% of CAD patients, but by 83% of AVR candidates. The mean PFA closure time in AVR patients was considerably higher than in CAD patients (231 +/- 59 s versus 153 +/- 60 s, respectively; p < 0.01). The mean platelet volume, platelet distribution width and von Willebrand factor collagen binding and antigen levels did not differ between the patient groups.CONCLUSION:It is assumed that, due to disturbed flow and shear exposition, following an initial activation, the platelets are partially degranulated, shed microparticles, and might become involved in the pathogenesis of microvascular dysfunction and thrombotic events in patients with aortic valve disease.

Summary Aim: Cardiac resynchronisation therapy (CRT) has been shown to improve haemodynamics and clinical symptoms in heart failure patients. The present study evaluated the effects of a 4-month CRT on myocardial blood flow (MBF) at rest, after vasodilation and on myocardial oxygen consumption (MVO2). Patients, Methods: We studied 16 patients with idiopathic dilated cardiomyopathy prior to and during CRT performed as biventricular pacing. Resting MBF and MVO2 were determined from an 11C-acetate PET study and vasodilator MBF from a 13N-ammonia study. Results: MBF at rest (0.55 ± 0.10 ml/min/g), after vasodilation (1.20 ± 0.45 ml/min/g), and MVO2 (0.082 ± 0.014/min) did not change by mid-term CRT at a global level (0.57 ± 0.11 ml/min/g; 1.32 ± 0.49 ml/min/g; 0.085 ± 0.018/min), whereas the rate pressure product (RPP) normalised MVO2 decreased from 0.104 ± 0.024 to 0.086 ± 0.018/min (p = 0.02). At baseline, the regional analysis revealed significantly higher values for all parameters in the lateral wall than for those in the other walls. Under CRT the regional differences between the resting parameters equalised and all parameters showed significant lower coefficients of variation. Conclusion: Effects of mid-term CRT on resting MBF, vasodilator MBF and MVO2 occur at a regional level. The resynchronisation is associated with a more homogenous distribution pattern of these parameters among the myocardial walls. Substantial alterations to global MBF at rest, after vasodilation or to MVO2 are not detectable. Regarding the RPP normalised MVO2, there is evidence of improved ventricular efficiency through CRT.

Cardiac resynchronization therapy (CRT) is a treatment option in patients with severe heart failure and left bundle-branch block (LBBB). This study evaluated the effects of 4 and 13 mo of CRT on myocardial oxygen consumption (MVO2) and cardiac efficiency as compared with mild heart failure patients without LBBB. Methods: Sixteen patients with severe heart failure and LBBB due to idiopathic cardiomyopathy were studied at baseline and after 4 and after 13 mo of therapy. Thirteen patients with mild heart failure without LBBB served as a comparison group. The clearance rate (k(2)) of C-11-acetate was measured with PET to assess MVO2. Stroke volume was derived from the dynamic PET data according to the Stewart-Hamilton principle and, furthermore, cardiac efficiency using the work metabolic index. Results: After 4 mo of CRT, stroke volume index (SVI) increased by 50% (P = 0.012) and cardiac efficiency increased by 41 % (P < 0.001). Global k(2) remained unchanged but regional k(2) demonstrated a more homogeneous distribution pattern. The parameters showed no significant changes during therapy. Under CRT, cardiac efficiency, SVI, and the distribution pattern of regional k(2) did not differ from mild heart failure patients without LBBB. Conclusion: CRT improves cardiac efficiency for at least 13 mo, as demonstrated by a higher SVI, whereas MVO2 remains unchanged. Cardiac efficiency, SVI, and the MVO2 distribution pattern reach the level of patients with mild heart failure without LBBB. The unfavorable hemodynamic performance in heart failure with LBBB is effectively restored by long-term CRT to the level of an earlier disease state.

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.

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.

Correlation between Cold Pressure Testing (CPT)/ 99 Tc MIBI-SPECT defects and intracoronary acetylcholine (ACH) paradoxical constriction was published by our group.The usefulness of CPT non -invasive diagnosis of dysfunction (ED) was demonstrated by our observation in coincidence with other authors.There is little information on ED incidence on moderate risk asymptomatic (MRA) patients according to ATP III/Framingham index.Objective: This study is aimed at analyzing the incidence and localization of 99 Tc MIBI/ SPECT myocardial perfusion (MP) defects during CPT as indicator of ED on MRA patients.Methods: 124 patients (78 female) currently compounding PARADIGMA Study Register were analyzed.PARADIGMA is a prospective multicenter study that will include once completed a total number of 450 MRA patients according to ATP III/ Framingham index (Ͻ 20% events at 10 years ), with normal exercise MP and no cardiovascular disease history.CPT-MP imaging was obtained in all these patients.MP extension score was used in a 17 segment model , reported by two observers on consensus.Mann-Whitney U Test statistical analysis was performed.l Results: positive CPT 25/113 patients (22,12 %).CPT extension perfusion score positive 5,77Ϯ2,38(pϽ0.0001).CPT was positive in 30,76 % men and 17,56 % women (pϽ0.001).Localization : anterior wall 4 3%,i n ferior wall 47 %, lateral wall 4,5% and anterior with inferior walls 4,5 %.Conclusion: These results suggest high incidence of ED on MRA patients, who are also free from exercise --related ischemia.There were no significant differences in clinical data and defects localization.Further studies will indicate whether this positive CPT population would have higher risk of cardiovascular events during follow-up Age, Bood Pressure and Cholesterol pns (*) AGE SBP DBP CHOLEST.HDL LDL TRIGL.CPT ( ϩ ) 55.

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 C-11-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. (C) 2004 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.

AIMCardiac resynchronization therapy (CRT) has been shown to improve haemodynamics and clinical symptoms in heart failure patients. The present study evaluated the effects of a 4-month CRT on myocardial blood flow (MBF) at rest, after vasodilation and on myocardial oxygen consumption (MVO(2)).PATIENTS, METHODSWe studied 16 patients with idiopathic dilated cardiomyopathy prior to and during CRT performed as biventricular pacing. Resting MBF and MVO(2) were determined from an (11)C-acetate PET study and vasodilator MBF from a (13)N-ammonia study.RESULTSMBF at rest (0.55 +/- 0.10 ml/min/g), after vasodilation (1.20 +/- 0.45 ml/min/g), and MVO2 (0.082 +/- 0.014/min) did not change by mid-term CRT at a global level (0.57 +/- 0.11 ml/min/g; 1.32 +/- 0.49 ml/min/g; 0.085 +/- 0.018/min), whereas the rate pressure product (RPP) normalised MVO(2) decreased from 0.104 +/- 0.024 to 0.086 +/- 0.018/min (p = 0.02). At baseline, the regional analysis revealed significantly higher values for all parameters in the lateral wall than for those in the other walls. Under CRT the regional differences between the resting parameters equalized and all parameters showed significant lower coefficients of variation.CONCLUSIONEffects of mid-term CRT on resting MBF, vasodilator MBF and MVO(2) occur at a regional level. The resynchronization is associated with a more homogenous distribution pattern of these parameters among the myocardial walls. Substantial alterations to global MBF at rest, after vasodilation or to MVO(2) are not detectable. Regarding the RPP normalised MVO(2), there is evidence of improved ventricular efficiency through CRT.

Aims Experimental studies indicated unfavourable effects on myocardial energetics and efficiency under asynchronous ventricular stimulation, also shown for left bundle branch block (LBBB) pattern. We noninvasively analyzed the effects on myocardial oxygen consumption (MVO2), perfusion (MBF) and pressure work efficiency by positron emission tomography (PET) before and after resynchronization therapy (CRT) in 31 patients with dilated cardiomyopathy (DCM) and LBBB.Methods 31 patients (19 mates, 12 females) with DCM were studied at baseline and PET 3-4 months follow-up. Baseline characteristics: age 61 +/- 7 years; NYHA class 3.0 +/- 0.4, ejection fraction 22.1 +/- 7.1%, QRS duration 187 +/- 19 ms. MVO2 and MBF were measured from C-11-acetate kinetics with PET by a one-compartment model. MVO2 and MBF were normalized to rate pressure product (RPP) to account for different pressure loads and predicted energy demands.Results Global MVO2 assessed from C-11-acetate clearance did not change significantly between baseline and follow-up (0.080 +/- 0.015/min vs. 0.082 +/- 0.020/min). RPP-normalized MVO2 significantly decreased after CRT (0.072 +/- 0.018/min) vs. baseline (0.081 +/- 0.017/ min; P < 0.05). Normalized MBF showed a concomitant decrease from 0.51 +/- 0.11 to 0.46 +/- 0.1 mL/min/g; P < 0.05 after CRT. Regional MVO2 significantly decreased in the lateral wall (0.083 +/- 0.020/min) compared to baseline (0.090 +/- 0.018/min; P < 0.05) and increased in the septum (0.081 +/- 0.022/min vs. 0.073 +/- 0.014/min at baseline).Conclusion 1. CRT does not increase absolute global MVO2 in the short-term. 2. RPP-normalized MVO2 even decreased suggesting improved pressure work efficiency. 3. CRT leads to a reverse remodelling of regional myocardial oxygen dysbalance. Q 2004 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.