A new strategy for easy volume conductor modelling in magnetocardiography.

Modelling the electromagnetic properties of the thorax in magnetocardiographic (MCG) studies is usually performed by the Boundary Element Method (BEM). Magnetic Resonance Imaging (MRI) scans are generally used as the basis for extracting the coordinates for BEM. As MRI is a (time) expensive technique and scanners have a high use demand, in this work a strategy is presented that reduces the costs and the need for additional MRI images. This strategy is based on the use of low resolution and incomplete MRI image sets of the thorax.

Assessment of left ventricular function with steady-state-free-precession magnetic resonance imaging. Reference values and a comparison to left ventriculography.

UNLABELLED: Ejection fraction (EF) and end-diastolic and end-systolic volume index (EDVI/ ESVI) derived from ventriculography are important prognostic parameters. Cine magnetic resonance imaging (MRI) using a steady-state, free-precession sequence (SSFP) offers excellent delineation of the endocardial borders and highly reproducible and accurate results for cardiac volumes. We evaluated MRI volumetry against routine x-ray ventriculography. In 200 patients EF, EDVI and ESVI were measured with MRI volumetry and x-ray ventriculography. The same MRI protocol was applied to 102 healthy persons in order to establish reference values. In healthy subjects mean EF was 68.8% +/- 5.4% (range 59-84%), mean EDVI 69 +/- 10 (43-90) and mean ESVI 22 +/- 5.8 (10-35 ml). In the patients, overall correlation (Spearman's R) of MRI with ventriculography was 0.86 for EF, 0.77 for EDVI and 0.88 for ESVI. For postextrasystolic beats (38% of the measurements), R was 0.73/0.65/0.73 for EF/EDVI/ESVI. MRI correlated best with biplane ventriculography during sinus rhythm (0.96/0.85/0.93); the worst correlation (0.78/0.81/0.83) resulted from patients with wall motion abnormalities in comparison to monoplane x-ray ventriculography. CONCLUSION: Contemporary MRI volumetry compares well to invasive data obtained under optimal conditions. In view of the known limitations of single plane ventriculography, MRI seems to allow exact volumetry independent from regional wall motion abnormalities.

[Effect of molsidomine on rheological parameters and the incidence of cardiovascular events]. / Einfluss von Molsidomin auf rheologische Parameter und die Inzidenz kardiovaskulärer Ereignisse.

BACKGROUND AND OBJECTIVE: In-vitro studies revealed that nitric oxide (NO) may affect rheological parameters. We studied the effect of highly-dosed NO-donor molsidomine on blood rheology and the impact of rheological parameters on the incidence of severe cardiovascular events. PATIENTS AND METHODS: In this randomized, placebo-controlled and double-blind trial 166 patients (60 +/- 10 years) with stable angina pectoris and coronary intervention received molsidomine 3 x 8 mg t. i. d. (controlled release tablets) or placebo for 6 months. Patients with inflammatory/neoplastic disorders or elevated values of C-reactive protein were excluded from analysis. A rheological profile (plasma viscosity, blood viscosity, aggregation and flexibility of erythrocytes, filtrability of leukocytes, fibrinogen levels) was done initially and after 6 months. Adverse cardiovascular events (death, myocardial infarction, stroke, coronary/peripheral revascularization) were recorded during 12 months. Furthermore, the impact of rheological parameters regarding the occurrence of severe cardiovascular events (death, myocardial infarction, stroke) was evaluated during a follow-up of median 38 months. RESULTS: The data of 137 patients (n = 71 placebo, n = 66 molsidomine) were analysed. The difference of rheological parameters between the two measurements did not vary between the two groups. Analysis of event-free survival with Kaplan-Meier technique revealed no difference between the two groups. Multivariate Cox regression analysis with adjustment for diabetes mellitus, smoking and therapy with statin showed a significant association of fibrinogen and plasma viscosity with the occurrence of severe cardiovascular events. CONCLUSION: Treatment with molsidomine 3 x 8 mg/day for 6 months does not improve blood rheology or reduce cardiovascular events. But elevated levels of fibrinogen and plasma viscosity were associated with the occurrence of severe cardiovascular events.

A randomized trial of elective stenting after balloon recanalization of chronic total occlusions.

OBJECTIVES: The aim of this study was to assess the role of Wiktor stent implantation after recanalization of chronic total coronary occlusions with regard to the clinical and angiographic outcome after six months. BACKGROUND: Beside the common use of stents in clinical practice, the number of stent indications proven by randomized trials is still limited. METHODS: Eighty-five patients with a thrombolysis in myocardial infarction grade 0 chronic coronary occlusion were examined. After standard balloon angioplasty, the patients were randomly assigned to stent implantation, or percutaneous transluminal coronary angioplasty (PTCA) alone (no further intervention). Quantitative coronary angiography was performed at baseline and after six months. RESULTS: The minimal lumen diameter did not differ immediately after recanalization (stent group 1.61 +/- 0.30 mm vs. PTCA group 1.65 +/- 0.36 mm), and increased after stent implantation to 2.51 +/- 0.41 mm. After six months, the stent group still had a significantly greater lumen (1.57 +/- 0.59 vs. 1.06 +/- 0.90 mm; p < 0.01) and a significantly lower restenosis and reocclusion rate (32% and 3%) compared with the PTCA group (64% and 24%); restenosis analysis according to treatment was 72% (PTCA) versus 29% (stent, p < 0.01). Late loss was equal in both groups. At follow-up, the stent patients had a better angina class (p < 0.01), and fewer cardiac events (p < 0.03). A meta-analysis including this trial and three other controlled trials with the Palmaz-Schatz stent showed concordant results. CONCLUSIONS: Stent implantation after reopening of a chronic total occlusion provides a better angiographic result, corresponding to a better clinical outcome with fewer recurrence of symptoms and reinterventions after six months.