Spatial correction improves accuracy of catheter positioning during ablation of premature ventricular contractions: differences between ventricular outflow tracts and other localizations.

BACKGROUND: Hybrid activation mapping is a novel tool to correct for spatial displacement of the mapping catheter due to asymmetrical contraction of myocardium during premature ventricular contractions (PVC). The aim of this study is to describe and improve our understanding of spatial displacement during PVC mapping as well as options for correction using hybrid activation mapping. METHODS AND RESULTS: We analyzed 5798 hybrid mapping points in 40 acquired hybrid maps of 22 consecutive patients (age 63 ± 16 years, 45% female) treated for premature ventricular contractions (PVCs). Median PVC-coupling interval was 552 ms (IQR 83 ms). Spatial displacement was determined by measuring the dislocation of the catheter tip during PVC compared to the preceding sinus beat. Mean spatial displacement was 3.8 ± 1.5 mm for all maps. The displacement was 1.3 ± 0.4 mm larger for PVCs with non-outflow-tract origin compared to PVCs originating from the ventricular outflow tracts (RVOT/LVOT; p = 0.045). Demographic parameters, PVC-coupling-interval and chamber of origin had no significant influence on the extent of spatial displacement. CONCLUSION: Ectopic activation of the ventricular myocardium during PVCs results in spatial displacement of mapping points that is significantly larger for PVCs with non-outflow-tract origin. The correction for spatial displacement may improve accuracy of radiofrequency current (RFC)-application in catheter ablation of PVCs.

Quantum beats and Kepler motion in fast competing photoionization and photodissociation processes

Electronic and nuclear wavepackets created by coherent excitation of an autoionized and predissociated 'complex' resonance in H2 are studied theoretically using time-dependent multichannel quantum defect theory. The calculations predict that quantum beats between the components of the complex resonance interfere with Rydberg wavepacket (Kepler) motion to yield characteristic 'mixed' flux patterns in the observable time-dependent ionization and dissociation signals.

The Electronic Structure of CaCl: Calculation by R Matrix and Generalized Quantum Defect Theory.

The electronic spectrum of CaCl has been calculated using the variational eigenchannel R-matrix method combined with generalized multichannel quantum defect theory. The motion of the unpaired (Rydberg) electron is represented as a double scattering process on the closed-shell Ca(++) and Cl(-) core ions. Electron penetration into Ca(++) is taken into account as well as polarization effects. The partial saturation of the Cl(-) free-ion polarizability is evaluated on the basis of an ab initio calculation of the dipole and quadrupole moments of the CaCl(+) ion core. The calculations reproduce the effective principal quantum numbers nu of the experimentally known states (including the ground state) to within approximately 0.04. States with high-orbital angular momentum up to l = 6 are predicted. Copyright 1999 Academic Press.