Primary Prevention of Sudden Cardiac Death: Can We Afford the Cost of Cardioverter-Defibrillators? Data from the Search-MI Registry-Italian Sub-study

Background: Large randomized trials show that in appropriately selected patients with left ventricular dysfunction, implantable cardioverter-defibrillators (ICDs) can improve overall survival at 2–5 years. Since direct implementation of the criteria used in the MADIT II and SCD-HeFT will lead to a marked rise in ICD implants, there is a growing fear that increased use of ICDs may cause a dramatic burden to health care systems. The ICD has traditionally been seen as an expensive form of treatment, which is difficult to accept at the first look. This is mainly due to the nonlinear character of the ICD investment, characterized by high initial expenditure, followed by a deferred pay-off in terms of clinical benefits. Cost-effectiveness analysis may help provide a different perspective on the problem of ICD cost, as may estimation of the daily cost of ICD treatment, assuming a time horizon of 5–7 years—a particularly interesting subject for further registry studies.
Methods and Results: Based on real expenditure data from 2002 to 2005, as recorded in the Search-MI Registry-Italian Sub-study of patients implanted on MADIT II indications, we estimated the daily costs associated with the device and leads. Over a 5–7 year time horizon, the average daily cost was estimated to be €4.60–€6.70. Translation of these figures into U.S. market conditions suggests a daily cost of around $7.90–$11.40.
Conclusions: These findings appear useful to help evaluate the affordability of ICD in comparison with other therapeutic options in a context of limited available economic resources.     

Clinical experience with minimal flow xenon anesthesia

Xenon is a more potent anesthetic than nitrous oxide, and gives more profound analgesia. This investigation was performed to assess the potential of xenon for becoming an anesthetic inspite of its high manufacturing cost. Seven ASA I—-II patients undergoing cholecystectomy (n = 4), hernia repair (n = 2), or mammoplasty (n=l) were studied. Denitrogenation by 15–20 min of oxygen breathing under propofol anesthesia was followed by fentanyl–supplemented xenon anesthesia administered via an automatic minimal flow system which held the oxygen concentration at 30%. Xenon anesthesia lasted 76–228 min and 8–14 1 of xenon (ATPD) was used, of which 5.6–8.1 1 was expended during the first 15 min. Anesthesia appeared to be satisfactory, and the patients woke up rapidly after xenon was discontinued. The automatic system made minimal flow xenon anesthesia easy to administer, but nitrogen accumulation is still a problem. Assuming a xenon price of 10 US $ per litre, the average cost for xenon was about 65 US $ for the first 15 min and then about 25 USS for each subsequent hour of anesthesia.     

Friction, capacitance and transepidermal water loss (TEWL) in dry atopic and normal skin

The biophysical properties of non-eczematous skin at three locations in atopics and non-atopics were characterized using non-invasive physical methods. Skin friction was measured with a newly developed sliding friction instrument, the degree of hydration with a capacitance meter (Corneometer CM 820), and the transepidermal water loss (TEWL) was determined using an Evaporimeter EP1. The areas examined (dorsum of the hand, volar forearm and lower back) showed lower values of friction and capacitance in the atopic patients than did corresponding sites in the normal controls. In most areas a significant correlation between friction and capacitance was found. The TEWL was increased in atopic skin, but TEWL seems to correlate neither to friction nor to capacitance.     

CARBON DIOXIDE ELIMINATION FROM EACH LUNG DURING ENDOBRONCHIAL ANAESTHESIA: Effects of posture and pulmonary arterial pressure

The ventilation and carbon dioxide elimination of each lung,and pulmonary arterial pressure, were studied in 17 patientsduring the carry phases of anaesthesia for pulmonary surgery.The patients were ventilated mechanically to moderate hypocapnia.Expired tidal volume and carbon dioxide elimination rate ofthe lung to be operated on, and of the other lung, were similarin the supine position. There was a significant (P<0.01)increase in ventilation and a decrease in end-tidal PCO₂ ofthe upper lung after turning the patient on to the side. Simultaneously,the physiological deadspace fraction of tidal volume (VD/VT)increased from 42 to 45% (P<0.05). Mean pulmonary arterialpressure (MPAP) increased slightly as surgery on the chest wallcommenced. A concomitant increase of carbon dioxide eliminationfrom the upper lung occurred also, although the distributionof ventilation, between the lungs, was unchanged in comparisonwith the conditions during undisturbed anaesthesia. Individualchanges in MPAP (MPAP) and corresponding changes in VD/VT ((VD/VT))were negatively correlated (r=–0.68, P<0.01). The regressionequation was (VD/VT) (%) = 0.7–0.83 x MPAP (mm Hg). Itwas concluded that variations in pulmonary arterial pressureduring surgical stimulation may significantly affect the patternof carbon dioxide elimination in the lungs. However, there wasno evidence that these effects were important clinically     

Alveolar Retention and Clearance of Insoluble Particles in Rats Simulated by a New Physiology-Oriented Compartmental Kinetics Model

Alveolar Retention and Clearance of Insoluble Particles in RatsSimulated by a New Physiology-Oriented Compartmental KineticsModel. STOBER, W., MORROW, P. E., AND MORAWIETZ, G. (1990).Fundam Appl. Toxtcol. 15,329–349. A physiology-orientedcompartmental kinetics model of alveolar retention of inhaledinsoluble paniculate matter in rat lungs was proposed in a recentpaper, (W. Stober, P. E. Morrow, and M. D. Hoover, 1989, Fundam.Appl. Toxicol. 13, 823–843), and the retention patternsobtained with the model for a hypothetical set of input dataappeared to simulate phenomena which were observed in inhalationstudies with Fischer 344 rats. The present paper representsthe results of applying the new model for simulations of theactual experimental retention data of five different inhalationstudies with Fischer 344 rats exposed to three different materials.The experimental data showed that model adjustments had to bemade in order to account for clearance effects that appearedto be influenced by the age of the animals. After these adjustmentswere made and an appropriate set of values for the model parametersdescribing the respective exposure conditions was used, themodel was constrained to represent the empirical data of allof the studies by one unique set of parameter values. Changesin particular values of this set were considered to be acceptableonly if they reflected changes of relevant properties of theinhaled paniculate matter. The final simulations did not completelycomply with this self-imposed criterion. However, the degreeof compliance and the simulation quality achieved with a minimumof parameter variations seem to be unprecedented in retentionmodeling. The results of the study encourage attempts for furtherrefining the present model     

Slowing of the Ventricular Rate During Atrial Fibrillation by Ablation of the Slow Pathway of AV Nodal Reentrant Tachycardia

Influence of Slow Pathway Ablation on Atrial Fibrillation. Introduction : The mechanisms whereby radiofrequency catheter modification of AV nodal conduction slows the ventricular response are not well defined. Whether a successful modification procedure can be achieved by ablating posterior inputs to the AV node or by partial ablation of the compact AV node is unclear. We hypothesized that ablation of the well-defined slow pathway in patients with AV nodal reentrant tachycardia would slow the ventricular response during atrial fibrillation.
Methods and Results : In 34 patients with dual AV physiology and inducible AV nodal reentrant tachycardia, atrial fibrillation was induced at baseline and immediately after successful slow pathway ablation and at 1-week follow-up. The minimal, maximal, and mean RR intervals during atrial fibrillation increased from 353 ± 76,500 ± 121, and 405 ± 91 msec to 429 ± 84 (P < 0.01), 673 ± 161 (P < 0.01), and 535 ± 98 msec (P < 0.01), respectively. These effects remained stable during follow-up at 1 week. The AV block cycle length increased from 343 ± 68 msec to 375 ± 60 msec (P < 0.05) immediately and to 400 ± 56 msec (P < 0.01) at 1-week follow-up. The effective refractory period of the AV node prolonged from 282 ± 83 msec to 312 ± 89 msec and to 318 ± 81 msec after 1 week (P < 0.05), respectively.
Conclusion : This study shows a decrease in ventricular response to pacing-induced atrial fibrillation after ablation of the slow pathway in patients with AV nodal reentrant tachycardia. Since the AV nodal conduction properties could be defined, this study supports the hypothesis that the main mechanism of AV nodal modification in chronic atrial fibrillation is caused by ablation of posterior inputs to the AV node.