Pulmonary Vein Isolation Supported by MRI‐Derived 3D‐Augmented Biplane Fluoroscopy: A Feasibility Study and a Quantitative Analysis of the Accuracy of the Technique

MRI‐Derived 3D‐Augmented Biplane Fluoroscopy . Background: Despite the advancement of technology in electroanatomic mapping systems (EAMS), fluoroscopy remains a necessary, basic imaging modality for electrophysiology procedures. We present a feasibility study of new software that enables 3D‐augmented fluoroscopy in biplane catheterization laboratories for planning and guidance of pulmonary vein isolation (PVI). The computer‐assisted overlay registration accuracy was assessed in a clinical setting using an automatic calculation of overlay projection geometry that was derived from hardware sensors in C‐arms, detectors, and patient table. Methods: Consecutive patients (n = 89) underwent left atrium (LA) magnetic resonance imaging MRI scan prior to PVI. Ideal ablation lines encircling the ipsilateral pulmonary veins (PVs) at antral level were drawn onto the segmented LA surface. The 3D‐model was superimposed onto biplane fluoroscopy and matched with angiographies of LA and PVs. Three‐dimensional‐overlay projection geometry was automatically calculated from C‐arm, detectors, and table sensors. Accuracy of technique was assessed as alignment of MRI‐derived 3D overlay and angiographic LA/PV anatomy. Integrity of registered overlay was quantified using landmark measurements. Results: Alignment offsets were 1.3 ± 1.5 mm in left PV, 1.2 ± 1.5 mm in right PV, and 1.1 ± 1.4 mm in LA roof region. Bravais–Pearson correlation of the landmark measurements was r = 0.978 (s  < 0.01), mean offset between landmark distance measurements was 1.4 ± 0.78 mm. Average time needed for overlay registration was 9.5 ± 3.5 seconds. Conclusions: MRI‐derived 3D‐augmented fluoroscopy demonstrated a high level of accuracy when compared with LA/PV angiography. The new system could be especially useful to guide procedures not supported by EAMS, such as cryotechnique PVI. (J Cardiovasc Electrophysiol, Vol. 24, pp. 113‐120, February 2013)     

Information processing during sleep: the effect of olfactory stimuli on dream content and dream emotions

Research has shown that external stimuli presented during sleep can affect dream content, thus reflecting information processing of the sleeping brain. Olfactory stimuli should have a stronger effect on dream emotions because their processing is linked directly to the limbic system. Because selective olfactory stimulation does not increase arousal activity, intense olfactory stimulation is therefore a prime paradigm for studying information processing during sleep. Fifteen healthy, normosmic volunteers were studied by intranasal chemosensory stimulation during rapid eye movement sleep based on air-dilution olfactometry. For olfactory stimulation, hydrogen sulphide (smell of rotten eggs) and phenyl ethyl alcohol (smell of roses) was used and compared with a control condition without stimulation. The olfactory stimuli affected significantly the emotional content of dreams: the positively toned stimulus yielded more positively toned dreams, whereas the negative stimulus was followed by more negatively toned dreams. Direct incorporations, i.e. the dreamer is smelling something, were not found. The findings indicate that information processing of olfactory stimuli is present in sleep and that the emotional tone of dreams can be influenced significantly depending upon the hedonic characteristic of the stimulus used. It would be interesting to conduct learning experiments (associating specific odours with declarative material) to study whether this declarative material is incorporated into subsequent dreams if the corresponding odour cue is presented during sleep. It would also be interesting to study the effect of positively toned olfactory stimuli on nightmares.     

Managing Difficult Common Bile Duct Problems With the Help of the Interventional Radiologist

Surgery is the mainstay of therapy for disorders of the common bile duct. In recent years, however, numerous radiological biliary interventional procedures have been developed. Sufficient experience with these techniques has now been accumulated such that the role of these procedures is now more clearly defined. A variety of transhepatic and transcholecystic biliary manipulations is described as an overview of the value of these procedures in difficult common bile duct disorders.     

Computer-Assisted Pacemaker Management Systems: Three Years of Clinical Experience

The implantation of large numbers of cardiac pacemakers and the increasing sophistication in engineering techniques has resulted in the demand for computer-assisted pacemaker management systems to remain on top of the available programmable features of the pacers as well as being able to access the follow-up data of pacemaker patients. A pacemaker patient management systems is introduced (PATIENTLOG™) that has been used in the clinical environment for a number of years. The menu-guided program is easy to handle and features a patient card for administration data, an implantation card for the technical data of the pacer, and a follow-up card where a large number of follow-ups can be stored side by side which are easily graphically displayable. An extensive statistical program, letter functions, automatic back-up and on-line communication with external equipment through an RS 232C interphase and a parallel adapter are available. The data base in Frankfurt holds 8,000 patients, 10,000 interventions and more than 30,000 follow-ups, the existing data base needs 20 M bytes storage space. Up to 96 different pacer types with their specific features can be introduced into the system. Software and hardware design complies with the recommendation of the NASPE Computer Committee.     

Studies of the Tissue Reaction Induced by Transvenous Pacemaker Electrodes. I. Microscopic Examination of the Extent of Connective Tissue Around the Electrode Tip in the Human Right Ventricle

The purpose of this study was to investigate the extent of connective tissue of the human right ventricle induced by cardiac pacing electrodes. Between January 1984 and July 1987, 34 consecutive patients with VVI-pacing systems were autopsied in the Department of Pathology at the University of Frankfurt/M. The surrounding tissue of these 34 electrodes (17 Siemens Elema 412 S, five Medtronic 6957, one Medtronic 6959, one Medtronic 4011, three Biotronik D2K, three Biotronik K10, two Osypka FY 62, one Biotronik N, and one Siemens Elema 588) in the right ventricle were investigated histologically. The tissue was stained with Giemsa and the thickness of the connective tissue layer was measured. Stimulation threshold data at various times were known in four of eight screw-in electrodes, in seven of 17 vitreous carbon electrodes and in two of seven smooth surface electrodes. Electrode surface area, implantation time, age of the patient and cause of death were comparable for all three electrode groups. However, a significant difference was found in the extent of connective tissue between the porous surface and screw-in electrodes (128 ± 55 VS 397 ± 269 μm, P 0.01) and porous surface and smooth surface electrodes (128 ± 55 vs 307 ± 117 μm, P 0.01). No relation (r = 0.106) was found between the duration of implantation and the extent of connective tissue for the vitreous carbon electrodes (Siemens Elema 412 S). The lowest chronic stimulation thresholds were measured in the latter type of electrodes (0.5 ± 0.3 V) as compared to the screw-in (0.75 ± 0.30 V) and smooth surface electrodes. We conclude from this study, that vitreous carbon electrodes induce only a small amount of connective tissue around the insertion site in the human right ventricle, as compared to other smooth surface or screw-in electrodes. Chronic stimulation threshold data parallel those morphological results.     

Stress Echocardiography

Stress echocardiography, both pharmacologic and physiological, is an established noninvasive diagnostic method of detecting coronary artery disease. It also has a role in the assessment of patients with chest pain, the assessment of cardiovascular risk before noncardiac surgery, the assessment of patients after a myocardial infarction, the detection of viability in dysfunctional myocardium, and the prediction of functional recovery. The prognostic value of stress echocardiography is emerging. In this article, we discuss the methodology, diagnostic accuracy, and various clinical applications of stress echocardiography. We also review its limitations and compared it with other noninvasive methods of assessing patients with coronary artery disease.     

Studies on the Inhibitory Effects of Analogues of Dapsone on Neutrophil Function In-vitro*

We have compared twelve sulphone analogues of dapsone in terms of inhibition both of zymosan-mediated human neutrophil respiratory burst and inhibition of interleukin-1-stimulated neutrophil adhesion to transformed human umbilical vein endothelial cells. Overall, there was a good correlation between the respective rank orders of compound potency in the two test systems. The most effective compounds in terms of respiratory burst and adherence inhibition were the 2-nitro-4-amino-, 2-hydroxy-4-aminopropyl-, and 2-methoxy-4-aminoethyl- derivatives. In general, potency was inversely associated with lipophilicity; compounds with bulky side-chains, e.g. the 2-methyl-4-aminopentyl, 2-methyl-4-aminohexyl and the 2-hydroxymethyl-4-aminoethyl derivatives, were less potent. A 2-hydroxy-4-amino- derivative was the exception, however, with low lipophilicity and relatively low potency. All of the compounds tested showed comparable or greater inhibition in both the neutrophil-mediated assays compared with dapsone. Some of the compounds might, because of their good tissue penetration and lower toxicity than dapsone, have the potential to undergo further development.     

The Effects of Extracorporeal Shock Wave Lithotripsy on Pacemaker Function

Twenty-two pacemaker pulse generators were exposed to shock waves of an extracorporeal shock wave lithotripter to assess the effects of the extremely high pressure transients on pacemaker function. The pulse generator and distal aspect of the lead were positioned 5 cm from the focal point of the lithotripter and 10 cm from each other. Pulse generator function was analyzed during shock wave delivery synchronized with pulse generator output, during shock waves at a rate faster than the escape rate, and after exposure to lithotripsy. During shock waves delivered synchronously with pulse generator output, only one of 22 pulse generators malfunctioned by intermittently reverting to the magnet rate. When subjected to shock waves at a rate greater than the escape rate, 50% of the pulse generators were inhibited by electromechanical interference from the lithotripter. Both bipolar and unipolar devices were affected. However, analysis after exposure to shock waves showed that none of the pacemakers was damaged or spuriously reprogrammed. In conclusion, cardiac pacemakers do not appear to be damaged or reprogrammed by exposure to extracorporeal shock wave lithotripsy. The likelihood of false inhibition appears to be very low if shock waves are delivered synchronously with the QRS.